January 2008

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Posted by Nicola Jones at 02:42 PM | Permalink

January 2008

We are experiencing a problem with links on Nature News at the moment, so that many do not work. There is, however, a work-around. if you see text like this
(see 'Scientists behaving badly/435737a')
You can obtain the proper URL by adding /435737a to the end of the URL obtained by clicking on the link. In this case the full, correct URL is:
http://www.nature.com/uidfinder/10.1038/435737a

We are working to fix this as soon as possible.

Posted by Nicola Jones at 02:38 PM | Permalink

First it’s rogue black holes on the loose, now it’s giant gas clouds speeding toward the Milky Way. Astronomers have identified a big glob of hydrogen that’s zooming towards us at more than 150 miles per second – and will hit our galaxy 20 million to 40 million years from now.

Scientists have known about the cloud since 1963, when astronomer Gail Smith identified it before dropping out of research. At the time, no one knew whether the cloud was headed for us, away from us, or something in between.

New observations from the Green Bank radiotelescope – the big dish in the West Virginia mountains that’s surrounded by a zone of cellphone silence, so as not to interfere with the telescope – have pinned down the cloud’s trajectory.

“I’ve been going around calling it the most interesting hydrogen cloud in the known universe,” says Jay Lockman, an astronomer at the National Radio Astronomy Observatory who is also known for his banjo-playing skills. Lockman and his colleagues looked at the cloud nearly 40,000 times with the Green Bank telescope and put together a detailed three-dimensional picture of it.

Right now Smith’s Cloud is about 40,000 light-years from Earth. But when it gets here, it is likely to slam into one of the spiral arms of the Milky Way – fortunately a couple of arms over from the one in which the sun, and you, reside. The collision will probably trigger a burst of star formation – lighting up the local sky in true celestial fireworks.

Lockman said that he was able to reach Gail Smith by telephone just within the past week, to let her know that her discovery of decades ago was literally about to come home. For pictures of where exactly it will hit, check out the NRAO's press release here.

Posted by Alex Witze at 08:06 PM | Permalink

Astronomers have gotten pretty worked up lately about what they see as a serious criticism of the way they do business – a paper published last spring by Simon White, director of the Max Planck Institute for Astrophysics in Germany. The paper is called ‘Fundamentalist physics: Why dark energy is bad for astronomy’ and as soon as White started circulating it among the physics and astronomy community, sparks started to fly. (Nature article here, subscription required)

I have to say that I’ve had a hard time getting worked up about the White paper. Basically he’s saying that certain work practices that are common in high-energy physics are threatening the very foundation of astronomy today. These are practices such as creating massive collaborations of coauthors to work on projects, like those needed at detectors at particle accelerators. According to White, astronomy is in danger of moving in the same direction – building giant facilities for doing astronomical research that will consume the creativity of individual scientists. There’s a lot more to his argument than that, but I’d refer you to his paper for the gorey details.

Anyway, last night came a much-ballyhooed ‘debate’ between White and cosmologist Rocky Kolb of the University of Chicago who has written in response to the White work. In my opinion, the debate ended up being a lot of griping about the nature of large collaborations and large facilities, and a lot of worrying about whether young astronomers are being driven away from the field because they don’t want to be the 300th coauthor on a massive paper.

Are you an astronomer? How are important are such working conditions to you? Or do you think creativity will win the day no matter what you’re working on – that there is plenty of good science to be done even under the framework of a massive, faceless machine?

Posted by Alex Witze at 05:47 PM | Permalink

Here’s the closest ‘look’ yet at dark matter in a massive galaxy cluster. Dark matter is that stuff that astronomers cannot see but know must exist, because without its gravitational glue to hold galaxies together, they would fly apart into pieces. Naturally, spotting dark matter is a hard thing to do, because it’s, well…invisible.

A team led by Meghan Gray, of the University of Nottingham, and Catherine Heymans, of the University of British Columbia, used gravitational lensing – the same trick described below – to measure how dark matter in space distorts the light from a massive cluster of galaxies known as Abell 901/902. This is a big thing: more than 2.6 billion light-years away, it measures a whopping 16 million light-years across and is composed of more than a thousand galaxies.

The concentrations of pink stuff shows where the dark matter lies. For more images see the main Hubble press release site here.

Posted by Alex Witze at 05:28 PM | Permalink

Those intrigued by the question posed in this post,

- What rock group had its members' names included in a reference in the Astrophysical Journal, unbeknownst to the editor?

