We’re more or less all done with comet McNaught up here in the North. We’ve handed it over to the Southern hemisphere viewers. That lucky lot are getting quite a show, since the comet seems to be outgassing more and producing a longer tail of debris. It is spectacular. Here is an image from New Zealand:
It was taken by Andrew Drawneek and I found ita on the SkyTonight site here, where Continue reading ‘Look Up Down South’
Comet McNaught seems to be a gift that keeps on giving. Last night here in Los Angeles, just after the sun set, I stepped out to look from a nearby elevated spot - and there it was. With binoculars, it’s an impressive sight, and possibly the last naked-eye visible comet sighting for a long time. Unfortunately, I have no equipment that I can use to take a decent photo for you, so I can’t share what I saw. (Some pictures from around the world are here.)
But you can go out and look. I give some viewing tips below. [See update at end, however.]
What you’re probably puzzled about now is why the experts kept getting the “last chance to see” message wrong. People seemed very sure back on Wednesday that it would be gone from view -and I did a post to that effect myself- and and the same thing was said on Thursday and then on Friday.
I’m guessing that this is because although they can track the position rather well, they Continue reading ‘Look Up!’
So the new comet, McNaught, is now very much a naked-eye visible object. Apparently it is the brightest comet in the last 30 years or so. I learned* that (for those in the Northern Hemisphere) Wednesday evening might well be the last chance to see it before it becomes a Southern Hemisphere object. [Update: It seems that it's still been visible these last few days. Maybe it will be tonight (Saturday).] [Update: See later post here.]
So take a peek outside if you can. It might be a chance in a lifetime!
Have a look at this SkyTonight page for finding instructions. Come back and let us know if you saw it! (If you get a picture, share it with us too! I can post it here for you. The one above, by Gary W. Kronk, is at the gallery at SkyTonight.)
-cvj
*Thanks Amara Graps, and Nick Warner.
The Andromeda Galaxy is bigger than previously thought. Perhaps as much as five times bigger. I know that you’re thinking - “Oh, that’s because most of it is dark matter, right?” No, this is not another dark matter story. In fact, there are many newly discovered stars from a recent study! The suburbs of the galaxy are much more extensive than previously identified. It’s rather good news, since the galaxy makes more sense than it did before, in the context of our understanding of how galaxies form and evolve. (Image above is of Andromeda in the infra-red, from NASA.)
The point here is that current theories of evolution for galaxies have the oldest stars Continue reading ‘Andromeda Now Makes Sense’
Have a look at this:
What is it? It is an image of part of the three dimensional (see below) distribution of clumps of dark matter in our universe, produced by an extensive survey using the Hubble telescope. How did they produce it, given that dark matter is -by definition- not visible? They deduced the presence of the chunks of dark matter by looking at the Continue reading ‘Dark Matter in 3D’
The Bad Astronomy Blog gives a top ten list of astronomy images for 2006. There are some really wonderful choices there, and Phil Plait gives a good deal of discussion of each one. The winner is this fantastic back-lit (by the sun, not some giant NASA flashgun) image of Saturn taken -of course- by the Cassini mission:
Now there’s another wonderful feature of this photo that makes it such a clear winner. Continue reading ‘A Different Perspective’
This is a diagram of the layout of the equipment on the Corot (COnvection, ROtation and planetary Transits) space telescope, launched recently from a site in Kazakhstan.
It’s a European Space Agency (ESA) mission, primarily run by the Centre National d’Etudes Spatiales (CNES - the French Space Agency, if you will) and it’s going to be looking closely at about 120,000 stars for signs of planetary bodies in orbit around them, in addition to studying the stars themselves. There’s a BBC story here, with video, more figured and images, and links to other sites, such as this condensed mission guide. The Proteus platform in the diagram refers to that fact that this is but one of a series of craft in the “Proteus” series, the platform itself being the design of the core containing the instrumentation and control systems of the device. Learn more about that here.
By going over to ESA’s site, you can learn a lot more about the scientific objectives Continue reading ‘Planet Hunter’
One sees them a lot around here, given the town I’m in, but that’s not what I’m talking about.
