astro
catdynamics | June 14, 2007EADS Astrium, the European conglomerate that builds the Ariane rockets has come up with a concept vehicle for suborbital flights
Hybrid jet and rocket plane about the size of a business jet. Capable of suborbital hops, allegedly, like the Rutan's Space Ship One
Nominal market is high end tourism at about 1/4 million $ per pop. 4 passengers for 3 minutes of free fall. Astrium unveiled a mock up of the forward section at the Paris airshow.
Sounds like it is currently a power point project, they're looking for investors to build - ie they won't risk the company's capital or credit.
I'd have…
catdynamics | June 13, 2007My earlier rumouring was false, I hear third hand that the NRC committee on Beyond Einstein has not consolidated their reporting and sent it to the NRC, they are having one more meeting right about nowish.
Interesting.
Still due to submit to NASA Sep 8th, with an announcement on Sep 9th from Griffin.
We'll see if NASA still has any of that money left by then...
catdynamics | May 31, 2007It is a Blue Moon tonight at 9 pm Eastern.
For some of us, but not everyone, strangely enough.
At least if you're in the Americas. Rest of the world sees this full moon, on June 1st and has a blue moon in June instead. They have full moons June 1st and 30th, whereas the US has full moons May 2nd and 31st.
That is even rarer than a normal Blue Moon, but not amazingly so,
catdynamics | May 30, 2007Interesting short opinion article in Wired
Gregg Easterbrook provides a sensible short list of what NASA priorities ought to be and contrast them with the reality.
Interesting reading, and some good points.
I don't know if Mike Griffin's thoughts on climate change will endear him to Easterbrook, but Griffin does rather clumsily raise an interesting point that we should return to.
catdynamics | May 30, 2007Why do black holes stick around in galaxies despite their violent dynamical history?
A brilliant young postdoc has an answer!
Dr Bogdanovic has a nifty press release on why black holes do tend to stick around in galaxies
Recent results in numerical relativity have shown that the gravitational radiation reaction is strong and asymmetric.
What this means is that when black holes coalesce through gravitational radiation emission, the final stage of emission is asymmetric, and if the black holes have different (but not too different masses) or different spins, there is an impulsive recoil to the…
catdynamics | May 30, 2007
Click through for high-res version
From Mathias Pedersen, with permission
This is excellent, even got the planets accurate and as close to scale as one might manage.
Good stuff.
catdynamics | May 29, 2007You have got to like a book which concludes with a tale from the Edda...
"Traveling at the Speed of Thought" is a new book by Daniel Kennefick on the history of the search for gravitational radiation.
It is a compact little book, at just under 300 pp.
Princeton University Press
ISBN-13: 978-0-691-11727-0
Daniel knows of what he writes, as a physics PhD from the Caltech Theoretical Astrophysics group (disclaimer: so was I, and I overlapped with Daniel by a year or two).
In addition to his work as a historian of science, he has also published a number of papers on gravitational radiation and…
catdynamics | May 29, 200728 new planets announced at the AAS summer meeting
it is the Berkeley/Carnegie/Australian group - interesting bunch, including mostly Jovian planets with orbital radii greater than 1 AU.
Several are around G-subgiants, which are mostly descendants of A and F stars, somewhat more massive than the Sun (mass estimates can be hard for those stars) , four multiple planet systems and three planetary systems containing a brown dwarf as well as planet.
Hm, the most interesting new one seems to be missing from the list... I guess we'll get a separate announcement on that one.
Good haul, not done…
catdynamics | May 29, 2007Not satisfied with having conquered the 17th century canon, the Astrophysical Data System has a new (to me) feature...
The ADS now lists proposals.
A colleague of mine found this by accident, when he came across the phrase "all important" in an abstract. This is a curiously immodest turn for a paper, but it turned out to be an XMM proposal... like this one
Wot?
A quick browse revealed a shocking number of "all important" entried in ADS, and the 2006 proposals for XMM and Chandra and NOAO
Cool.
