Disturbing the Universe

David L Clements, science and science fiction


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Press Release: Star Factory in Distant Universe Challenges Galaxy Evolution Models

We have a Press Release out!

Sadly, the news from Waco, Texas bumped us off the Today programme this morning, but we may be back tomorrow. In the interim you can read about our new results, out in Nature today, below and at other places like ESA and Universe Today.

Imperial College Press Release:

Astronomers have discovered an extremely distant galaxy that is expanding by more than 2000 new stars each year.

Using the European Space Agency’s Herschel space observatory they have seen images of the galaxy as it was when the Universe was less than a billion years old.

This is the most active that astronomers have seen such a young galaxy and since this discovery they are re-thinking some fundamental ideas about how galaxies form and evolve over time.

The newly discovered galaxy, known as HFLS3, appears as a faint red smudge in images from the observatory’s Herschel Multi-tiered Extragalactic Survey (HerMES). In reality, this represents the activities of a star-building factory, which is transforming gas and dust into new stars.

“This particular galaxy got our attention because it was bright, and yet very red compared to others like it,” says Herschel researcher Dr Dave Clements from the Department of Physics at Imperial College London.

Tens of thousands of massive, star-forming galaxies have been detected by Herschel as part of HerMES and sifting through them to find the most interesting ones is a challenge.

HFLS3 has one of the highest star formation rates astronomers have seen; over a thousand times faster than our own galaxy, the Milky Way.

According to current theories of galaxy evolution, galaxies as massive as HFLS3 should not be present so soon after the Big Bang.

Even at its young age of 880 million years, HFLS3 was already close to the mass of the Milky Way, with a mass of stars and star-forming material roughly 140 billion times that of our Sun.

The astronomers have calculated that light from HFLS3 has travelled for almost 13 billion years across space, and that by now, it may have grown to be as big as the most massive galaxies known in the local Universe.

The first galaxies were thought to be relatively small and lightweight, containing only a few billion times the mass of our Sun.

They formed their first stars at rates just a few times more than the number the Milky Way does today, then grew by feeding off cold gas from intergalactic space and by merging with other small galaxies.

“With these observations, Herschel has found a rare example of a galaxy bursting with stars at a time in cosmic history when there were very few such galaxies,” says Göran Pilbratt, ESA’s Herschel Project Scientist.

The mere existence of a single such object so early in the Universe poses a challenge to current theories of early galaxy formation, which predict that they should reach such large masses only much later.

The team are continuing to comb the enormous dataset from Herschel looking for more examples of such extreme, early galaxies.

“A DustObscured Massive HyperStarburst Galaxy at Redshift 6.34” by D. A. Riechers et al. is published in Nature, 18 April 2013.

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Massive Martian Nuclear Reactor!

It’s only a conference paper, so it needs some more work and refereeing before the case is more secure, but I was pointed to this paper today which reports the possibility that a natural thorium-based nuclear reactor once functioned in the northern regions of Mars:

Evidence exists that a large natural nuclear reac- tor formed and operated on Mars in the northern Mare Acidalium region of Mars. However, unlike its terre- strial analogs this natural nuclear reactor was apparent- ly much larger, bred 233U off of thorium, and appar- ently underwent explosive disassembly, ejecting large amounts of radioactive material over Mars surface.

Natural fission reactors are known on Earth, in the Oklo region of Africa, but this is the first extraterrestrial one to be claimed, and the first based on thorium.

There are clearly science-fictional implications in this – Stephen Baxter used Oklo in his novel Origin – but this has other implications for me, since I’m giving a lecture on terrestrial planets tomorrow, including Mars.

I wonder if any of my students will ask me about this?


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A Merger Denied

I’m pleased, and not a little surprised, to read that the planned merger of the British Antarctic Survey (BAS) and the National Oceanographic Centre in Southampton has been called off. The BAS has a proud tradition and an excellent science driven record including, among many other things, the discovery of the Antarctic ozone hole, which eventually led to the Montreal accords, generally recognised as the single most effective international environmental treaty to date. Would that we could have something similar on carbon dioxide production.