There’s a Spitzer telescope press release about the possible discovery of the most early stars detected to date. These would be the very first stars to have formed in the universe. Remembering that the universe is 13.7 billion years old, pause for a moment to be impressed by the claim of Kashlinsky, Arendt, Mather and Moseley that these stars appeared less than a billion years after the big bang. You should also read some discussion in John Baez’ recent post. [Update: See remarks from Ned Wright at the end of this post.]
The new milestone on the timeline of the universe’s history, if this is correct, would look roughly as in this image (from the press release):
Extraordinary claims (like this one) require extraordinary evidence, and so there’ll no Continue reading ‘Really Old Stars?’
Yes, in other words, tonight and tomorrow night are the maximum event rates for the Geminids, the meteor shower that originates from the direction of the constellation Gemini. From Gary Kronk’s site, I borrowed this diagram that shows roughly where to look:
So as you can see, you’re popping out to look in a Easterly direction, more or less, and after about 9:00pm you should get some results. There’s some more information here at this site.
You’ll recall from a number of earlier posts on meteor showers that I’ve mentioned that they are caused by the Earth passing through the debris field of a comet. The Geminids are somewhat different. Well, yes and no. They are actually passing through Continue reading ‘Twin Peaks’
In case you have not heard, NASA announced today that they have evidence that water flows on Mars. That’s the present tense, note. Not flowed some time ago - flows currently (albeit perhaps only in intermittent bursts). Here’s the link to their announcement. The picture:
An extract:
There’s a new paper coming out telling of the observations (over two years) of the swallowing of a star by a black hole, from beginning to end. There’s no nice picture showing this, I’m afraid - the picture to the right (click for larger) is an artist’s impression (see description below). The team, led by Caltech’s Dr. Suvi Gezari, used the Galaxy Evolution Explorer and data from Chandra and some ground based telescopes, to track the ultraviolet radiation emitted from the star as it was consumed by the hole.
From the NASA/JPL press release:
So, I have questions.
About what? Well, by now you’ve heard about this wonderful machine that was found 100 years or so ago, which after a lot of research, has been found to be a remarkably sophisticated mechanical computer designed and built in ancient Greece about 2,100 years ago. There’s a nice LA Times story on it by Thomas H. Maugh II here, and a New York Times story* by John Noble Wilford here and a Reuters article by Patricia Reaney here. (The image to the right (click for larger) is from the University of Cardiff.)
From the articles you can learn that the machine was able to perform computational tasks 1400 years or so before the time when machines of this sort (but less sophisticated) were thought to have appeared. What sort of tasks? Well, using 37 gears or so it can do subtractions, multiplications and divisions to show the cycles of Continue reading ‘The Antikythera Mechanism’
I learned from Often In Error that the paper of Riess et al, reporting on the research that was in the recent NASA press release, is out. It is here.
(Aside:- I must use the term “cosmic jerk” in an everyday sentence one day…. probably not as a term of endearment….)
-cvj
Remember the Orionids? Well, it is the turn of the Leonids, this Saturday and Sunday (although those are just the peak days). These comets are the result of us passing through the debris left by comet Tempel-Tuttle. The peak will be on the 19th November…. Viewing and other information here (Armagh Observatory), here (a NASA site), and here, from Gary W. Kronk’s site (as is the diagram below). Here’s a nice Space.com article by Joe Rao.
There is expected to be quite a spike in the viewing rate this year… enhanced by a factor of ten to maybe as many as 100 or 200 per hour. This is for the lucky viewers in Western Europe (and the British Isles 
), North Western Africa, North Eastern USA and Eastern Canada, Continue reading ‘The Lion’s Share’
So the press conference is over. I did not listen to it, but the gist of it, from the press release, seems to be that they’ve observed several more supernovae to pin down even more accurately what the universe’s expansion rate was at very early times (up to nine or ten billion years ago). Image below from their site:
From the site, we learn (for background):
From NASA, tomorrow, at 1:00pm EST: An announcement about Dark Energy. If the pattern of last time is to be followed, there must be new evidence from the space telescope team (represented by Riess and Livio at the press conference) in favour of one interpretation or another. Since they are saying that they will “announce the Continue reading ‘Less In The Dark Than Before?’
