Happy Halloween!

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Things have been a little quiet around here lately, mainly because things have been extremely busy offline! That’s all quieting down now, so fingers crossed I’ll get back to posting soon… In the meantime here’s an old APOD with an appropriately spooky theme:

It’s a composite of a total lunar eclipse from October 2004. If, as Rolf Harris might not say, you can’t see what it is yet click here!

When a comet’s not a comet after all

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Back in January the Lincoln Near Earth Asteroid Research (LINEAR) survey saw something a bit odd amongst the asteroids in the main asteroid belt (found between Mars and Jupiter). Initially the mystery object, P/2010 A2, was designated as a main-belt comet (a rare object found within this region of the Solar System, unlike the majority of comets which orbit a lot further away) because of its elongated fuzzy appearance. However, two sets of results published in Nature today suggest that this thing is actually the aftermath of a collision between two asteroids that occurred some time in February or March 2009.

A comet generally has a fan shaped tail, topped with a dust-enshrouded nucleus; when the first team looked at P/2010 A2 with the Hubble Space Telescope though they saw that it has a more rectangular shaped tail, beginning in an X-shape:

The second team also saw a distinctly un-comet like structure (shown left) when they imaged the object with the OSIRIS camera onboard the Rosetta spacecraft. This had a really good view as it was approaching the asteroid belt at the time, in preparation for its flyby of the asteroid Lutetia.

Modelling the structures seen in both images by the two teams independently revealed that the main body of P/2010 A2 is about 120 metres across, that it was formed from a collision with a much smaller body, and that all this occurred about a year before we first saw it. Discovering all this isn’t possible from Earth though, as ground based telescopes, such as the one used by LINEAR, can’t see it from the right angle.

This sort of collision between asteroids of this approximate size are only predicted to occur roughly once every 12 years, so its likely that P/2010 A2 will remain unique for a few years yet.

Images credit NASA & ESA

ResearchBlogging.orgJewitt, D., Weaver, H., Agarwal, J., Mutchler, M., & Drahus, M. (2010). A recent disruption of the main-belt asteroid P/2010 A2 Nature, 467 (7317), 817-819 DOI: 10.1038/nature09456

ResearchBlogging.orgSnodgrass, C., Tubiana, C., Vincent, J., Sierks, H., Hviid, S., Moissl, R., Boehnhardt, H., Barbieri, C., Koschny, D., Lamy, P., Rickman, H., Rodrigo, R., Carry, B., Lowry, S., Laird, R., Weissman, P., Fitzsimmons, A., Marchi, S., A’Hearn, M., Angrilli, F., Barucci, A., Bertaux, J., Cremonese, G., Da Deppo, V., Davidsson, B., Debei, S., De Cecco, M., Fornasier, S., Gutiérrez, P., Ip, W., Keller, H., Knollenberg, J., Kramm, J., Kuehrt, E., Kueppers, M., Lara, L., Lazzarin, M., López-Moreno, J., Marzari, F., Michalik, H., Naletto, G., Sabau, L., Thomas, N., & Wenzel, K. (2010). A collision in 2009 as the origin of the debris trail of asteroid P/2010 A2 Nature, 467 (7317), 814-816 DOI: 10.1038/nature09453

The end of an era

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Coming out of lurking mode for a very brief post that notes the end of one of the most important experiments to cosmologists, astronomers, scientists and just about anyone who has an interest in how our Universe came to be.

After 9 years of peering through billions of years of cosmic history, the WMAP satellite has now stopped taking data – you can read the press release here.

The importance of WMAP to the confidence we have in the standard cosmological model today can’t easily be over-stated. We look forward to Planck taking over, and launching us into yet another era of precision cosmology and new and exciting discoveries!

Playing catch-up

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It feels like its been a busy week in science, but unfortunately its been even busier for my particular astro bit of it. I’ve wanted to blog about so much stuff but not got round to any of it, so I’m going to put it all here, in one catch-up post!

The first, and most important, thing I have to mention is the Science is Vital campaign against cuts in science funding in the UK. Please go and sign their petition if you agree with me that science is vital to the economy, to our health, to just about our entire way of living. There’s also a rally planned for this Saturday in London which disappointingly I can’t make, but I think there’s going to be a good turnout, given the amount of #scienceisvital activity on Twitter.

The campaign is also currently asking scientists to write about “What don’t we know yet”, to show what questions could remain unanswered if funding is cut (check out The e-Astronomer for a good list of the outstanding astronomy problems). One group of scientists who set out to solve some of the more unusual conundrums are this year’s crop of Ig Nobel Prize winners, awarded “..for achievements that first make people laugh then make them think”. We now know, to pick a few, that asthma can be treated be riding rollercoasters; that its best to promote people at random; that swearing does actually help to relieve pain, and that fruit bats have rather more interesting personal lives than previously suspected.

One of the winners of this year’s Nobel Prize for physics is also an Ig Nobel laureate (with some interesting previous co-authors). He was awarded one for his work on levitating frogs and the other for pioneering work on the manufacture of graphene (I’m sure you can guess which is which!) To find out how sticky tape is involved (and what the Nottingham connection is) watch this neat video from the Sixty Symbols project:

The other big news of last week was the potential identification of the first Earth-like extrasolar planet, Gilese 581g, orbiting in the Goldilocks Zone – the region in a planetary system where liquid water is possible which means that life could exist there. Unfortunately the story was dominated by a quote from one of the astronomers involved, who said that his “…own personal feeling is that the chances of life on this planet are 100 percent” which is a bit optimistic given that very little is currently known about it. There’s a good discussion about this over on Universe Today.

The media are also involved in the last of the things I want to catch up on. Last Tuesday the Metro newspaper published this small article:

As you may have guessed, I couldn’t find a version of it online! In case you can’t read it, the text says:

X-Ray Vision
The largest ever X-ray telescope is scheduled to launch in 2021. US, European and Japanese scientists believe it will give the most detailed insight ever into the dawn of time. The 1,300 sq. metre International X-Ray Observatory will be able to identify 3million new black holes. Some of these may even be supermassive black holes which probably developed before the first stars.

When I first read this I was really annoyed by the errors it contains, the biggest of which is the suggestion that scientists are planning to launch a telescope into space that’s bigger than the floor plan of my flat! However, in this case, the journalists aren’t really to blame. After I complained about the story on twitter @chrisenorth sent me a link to the original press release, which isn’t very good at clearly explaining the facts of the project.

In case you’re wondering the x-ray telescope in question (IXO) will actually have an effective 3 sq. metre collecting area. The 1,300 sq. metre figure will be the total surface area, but this will consist of stacks of nested silicon wafers, because x-rays are detected through grazing incidence techniques.

So, that’s me all caught up. It’s been an interesting week – if you thought so too, don’t forget to sign the petition and hopefully there’ll be lots more interesting weeks to come!