According to Alex, the answer is The Byrds (which I would not have guessed) and has to do with SETI (which if I'd thought harder I might have guessed). I thought I knew quite a lot about the pop-culture side of SETI, but this lovely little story had escaped me. So as it may also be news to others, here it is.

IIn the mid 1960s, Caltech radio astronomers identified an unusual radio source catalogued as CTA 102. The speed at which it fluctuated led astromers in the USSR to suggest that it was an artificial source -- a signal from a higher civilisation. This inspired Roger Mcguin and Robert Hippard to write a song, CTA 102, which can be found on The Byrds 1967 album "Younger than Yesterday".

C.T.A. 102 year over year receiving you

Signals tell us that you're there

We can hear them loud and clear

We just want to let you know
That we're ready for to go
Out into the universe, we don't care who's been there first

On a radio telescope
Science tells us that there's hope
Life on other planets might exist

According to the first critical site my browser has led me to,

The song combines the scientific abstraction of "5D (Fifth Dimension)," the jaunty melody and whimsical extraterrestrials of "Mr. Spaceman," and the playful sonic experimentation of "2-4-2 Fox Trot (The Lear Jet Song).

Others -- notably Gav378 over here -- are less impressed

I don't love "So You Want To Be A Rock N Roll Star" and I hate "CTA 102". It wouldn't matter if the rest of the album was Abbey Road, with the inclusion of these tracks, it puts me off listening to the whole album.

Anyway, enough of the music criticism -- on with the astronomy. CTA - 102, as you will undoubtredly have realised, was not in fact an alien civilisation sending out peace and love to all southern Californians. It was just a quasar acting in the flickering ways that astronomers quickly came to expect from such things. Nevertheless when researchers at Caltech and elsewhere went on to study other quasars and related objects at wavelengths at which CTA 102 was invisible (Schorn et al, ApJ 151, L27-L31, 1968) they noted archly that were "unable to comment upon the discussion by McGuinn, Clark, Crosby, Clarke and Hillman (personal communication)." (Hippard, while he co-wrote the song, wasn't on the album and thus missed out.)

The man responsible for this nod seems to have been Eugene Epstein, then at the Aerospace Coropration, about whose taste in art you can read more here.

Here's the CTA-102 story in what appear to be Roger McGuinn's own words:
http://solar-ice.blogspot.com/2007/09/cta-102_01.html
And here's the paper in pdf

Posted by Oliver Morton at 05:10 PM | Permalink

Some talks have titles you just can’t pass up. So it was with “How astronomers die,” a presentation by historian Thomas Hockey of the University of Northern Iowa. Hockey exercised tact in not including perhaps the most famous astronomical death of recent decades, when a young researcher named Marc Aaronson was crushed in 1987 by a rotating observatory dome on Kitt Peak in Arizona. Such modern tragedies aside, Hockey clearly relished the gorey details of astronomers biting the dust in eras long past.

Most astronomers, he told his clearly relieved audience, die natural deaths. But others have gone down in flames in the annals of history – literally. Giordano Bruno, after all, was burned at the stake in 1600, though his crime was heresy, not astronomy. The philosopher Boethius, whose writings covered astronomical topics, was executed by having a cord tightened around his forehead so tightly that his eyes “cracked in their sockets,” says Hockey, and then was bludgeoned to death. And the 4th-century mathematician Hypatia of Alexandria (right) suffered a gruesome death at the hands of Christian mob, who pulled her from her chariot and skinned her alive with oyster shells, as some accounts have it.

War has claimed a fair number of promising astronomers -- from Archimedes who expired via a Roman sword, to British astronomer William Gascoigne, who died at the battle of Marston Moor in Yorkshire in 1644. Travel has also been “quite a grim reaper,” Hockey noted – taking out astronomers in car crashes, shipwrecks, and even a freak blimp accident. Finally, John James Waterston may have actually given his life for his work – while attempting to precisely measure solar radiant energy, he suffered heatstroke that later brought him regular fits of dizziness and may have contributed to his falling, and drowning, in an Edinburgh canal in 1883.

Posted by Alex Witze at 05:07 PM | Permalink

Sometimes a picture can be more profound than it looks. This unassuming black-and-white image shows something never seen before – a double ‘Einstein ring’ created by a chance cosmic alignment.

Look closely – you should see not only a bright, nearly circular ring, but also fainter, interrupted arcs of light outside it. That second concentric ring is what makes it a double Einstein ring.