The Eye of Sauron is rising again, but now on Saturn!?
No, here’s what’s actually going on:
On the site Space.com, I found a nice article by David Powell about the Cassini spacecraft’s future. (Cassini has done some wonderful work recently, including bringing us wonderful images such as the one below of Titan and Epimetheus, and Saturn’s rings.)
Cassini’s NASA handlers are wondering about what they will do with it when its mission is over. Here are some of the options they are considering: Continue reading ‘Better To Burn Out, Or To Fade Away?’
So did you see yesterday’s event? (Above is a snapshot of a movie of the event from a SOHO image capture sequence. Mercury is a tiny dot just below the structure on the right that is not far from one of the remarkably few sunspots on the sun at present (it is low season for them). Go there for more images to see Mercury in action.)
Joe Vandiver (centre, below) here at USC had a telescope set up for all on campus to view:
(Oh no! another post from cvj about buses and trains and the environment to make us all feel bad?! Scroll away, scroll away!)
No.
Just a reminder about the transit of Mercury today!
The innermost planet passes across the face of the sun, from our point of view. At USC Continue reading ‘Mass Transit’
Well, you’re sitting there at the desk, so might as well put on the radio to keep yourself company. Do in on the web, and I suggest that you listen to:
Radio Lab episode #205
This one was about Space. It has a lot of good stuff in it: excellent speakers, very good clips, and playful (rather successfully, surprisingly often) presenters. My favourite bit? Neil DeGrasse Tyson being interviewed about our place in the universe. If you’re not an expert on the anatomy of the idea, please have a listen, since this is one of the best (and quite funny) layperson’s quick descriptions I’ve heard on the subject.
Tim Ferris (on the unlikelihood or likelihood of travelling vast distances for expeditions in space) and Brian Greene (on the geometry of our universe - another good layperson’s level chat) are also in this segment, just before. Direct mp3 file link to that particular piece here. Main link here for all the other really good segments.
-cvj
So I must apologize. I went to the preview of the Griffith Observatory so long ago now and did promise to blog about it with more than just one nice picture, but it did not happen. Partly because I had to go back across the Atlantic to do some work, and then got ill over the weekend I was planning to do it, and then...
Anyway, here are some of my thoughts. First note that my two week delay means that this is no longer a scoop, since even the LA Times had a spread on the whole thing on Thursday. A rather nice one as well. I urge you to consult it for a lovely pull-out graphic of the whole site. There is also a special website with picture tours, nifty 360 degree interactive shots of the spaces, and other information. The Griffith opened yesterday.
What they’ve done over the last four or five years is simply shut down the entire building and rethink and redo a great deal of it. How to preserve the lovely 70 year old landmark, while making it even better? Simple question - simple answer: Get $93 million for your project (I find this number, the earth-sun distance in miles, suspicious), and then go underneath the existing building and hollow out about the same amount of space that is has, but underground. Fill it with lots of goodies. And I mean lots and lots. What goodies? We’ll see.
Continue reading ‘Some Observations at Griffith Observatory’
“According to So Long, and Thanks For All the Fish, God’s Final Message To His Creation is written in fire in letters thirty feet high on the far side of the Quentulus Quazgar Mountains in the land of Sevorbeupstry on the planet of Preliumtarn, which orbits the star Zarss, which is located in the Grey Binding Fiefdoms of Saxaquine. The long path to the message is lined with souvenir stands at spaced-out intervals.When Marvin reads the message, it says, “We apologise for the inconvenience.” However, Fenchurch’s reaction suggests that the message she saw was the Ultimate Question of Life, the Universe, and Everything (and that presumably, therefore, the Message is personalized to each viewer).”
–Douglas Adams, The Hitchhiker’s Guide to the Galaxy.
Or perhaps this* is God’s Final Message:
When I was a child, I was fascinated with a straight line of three stars that were evenly spaced. Whenever I looked up in the sky, I would be comforted by being able to find those stars, especially when I was about to embark on a long walk home at night. I later learned that they were actually known as Orion’s Belt, part of the constellation of Orion. So Orion remains my favourite constellation.
