Most people prefer a good Tyrannosaur to a lowly duck. It’s a matter of choice of course, but when thinking about dinosaurs you probably have visions of ruthless predators with teeth the size of meat cleavers, or titanic herbivores bigger than small buildings, whereas ducks tend to float around in ponds inquiring after handfuls of bread.

However palaeontologists and biologists have revealed evidence that the humble duck may have triumphed over the mighty dinosaurs.

You may have heard the theory that birds evolved from dinosaurs. It’s actually quite an old idea, and dates from 1861 when Christian Erich Hermann von Meyer described a newly found fossil dinosaur called Archaeopteryx. This winged creature had features that were reptilian, such as teeth (birds don’t have teeth) and a long lizardy tail, but also had bird-like features too, such as upper arms adapted into wings and, wait for it, wait or it, feathers! Dinosaurs had feathers. Think about that for a minute. It’s pretty awesome. (What d’ya mean that’s old news?)

Yep, you heard right, feathers!

Since Achaeopteryx was first discovered more feathered dinosaur fossils have been found, like Caudipteryx and Microraptor, mostly in China as it happens. Brilliantly, it seems that loads of dinosaurs probably had feathers.

The idea that birds evolved from dinosaurs is now well accepted. In fact, birds actually are dinosaurs. Next time someone confidently mentions that dinosaurs went extinct you can ruin their fun, and look like a right smart-arse, by proudly pointing to the Blue Tits dancing around the bird feeder in the garden and loudly pronouncing “there be dinosaurs!” Take my word for it; people will love you for this.

Blue Tits, not just a funny name, also actual freakin’ dinosaurs (kind of)

The mainstream view of this theory was that a group of dinosaurs called theropods evolved into the first early birds before the mass extinction that wiped-out the “proper” dinosaurs, and that after surviving this catastrophe, these early forms evolved into the wide variety of modern birds we see decorating our trees and sky today.

But, this may not have been the case. Modern birds may have actually evolved from the early ancestral birds before the mass extinction, so that dinosaurs, ancestral birds (flying dinosaurs with feathers), and modern birds may have all lived together at the same time. I like to imagine a jaunty little Robin perched on the back of a mighty sauropod. OK, Robins themselves didn’t exist 70 million years ago, but one of their modern bird ancestors probably did, so you get the picture, capiche?

This evidence comes from both fossils in rocks and birds living today.

Biologists have examined the DNA of living birds using a technique called a “molecular clock” in which they look at how different the DNA of two related bird species is, and then estimate how long it would have taken for evolution to produce such differences (it’s a little more complicated than that, but you get the picture). This molecular clock evidence suggested that some modern bird families were as old as 70 million years, whereas the dinosaur-killing mass extinction happened 65 million years ago.

And in recent years palaeontologists have found a number of fossils that look suspiciously like modern birds, with features such as fingerless wings and modern-looking wrist bones, that predate the K-T mass extinction and roughly match the timing suggested by the biological evidence.

Modern birds were around before all this malarkey happened

This begs a question though, why did the “proper” dinosaurs and “dino-birds” like Archaeopteryx go extinct, but not the first modern birds? How did they survive the K-T mass extinction?

A palaeontologist called Dr. Gareth Dyke believes that ducks may hold the key.

The modern bird fossils found before the mass extinction boundary look distinctly duckish, and most likely lived in the same kind of environments we find ducks today, like seashores and ponds. Ducks are generalist birds, they eat all kinds of things and can live in a range of habitats and climates, basically you see ducks all over the place.

Ducks, not that bothered by whatever happens really. In fact, you might even call them unflappable (sorry)

Dr. Dyke, and many others, believe that many of the dinosaurs living at the end of the Cretaceous, just before the mass extinction, were specialised, adapted by natural selection to very specific modes of life. So when the catastrophe struck, probably in the form of a massive meteor strike, but maybe also a monstrous volcanic eruption, these specialists couldn’t cope, as the rapid environmental change destroyed their ecological niches.

I’ll give you an example to make it a bit clearer. Suppose Archaeopteryx ate only one kind of prey, say a specific kind of fish, if these fish were wiped-out in the mass extinction, then Archaeopteryx may not have been able to adapt to new prey and will have gone extinct.

Ducks however eat pretty much anything, plants, insects, fish, frogs, small children, Nando’s, the lot. Ducks may be a lot of things, but they aren’t fussy eaters. Neither are they too picky about where they live. Dr. Dyke’s hypothesis is that these early duck-like modern birds were also generalists, thus were able to adapt to the changing conditions of the K-T environmental disaster and survived where many other species could not, by eating whatever and living wherever.

As the world recovered, these early modern birds could then fill many of the niches vacated by “proper” dinosaur species and diversified into the wild variety of birds we see in the later fossil record and all around us today, from eagles, to sparrows, and to the greatest bird of our times, the Kakapo.

The Kakapo, probably the best bird, ever

So there you have it. Early modern birds survived the mass extinction that wiped-out the dinosaurs by basically being like ducks.

Ducks, Nature’s greatest survivors?

Disclaimer, I’ve written this in the style of an idiot, I’m not attempting to make light of Dr. Dyke’s theory though, it’s great, and it holds a lot of water (crap pun intended).

In a previous post I wrote about how we discovered the age of the Earth, and I mentioned that our planet formed at the same time as the other rocky bodies in our Solar System.

I didn’t say HOW this happened though. So now I will.

Happy now?

It all begins with a cloud of dust and gas out in space that astronomers call a molecular cloud. Space is generally pretty empty. There’s the occasional star, planet or comet, but the vast voids between these objects have little in them, perhaps some molecules of hydrogen and helium gas, and maybe some “space dust”, which is mostly bits of silica, carbon, iron and some other elements (basically very small bits of rock), but mostly space is filled with empty, erm, space. In some regions inside galaxies dust and gas accumulates though, these are the molecular clouds I just mentioned.

The Horsehead Nebula is actually part of a molecular cloud. And you thought they sounded a bit boring too. Shame on you

In our Universe, everything that has mass attracts everything else that has mass, this is gravity. So all these molecules of gas and dust within the molecular clouds are gravitationally attracting the other molecules of gas and dust in the cloud. The force of this gravitational attraction is pretty weak though, as molecules have comparatively low mass and gravity weakens quickly over distance.

However, if the cloud can become large and dense enough a limit is breached and gravitational attraction begins to kick-in, pulling the molecules towards each other. As the molecules move closer to each other the force of gravity increases, and a runaway effect begins, causing the molecular cloud to start collapsing, and as it collapses it begins to spin.

What causes the cloud to reach this required density is not known. It’s thought that the dust and gas in the cloud could be compressed by passing gravity waves (a pretty cool phenomena, but one I’ll save for a later post), but no ones ever actually seen a gravity wave, so we can’t be sure.

The collapsing molecular cloud begins to spin faster and faster as it gets smaller. This happens as the cloud has momentum, and if a body with a fixed momentum becomes smaller, it spins faster, a nifty trick called the “Conservation of Angular Momentum”. You can perform a quick experiment yourself to test this. Stand up and put your arms out and begin to spin. If you continue spinning and then pull your arms in towards your body you should find that you’ll spin a little bit faster. Then vomit.

A bit like this. No vomiting though. I promise

As the molecular cloud continues to spin faster it will first form a spherical shape but then will start to flatten into a disc, as if you rotate a sphere at a uniform speed its equator will spin faster than its poles.

You can also try this at home too. Take a ball, like an orange or a tennis ball or something, and draw one dot at its equator and one near the pole. If you spin the orange so that it takes five seconds to turn full circle (with the poles facing up and down) then both dots will take five seconds to rotate, but the dot near the pole will complete a much smaller lap in terms of distance covered than the one at the orange’s equator. Thus the equator dot will have covered more distance in the same time and therefore will have moved faster. This is why a spherical piece of pizza dough becomes flat when spun by a pizza chef, the centre of the sphere spins faster and moves outwards, compressing into a flat pizza base. (I actually used to be a pizza chef for a bit, I used a spinning machine though, so I was a cheap fraud.)

At the core of the molecular cloud the contraction will be the most intense, as the core will be the densest region and will thus experience the greatest gravitational attraction. As the core contracts it becomes denser still, experiences stronger gravitational attraction, contracts some more, becomes denser, and so on and so on, I think we can all see where this is heading.

