Goldilocks, and other Habitable Zones for Life

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…

Life in our Solar System – Earth

In previous posts I’ve looked at some likely, and some less likely, candidates for planets or moons in our solar system that could harbour life, including Jupiter, three of it’s moons, two of Saturn’s moons, and Mars and Venus.

Now its time for Earth. Yep, you read right.

In 1990 NASA used the Galileo spacecraft to look for life on Earth. Why bother you scream, whilst hurling your cup of tea violently against the wall? Well, NASA did it to test how well spacecraft like Galileo can find life on planets and moons from space. Call it a proof of concept, if NASA can find life on Earth, then at least they know the tech works, and hopefully won’t miss signs of life on other planets.

Here’s what they found on Earth:

Has Kepler already found the first Earth-like exoplanet?

The holy grail of exoplanet hunting is to find a planet like Earth orbiting a distant star in its habitable zone (the region around a star where life can exist).

Since 1992 the pace of exoplanet discovery has accelerated, with 538 confirmed planets found as of March 2011, and the space telescope Kepler, launched in 2009, has already made some exciting planetary discoveries, including a 6 planet solar system. And now it may have found the first known Earth-like exoplanets.

Kepler discovers a 6 planet mini-solar system

Kepler’s done it again; this time the space telescope has found 6 exoplanets orbiting a distant star called Kepler 11, but this mini-solar system is vastly different from ours, and may have implications for the search for alien life.

How to find a planet

Its been announced that the Kepler telescope has found a ‘scorched super-Earth’ exoplanet (see my previous post). Ever wondered how astronomers actually find planets orbiting distant stars?

By the way, the Kepler telescope is in space, it orbits the Earth, which is pretty cool.

Did someone say ‘scorched super-Earth’?

A what? Yep, a ‘scorched super-Earth’. A rocky planet, like Earth, but bigger, and extremely hot, hot enough to melt silicate rock. The Kepler space telescope has just found one.

But so what, is this really exciting news? Surely we’ve discovered loads of exoplanets (planets outside of our Solar System); there are hundreds of billions of stars in our galaxy and if they all have planets then there must be loads of exoplanets, right?