What are currently the most exiting areas of space research?
There are two. Let's start with the one relatively close to home, which is that we're beginning to see planets around other stars. The first was discovered in 1995. The latest count that we know of is about 300 planets around the stars, other than the sun. We're beginning to get a sense of whether our solar system is unusual or not. For the last 2000 years of astronomical history, we've only been able to look at our solar system. If you think about it, we've got the sun, and then there are rocky planets like Earth and Mars, and big gas things like Jupiter and Saturn. We thought that was normal. We came up very cleverly with a whole series of theories that explain why you have rocky planets close to the sun and big gaseous things further out. The only problem is that none of the other solar systems that we've seen look like this. You have large Jupiter-like planets closer to their stars than Mercury is to the sun. We have several large planets in the same solar system, and all of them close. We have planets on elliptical orbits, ones that are almost circular. We're beginning to see the whole range of planets, and we're nearly at the point where we can see Earth-like planets. At the moment, our techniques are not quite sensitive enough. In maybe the next year, or maybe the next 10 years, we'll be able to see if there are Earths out there and see how special this blue rock that we're standing on actually is. That's one thing. The other one that we've touched on is dark matter. Roughly ten years ago, for the first time in a long while, lots of different measurements about the universe came together to produce a theory of cosmology, a large-scale history of the universe that actually made sense. We know how old the universe is. In fact, we know how old the universe is more accurately than we know the age of the earth. We know that the universe began in a hot dense state that we call the Big Bang 13.7 billion years ago, plus or minus one hundred million years. We know that it expanded, we know what it's made of, although we don't know what dark matter is. We can predict what's going to happen in the future. It's great to have ticked off all of these boxes, but the best bit is that this picture makes no sense at all. We don't know what most of the matter is. There's also a mysterious force which is causing the universe to accelerate, and this goes by the name of dark energy. Trying to understand what that is and what on earth beyond Earth is going on is the challenge for the next 50 years.