Eventually the core of the cloud will become so dense that another critical point is breached, the point at which hydrogen atoms in the cloud begin to fuse together to create larger atoms in a process called nuclear fusion. Nuclear fusion releases energy in the form of light and is the process that powers our Sun. Thus in the heart of the collapsing molecular cloud a star is born. This is how our Sun came into existence around 4.56 billion years ago.

An artist’s rendition of a protostar surrounded by its circumstellar disk of gas and dust. Yeah I know, its pretty damn cool looking

Around 99% of the mass of the molecular cloud will have ended up in the Sun, whilst the remaining 1% of the gas and dust will have continued to spin as a circumstellar disc around our young star. Over time the dust molecules in this cloud will have begun to collide with each other as they bounced around chaotically within the circumstellar disk. In most collisions the molecules will have bounced-off each other, but sometimes they will have stuck together, and over the course of hundreds of thousands of years they will have begun to form larger and larger clumps of rock. I think a similar process causes the dust under your bed to coalesce into larger and larger clumps (dust bunnies!)

Over time some of these clumps of rock will become pretty big, and after they became larger than roughly one kilometre across another trigger point will have been breached as their gravitational attraction became strong enough to begin attracting other larger clumps of rock. In this fashion larger and larger pieces of rock begin to smash into each other and are remoulded to form planetesimals, the first step in the creation of planets.

Planetesimals drifting around a young star. Purdy.

Over the next tens of thousands of years these planetesimals will have continued to grow larger and larger by the process of gravitational focussing, with the largest planetesimals greedily cannibalising the smaller ones and growing the fastest.

Eventually the accretion of these planetesimals will have led to the formation of a small number of planetary embryos of around 1000 km in diameter, and further collisions over the next 100 to 300 thousand years will have caused these embryos to accrete into an even small number of planets around the size of the Moon and Mars. Collisions will still have occurred between these bodies, but as there were so few of them at this point the collisions would have been far less frequent, and it may have taken another hundred million years or so for the inner rocky planets of our Solar System to form, eventually leaving us with Mercury, Venus, the Earth and Mars.

A fifth rocky planet likely tried to form between the orbits of Mars and Jupiter, but Jupiter’s strong gravitational attraction will have ensured that the rocky bodies in these regions will have collided with too much force to properly coalesce, leaving a belt of asteroids rather than a fifth planet.

Nearer the centre of the disc the temperature will have been hotter than the outer regions. Thus substances with a high boiling temperature will have solidified nearer to the Sun, and substances with a low boiling temperature will have solidified further out. The inner planets and asteroid belt are therefore mostly formed of iron, nickel and silicate rocks, but further out ices of different types could also solidify, such as water, ammonia and methane ice. Planets like Jupiter, Saturn, Uranus and Neptune therefore formed initially from mixtures of metal, rock and ice.

At some point in your life someone probably confidently told you that you could drive a bus straight through one of the giant planets as they’re entirely made of gas. This is pure madness. As at the heart of each of these planets is one of these central kernels of metal, rock and ice.

The outer regions of the circumstellar disk also contained much more hydrogen and helium gas, that these icy and rocky kernels could hoover-up in vast quantities due to the power of gravity, creating the thick covering of hydrogen and helium we see on the gas giants today, hence the name.

That’s the inside of Jupiter you’re looking at. You can see the inner kernel of metal, rock and ice, then a layer of liquid hydrogen & helium (you do not want to drive a bus through that), and then an outer layer of gaseous hydrogen & helium, you could probably get a bus through that, if you didn’t mind dying

Back to the Earth.

As the Earth first formed it will originally have been a ball of molten metal and magma. The denser elements of this liquid inferno, such as iron and nickel, will have begun to solidify first and will have sunk towards the core of the Earth. As the Earth solidified further it will have differentiated by this process into a solid metallic inner-core (although it was extremely hot in this core the pressure was sufficient to cause the iron and nickel to solidify), a liquid metal outer-core where the pressure wasn’t quite so intense, surrounded by a rocky outer mantle.

The early Earth will have been a hellish place to visit, and its first half a billion years or so are referred to as the Hadean (Hell like) Eon by geologists. The intense heat inside the Earth will have caused large regions of the rocky mantle to melt and burst onto the Earth’s surface as massive volcanic eruptions. As the mantle melted, the magma it produced will have had a slightly different composition to the mantle rock, as not all of the minerals in the mantle will have melted, and as the magma erupted on the surface and cooled a differentiated crust will have began to form around the Earth. Thus the structure of the Earth we know today was formed, with a rocky crust and mantle, and a metalic inner and outer core.

The Solar System will still have been full of large chunks of rock in the Hadean, many of which will have rained down on Earth’s surface as meteorite impacts. But early in the Earth’s life, around 4.533 billion years ago, in an act of supreme planetary vandalism she was struck by a much larger object, a proto-planet the size of Mars called Theia. A bit like your house colliding with a slightly smaller house, at the speed of a bullet.

Or, a bit like this. Forget the whole house thing.

Such a monumentally enormous collision will have released a vast amount of energy, fracturing and melting large chunks of the Earth and probably completely destroying Theia. As the Earth recovered, the debris from this collision will have been gravitationally bound to the Earth, initially forming a ring around our planet similar to that of Saturn’s. But over time the chunks in the ring will have began to coalesce, accreting into a separate planetary body that orbits our planet today, thus the Moon was born. So the Theia collision was actually a blessing, if an initially very destructive one.

So there you go, the Earth, our very own planet is basically made out of a bunch of dust that stuck together, melted, cooled again, and then got hit by another planet to provide us with the Moon we see in the sky above us today. As Professor Brian Cox would say, brilliant.

Imagine that an intelligent alien species has discovered us, and that they have the ability to journey to Earth to make first contact.

It may sound like a fantastical scenario better suited to fiction than to science, and for more than two centuries this has largely been the case, but over the last few years a number of scientists have begun to debate first contact scenarios, both in scholarly domains and in the mass media.

What do you think first contact would be like?

I’ve had a few ideas of my own, inspired heavily by sci-fi I admit, and in previous posts I’ve looked at scenarios in which the aliens may not even be interested in us, or that they may make first contact with us, but covertly. In this post I’ll look at the idea that they do try to make an overt first contact, but that we may have a mutual problem in understanding each other.

If we make first contact with an intelligent extraterrestrial then a certain degree of confusion will likely abound.

Understanding stems from empathy, which is founded in shared beliefs, attitudes and experiences. But there’s no guarantee that we would have any of these in common with an extraterrestrial. After all, different cultures on Earth can vary markedly in these areas and confusion between people from different nationalities is common (just think how different the English and the Welsh are!) Thus I’d hypothesise that the more like us a hypothetical alien visitor was, the more likely we’d be able to understand each other.

If an alien race evolved on a similar planet to Earth, orbiting a similar star to our Sun, and were also derived from carbon and water chemistry then this would be a good start, as a shared biology would give us some important areas of commonality and may provide similar foundations to our cultures.

Notice Glaxitian is English people, not Welsh

But even if an alien race was biologically similar to us, they will likely be far in advance of our own civilisation, and this may cause problems.

If an alien race has managed to traverse the great distances of space to make contact with us then they will likely be hundreds to billions of years more technologically and intellectually advanced than us. Although they may once have been culturally similar to us in their past, they may have since developed to become so different that any degree of understanding may prove extremely difficult. Advanced biotechnology for instance may have allowed them to adapt their own biology to fantastical ends, resulting in them having a very different experience of the world around us than we do.

I’d suggest that in this situation understanding might be easier for the aliens than for us. If they were our intellectual superiors then they may be able to fathom our motivations, languages and culture more easily than we could theirs. To us, such as species could be so advanced that their science, technology and civilisation may be utterly unintelligible, just as our society today would probably be largely unintelligible to a human from 200,000 years ago.

And what if the hypothetical alien species wasn’t biologically similar to us? The confusion would then likely be magnified exponentially.

All life on Earth today has a common ancestor, we’re all offshoots from this original biology, so although life on Earth may look wonderfully diverse, at its most basic level its built on the same building blocks; carbon molecules, liquid water and DNA as the code of life.

Life may not necessarily have to be like this though; we only know of this one kind of life on Earth, so we can’t know either way, but life could be based on alternative chemicals, such as silicon rather than carbon, could use a different code, such as RNA, or could use a polarising liquid other than water.

For instance, Saturn’s moon Titan could potentially house a biosphere based on carbon, but with liquid methane rather than liquid water. Its unlikely, but not impossible, that Titan has any life, let alone advanced life, but organisms based on different bio-chemistry from ours could be possible, and would likely have substantially different life processes and life histories from ours, making mutual understanding even more difficult.

