The Shape of the Universe is...

...football (soccer for Americans), a volleyball , a doughnut or even a pringle. However, according to New Scientist on Thursday, the Universe could be shaped like a medieval horn.

Once again this is someone's pet theory for the shape of the Universe that has been invented to explain the data from NASA's Wilkinson Microwave Anisotropy Probe (WMAP). One of the biggest puzzles to come from the data is the low l multipole or more simply, why there isn't as much large scale structure in the background radiation from the Big Bang as was expected. This also comes at a time when the football shaped Universe might be running into some problems as it predicts repeating structure which isn't seen.

It can't be long before we get a Universe shaped like a small plastic toy from a Christmas cracker.

Posted in astro blog by Stuart on Sunday 18th Apr 2004 (15:47 UTC) | Permalink

BBC Cone of Light

Big beams of light shining up into the sky seem to be becoming more and more popular and many people who care about light pollution object to them. Previously I have mentioned Barnsley's Halo of Light but now it seems that the BBC have decided to get in on the act by creating a 900m (3000ft) light sculpture at BBC Broadcasting House. They have commissioned artist Jaume Plensa to design it and have so far got approval from the Civil Aviation Authority and Westminster Councils Planning and City Development Committee.

Although the sculpture has a very worthy purpose - to commemorate news journalists around the world who have lost their lives - it will add even more light pollution to an already very bright capital. Why not put a time limit on it so it doesn't stay on all night? I wonder what planet hunters around other stars would make of the faint orange glow coming from the Earth?

Posted in astro blog by Stuart on Sunday 18th Apr 2004 (15:09 UTC) | Permalink

Stupid Questions

I discovered the weblog of Carolyn Petersen who writes about space and astronomy related things (note the image of Venus and the Moon which looks quite similar to mine). I was interested in her story about a teacher in a planetarium lecture she was giving. It seems that a young girl asked her a question and before Carolyn had chance to answer, the teacher interrupted saying it was a stupid question. As Carolyn rightly points out, most questions about astronomy are not stupid and children quite often ask really good ones. If we don't ask questions how will we ever know the answers?

Posted in astro blog by Stuart on Monday 12th Apr 2004 (16:41 UTC) | Permalink

The Big Rip

You may have heard of the Big Bang, the Big Crunch and possibly even the Big Chill as fates of the Universe. A new one on me was the Big Rip which was mentioned yesterday morning at one of the sessions in the National Astronomy Meeting at Milton Keynes. The talk was by Isobel Hook - an astrophysicist who works at the University of Oxford.

Using information from things such as the Supernova Legacy Survey and the Supernova Cosmology Project, it became apparent that the Universe seems to be expanding and the expansion is getting faster. This is caused by what is known as 'dark energy' which we now think is what about 70% of the Universe consists of (normal matter that we are made of is only a few percent!). If the Universe expands and this expansion is accelerating faster than a certain amount, we will gradually lose sight of other galaxies - it was pointed out that extragalactic astronomy will gradually become less interesting! However Caldwell et. al. (2003) say that if the acceleration is large enough, matter could be pushed apart violently by 'phantom energy' and this is termed the Big Rip.

In other words, in the future, the galaxy may not be able to hold itself together by gravity as phantom energy works against it. In one model this would happen 60 million years before the end of the Universe. At End of the Universe - 3 months, the solar system would be torn apart, closely followed by the Earth exploding with only 30 minutes to go!

We really need to write a book titled "101 ways to end the Universe".

Posted in astro blog by Stuart on Friday 02nd Apr 2004 (22:44 UTC) | Permalink
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