The idea that the BAS could retain its science-led tradition when moved to new premises and management, and when given an explicit instruction to help oil firms wishing to drill in polar regions is clearly nonsense, and the ensuing protests about the merger from scientific, environmental and political directions have clearly helped save them.

Even the name ‘British Antarctic Survey’ has a romantic ring to it. It brings visions of the heroic days of Scott and Shackleton, when the UK was a world leader in the exploration of the unknown. Work like the discovery of the ozone hole, and BAS’s current efforts to drill into lakes buried for millions of years beneath the surface of the ice, demonstrate that it is still, to quote Al Gore, ‘a globally significant institution’.

Needless to say there will still be battles, and while this one may have been won, there must still be questions over BAS’s long term future and independence, since it is clear that some people at NERC and elsewhere don’t think it should have one.

It’s good to see that science and scientific independence can beat political and financial expediency at least sometimes, but it is a bittersweet reminder to those of us in astronomy and particle physics who recall the shotgun wedding of our research council, PPARC, and the CCLRC (Council for the Central Laboratory of the Research Councils) that formed STFC. This was a wheeze dreamt up by Gordon Brown, then Chancellor and soon-to-be Prime Minister, for reasons that nobody on the science side of PPARC has ever fully understood.

Unlike the BAS, PPARC didn’t have a political and environmentalist hinterland of support to defend it against this merger, though, since the idea originated from the top, that would have been unlikely to change things. The rest, as they say is history. There are conspiracy theories, incompetency theories, and the general financial doom of the times to explain it (Paul Crowther maintains an excellent record of all the comings and goings to this day), but the end result is that UK astronomy is now much less well funded than it was before the merger (the exact amount is subject to dispute discussion), and we are closing many of the uniquely British facilities that gave us an independent role in the field.

At this point I am unaware of any university astronomer who thinks the STFC merger was a good idea. If there are any, please speak up! I’d also be interested to hear from the particle physics side.

Sadly, unlike scientists, politicians and managers find it difficult to admit to being wrong, so it is unlikely that the clock will be turned back to allow astronomy and particle physics a resumed independent existence, separated from the very different resource demands of the likes of ISIS, DIAMOND, RAL and Daresbury. We’re still riding high in scientific terms, thanks to the long term technical and intellectual investments of the PPARC and, before that, SERC eras, but I can’t help but feel that the future will be one of managed decline, to being just one of the general European herd, and arguably one of the few without independent facilities of its own.

I’m glad, though a little envious, that BAS has yet to share a similar fate.


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News from the Sky

As many of you will have heard, two satellites – an Iridium communications satellite and a defunct Russian vehicle – collided in low earth orbit yesterday. This didn’t immediately mean much to me until the phone started ringing in my office. The college media office were looking for someone who could talk to the media about this. Since they know I’m involved with satellite astronomy I got the call.

I thus ended up waiting a fair bit for people to call back, and for a while I thought it would amount to nothing. But I’ve just finished a radio interview with IRN (independent radio news, the radio equivalent to ITN, and serving commercial stations across the UK). Seemed to go well.

If you hear me on your local station let me know!


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Cosmic Radio Background discovered?

A balloon borne instrument called ARCADE-2 is causing some excitement as it seems to have discovered an excess of extragalactic emission at frequencies around 3.3 GHz. The above link points to a New York Times article on the result, which shows the prominence it’s achieved. The relevant papers can be found here on the arXiv, including the basic result here and discussion of the excess here.

The three most likely sources for error in these observations are stated as being galactic emission, systematic effects and unaccounted for radio emission from faint known sources. The authors conclude that the signal they see is grater than these possible contributions and suggest radio emission from the first generation of weak active galactic nuclei at high redshift.

I’m not sure what to make of this just yet. Claims like this from single experiments need to be checked and independently confirmed before we can give them serious weight, but it is an interesting result. The most interesting thing is that the waveband where the signal is detected, 3GHz, can be observed from the ground, so the next generation of sensitive radio telescopes, like eMERLIN and EVLA, should be able to make rapid progress on the problem once they start to operate.