I’ve read of a beautiful fictional account of intelligent life living on Europa in the ocean under its icy surface (I’m trying to find it again!) In the story the Europans were intelligent and had levels of science and technology comparable to our own, but couldn’t see the night sky above them because their world was trapped under kilometres of ice. Consequently they didn’t realise that they lived on a moon, and didn’t realise that there was an entire Universe existing outside of their own world, thus they were inward-looking and parochial. Of course, this is unlikely, but is a great reminder that we shouldn’t assume that all intelligent life views the world as we do, especially if they originate from a world that’s different from our own.

Tribbles, possessors of a different and utterly confusing view of the world

There is of course the possibility that life could be much more exotic than this.

Life could potentially evolve in any pattern of matter and energy that is capable of encoding information and passing it on to subsequent generations. One of the commenters’ from a previous post mentioned the possibility of life existing among the rings of Saturn as “information encoded in the twisting spirals of electrically charged dust creating self-replicating patterns which could evolve and progress in response to changes in either the electromagnetic environment or the physical composition of the ring material itself”.

It could be even more exotic still, how about photino ecosystems living within the hearts of stars, quark biospheres within black holes, or even an entire unseen world-of-life existing within the dark matter component of our Universe? It may sound unlikely, but I’d hesitate to say it’s impossible.

Such exotic life forms could have wildly different conceptions of consciousness and the world to us. An alien species could exist as a colonial organism, or could have hive identities rather than single personalities, could experience time differently or could even exist in different/more dimensions to us. Communication with such bizarre forms of life may be extremely difficult and we may not even recognise the very existence of each other as forms of life.

A bit like this…

This all may sound a little far-fetched and fanciful, but our conception of life has been challenged a number of times on Earth, with the discovery of microscopic life and the discovery of extremophile ecosystems, so I’d argue that trying to put limits on the possible boundaries of life may be a foolish exercise.

So far I’ve sounded a bit glass half-empty. Alien life could be completely beyond our comprehension, they may be way too advanced for us to understand, or could be so different from us that any mutual comprehension could be impossible, but there is a beacon of hope though, a mutual understanding of mathematics.

Maths (or math if you’re American) is the basic language of our Universe. Wherever you go, scientists are pretty sure that maths will be there waiting for you us. Maths isn’t a human creation, it exists outside of us, it appears to be a logic that underpins the Universe. If you have two of something, and then add two more, you will always have four. If you take one of these away, then you will always have three, you won’t have five if you’re on Mars, or you want have two if you’re on a space station orbiting Proxima Centauri. Sure, the actual words and symbols we use to describe maths are human inventions, and will differ between cultures and civilisations, but the underlying maths isn’t a human invention, its something we’ve discovered, it’s an inherent feature of our Universe.

So it may take time to initially learn the different symbols used to represent mathematical concepts, but maths should provide a basis for communication with any intelligent alien life, as long as communication is actually possible. From this initial foundation mutual understanding may develop and maths may become the shared language our two species.

See, Chloe gets it, but then she is part alien (kind of)

It’s hard to know how to judge this scenario. As it all depends on how similar the hypothetical alien visitors are to us. But whilst I do think its possible that many different styles of life may exist in our Galaxy, some like us and some far more exotic, I think that if an extraterrestrial civilisation is interested in examining life on a terrestrial planet orbiting a G-type star, then they probably will be relatively similar to us.

If they seek to find and contact life on a planet such as Earth, then its likely that they may also have evolved on a similar planet, and if they are curious enough to explore the Galaxy and to search for other intelligent species then we may share a similar psychology and culture too. I’m sure such a race would be far more advanced than ours, but hopefully we’d be able to forge a mutual understanding based on mathematics.

In 1650 the Archbishop James Ussher announced that the Earth was thousands of years old.

Almost six thousand years old in fact. He had discovered that the world had been created on the 23^rd of October 4004 BC. At lunchtime.

This was a pretty momentous conclusion. Not only had Ussher calculated the age of our world to a superhuman degree of precision, he was also lending credence to the idea that the Earth had a beginning (many cultures believed the Earth has always existed, and always will) and that it was pretty damn old, 6,000 years-worth of old.

Today, most people are comfortable with the idea that the Earth hasn’t existed in perpetuity, and most people are OK with the fact that the Earth is billions of years old. But this is a pretty recent mindset. Up until about one hundred years ago, no one really had any idea how old the Earth was.

Here’s what happened…

It might sound pretty crazy to hear that the world is only six thousand years old. After all, a lot of us discover at a young age that the dinosaurs lived many millions of years ago, so we grow up comfortable with the concept of “deep time”, the idea that the Earth is ancient almost beyond comprehension, so its easy to laugh at Ussher and dismiss him as a religious crank. We shouldn’t though.

In 1650 no one knew how old the Earth was, people simply had no idea. Some thought our world could be hundreds of years old, others thousands. At this point I don’t think anyone was considering the possibility that the world was millions to billions of years old, as science was still very much in its infancy, Galileo had only just died, Newton has just been born, and the first dinosaur would not be described by a scientist for another 74 years.

Given this context I think Ussher should be commended. Although his estimation was somewhat wide of the mark, at least he adopted an almost scientific approach to his calculation by basing it on evidence. Ussher painstakingly trawled through masses of ancient biblical texts in order to establish a family tree for the whole of humanity. He literally went through all of the “Abraham begat Isaac; and Isaac begat Jacob; and Jacob begat Britney” stuff and worked-out how many generations of humanity there had been since Adam and Eve. The Bible taught that Adam and Eve were created at the same time as the Earth, thus Ussher realised that if you could work out the age of humanity, you could work out the age of our world.

Here’s Ussher at work. You can tell he’s not quite a full scientist as his beard is too small

Unfortunately Ussher made a few errors in his assumptions. Firstly he assumed that the Earth is as old as humanity, this isn’t the case though, as humans are an extremely recent genus. If we think of the lifespan of the Earth as a 24-hour day, with the Earth created at 00:00 and today being 24:00, then our species has been on the Earth since 23:59:56. Not very long. Secondly, he assumed that religious texts were an accurate account of the history of humanity. They aren’t.

Again, its quite tempting to mock Ussher for these assumptions, particularly the second one, but I think he should be lauded, as questioning the veracity of the Bible was probably a pretty radical thing to do in the 1650s, and at least Ussher had based his calculations on evidence, not great evidence admittedly, but I can forgive him that. In many ways Ussher had approached the question of how old is the Earth as a scientist.

Since Archbishop James Ussher’s calculation a number of other enquiring scientists made their own estimations of the age of our planet. Many of these people were an odd breed of scientist called geologists.

In the late 18^th century a new science was born, the science of Geology. Most people have a vague idea of what Geology is, something to do with bearded men in inadvisably-small shorts striding up and down the countryside worrying rocks. Geology isn’t just about rocks though, it’s actually the study of the Earth, which does happen to be mostly made of rock, hence geologists fascination with them, but geologists are also into plants and animals, the weather, flowing water, sunset walks along the beach etc etc.

A geologist in action, notice the predilection for unfeasibly small shorts

One of the early titans of Geology was a Scotsman by the name of James Hutton. Hutton made lots of contributions to the science, but his greatest was the concept of Geological Time, the idea that the Earth is extremely old, not just hundreds or thousands of years old, but many millions.

Hutton reached this conclusion by observing the world around him. He realised that processes like weathering and erosion (large rocks being worn-down by the weather to produce small bits of rock) sediment transport (water moving bits of rock), deposition (those bits of rock travelling in water being “dropped-off” and collecting together) and lithification (those small bits of rock slowly transforming into large beds of rock again) were happening around him all of the time. He also realised these processes happened extremely slowly, that it would probably take thousands of years for rock strata to form, and that these processes probably occur at the same speed today as they always have (geologists call this the Principle of Uniformitarianism), so that if rocks take thousands of years to form today, they took thousands of years to form in the past too.

Hutton realised that if the “present is the key to the past” then there is literally hundreds of millions of years worth of rock all around us. On learning about Hutton’s revelation, the geologist John Playfair later wrote “the mind seemed to grow giddy by looking so far into the abyss of time“. Many geologists today also speak about the strangeness of contemplating geological time, and even claim that geologists often have a different concept of time to other, more normal people.