These nights, Orion takes centre stage in stargazing circles since the Orionid meteor shower will be originating from a point near the constellation. Of course, Orion has nothing to do with the shower. It merely marks the apparent direction that it comes from (see red dot in image below).
(Above is the view of the sky looking Southsoutheast from mid northern latitudes at 3:00am today.) We will be traversing a debris field made of stuff left over from Halley’s comet’s tail. That stuff will rain down into our atmosphere, glowing brightly as Continue reading ‘Finding the Orionids Tonight’
Well, I’m back from the visit to the preview of the Griffith Observatory that I mentioned to you I was going to. It was a rather good visit. They organised it well, and -boy!- have they done a great job on the restorations! I’ll try and assemble the several pictures that I took into some sort of narrative for you, and report soon. While you wait, here’s one of my favourites:
This is particularly poignant, in my opinion. The children are looking at the lovely Continue reading ‘The Lives Of The Stars’
Ah! The joy of new colleagues! I have somehow forgotten to tell you one piece of the great news that we had here at USC Physics and Astronomy recently. We got three new faculty, and one of them is here in action (I’ll tell you about the others later), telling us about the physics behind the 2006 Physics Nobel Prize. This is Cosmologist/Astrophysicist Elena Pierpaoli:
She’s one of those people who works closely on (among other things) the data from Continue reading ‘New Colleagues’
Yesterday, I forgot to point you to the press release from the observatory itself. There, you will find more information about the opening, on November 3rd, and about how to actually get there. They are forbidding access to the parking lot, and so you either take a shuttle bus, or you walk or cycle. It is depressing to me that people are already complaining about having to walk up a small hill from the picnic sites below (people who walk up are generically referred to as “hikers”, in the press release, which would give someone the impression that you need special equipment or something just to walk up the hill. Sigh.).
Anyway, some chatter from the press release. Let’s start out with 4th District Councilmember, Tom LaBonge, a veritable Paul Dirac of understatement and wall-flower-hood:
“Griffith Observatory is one of the best public spaces in the world if not the universe…”
Oh yes. Good ol’ Tom. He makes statements like this all the time. How can you not Continue reading ‘Griffith Announces Opening’
From the press release:
The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2006 jointly to
John C. Mather
NASA Goddard Space Flight Center, Greenbelt, MD, USA,and
George F. Smoot
University of California, Berkeley, CA, USA“for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation”.
COBE is the experiment that really blazed the trail for all the wonderful physics that was to come from WMAP, and various other experiments such as Boomerang. And Planck is about to fly as well, giving even more precise information about our universe.
I was an undergraduate when this was announced. [Update: Oops...not quite: I had just started graduate school. Thanks Chad!] It was a wonderful feeling that all of us students had, partly gleaned from the feelings of our lecturers, I suspect. The thing that struck us as most appealing (I think) was the idea that the black body radiation spectrum (click on the image on the right for larger) that we’d been learning about in the abstract, during lectures, was sort of “out there”, writ large…. as large as can be in fact, on the whole universe! It’s always good to learn that physics -or any field- is still alive, especially when you’re still on the cusp of making a career in it.
Some more imformative background information (forgive the pun) from the press release: Continue reading ‘Physics Nobel Prize 2006′
As mentioned before, I am really excited about the re-opening of the Griffith Park Observatory. See this earlier post. [Update: See post about my viisit here.]
[Further Update: After reading the rest of the post, be sure to read the comments (starting here) for some commentary on the planetarium show since it was launched.]
[Yet another update: The discussion has continued to another post, with more contributions from various people concerned with the shows and the observatory, past and present. Link here.]
I’d noticed (on their site) the employment notice:
The Observatory will complete its four year renovation and expansion project in the Fall of 2006, with improvements including the new 200 seat Leonard Nimoy Event Horizon theater, doubling of the exhibit space to house more than 60 new and exciting exhibits, and new sound, lighting, interior dome and digital laser projection technology in the refurbished Samuel Oschin Planetarium theater. Employment opportunities will continue to increase as we approach our reopening date.
