Life on Kepler 22b

Since its announcement earlier this week, Kepler 22b seems to have captured the imagination of the public more than any other exoplanet we’ve discovered so far. Personally, I’ve spent a lot of time answering questions about what it would be like to live on the planet, or if it’s likely that anyone already lives there. Anything that gets people excited about science is a good thing, and while we aren’t likely to be flying to Kepler 22b any time soon, it would be useful to take some time to ask ourselves what this discovery does mean for us today.

Artist's impression of Kepler 22b

Our species feels like it is special. You only have to look at our fiction; we always win in sci-fi alien invasion films, and we are always the good guys teaching aliens what it means to be ‘human’. And even outside of science fiction, our basic belief systems are often based around us being the focal point of the physical universe.

We could (and have) been naïve enough to assume that because our planet lies squarely in the habitable zone of our star, the improbability of this suggests that we and our environment are deliberate and special. Kepler 22b suggests that this is simply not the case. The Kepler mission studies a relatively small fraction of the sky, covering an unimaginably small portion of our galaxy. Of course, our galaxy is only one of billions in the cosmos. So the fact that we have found even one such planet should lead us to question our view of our solar system being ‘special’. And it isn’t just one.

Source: SPACE.com: All about our solar system, outer space and exploration

We have discovered over 700 exoplanets so far, with the list of hundreds of other potential candidates growing each month. Of these, at least a few dozen sit in their habitable zones, and of these we know that many are earth-sized. And even if they aren’t, they could easily hold moons that are habitable. Given the fact that all this has come from one mission looking at a small piece of sky, we can safely say we are not special.

Add that to the fact that Kepler only uses one method of the several we have for detecting exoplanets and, well, you get the picture. The universe is likely teeming with planets, a good number of which could (and probably do) harbour life. But what can we realistically expect to find out about life on Kepler 22b?

Kepler Space Telescope (Credit: BBC)

We are pretty good at understanding and measuring light. It has been said that so accurate is our understanding and measurement, if you laid grains of rice end-to-end over a length of one light-year, we can measure attributes of light to within one grain. That’s how accurate we are. And light tells us a story. Spectroscopic analysis is the process of splitting light out into its various wavelengths and analysing absorption lines to work out what elements emitted/ reflected the light. We use this highly accurate, proven method to understand what distant objects like stars are made of. Equipment such as The Kepler Space Telescope watch silently as planets pass in front of their stars, in a sort of interstellar-eclipse event. This affords an opportunity to analyse light passing through the thin band of the planet’s atmosphere, and thus run a spectroscopic analysis.

So it is reasonable to assume that we have the technology to analyse the chemical makeup of an alien atmosphere. Ask yourself- “what if we detected signs of artificial pollution?” That would certainly infer the presence of intelligent, technologically developed life. The only catch is that Kepler 22b is 600 light-years away, so anything we detected would have existed 600 years in the past. Does that mean we could never communicate with the inhabitants?

Radio Telescopes could be used to 'scan' the planet.

We could certainly use radio telescopes to scan the system for signs of broadcasts. But likely they would be too degraded at that distance to do anything meaningful with. We could attempt to fire high-energy signals at the planet for their scientists to detect, but here you have two problems. Firstly, the signal would take 600 years to reach them. Secondly, would you even want to do so, before you understood their nature? The ethics are certainly debatable. For example, just think of how our species would react to news of intelligent alien life. Panic would be possible. Religions would be torn apart by the philosophical implications. Who are we to unleash this on another planet remotely, over 600 years?

Could we fly there and make first contact? Not with current technology. The fastest spacecraft we have ever produced would still take nearly 19 million years to cover 600 light-years. Even if we harness nuclear power to reach a significant percentage of light-speed, we would still have the problem of time-dilation. Back on Earth, one round-trip would take over 1,200 years, yet only a matter of days or months for the astronauts.

So to the real world Kepler 22b means very little, yet at the same quite a lot. In practical terms, we won’t be packing our bags any time soon to move there, or be preparing emails to send to our new alien friends. However, we do well to question our world-view, because this finally proves that planet Earth is not so rare, and thus not so special.