James Hutton, not wearing proper small geologist shorts here, but I bet he had some

At first I thought this was a bit pretentious, as the idea that the Earth was billions of years old certainly wasn’t that strange to me. But I admit, after studying geology for a few years I’ve had a couple of occasions when my mind expanded in a kind of intellectual vertigo, as I got fleeting glimpses into understanding just how in-humanly massive such a time-scale really is. Anyway, on with the story.

After the idea of deep time became more-and-more established in Victorian-era scientific circles, the race was on to try to work out exactly how old the Earth really was.

The astronomer Edmund Halley proposed a method based on sea salt. Halley knew that “salt” in the sea was actually small pieces of rock (OK, ionic minerals from rocks) that had been eroded from the land and washed into the sea, so he concluded that if you could work out how much salt was in the sea, and how much salt is washed into the sea each year, then you could work out how old the sea was and thus the age of the Earth. A number of Victorian scientists made calculations of this kind. In 1876 T. Mellard Reade calculated the Earth was 25 million years old, in 1899 John Joly reached a figure of 99.4 million years, and in 1910 George F. Becker estimated the age of the Earth to be between 50 and 70 million years.

The keen-eyed amongst you will notice that these estimates sound a little on the short-side. Unfortunately the sea salt method is based on faulty assumptions, the most important of which is that once salt is in the sea, it stays there. This isn’t true though; the sea can lose salt through evaporation, meaning it can’t be used as a clock to work out the age of the Earth.

Another method was proposed by the great William Thomson, a.k.a Lord Kelvin. Kelvin, was a superhero of science, he was a pioneer of physics and amongst many other discoveries, was the first person to realise that temperature had a bottom limit of -273°C, or zero degrees Kelvin (he got his very own scale!)

Kelvin used a heat-loss method to estimate the age of the Earth, he calculated the initial temperature of our planet when it first formed (it was hot, think entire seas worth of molten lava), estimated how much heat the Earth loses over time, and was thus able to work out the age of our world.

Lord Kelvin. He’s got a proper Victorian scientist’s beard, so you know he’s legit

Kelvin’s first published estimates dated the Earth at 400 million years old, but as he refined his calculations he continually revised the age of the Earth down, and finally concluded that it was 24 million years old. Unfortunately, the more Kelvin had worked on this theory, the further from the truth he got. However, in a demonstration of great insight, Kelvin conceded that his calculation would only be accurate if no another source of heat existed within the Earth. He didn’t really think this was the case though, so he was confident on his predicted age of 24 million years. He was wrong though, there is another heat source within the Earth, its radioactive decay.

In 1904 a scientist called Ernest Rutherford presented a paper at the Royal Institution in London (an organisation of Victorian scientists who enjoyed debating, drinking wine and eating large meals) in which he announced that the world was 700 million years old. Older than anyone else had so far claimed, at least in public. Kelvin was actually at this meeting, but apparently slept through most of Rutherford’s presentation, possibly on account of one of those large meals.

The impudent Ernest Rutherford brazenly flouted convention by not even having a beard!

Rutherford had found the cause of radiation. Marie Curie had already discovered radiation itself (energy emitted from objects, quite often rocks), but Rutherford had realised this energy came from radioactive decay, the breakdown of large unstable atoms, like uranium, into smaller stable ones, like lead. Rutherford also realised that the Earth’s crust and mantle was chock-full of such radioactively unstable elements, thus he’d found an additional heat source within the Earth that Kelvin had overlooked. Rutherford was therefore convinced the Earth was far older than Kelvin’s estimate.

Radioactive decay wasn’t just useful for embarrassing Lord Kelvin though. It also provided a way to date rocks. Rutherford realised that radioactive elements decayed into stable elements at a fixed speed. Therefore, if you could work out how much of a parent radioactive element, and how much of a daughter stable element is found in a rock, say the proportion of uranium to lead, you could work out how long it would have taken radioactive decay to produce that proportion, and thus you could calculate the age of that rock. Rutherford realised that the rocks themselves could be dated.

The race was then on to find the oldest rocks on Earth. Unfortunately the Earth has a rock cycle (although I should probably say fortunately, as it keeps life on Earth alive), which means that the Earth’s rocks are continually, if very slowly, being recycled by weathering and erosion. This means that old rocks are very rare and hard to find. The oldest found so far is 4.28 billion years old, and was discovered in Canada in 2008. So we know that Canada, and therefore the Earth, is at least this old.

But to get the most accurate date we need to find rocks that were formed at the same time as the Earth, but which haven’t been recycled in any way. And these rocks are found in space, they’re asteroids.

Like this (a carbonaceous chondrite meteorite)

Certain types of asteroids were formed at the same time as the Earth, in fact, the Earth was basically formed from asteroids smashing together and accreting into the planet we live on today. Some asteroids avoided this fate though, they weren’t incorporated into a planet and survived untouched in space, mostly in a belt of asteroids between Mars and Jupiter. Some of these asteroids have fallen to Earth as meteorites, and many have been dated using Rutherford’s radiometric technique.

These asteroids all provide a date very close to 4.54 billion years. Thus, today, we now know that the Earth, and the other rocks in our Solar System all formed at this time.

So there you go. This post could have been a lot shorter, but I enjoy this tale and couldn’t help indulging myself. The Earth is 4.54 billion years old, and we know this from the radiometric dating of asteroids.

Imagine that intelligent alien life exists, that its discovered humanity, and that it has the technology to reach us. What would first contact between humanity and aliens be like?

In the first post in this series I looked at the idea that advanced alien civilisations might be totally indifferent to our existence and would simply choose to ignore us.

In the other scenarios in this series I’ll assume that they are interested in us, and in this post, that they arrive on Earth, but in a rather covert fashion.

In lots of Sci-Fi stories alien visitors make a big entrance, gliding over our cities in gigantic flying saucers or crashing into the Earth in a blaze of fire and glory.

Aliens, sometimes not so subtle

But this may not necessarily be the most likely scenario (if any scenario for alien contact can be called likely). Perhaps alien life would make a much more subtle entrance into our society, rather than revealing themselves right from the start, aliens may choose to remain hidden for a time. We may make first contact without even realising it.

I can think of a number of reasons why extraterrestrial visitors may choose to do this. One is that they may wish to learn more about our species before they make a formal contact with us, purely to make sure they have a good understanding of us, such as learning our languages and customs. This would be done most effectively if the aliens remained hidden, as we could be studied behaving normally in our natural habitat. This scenario is comparable to scientists studying other animals in the wild, such as Dian Fossey studying mountain gorillas, the less obvious the observer is, the more likely the subject is to behave normally.

A great example of this scenario in science fiction is the Prime Directive in Star Trek, in which the Federation studies pre-warp civilization, but does so covertly in order to avoid influencing the development of the civilisation. The Federation may choose to infiltrate and study a society, but this is done for noble reasons, such as aiding in the understanding of the structure and development of other cultures.

A bit of Prime Directive wrangling

More disturbing scenarios can also be imagined though. An alien species may choose to infiltrate our civilisation for a number of nefarious reasons, they may seek to understand us in order to better exploit or even conquer us.

Call me an optimist, but I think this is less likely. If an alien species has the technological sophistication required to travel to Earth, I’m sure they would have little trouble in conquering our planet. If they desired our destruction then I see little point in them taking the time to carefully infiltrate our society to study us. Why not simply “glass” our planet from orbit, or release a swarm of flesh-eating nanobots? (Yep, I know, I’m straying quite far into the bounds of speculative Sci-Fi here).

To me, it makes much more sense that an alien intelligence would spy on us in order to decide whether or not to make first contact and how best to do this. First contact with an alien race would likely be traumatic for our society, and I’d like to thing an intelligent alien would realise this, and would seek to learn as much about us as they could before revealing themselves.

I know many people believe that aliens have already infiltrated our civilisation and that they are amongst us today. These beliefs range from simple reports of alien abduction, to vast conspiracy theories claiming aliens have covertly conquered our society and are running our world through puppet governments. This includes David Icke’s belief that we are ruled by a reptilian alien race called the Anunnaki, and that the Queen of England is a reptilian-human hybrid.

Her Majesty Elizabeth the Second? Probably not.

I’m not convinced by any of these claims. Quite simply, I’m a rationalist, and I base my beliefs and worldview on evidence. And there’s no evidence for alien activities on Earth, not for abductions, or for an alien influence amongst our rulers. As enthralling as some of these stories can be, they aren’t real.