The regular Einstein rings are pretty cool in themselves. They’re optical illusions of a sort, created when light from a distant object (like a galaxy) gets bent by the gravity of a second object that lies along the line of sight between us and the first object. Tommaso Treu, of the University of California Santa Barbara, likens it to holding up a wine glass and looking at a candle through its stem; the distortions in the glass smear out the candle flame into arc-like shapes.

There are only about 50 regular Einstein rings known to date, and Treu and his colleagues were recently hunting for more. And that’s when they stumbled across the double ring. The geometry is complicated: first there’s us; then, 3 billion light-years away, the ‘lens’ which is some object like a massive galaxy; then, 6 billion light-years away, another galaxy whose light has been smeared by the lens to create the inner, bright ring; and finally, 11 billion light-years away, the galaxy whose light has been similarly smeared into the outer, fainter arcs.

It’s a rare alignment, but Treu thinks there may be more out there. Future space missions could potentially spot as many as 50 of the double rings, he says. And with that, astronomers might be able to use the rings to start answering questions about how matter and energy is distributed throughout the universe.

Posted by Alex Witze at 04:40 PM | Permalink

It’s almost as startling as 60-year-old women giving birth. Astronomers think they have spotted two stars that are well into middle age and shockingly may still be forming planets around themselves.

Most of the time, planets are born soon after their parent star is. Think of our sun, which in its infancy 4.5 billion years ago also saw planets forming right away, condensing out of the cocoon of dust and gas that swirled around it. You don’t see any newborn planets popping into existence in our solar system today.

But that may be exactly what’s happening at two puzzling stars, says Carl Melis, a graduate student at the University of California, Los Angeles. Despite being well advanced in age, both appear to be surrounded by a dust disk that could be forming planets now. It could, in fact, be a second wave of planetary formation for these stars; the first coming soon after they were born, possibly hundreds of millions of years ago, and the second happening now.

The two stars are odd. One, called BP Piscium in the constellation Pisces (right), was thought to be a young star because of the dusty disk that surrounds it. But studies of its chemical composition and other factors revealed that it is in fact quite old – maybe not to menopause yet, but definitely pushing the limit. The second star, called TYC 4144 392 2 in the constellation Ursa Major, has a dust disk and itself orbits a separate star, which does not have such a disk.

So how did these two old stars end up with dust disks around them? Melis thinks they may have, in the recent past, each swallowed another companion object – something a bit too small to be called a proper star – and, in the digestive process, belched out a giant wave of dust. That dust settled into orbit around the star.

Sara Seager, an expert on extrasolar planets at MIT, says Melis’ idea is plausible. There’s no getting around the fact that these two stars have dust disks, she says. The question now is, how exactly did they get there, and are planets in fact actually forming within them?

Posted by Alex Witze at 08:42 PM | Permalink

Stop the presses: Hundreds of rogue black holes are on the loose in the Milky Way!

It’s a good thing that black holes are only dangerous if you’re within about 100 kilometres of them. And the Milky Way is a big enough place that we needn’t worry, says Kelly Holley-Bockelmann, an astronomer at Pennsylvania State University.

Her research team discovered the errant black holes – each of which is 100 to 1,000 times the mass of our sun -- by studying clumps of ancient stars known as globular clusters. These are rough environments, in which black holes are constantly sinking toward the center of the cluster, occasionally meeting in a violet merger that throws one or the other of them out of the cluster at speeds up to 9 million miles per hour. Holley-Bockelmann’s computer simulations show that scientists haven’t spotted nearly as many black holes getting kicked out of globular clusters as one might expect. And so, she says, there must be extra black holes lurking there, invisibly -- some of the biggest rogues ever spotted in our galaxy.

Posted by Alex Witze at 08:20 PM | Permalink | Comments (1) | TrackBacks (0)

I'll be sad to miss the public lecture tomorrow night by Andy Fraknoi, as there is a previously scheduled press event at the same time. But for you science/pop culture buffs out there, see if you can answer some of the questions Fraknoi poses in his abstract:

- In what popular movie does Daryl Hannah play an astronomer? (Answer.)
- What Japanese car company is named after a well-known star cluster? (Answer.)
- What science fiction story, written by an astronomer under a pseudonym, features a Hertzsprung-Russell diagram of stellar evolution? (Answer.)
- Can you recite the most famous neutrino poem, and name the poet? (Answer.)

And here's really geeky one I haven't a clue about - if you know, comment below please!
- What rock group had its members' names included in a reference in the Astrophysical Journal, unbeknownst to the editor?