… and the job decriptions for the Museum Guide:
Job Qualifications
12 semester units or 18 quarter units in a recognized college or university in Architecture, History, Physics, Chemistry, Biology, Astronomy, Zoology or related field. Six months experience working in the above fields may be substituted for education.Job Description
Demonstrate and explain exhibits relating to astronomy and related sciences. Answer questions related to the observatory, astronomy and related sciences. May be asked to safeguard exhibits, and open or close
facility.
and thought it was ok (”may be substituted for education” was a bit worrying, but I think I know what they really meant), and assumed that the guides would be supplementary to more experienced staff who know more about the actual science, etc.
It seems I was wrong. A newspaper from the neighbourhood that the observatory is in, the Los Feliz Ledger, has a story (by Kimberly Gomez) entitled “Actors Get The Call Over Astronomers”. It seems that:
The traditional planetarium lecturers, who in the past led hour-long talks in the planetarium at Griffith Observatory, are upset that when the observatory re-opens this fall, they will be out of a job. According to four past lecturers, their position which traditionally required an education in astronomy, has been changed.
Continuing… Continue reading ‘Acting Up At Griffith Observatory’
Well, before disappearing into a long session of thinking about some funny behaviour my strings are up to (more later) I’d like to do a quick report on the departmental colloquium that I went to just now. We had Gary Zank, the Director of the Institute for Geophysics and Planetary Physics of the UC system (he’s based out of UCR) give us a talk entitled: “Particle Acceleration in Cosmic Plasmas”, and it was quite fascinating (and very well presented).
It is all about the physics of cosmic rays (here’s a NASA link called Cosmicopia for a little background on them). Here is a section of the abstract he sent to us prior to the talk:
An outstanding problem in astrophysics is to explain the origin of the almost featureless cosmic ray spectrum extending up to energies of some 1020 eV. A very small feature is apparent at between about 1013 – 1015 eV, the “knee.†In the late 1970’s, a suite of papers was published establishing the idea of diffusive shock acceleration for cosmic rays, essentially a first-order Fermi mechanism, which appeared to provide an explanation for the observed cosmic ray spectrum up to the knee. Diffusive shock acceleration is probably the most widely used particle acceleration mechanism in astrophysics and space physics, yet the theory is based on some stringent simplifications. The detailed [plasma] physics of the acceleration mechanism requires elucidation. We are fortunate in that very detailed observations of particle acceleration at shock waves, particularly in the guise of Space Weather, are providing considerable experimental insight into the basic physics of particle acceleration at a shock wave.
He gave us an overview of the remarkably detailed series of studies that his group has been carrying out (with the aid of an impressive multitude of computer simulations of the magnetohydrodynamics involved) in converting the various suggested acceleration mechanisms into detailed output that can be compared to experimental observations. Here’s a bit from their website:
The dynamical acceleration of particles at shocks waves propagating in the heliosphere is very poorly understood, yet shock waves are ubiquitous and almost all shocks are observed to energize ions and electrons. An understanding of particle acceleration at solar wind shocks has far reaching astrophysical implications. Furthermore, since energetic particles accelerated in either solar flares or in CME-driven shocks arrive at the Earth well before solar ejecta driven disturbances, an understanding of particle acceleration at interplanetary shocks is an integral part of the NSF and NASA Space Weather program.
He spoke quite a bit about shock wave mechanisms and how they work in supernovae Continue reading ‘Explaining Cosmic Rays’
I forgot to tell you about this. The name Eris has been officially chosen by the International Astronomical Union for the astronomical body so many wanted to be called Xena. (Keck image, left) Eris is the goddess of discord and strife, by the way. The moon of the body, that was tentatively called Gabrielle, after Xena’s sidekick in the TV show (Universal Studios image, right) will be called Dysnomia.
The Xena supporting community will be disappointed about this decision (watch out IAU, they have sharp swords, see image on left), but maybe comforted a little by the fact that Dysnomia is “a spirit of lawlessness”. Recall that Xena was played by Lucy Lawless. (Whatever happened to her, by the way? I think I recall seeing her briefly in something last year.) Anyway, there’s a New York Times article about it, by Kenneth Chang, here. It’s a rather nice account of the saga of the naming, by Michael Brown (of Caltech), who discovered Eris.