But what if an alien civilisation has infiltrated our society? What affect could this have on humanity?

If the hypothetical alien race remained undiscovered then obviously it wouldn’t mean anything for us, as we’d be ignorant. But if an alien species has infiltrated us, and then reveals that it’s amongst us and had been for some time, then I imagine the reaction would be a mix of excitement and fear.

Some of us may understand why such a visitor would remain hidden for a time, and would probably see the sense in this, but still, it would raise a lot of suspicion, and I imagine most people would be quite scared that we had no idea that they were amongst us. Many may be distrustful; as they may feel the aliens have acted dishonestly and probably shouldn’t be trusted. This may well put a strain on relations between humans and the visitors, but a certain degree of caution on the side of humanity may be a sensible mindset.

Hint, they want to eat us!

A more disastrous scenario would be if an alien race had infiltrated our society and was then discovered before they chose to reveal themselves. To say that this would make us suspicious of their intentions would likely be a colossal understatement. It could lead to an attitude of anger, resentment and fear towards the aliens, and could even spark conflict with them, or between different nations on Earth, as the global political climate descended into suspicion and panic. This would likely be a foundation-shaking discovery for humanity, and one with very dangerous implications.

Throughout this post I’ve make one huge assumption though, that alien life would be able to understand us. If an alien species is ancient and far more scientifically advanced than ours, it may be easy for them to penetrate and study our civilisation in terms of the technology required, but penetration and surveillance may not be so simple in terms of culture. The actual spying may be straightforward for aliens, but understand what they are seeing may be much more complex.

Dude… Wait, what?

If the hypothetical alien infiltrator is biologically and culturally similar to us, then achieving an understanding of our behaviours and society may be within their grasp, but if this race was more exotic and significantly different from ours then we may always remain an enigma to them. I plan to expand on the idea that we would be difficult to understand in the next post in this series, but its an idea worth considering for this group of scenarios, as it may mean that an alien surveillance of our civilisation could last for a long time, if not indefinitely.

It’s a depressing idea that alien’s could make a covert contact with our species, but that they would never reveal themselves to us, because they found us too confusing. This may sound unlikely, but I believe it all depends on how biologically similar they are to us. If all life is carbon-based and evolved in liquid water then maybe this eventuality is less likely?

However, I do think the espionage scenario is one of the more likely versions for first contact with extraterrestrials.

In the next post, more confusion!

PS. Please let me know if you have any ideas or reactions to this post, as I think its a fascinating topic that’s great to debate, and please let me know if you can think of any good examples of such espionage scenarios in science fiction?

Heard of the Goldilocks zone?

It’s the idea that an area of space around a star will be at the right temperature for life to exist. Not too hot, not too cold, hence Goldilocks.

It’s a bit like standing around a campfire on a very cold night. Stand too far away and you freeze, stand too close and you catch on fire and burn to death.

It’s the same with planets orbiting stars too, if they’re too far away then water freezes and life can’t emerge, and if they orbit too close the planet is roasting hot and nothing can live.

It gets a bit more complex than this though, but complex in a fun way. Oh and its also got some pretty big implications for the search for extraterrestrial life…

This Goldilocks zone is more usually called a habitable zone (HZ for short). It’s the distance around a star at which a planet can maintain surface liquid water.

Scientists care about liquid water, as all life on Earth needs liquid water to survive (life on Earth is basically bags of water with a few other ingredients thrown in). Scientists’ care about the idea of a HZ as it guides our thinking as to where in our Solar System life could potentially be found, and where it could be found in other solar systems too. And we all care about finding alien life, right?

Earth is in the HZ of our star, obviously, whereas Venus is too close to the Sun, as it’s surface is almost hot enough to glow, and Mars is probably right at the outer edge of the habitable zone, as its surface is too cold for water to remain liquid for long.

A simplified representation of our Sun’s habitable zone

A habitable zone is therefore defined as the region around a star between the distance at which water would evaporate and the distance at which surface water begins to freeze. (Sometimes the outer edge is set at the distance at which carbon dioxide would freeze out of an atmosphere, as CO₂ is a greenhouse gas that can heat a planet, meaning that planets rich in CO₂ could be warm enough to enjoy liquid water at a distance a bit further out than we would normally expect to find it).

The HZ doesn’t just depend on the distance from a star though; it also depends upon the features of the planet. If Mars had been slightly bigger it would have been able to maintain an atmosphere (it lost most of it’s initial atmosphere to space as its gravity isn’t strong enough to capture it permanently, more here) and if this atmosphere contained enough greenhouse gassed Mars could have a warm and wet surface today. Thus a HZ is typically defined as the region around a star in which an Earth-like planet could maintain surface liquid water.

A HZ also depends upon the star too. Larger stars emit much more heat, thus the zone in which an Earth-like planet could maintain surface liquid water would be much further out than for our Sun, and much closer in for stars smaller than ours.

Like this (click to enlarge)

Habitable zones are also affected by time. Over their lifetimes the heat output of stars changes. Our Sun has increased in luminosity since it first formed and is roughly 30% hotter today than it was 4.6 billion years ago. This means that the habitable zone must have moved outwards throughout the life of our star. Astronomers and astrobiologists believe that Earth has always been inside our Sun’s habitable zone, but it inspired a scientist called Michael Hart to come up with the idea of the Continuously Habitable Zone (CHZ). This is the region around a star in which an Earth-like planet can sustain surface liquid water for most of the lifetime of its star.

The idea of a CHZ is important, as the fossil record indicates that it took a long time for complex life to evolve on Earth. Palaeontologists have discovered that single-celled life emerged early in Earth’s history, possibly as far back as 4 billion years ago, but that it took more than 3.5 billion years for this bacterial life to evolve into the first animals. If the Earth had formed 5% closer to the Sun, or 15% further away, its likely that it would have been outside of this CHZ and thus animal life would not have been able to evolve on Earth (yes, that includes us).

This leads to a really cool habitable zone idea, that there may be different HZs for different types of life, an Animal Habitable Zone (AHZ) and a Microbial Habitable Zone (MHZ).

It’s likely that the AHZ would be very narrow, and would be confined to a star’s CHZ, as the planet would need to have surface liquid water for billions of years to allow animals time to evolve.

The animal habitable zone, narrow

The MHZ will likely be much wider, as microbial life may well take a mere few hundred millions years or so to emerge, thus can live on planets that may only spend a short time in a star’s HZ. Venus and Mars may well have had their own microbial life early in their histories, and thus may have been inside our Sun’s MHZ for a time.

Two other discoveries have also expanded the possible boundaries of a MHZ. The first of these was the discovery of extremophiles in the 1970s. Extremophiles are single-celled life forms that thrive in extreme conditions such as boiling water, sulphuric acid or inside rocks deep within the Earth’s crust. Extremophiles expanded the range of conditions in which life can be found and thus expand the range of the MHZ.

The second discovery is that liquid water can exist below the surface of planetary bodies that orbit way outside of a star’s HZ. Evidence suggests that some of the moons orbiting gas giant planets in our Solar System, such as Europa and Enceladus, may have vast subsurface oceans that could support life. I won’t go into the details here (if you want to know more than please see these posts; Europa, Enceladus) but it’s possible that these moons may have their own biospheres in underground oceans, but its more likely that these biospheres are microbial rather than animal. The existence of these moons suggests that the MHZ may be huge, and could potentially span between the orbits of Venus and Saturn in our Solar System.

Europa, within our Sun’s microbial habitable zone?

So what does this mean for the search for alien life?

Firstly, it means that if we hunt for advanced alien life, such as alien civilisations with radio technology, then we need to confine our searches to exoplanets that orbit in a very narrow CHZ around their stars.

Secondly, it suggests that microbial life may be relatively common in our Galaxy, as the MHZ is potentially so wide, but that complex life may be extremely rare, as it likely requires a planet of the right size and composition to orbit stars with a stable temperature at a precise distance. This means that planets that can support animal life in our Galaxy may be rare.

So maybe we aren’t alone in our Galaxy, but maybe most of our alien cousins are simple bacteria.

I think they’re insane though. It’s a great film and a great way to revitalise a frankly tired franchise.

There’s a lot to like about Star Trek, but Abrams realised what its best asset was, and consequently hit the nail square on the head when he made his film…

I should confess that I’m not a massive Star Trek fan. I always quite liked it, but I was never obsessed. I like the values of Star Trek, I like many of its ideas and many of its characters, but I also feel that the writing was often a bit formulaic and schlocky, and thusly that it never reached its full potential. Sure, some of the many Star Trek adaptations were better than others, I prefer the Original Series and the Wrath of Khan, but Star Trek was never quite what I wanted it to be.

