How many other planets have we discovered – and does any other planet support intelligent life?

This week, we saw fantastic pictures of Pluto which we used to call a planet and now call a dwarf planet. Whatever we call it, Pluto is on the very edge of our solar system – but we’ve been able to detect other planets in other solar systems.

I’m currently reading “The Magic Of Reality”, a science book by Richard Dawkins which was published in 2011. He writes of discoveries of other planets that “the present grand total is 519 planets orbiting stars in our galaxy other than the sun”.

But that was four years ago. As this report makes clear, NASA’s Kepler spacecraft has now located more than 1,000 planets bringing the total number of planets that we have discovered to around 2,000.

But there are something like 10,000 billion billion stars in the universe and about 10% of known stars are described by astronomers as ‘sun-like’, meaning that they are likely to have planets that might be able to sustain life.

So the odds are that intelligent life has evolved on other planets too. ¬†Dawkins writes: “I think there probably are [aliens]”.

So why haven’t we heard from them? There are two major complications: time and distance. The universe is around 13.8 billion years old – other life forms could well have been and gone by now. The universe is huge and expanding rapidly – the distances are so great that any communications from other beings could take millions and millions of years to reach us.


 




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