Posted by Alex Witze at 11:11 PM | Permalink | Comments (3) | TrackBacks (0)

Young stars floating together in isolated gangs, nowhere near adults and asking for trouble. It sounds like the perfect setup for a teen slasher flick, but it’s really a cosmic mystery just discovered 12 million light-years from Earth.

Diulia de Mello, of the Catholic University of America and the Goddard Space Flight Center, and colleagues spotted the stragglers near a smashup of three galaxies (including the well-known pair M81 and M82, right). De Mello calls them “blue blobs”. They are “weird,” she adds – “in regions they are not supposed to be.” That’s because they appear relatively far away from the galaxies, where gas and dust – ingredients generally needed to make stars -- are sparse.

It turns out that the blobs are actually clusters of young stars, born as the galaxies collided with each other over the past 200 million years. The cosmic disruption led to spots locally richer in gas, which then condensed under its own gravity to form newborn stars.

Eventually, the young hoodlums could grow up to throw their own trash into space – by exploding at the ends of their lives and spewing their chemical elements back into intergalactic space. It seems they may never be up to any good.

More details and images are available here.

Posted by Alex Witze at 11:03 PM | Permalink

Shuttle schedules willing, astronauts will be going back to the orbiting Hubble Space Telescope this summer. The next and final servicing mission to the telescope (right) is slated for early August, and top NASA brass were out at the astronomy meeting today to tout it.

It’s a far cry from a couple of years ago, when in the wake of the disintegration of the shuttle Columbia NASA’s chief at the time, Sean O’Keefe, cited safety reasons in canceling the final trip to Hubble. That decision prompted an outcry from astronomers and others (Nature story, subscription required) and NASA eventually reversed its decision – after first looking into options to send robots instead of astronauts, and then getting a new administrator in the form of Mike Griffin.

Now the trip is hostage only to delays in shuttle launches; right now, the shuttle is backed up on delivering the European Columbus science module to the international space station, a trip that was supposed to go in December but now looks more likely for February. If other launches continue to slip, an August date for the Hubble mission doesn’t look likely.

No matter – astronomers don’t seem to mind waiting. The next servicing mission will bring two new scientific instruments up to Hubble, plus fix two other ones already up there.

If all goes to plan, here are the new tools that researchers will have to play with once the astronauts undock from Hubble:

- A new wide-field camera, the most powerful ever flown in space. The Wide Field Camera 3 will span the wavelengths of light most coveted by astronomers: ultraviolet, visible, and infrared. It covers more of the sky, with better resolution, than ever before. “This just really shows what we’ve been missing,” says astronomer Mark Dickinson, talking about a gap in near-infrared wavelengths where there really isn’t just much good data … yet.

- A new ultraviolet spectrograph, the most sensitive ever flown in space. The Cosmic Origins Spectrograph is designed to study point sources such as stars and quasars, revealing more about both the near and far universe.

- Repairs to the ACS camera and STIS spectrograph, two instruments already on Hubble that have suffered electronics failures. Astronauts will have to do some tricky work to extract the malfunctioning components from the instruments – involving hundreds of tiny screws that have to be extracted in space, as astronaut John Grunsfeld – the man who has to do the work – points out.

- New gyroscopes to help the telescope point itself, and new batteries to keep it alive. These are the ‘consumables’ that otherwise would eventually limit the physical life of Hubble itself.

- A new thermal blanket to insulate it from the cold of space.

- Some docking hardware that will, sometime around 2020, allow a robotic spacecraft to hook onto the telescope and then guide it into a safe burnup and crash into an ocean somewhere.

If it sounds like a lot of work, it is. Astronauts are budgeting five full days of 6.5-hour spacewalks to get it all done. Grunsfeld and the other crew members have been spending a lot of time in the giant swimming pool training area in Houston, in which astronauts practice spacewalks underwater. But if they manage to pull it all off, Hubble will be in the best scientific shape of its life. “We will have more scientific capability on this mission than ever before,” Grunsfeld said excitedly this morning. Sandra Faber, an astronomer at the University of California at Santa Cruz who uses Hubble, notes that, roughly speaking, the telescope will be *90 times* more powerful after the servicing mission than it was when it was launched back in 1990.

Hubble is expected to last another 5 to 10 years after this final mission. Now it’s up to astronomers to see what they can dream up to do with it before Hubble goes dark for good.

Posted by Alex Witze at 05:19 PM | Permalink

Join Alexandra Witze at the American Astronomical Society meeting in Austin, Texas from 8-11 January. She'll be sending diary reports back here as astronomers gear up for the International Year of Astronomy in 2009.

Posted by Nicola Jones at 10:08 AM | Permalink