Sometimes Star Trek was less than perfect

Abrams got a hell of a lot right with his re-boot, such as the fact that he made an actual film. Previously, most of the Star Trek films haven’t actually been films, they’ve been more like extended versions of a TV episode. But the 2009 Star Trek had film written all over it. I’m not talking about pace and action scenes here, I don’t particularly need either in a film, in fact I prefer my films to be slow moving and cerebral, as opposed to a Michael Bay-style explosion nonsense-fests.

Good films tend to have a number of common structure; they begin by introducing characters, usually including a protagonist who we can relate too, then in the second act they introduce a problem, usually the impending end of the world of something, then in the third act the heroes resolve the problem. In previous Star Trek movies they tend to ignore the first act, skipping straight to the problem, probably on the assumption that we already know all of the characters so why bother focussing too much on their back stories? This is generally what happens in Star Trek episodes too. But I feel that they’re skipping in important part of cinema that builds the initial emotional investment.

Oh, and whilst we’re talking about building initial emotional investment, how about that opening scene? Holy f*cking wow! That’s cinema at is best. Not the special effects, the emotion. George Kirk sacrificing his own life to help the crew of the USS Kelvin (brilliant name by the way) escape as his wife gives birth to Kirk. When has Star Trek ever been so emotional? Honestly, I’m not crying, I’m just watering my eyes. Shut up!

Some of the other things Abrams got right include the visuals and art design. The USS Enterprise looks absolutely stunning, from its clean and crisp bridge to its industrial looking nether-regions, and the external shots of the Enterprise whipping through space are dripping with gorgeous, the scene when it rises out of the thick atmosphere of Titan is a real visual treat.

The casting is brilliant too. Karl Urban was an unconventional choice to play Bones, as he’s more likely to be seen playing a Rohan warrior or a space marine than a mild mannered and conscientious ship’s doctor, but he played the role wonderfully. John Cho as Sulu was perfect, and Anton Yelchin playing a 17-year old Chekov with a thick Russian accent was adorable.

Yomayo!

Zoe Saldana as lieutenant Uhura was superb, sure she’s breathtakingly beautiful, but she proved she’s no mere eye-candy, particularly in the Kobayashi Maru scene with her irreverent mockery of Kirk. And Simon Pegg as Scotty. That was inspired casting. Pegg absolutely radiates pleasure at being in Star Trek and his interpretation of the crusty old engineer is a breath of fresh comic air. I strongly suspect he wrote some of his own lines too, as they certainly stand out from a lot of the other dialogue.

Most of the criticisms of the film have centred on two key issues, the fact that Abrams broke a number of Star Trek conventions/ interfered with its history (stuff like Kirk not being able to drive, or Kirk not meeting Captain Pike until after he’d taken over the Enterprise, stuff like that), and the fact that the plot is a bit crap.

On the first criticism, I get it. Star Trek is very dear to a lot of people and I’m sure they cherish its rich history and detail, so a remake that sweeps away a lot of this is probably horrifying. I felt the same with Star Wars when those appalling prequels were made, suddenly Jedi’s weren’t rare mystic warrior-monks anymore, but shit intergalactic police with midi-chlorians, and Anakin Skywalker was no longer a righteous warrior and “dear friend” of Obi Wan Kenobi, but a whiny little emo kid with crap dialogue. I was horrified.

But in the case of Star Trek I think Abrams was right to do this. After all, he wasn’t trying to progress and build upon the Star Trek Universe; he was re-making it from scratch. Despite not being an obsessive fan I’ve watched a lot of Trek, and I was pleased to see that Abrams had riddled his film with in-jokes and references to the existing Star Trek cannon, stuff like Sulu being a trained fencer, Olson the red shirt dying almost instantly on an away mission, or the way Chris Pine leans on the captain’s chair just like Bill Shatner did. For me, all of this showed a respect and appreciation for the original material.

Tribble!

I know a lot of Trekkies feel different through. But trying to stay 100% true to a body of work with such a history and with so such detail would have undoubtedly constrained the film. I think it was a much more sensible choice to begin again from square one, but to include some knowing references to Star Trek’s past. As annoying as this must have been for the die-hard fans, nothing stays the same forever, the franchise needed to evolve and Abrams gave it the kick up the arse it so desperately needed.

As for the crap plot, yes, I admit, the plot wasn’t great. There are a couple of gaping holes in it and the “red matter” felt like a lazy plot device (crystal skulls anyone?), but this is totally missing the point.

Star Trek hardly ever had a good plot (apart from that one Next Generation episode called The Inner Light, that was beautiful storytelling), it’s a bit like criticising Stephen Hawking because he’s not very good at football, or Al Pacino because his soufflés are a bit flat, soufflés aren’t the point of Pacino, the Godfather is.

The best thing about Star Trek was always the characters and how they interacted, particularly the dynamics between Kirk, Spock and Bones. Bones represented the compassionate side of humanity, despite his external grizzle he was a real softy and a true humanitarian. Spock represented the cold logical capacity of humanity, showing both its benefits and weaknesses, whilst Kirk represented our egos. All Kirk ever really wanted was to be in charge, and to be either fighting something or fucking it.

Abrams clearly understood this, and so he made a character movie.

This was what Star Trek was always about

The film isn’t really about Nero and red matter, it’s about establishing the characters and their relationships, particularly Kirk and Spock. Chris Pine plays a brilliant Kirk, an arrogant dick but still lovable, whilst Zachary Quinto gets Spock just right, a mix of pompous know-it-all and child-like vulnerability. These two guys are the real focus of the film, and are the only part of it that has a true arc, with the initial animosity between the two growing into a reluctant understanding and respect, which builds to friendship in the final scenes as they begin to realise they’re a perfect fit for each other.

That’s why “Abrams Trek” is superb, because he understood that the most important thing in Star Trek is Kirk, Spock and the other fine characters. He’s set-up a great foundation in revitalising these roles and I look forward to the sequel with an ill-advised level of optimism.

LLaP.

I leave you this this…

I’m planning on writing a series of posts on different scenarios for first contact with intelligent alien life. I’ve been inspired by some insightful comments from this post and have taken lots of my ideas from those who commented there. Thanks everyone who commented.

It’s feels as though this topic has been treated as a fanciful distraction by much of the serious scientific community until quite recently, and has very much been delegated to science fiction authors, fringe scientists and assorted lunatics. But as of late some big-name scientists have joined in the fun, and this topic is gaining an air of credibility. This isn’t to say that science fiction hasn’t made contributions to this field; I think Sci-Fi has provided some intelligent and very creative first contact scenarios and much of what I’ll be writing has been inspired or explored by Sci-Fi.

So lets assume that intelligent alien life exists, that its discovered humanity, and that it has the technology to communicate with us, either face-to-face or using an alternative method.

The first of my proposed scenarios is that the aliens will be totally indifferent.

Imagine the excitement of finding proof of intelligent alien life. Suddenly humanity would know that it isn’t alone in the Universe, that life has emerged on a distant planet and that some of this life has attained sufficient technological mastery to traverse the stars. It would be the greatest scientific discovery since Scarlett Johansson realised she could photograph her own derrière in a mirror.

Imagine what they could teach us about science, about society and about ourselves. And imagine the impact on our own global culture, would we cast-off the smothering comfort of religion? Would we recognise that all humans are essentially the same and unite under a new banner of peace and tolerance? Or would we panic and fracture into selfish interest groups and continue to bicker and slaughter each other?

Probably a bit of each of the above. But the affect would undoubtedly be profound.

Now imagine the impact on humanity’s fragile sense of self-worth if we discovered that these aliens didn’t want to communicate with us, that they were totally indifferent to our very existence. I think it would be crushing, it’d deal humanity a pretty devastating blow to realise that all we had achieved and represent, all of our discoveries and progress, and all our future promise, could be judged as utterly trivial by another intelligent species.

In hundreds of films, books, TV shows and video games intelligent aliens seem quite interested in humans. Sometimes they seek to communicate with and better understand us, other times they want to enslave us and steal our women. But is this an act of massive vanity on our part?

Aliens be stealing our wimen

If a civilization mastered the technology required to conquer the vast distances of space then they would probably be thousands to millions of years older than us. Our Galaxy, the Milky Way, is around 13.2 billion years old, so an alien civilisation could even be many billions of years older than our own.

