Question: do you belive that there is life on other planets?:)

Jen Gupta answered on 14 Jun 2011:

I think it’s extremely likely that life exists on other planets in the universe. There are about 100 billion stars in every galaxy and about 100 billion galaxies in the universe. Even if only a small percentage of these stars had planets around them and only a small number of those planets could support life, that’s still a lot of planets that could have life on them! There’s an equation called the Drake Equation that explains this a lot better for our Milky Way galaxy (eg http://www.seti.org/drakeequation)

Whether or not we will be able to detect these other lifeforms though is a completely different issue! At the moment we tend to assume that extraterrestrial life will be like us, i.e. carbon-based. If this isn’t the case then you can imagine that we might find life in other parts of the universe but we wouldn’t realise that it’s life! There are a few ways that we can search for extraterrestrial life. If the life is intelligent like us, then we can look for radio waves from their planet. We broadcast TV and radio via radio waves and these waves are also sent out into space. So if someone on another planet was looking, they could detect these waves. However, we’ve been broadcasting TV and radio for less than 100 years so our radio waves won’t have got very far yet! Even if we find radio waves from extraterrestrial life, by the time it gets to us and we send a message back, the life could have stopped using radio waves or they could even no longer exist! A new idea I heard recently was that we could look at the elements in the atmosphere of other planets because it’s likely that life will change what chemicals are in the atmosphere. However I don’t think much research has been done into this yet.

If you want to know more about this, I would check out website like http://www.seti.org/ andhttp://www.jb.man.ac.uk/research/seti/questions.html. The technical term for looking for aliens that could communicate is the “Search for Extraterrestrial Intelligence” or SETI. I’d love to hear what you guys think on this subject!