Pluto, as part of its initiation into the family of rubble known as the Kuiper belt (a mass distribution so important to understanding our solar system…see here), has been given a number. It is minor planet number 134340. I hope you can remember that. Eris has the number 136199.
-cvj
This is the penultimate line in an article today in the Science Times:
“Sometimes how the blood is splattered on the wall tells you more about what happened than the body,â€
It is a quote from Harold Levison of the Southwest Research Institute, in the context of understanding the origins and dynamics of our Solar System. The article is by Kenneth Chang, and a link to it is here.
It is a lovely article, focusing on the continuing series of discoveries being made about Kuiper Belt objects (e.g. Sedna, “Xena”, etc…), those cousins of Pluto that, thanks for better detection technology, have turned out to be quite numerous (click on image above… more of it at the NYT site):
More than 1,100 Kuiper Belt objects have been found so far. Astronomers estimate that half a million bodies larger than 20 miles wide are floating out there. At least one appears to be mostly rock with a coating of ice. Some are mostly ice. Some are less dense than ice, indicating a Swiss-cheese-like structure. A surprising number of them have moons.
Levison says:
“The more we learn, the weirder it looks.â€
It is quite a fascinating subject, a detective story full of wonderful science, and illustrates -as I have said earlier in the post called “Spinach Blogging”- how the “demotion of Pluto” story opens the door to so much active planetary science. It also illustrates why it it is interesting to keep an eye on the debate about the “demotion”. which is still ongoing. The nature of the Kuiper belt is teaching us a huge amount about the other bodies in the solar system. For example:
The distribution of Kuiper Belt objects has already provided decisive evidence that Neptune was once perhaps nearly a billion miles closer to the Sun and was then gravitationally nudged outward. Astronomers also hope that the Kuiper Belt preserves a frozen record of the earliest building materials of the solar system.
Another nice analogy from S. Alan Stern (of the Southwest Research Institute and Continue reading ‘Clues in the Blood Splatter Patterns’
I learned from New Scientist just now that various researchers working on modified gravity theories are casting doubt on the direct evidence of Dark Matter that was presented by Douglas Clowe and collaborators a few weeks ago. Recall an earlier post on it, here, and Sean Carroll’s post with more detail here.
Some quotes from the New Scientist article, written by Stuart Clark:
“One should not draw premature conclusions about the existence of dark matter without a careful analysis of alternative gravity theories,” writes John Moffat, of the University of Waterloo in Ontario, Canada
There’s more in the paper astro-ph/0608675, where there is an analysis of the gravitational lensing seen in the merging cluster observations. Recall that the it is the lensing that was used as a key part of the story to show the separation of the dark matter from the ordinary matter. Moffat claims that this lensing can be explained in his modified gravity theory, “MOG”. There’s a real calculation suggesting this, apparently, although a full computation is still in progress:
Moffat has worked this out for the Bullet cluster using a one-dimensional model, and is now trying to extend this to two dimensions. If he succeeds, it will contradict Clowe’s direct evidence of dark matter.
(In other words, Moffat has not worked this out for the Bullet cluster.)
In related work,
HongSheng Zhao of the University of St Andrews in the UK and his collaborators applied a theory of modified gravity called TeVeS to the Bullet cluster.
This theory uses at least one extra field, which kicks in to affect the modification when Continue reading ‘Bullet Not Silver?’
The BBC’s Radio 4 starts a new programme about astronomy tonight. Called “The Cosmic Hunters”, it sounds as though it will be rather good, so do tune in. It will be on Wednesdays at 9:00pm. It will be discussing various areas of recent research, using some of the optical telescopes that we’ve come to know and love (like the Hubble) and will also talk about future telescopes, such as the Webb.
There’s a little article written by the presenter, Chris Riley, here. It is as a sort of preview of the radio show in which he talks about the search for extrasolar planets and the hunt for the oldest galaxies, among other things. Of course, if you don’t get a chance to hear the broadcast, you can always go to the programme’s website to hear archived programs (for a short period).