Such a species would likely have reached a level of technology, biology and culture that would appear beyond god-like to us, and perhaps we would offer such a civilisation nothing of value. Such a race may be able to understand us, to sum up the entirety of humanity in a mere glimpse, and decide that we not worth their interest.

I’ve seen some argue that even if an alien civilisation was vastly more intelligent than ours they’d still be interested in communicating with us, after all, many humans are attempting to communicate with other species on Earth, such as primates, birds and various marine mammals. And scientists of various different ilks are fascinated by the study of different forms of life, from the mighty dinosaurs to humble bacteria. Surely all life would be interesting to intelligent aliens?

If life in our Galaxy is rare, then this may be the case. But if life is prevalent, including life that can harness radio-wave technology, and if this life is relatively similar, based on carbon, liquid water and DNA, then maybe intelligent aliens would be profoundly disinterested in us. We may just be another primitive technological species infesting the Milky Way.

This idea horrifies me. I think many of us want to be understood, we want other people to show interest in our ideas and passions, and I think this is expressed in much of the Sci-Fi literature and films/TV, as invariably aliens tend to be interested in humanity, both for good and more nefarious reasons. Even if they’re abducting us and inserting probes into various parts of our bodies, at least they’re showing an interest.

Well, at least it cares, I guess…

But I think it’s all too easy to imagine that an alien race would ignore us. And not for the reason often forwarded by schlocky Sci-Fi, that humans are bad, that we’re too selfish, destructive and dangerous. I think this idea is more born out of a sense of guilt and anger that many of us feel for our own race, but I doubt an alien race would be so judgemental (I plan to expand this point a bit more in a coming post), I think its much more likely that we’d be judged merely unimportant rather than dangerous or evil.

It’d be pretty depressing is this was so. If we discovered evidence of advanced alien life, and it totally ignored us.  What would it mean for humanity?

The brilliant Sci-Fi author Stephen Baxter explored this idea in a short story called the “The Invasion of Venus”. In the story astronomers realise that a comet passing through our Solar System is decelerating and leaking highly structured radio waves. They realise that an alien spaceship is headed our way. But the scientists then realise that the craft isn’t headed to Earth, but towards Venus. An intelligent civilisation on Venus then reveals itself. All the attempts by Earth to communicate with each civilization are utterly ignored.

It’s an insightful piece of writing by Baxter, initially there is panic on Earth when we realise that intelligent aliens are headed our way, and argument over whether humans should attempt contact or not. But then humanity is hit by a one-two-blow when we realise we are being ignored, and have been ignored by Venus for thousands of years. The story ends with a feeling of depression and despondency falling over much of the human race.

I do think if this were to happen to humanity, that we were utterly ignored, it would be crushing. Perhaps humanity would still achieve a greater sense of unity in the face of alien life, and perhaps we could gain a sense of hope that other civilisations have arisen to such technological greatness, but still, such an intergalactic snub would be a bitter blow.

In a previous post I described how evolution works.

Lots of people have some vague ideas about evolution, but don’t really know how it actually happens. Don’t worry if this is you, most people are like this, even some scientists! (Mostly physicists)

You can read the post here if you want; I tried to make it as simple but as accurate as possible.

And once you begin to understand evolution, you realise there are some pretty huge implications…

1. Evolution has no purpose, its random. Evolution is a mechanical process; random variation is acted on by blind natural selection. There is no design, purpose or intent. In the previous post I talked about how giraffes evolved long necks to allow them to feed on leaves higher in trees. But just because there was a benefit to having a long neck doesn’t mean that a species will evolve a long neck, the giraffe species was lucky that such a mutation occurred. Other solutions to the problem may have evolved instead, such as an ability to jump, or an ability to knock-over trees. Many species don’t “get lucky” and don’t evolve a useful adaptation to a change in their habitat, and many of these species go extinct.

2. Evolution has no destiny. Because evolution is random it means that no form of life is destined to evolve. Many people believe that humans are in some way destined, that if life emerged on a similar planet to Earth evolution would produce something like humans. But this isn’t the case, as evolution is random. If you could rewind time on Earth right back to the start of life, and then let evolution take its course again, then it’s very unlikely that humans would evolve. Maybe this time life would die out completely in a huge mass extinction, or maybe life would stay as simple as bacteria forever, or maybe something much more wondrous than humans would evolve, like super intelligent squirrels!

3. Humanity is not the peak of evolution. A lot of people also think that evolution has been perfected in humanity, that we are the peak organism never to be bettered. But if evolution is random and has no destiny or goal, then there is no such thing as a peak of evolution. Deciding which species is “best” or “most important” is a subjective choice that is meaningless to nature. One person may decide that humans are the most important species because we have complex technology and culture, but another person may decide that plants are more important, because without plants no complex life could exist on Earth. We are not evolution’s peak, we will likely go extinct, and other species will replace us.

The squirrels are next I tell you!

4. Humans are animals. We may think of ourselves as something a bit special, and yes, humankind has made some pretty huge achievements, like going to the Moon, or having a space station that has been inhabited continuously for over ten years. But evolution teaches us that we are a species of animal, and that everything that makes us unique was given to us by the process of evolution by natural selection. Some people are offended by the statement that we are animals, but this is a peculiar form of narrow-mindedness. We arose from the tree of life like every other species, we have a genealogy of ancestors, and we have relatives who are alive today in the form of the other Great Apes. We shouldn’t try to deny our animal-ness, we should celebrate it, particularly at a time when we are driving so many other animals to extinction.

5. Life has a function, but not a meaning. What is the meaning of life? Evolution teaches us that there isn’t a meaning or a purpose to life, just a function. Humanity was not put here for a reason, we evolved by chance, as with all other species. Bees don’t have a meaning of life, but they do have a function in an ecosystem, they help to pollinate plants. All species have functions within an ecosystem, including us, but these were not chosen or designed, they arose by chance. I think many people don’t like this implication, they want their life to mean something, and they want there to be hidden answers to some of their deepest questions. But there aren’t. We were created by a blind and random process, there was no intent, and we were not its destiny. There is no meaning to life. This might sound a bit depressing to some, but I don’t think so, you’re free to give your own life meaning by choosing your own purpose in life.

6. The diversity of life on Earth does not need to be explained by a creator. Don’t read this as an attack on religion. Evolution and religion can live peacefully together. All I’m saying is that once life got started, we now know that it could have diversified into all the different forms we see today by the natural process of evolution alone. No designer or creator is required to explain why we have dolphins, squirrels and apes with five fingers. This does not mean that evolution kills god. You could very easily argue that a creator designed life to evolve in this way. Personally I don’t believe this, as I don’t believe in any god, but evolution does explain how new species can be created by a random process without the need for a conscious “designer”.

I leave you with a picture of a dinosaur. Just because.

In this series of posts I’ve looked at planetary bodies in our Solar System that could support life, from the moons of Saturn and Jupiter, to the cloud layers of Jupiter itself, to the ephemeral-once-jungles of Venus, I’ve even looked at Earth itself.

Now one of my favourites, Mars, the Red Planet.

Like Venus, both scientists and artists have long thought that Mars could be a potential home for alien life.

In the 1870s an Italian astronomer called Giovanni Schiaparelli examined the surface of the Red Planet with a (then) powerful telescope. He claimed to have found a series of long straight grooves cutting across the planet’s surface that he called canali, as he believed they were formed by running water. In Italian canali literally means groove or channel, but many English-speaking readers mistakenly translated canali as canal, a man-made rather than natural feature, and thus read more into Schiaparelli’s finding than he intended.

One such person was the American astronomer Percival Lowell, who adopted the idea of artificial canals on Mars with great excitement. He began a detailed examination of Mar’s surface from 1894 onwards and reported to have found evidence of a technologically-advanced alien civilization, and was convinced that Schiaparelli’s caneli were Martian-made canals created to transport water from Mars’s polar ice caps to its lower latitudes. Lowell constructed a vision of Mars as a dying planet with an ancient technologically-advanced alien civilisation struggling to keep itself alive.

An atlas of Mars based on Lowell’s observations, showing the structures of an alien civilization

Unsurprisingly Lowell’s ideas birthed a Sci-Fi obsession. From the 1880s onwards alien life on Mars became a staple of science fiction, from the comic book stories of Dan Dare and Flash Gordon, to one of the greatest works of fiction ever written, H.G. Wells’s War of the Worlds (if you’ve not read this then you really should, Wells dreamed-up a story of technologically-superior Martian invaders striding across London in walking tripods armed with lasers cannons, at a time when humanity was still getting around on the back of horses, cars hadn’t even been invented yet!)