Now, NASA usually publishes successful proposal abstracts as a matter of policy, if you know…
catdynamics | May 28, 2007So the "possibly habitable planet" probably isn't, as a number of people pointed out,
but the outer planet in the system may be, given some optimistic albedo and greenhouse assumptions
There was an interesting discovery last month, of a "super-Earth" formally within the habitable zone of a nearby star.
As a number of people pointed out, the habitability assumption was not really consistent, it looked more likely to runaway to a Venus like state if it had water and atmosphere.
Now there is a short formal analysis, but they also point out that while GJ581c may not be habitable, the outer planet…
catdynamics | May 27, 2007PulsarAstronomy.net
wiki based pulsar resource.
Catalogs, preprints, links to the people and institutions.
Go wild.
catdynamics | May 22, 2007There is a most curious paper out on CU Virginis
CU Virginis is a magnetic chemically peculiar star about 250 light years away.
By peculiar, we mean it has significant overabundance of some elements (factors of ten or more), and the surface composition is visibly inhomogenous and variable.
It is rotating rapidly, period of just over half-a-day, and the rotation axis is approximately orthogonal to our line of sight, while the magnetic field is dipolar, off-center, and approximately orthogonal to the rotation axis.
There is strong radio emission from the stellar magnetosphere, and as it…
catdynamics | May 20, 2007Do not invite me to observatories - I have the Pauli effect
The Green Bank Telescope is very pretty.
But I'm not going to get to see it move...
seems it just broke.
Just a little bit. I'm sure they can fix it soon...
Could be worse, at least the mountain is not on fire.
catdynamics | May 17, 2007I was shown this today, and it totally rocks.
ADS archives have gone back, just a wee bit...
The Smithsonian/NASA Astrophysics Data System, ADS, is one of the most amazingly useful and comprehensive scientific data bases on the planet.
It covers all the major astronomical journals, including electronic or scanned images of essentially all the articles, as well as links to all the major online astronomical databases - including searchable and browsable images and links to published data by object.
Now, if you go to ADS and enter just a data in the "Publication Date between" field - in the…
catdynamics | May 16, 2007The amazing Swiss team (Gillon et al A&A L in press) have another amazing planet pick for us...
...as pointed out to me by Dunkleosteus in the comments.
Greg at systemic has the full story
This is a good one, with all the ingredients - and the competition aspect also.
Teaches us to a) read astro-ph when it comes in at night, not the next morning and b) always follow up your hot RV detections with systematic transit surveys.
So, what have we got this time?
Gliese 436b - an 23 Earth mass planet around a nearby M star (0.44 times the mass of the Sun). It has a 2.6 day orbital period - it…
catdynamics | May 16, 2007Ringlike dark matter paper is out.
But Chad explains the essence of the issue much better
catdynamics | May 16, 2007The Texas HET group has discovered a couple of very interesting new planets which have not received the attention they deserve, yet.
HD155358 is a 0.9 solar mass G0 main sequence star, it is about 130 light years away, it is about 10 billion years old, and it is now known to have two planets.
It is also metal poor.
Two planets, 0.9 and 0.5 Jupiter masses (/sin(i)), orbital radii of 0.6 and 1.2 AU and near circular orbits.
Stellar metallicity is about 1/5th of solar
Paper is in press in ApJ, I'll pass the link (ApJ preprint - subscription) along when I have access.
We know of over 200…
catdynamics | May 15, 2007Virginia Trimble's legendary annual survey of hot research in astrophysics is out
References are kinda annoying this year, first author only and no titles!
Ah well, I see at least one of my papers in there...
Always a fun read.
catdynamics | May 12, 2007experimental results show strong negative refraction in the optical
this could be very useful for astronomical imaging
Lezec et al report n ~ -5 negative refraction synthetic material that works in the optical (~ 500 nm) over a respectable bandwidth (~ 50 nm) (website and link here).
Negative Refractive Index materials were pointed out by Veselago (1968) and made concrete theoretically by Pendry (2000).
Shortly after synthetic metamaterials were constructed with the requisite properties at microwave wavelengths, demonstrating the reality of some of the more interesting properties such as "…