Claire Bretherton answers your questions about telescopes in space and dark matter

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Claire Bretherton answers your questions about telescopes in space and dark matter

Astronomer Claire Bretherton answers some of the more challenging questions you’ve left on the Big questions answered phone line. This time it’s all about telescopes in space and the ever-mysterious dark matter.

Claire:
Hello, I’m Dr Claire Bretherton, and welcome to April’s edition of Big questions answered. This month we’ve had some really interesting but somewhat difficult to answer,questions. But let’s give them a go anyway.

Kevin:
Good morning! Hi. Thank you so much.
I’ve been trying to find out if there is a telescope on the International Space Station. And I did read of talk of one, an X-ray telescope called the ISS-AT, AT for amateur telescope, but I haven’t been able to find anywhere that they are putting up another one or that there is another one there already. I was just wondering if you happen to know, and could point me in the right direction. Thanks so much. My name’s Kevin, I’m sorry!

Claire:
Thank you Kevin. That’s a great question, and I have looked into this and haven’t been able to find much information about specific telescopes actually on the International Space Station.
However, there is a lot of other research going on in biology, physics, astronomy and things like meteorology. But most of this concentrates on the effect of microgravity and weightlessness on things like the human body and on the evolution of plants and animals. And it’s also a great place to test new technology, and of course to look at our own planet, the Earth.

But there are certainly telescopes in space. In fact, it’s a great place to put them, because of course, if something’s in orbit around the Earth, it’s above the atmosphere. And it’s the atmosphere moving around that makes the stars twinkle, so if we can get above this atmosphere then we get a much clearer, steadier view of objects in space.

Probably the most famous of the space telescopes is of course Hubble, which was launched in April 1990. It’s a joint mission between NASA and the European Space Agency. And Hubble has taken some absolutely fantastic pictures that we see in the news on a regular basis.

You mentioned an X-ray telescope, and actually space is the only place that we can really do these X-ray observations. X-ray telescopes detect very high energy radiation coming from objects in space. But this radiation doesn’t actually get through our atmosphere, so it’s impossible to detect from here, on Earth.

You may actually have heard on the news recently about a new NASA space telescope called Kepler. It was launched on 7 March, and at the moment it’s going through around 60 days of calibration and testing before the science really begins.

And this telescope is really exciting because it’s designed to look at stars, and some of these stars may have planets going around them. And if the planet goes in between the star and the telescope, then the light from the star will dip slightly. The telescope will pick this up and be able to tell that there is a planet orbiting.

The idea is to try and look at stars similar to our own Sun, and hopefully find planets that may be around the same size as the Earth.

In the future, we also have more high-tech telescopes going into space. In around 2013, the James Webb Telescope is due to be launched. This is going to look for the light from the very first stars and galaxies and study things like the formation and evolution of galaxies and the formation of stars and planetary systems, and perhaps even look for the origins of life.

OK. So on to our next question.

Alan:
Hello, my name is Alan, and I want to know what dark matter is. Thanks very much! ‘Bye.

Claire:
That’s a really great question, but unfortunately, it’s not one that I can actually answer. But nobody else can answer it either, because we just don’t know. But we do know that dark matter exists.
Only about 4% of the stuff in the universe is made up of the things we can see, which we call baryons. About 22% is made up of this dark matter, and the rest is made up of something called dark energy, which is even more mysterious.

We know dark matter exists because we can look at galaxies – galaxies a bit like our own, which are spiral galaxies – and we can look at the amount of light coming from those galaxies and we can work out how massive they are.

But, we can also look at how fast those galaxies turn, right from the centre out to the very edges.

From this, we can also work out how massive they are. Unfortunately, the two numbers don’t quite add up, so the number that we work out from looking at the rotation, how fast the galaxy spins around, suggests there should be a huge amount more mass that what we can actually see from the light. So, there must be something there that’s dark, that doesn’t give off any light, and that we can’t actually detect.

We can look on bigger scales: we can look at clusters of galaxies. And again, we can look at how fast the galaxies are moving on the outskirts, and we find, again, that there must be so much more stuff there than we can actually see.

Unfortunately, we still can’t tell what the stuff is. There are a couple of options. It could be things which are a bit like the normal matter, things like brown dwarfs or dark galaxies or dust and rock that we actually haven’t detected. It could be things like a particle called a neutrino, which we think has got a very little bit of mass and moves very, very quickly.

It could be other more exotic particles. There’s one called a WIMP, which is a weakly interacting massive particle, which has been suggested as a candidate for dark matter, but we don’t know anything about them.

But this is hopefully something that the new Large Hadron Collider can help shed some light on.

The Large Hadron Collider is the world’s largest and highest-energy particle accelerator, based at CERN, on the Swiss border near Geneva. And the LHC fires beams of particles very, very quickly around a 27 kilometre-long loop in a tunnel 50 to 175 metres underground.

It first became operational on 10 September 2008, but unfortunately two of the magnets that keep the beams of particles on their paths failed, so it’s currently undergoing repairs. But because it’s kept at such a low temperature, it takes some time to let it warm up, do the repairs necessary, and then cool it back down again.

Hopefully, it will be operational again towards the end of this year, and will shed some light on the nature of this mysterious dark matter.

Well, that’s it for this month, but do please keep those questions coming in on 0208 123 9911. I look forward to answering a few more in the next episode.

Goodbye!

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