-cvj
This is the lovely composite Hubble space telescope picture that is going around, showing the debris of a supernova - a star’s explosion. This is Cassiopeia A, and the explosion happened in 1680 AD, our time. See HST’s website for more on this , and discussion on the Bad Astronomy Blog.
In other supernova news, there’s a lot of news today (Wed) about a new supernova explosion, recorded this year (2006). This particular event is highly significant since astronomers were able to watch most of the entire event in real time. The thing that signalled that something was about to happen was a (relatively mild) gamma ray burst (GRB060218 - it was seen in Feb. 18th) picked up by the Swift telescope. After the burst (really it was an X-ray flash… a GRB’s younger sibling, as it were) faded, the star exploded -essentially on camera.
Quote from an AFP (via Yahoo News) article:
“Usually these events are not detected until after the supernova has brightened substantially in the optical wavelength, many days after the initial explosion,” said Keith Mason, chief executive of Britain’s Particle Physics and Astronomy Research Council (PPARC), which operates an ultra-violet/optical telescope aboard Swift.
“But on this occasion we were able to study the remarkable event in all its glory, from the very beginning.”
Other articles at the BBC (with images of the event - an article is due to appear in Nature tomorrow), and Reuters (via Yahoo).
-cvj
[Updated, see below.]
You’ll recall the news I reported about a number of members of the astronomy and planetary science community asking people to sign a petition to get the IAU to reconsider their Prague decision to accept the planetary definition that resulted in the “Pluto demotion”. See this link where you can find the precise language of their objection. (HST image of Pluto and Charon on right. Click for larger.) The short statement at the header of the petition itself is:
We, as planetary scientists and astronomers, do not agree with the IAU’s definition of a planet, nor will we use it. A better definition is needed.
Well, this is an update to let you know that they have gathered all the signatures that they wanted, from members of the scientific community. The petition is now closed. I don’t know if I’m allowed to point to the website where you can see the list of signatures (I hope someone will let me know), but I can report that there are 300 signatures (after a quick count), from a truly international group, from every continent, and from pretty much every astronomy department (or other institution) that I’ve heard of. [Update: I've got permission from Mark Sykes, one of the proposers of this petition, to make public the website. It is here, and has the list of signatories. There is now a press release there. If you're a member of the press, I imagine it might form the basis for an interesting story.]
Also on the website is the following:
I learned from an article in New Scientist by David Shiga that there have been recently found four more small satellite galaxies of our Milky Way galaxy.
The satellites are dwarf galaxies a few hundred to a few thousand light years across. The tiny galaxies are thought to be the building blocks of large galaxies, such as our own Milky Way – which is about 100,000 light years wide.
As you may know, we’ve known for some time that there have been such satellites (the number knwon has gone from 10 to 20 in the last two years, and some models expect as many as 50), but the small ones are very hard to detect. How do you distinguish them from other stars in the way? As part of the Sloan Digital Sky Survey (SDSS), the researchers have been looking for….
the particular types of stars expected to lie in dwarf galaxies, then detect the dwarfs as slight “overdensities” in these types of stars – patches of the sky where there are more of the stars than in surrounding areas.
The Cambridge team named them after the constellations in which they were found:
[...] Coma Berenices, Canes Venatici II, Hercules, and Leo IV, all of them lie between roughly 100,000 and 500,000 light years from Earth.
[...]The largest and smallest are Hercules and Coma Berenices, which are about 1000 and 200 light years across, respectively. Like most of the other dwarfs discovered by SDSS, the new finds are much smaller and fainter than the 10 dwarfs that were known previously, [Vasily] Belokurov [the team leader] says. “They should not really be called dwarfs – they are more like hobbits,” he told New Scientist.
Hobbits. Right. Does that make the Milky Way a Cave Troll? Or maybe a Numenorian? (Picture above is one of them. This one’s Farmer Maggot, I think. They’re not as Continue reading ‘From Dwarf Planets to Hobbit Galaxies’
…And from serious protests of the previous post to humourous (fictional!) ones.
Go check out the Worth1000 photoshop competition on the subject, linked here.
Some of them are great! Here’s one I liked:
Creator’s caption: “Don’t argue with him, the man’s a genius.”
-cvj