However, the canali seen by Schiaparelli and the other structures observed by Lowell were likely a mix of optical illusion created by the telescopes used at the time, and particularly on Lowell’s part, wishful thinking. The surface of Mars, whilst interesting, shows no evidence of Martian civilisation, not even the “Face of Mars”, which was actually an optical illusion caused by shadows cast by the Sun over rocky terrain. If you look at the exact same spot on Mars from a different angle the “face” vanishes. Don’t take my word for it? You can look it up yourself on the brilliant Google Mars.

The “Face of Mars”. Despite what the internet may try to tell you, its not a real face, just a face-like shadow

In 1965 the NASA spacecraft Mariner 4 arrived at Mars and examined it from orbit. It found no evidence for civilisation, current or ancient. In fact Mariner 4 found that Mars was a cold planet (daily temperatures range from -125°C to 17°C), with no surface liquid water, almost no atmosphere and no magnetic field. This meant that the surface of Mars would be uninhabitable, as life as we know it requires liquid water, and a magnetic field is useful as it shields a planet’s surface from much of the harmful radiation emitted by our Sun. If a little green man was to find himself on the surface of Mars today he’d be quickly be killed by freezing, desiccation and radiation.

Mars is a dead planet, with an inhospitable surface. None of this sounds good for Martian life.

However, remember before I said the surface of Mars is interesting? No? Well it is. It doesn’t show signs of civilisation, but it does display evidence that water may have run over the surface of Mars in the past. Various missions to Mars from the 60s onwards have revealed geological features that look a lot like branching river channels, canyons, valleys, debris fans from floods, and even sedimentary rocks. Mars may be dead today, but earlier in its history it may have been wet and alive.

These look a lot like river channels on Earth, suggesting that Mars once had water flowing over its surface

There are two versions of this idea, the more traditional view is that Mars was once a warm and wet planet, with flowing rivers, lakes and even large oceans of water covering its surface, similar to the early Earth. More recent evidence suggests that Mars may have been wet but cold instead, with conditions more like the Arctic on Earth, with cold oceans surrounded by ice and glaciers. Either way, where there is liquid water there is a chance that life could have existed, and Mars may well have seen the emergence of single-celled life early in its history.

So what happened? How did Mars die?

It’s mostly to do with internal heat. As planets form they trap heat deep inside their cores (more about planet formation here), and Mars was no exception. This internal heat melts part of the core of rocky planets producing an internal layer of liquid metal, and flows in this liquid metal produce a planetary magnetic field.

Internal heat also causes processes like tectonics and volcanism. It’s not clear whether or not Mars had tectonic plates like those on Earth, but it did have volcanoes. The largest volcano in our Solar System is found on Mars, called Olympus Mons, it’s almost 22km tall, that’s about three times as high as Mount Everest!

Olympus Mons compared to Earth’s largest volcano Mauna Kea (Hawaii)

Volcanism on Mars would have caused gas to escape from the planet’s interior and would have created an atmosphere. Atmospheres are important for two reasons. Firstly, greenhouse gasses in an atmosphere raise a planet’s temperature, such an affect on Mars may have raised the surface temperature to a level that ice could have melted.

Secondly, an atmosphere provides pressure. Mars is a much smaller planet than Earth, it has less mass and so gravity is not as strong on Mars. Today if ice melts on Mars it sublimes straight from a solid to a gas as there is not enough atmospheric pressure to allow water to exist as a liquid. This sounds pretty crazy but its true, without enough pressure, any substance that melts from a solid will change straight into a gas.

A short video on sublimation as its quite a cool concept. Iodine sublimes from a solid to a gas on Earth because the atmospheric pressure of the Earth isn’t strong enough to allow it to become a liquid.

So the heat within Mars created volcanic outgassing, which allowed the planet to maintain an atmosphere that warmed the surface of Mars melting surface ice, and the pressure from this atmosphere also allowed the ice to melt to liquid water rather than vapour. The internal heat also produced a molten outer-core, creating a magnetic field that will have shielded the planet’s surface from harmful radiation.

Unfortunately Mars is a much smaller planet than Earth though, and it lost its internal heat much faster.

See, Mars is quite a lot smaller than the Earth

The smaller a sphere is, the larger its surface area to volume ratio. Basically, for every square meter of surface area, Mars has less volume of material under that square meter than the Earth does. This meant that Mars lost its internal heat much more quickly than the Earth will. As this heat was lost, volcanism will have slowed to a stop and gasses would no loner be vented into Mars’s atmosphere.

Being small has another drawback too. Gravity on Mars is not strong enough to stop most gas molecules in its atmosphere from escaping into space. So as outgassing stopped, its atmosphere will have slowly eroded and escaped into space, stripping the planet of its warm greenhouse blanket.

Mars will have cooled and lost its atmospheric pressure, causing liquid surface water to freeze at the poles, and sublime to gas and escape into space at lower latitudes. As its core solidified, Mars will have also lost most of its magnetic field, causing its surface to be bathed in sterilizing radiation.

So Mars may once have been a living planet, but as the planet died internally this surface life was likely extinguished in turn.

Did Mars once look like this? (Artists impression)

One hope of planetary scientists and palaeontologists is that fossils of ancient Martian organisms will be found by future expeditions to Mars. Such life would have long since turned to stone, but would still be an immensely important find as we would have proof of life emerging on our nearest planetary neighbour.

Another intriguing idea is that life may have emerged first on Mars and was then transported to Earth, so that all life on Earth may be Martian; you, your mum, and your cat. (The idea that life can spread between planets is called panspermia; you can read more about here if you want).

This may sound like madness, but we know that rocks from Mars’s surface have travelled to Earth in the past. If Mars is hit by an object with sufficient force, such as an asteroid or a comet, parts of the Red Planet’s surface can be ejected into space, and some of this rock will fall to Earth. Some scientists believe that single-celled life may be able to survive the harsh conditions of space and the fall to Earth protected inside such rock, and could then emerge on the Earth’s surface and prosper.

In August 1996 NASA held a press conference in which they announced that a team of scientists had found fossilised microbial life inside a meteorite that had fallen to Earth from Mars, giving support to both the idea of Martian life and infection by panspermia. Sadly this evidence has since been discounted, and the consensus opinion is that the shapes are not fossils but are the result of non-living geological processes.

Here’s an image from the ALH 84001 meteorite from Mars. The long-thin segmented object was thought to be a fossilised mircoorganism, but it most likely isn’t

Another exciting, and equally controversial idea is that life could still exist on Mars today.

From studying extremophlile life on Earth (single-celled life that lives in extreme conditions like in acid or in boiling water, more about extremophiles here) scientists now know that life can survive in some pretty harsh environments, including in areas of water deep within the Earth’s crust and in ice. And in 2002 the NASA Mars Global Surveyor spacecraft began imaging Mars’s surface in great detail and found evidence that liquid water may still exist, trapped underground, but close to the planet’s surface. The best evidence came from images of erosion channels cut into the side of craters, which were probably formed by floods of running water. Incredibly, some of these erosion channels were seen on images taken in 2006, but not in images of the same craters taken in 2002, suggesting they had formed in the time after Surveyor began orbiting Mars.

A Mars Global Surveyor image of erosion channels cutting the sides of an impact crater

Its therefore possible that areas of liquid water still exist below Mars’s surface, kept liquid by a high salt content (salty water is harder to freeze than fresh water), and prevented from vaporising by being trapped underground. This water may periodically break through the side of a crater, creating the channels seen by Surveyor, and once exposed on the surface of Mars will quickly sublime to gas, but still, pockets of underground salty water could provide a habitat for the last remaining Martian life to survive in the form of extremophile microorganisms. This may be a long shot, but it means that life on Mars today is not totally impossible.

A diagram showing how these erosion channels could form

Bacterial life may be less awe-inspiring than Lowell’s ancient advanced Martian civilisations, but any alien life on Mars would be a momentous discovery.

So there you have it. An intelligent civilization does not live on Mars today, and likely never did, but life may have once emerged on Mars and may have left fossil evidence. Martian life may still even survive today, trapped in underground water caches, or may live on as life on Earth. Come to think of it, the panspermia hypothesis may explain Bowie…