Article in Independant

[China Doll]

Hi All,

I read this article in the Independant last week.

http://news.independent.co.uk/sci_tech/article 2800183.ece

I think I got my head around most of it but point 6) still leaves me a bit confused. I wondered if anyone could put it in to (even simpler) layman's terms for me please? And possibly what the implications are if stars do create their own telescopes? (At the moment I have images of stars with big telescopes looking down at us and I'm fairly sure that's not the point that was being made!)

Cheers
China

[kempie]

A glass or plastic lens (such as found in a telescope) is a device that causes light to either converge and concentrate or to diverge; in other words the light is "bent". Likewise the gravity of a massive object will bend light (and other radiation), creating a "gravitational lens"...

http://en.wikipedia.org/wiki/Gravitational_len s

[jake-the-peg]

:c) I used to work there!

In 1915 Einstein published his general theory of relativity - one f the things he said was that light travels in a straight line but that space is warped by gravity - a bit like a marble in a glass tube with a kink in it.

Well anyway this prediction meant that the sun should bend light and everybody ran off at the next total eclipse and lo and behold stars close to the sun appeared slightly away from where they should have been - Einstein was right!

http://sunearthday.nasa.gov/2006/images/news_e instein2.jpg

Now sometime after people worked out that large clusters of galaxies could do the same thing but act like a lens so we could see things fainter than we'd otherwise be able to and some other strane effects too - for example telescope like hubble have photographed "pairs" of galaxies that are in reality the same one but appear as two as gravity has caused a double image.

Most importantly though we can use the effect to effectively weigh the galaxies or areas of space that the light passes through

[China Doll]

Thank you both! Much clearer now.

Jake - Did you work at the Culham Science Centre? Did you make stars? I found that quite an unusual concept. I mean, making stars? I'm not sure if I'm very impressed or kind of sad about it! I think both.

[jake-the-peg]

I worked at what was then Culham Laboratories under the UK Atomic Energy Authority. I was a Scientific Officer (Junior physics prole in other words) on some of the Tokamak experiments where we were doing studies into plasma physics as part of the overall fusion program.

The big JET torus was next door and in those days they'd not yet achieved fusion reactions so you could still go in and see it like this:

http://www.toodlepip.com/tokamak/pictures/j91- 212cmed.jpeg

It was a really cool place to start your working life but after a couple of years I made the fundamental discovery that they don't pay physicists enough and sold out for a career in computers.

Nuclear fusion is really a holy grail of energy and has been for about 50 years - like I say JET managed fusion reactions but used more energy than it made. ITER is being built now in France and will exceed breakeven - that is will actually create more energy than it uses.

After that DEMO will be the first fusion reactor - probably be about another 30 years but the raw material is water there's no CO2 produced and the radioactive waste should last about 100 years rather than 100,000.

If I'm lucky I should live long enough to see it - and think that I was once a very, very tiny cog in that.

It's a long road but it took them 70 years to write the Oxford English Dictionary and you can't generate electricity out of that!

[China Doll]

Wow! Very impressive.

I hope I live to see that too.

Cheers Jake.

[brachiopod]

What a fascinating answer, j-t-p, and once again me ol' China, you are too modest with your "am I being silly, but...." questions - they are always welcome and, as ever, generate excellent replies*

pod x

* - trolls excepting.

[China Doll]

Aww shucks 'Pod, thanks. xx