Astronomy and Cosmology

The Hubble Constant is the rate of expansion for the universe and according to a new study maybe off by as much as 15%. This may not seem that big of a deal but it is since this is needed to estimate the size and age of the universe. Here's a link to a podcast about it that has links to more information. http://hubblesite.org/explore_astronomy/skywatch/#66

A creationist friend of mine is claiming that the reason we see distant starlight is because there was a rapid expansion of the universe at creation. The universe expanded for about 2 picoseconds to its present size, and lightwaves along with everything else were stretched. This, he says, explains the redshift of distant galaxies. The farther the galaxy, the more expansion had to have occured, the more redshift (stretched light) we see. Is there a way to test this idea? I'd imagine there's got to be a way to measure the spectral emissions of distant elements, note the redshift, and calculate what kind of expansion could have created this redshift and see if it correl…

I don't know if this is the right section for this...I apologize if it's wrong. Nova: Magnetic Storm http://www.pbs.org/wgbh/nova/magnetic/ Transcript http://www.pbs.org/wgbh/nova/transcripts/3016_magnetic.html "There's a region of our planet that no human being has ever visited. No one has ever seen this place, yet what happens here affects every one of us every day of our lives. It's 2,000 miles beneath our feet, the Earth's molten core. Here a vast ocean of liquid iron generates an invisible force, the Earth's magnetic field. It's what makes our compasses point north. But it does a lot more: it helps to keep the Earth a living planet. Our neighbors, Venus…

I wanted to know if any of you are members of an astronomical society? Joining a society is a great way to learn new skills and to spread ones interest in astronomy. Maybe members would like to post links to their society? I am going to join the Manchester Astronomical society, which is one of the oldest societies in the UK. http://www.mikeoates.org/mas/

I recently saw the documentary, The Great Year, and toward the end they bring up the idea that our sun is actually part of a binary star system. Our astronomy class never covered such a concept, and the idea boggles my mind. Could this be true?

Is it possible for there to be a "twin-planet" situation? So that, a so called "planet" and it's satalite of near-equal size would orbit eachother in much the same way that binary stars do in binary systems? Just a thought...

I am from India and want to do certification in Astro Physics, but here in India there is no such organization offering so... Can you please give me any link of any such University/Institute/Organization offering the same online or via correspondence? I am very much keen to do same. Please also provide me some web links too...

http://news.bbc.co.uk/2/hi/science/nature/5407038.stm Yikes! Those planets must be incredibly close to their stars to be able to make such a quick orbit. Well I just tossed out a quick calculation, with a period of 1 day, a planet the mass of 10^27kg (around that of jupiter) around a star of mass 10^30 (around that of the sun) I get a semi major axis of just over 2 million km (!) and an orbital velocity of 27 000m/s (!!). I have to think that planets in such a position much have fairly short life spans, as massive as they are they must be getting a ton of their mass blown off by solar radiation. Or maybe not, what do I know.

John C. Mather and George F. Smoot are our newest Nobel prize winners in physics! unofficial rumor, have to confirm yeah! http://www.bloomberg.com/apps/news?pid=20601085&sid=a8k2ZYLGNxTE&refer=europe http://nobelprize.org/nobel_prizes/physics/laureates/2006/index.html The Nobel Prize in Physics 2006 "for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation"

hi! Do u know that U.S.A has 413 satellites in the space while the rest of the world has only 382 all put together. The figures released by the union of concerned scientist provides datails on some of the Pentagon's most secret satellites. The Russians, who follow U.S in otal number,have 87.The Chinese have 34. can any one tell that rest of the satellites belong to which countries???????? plz try finding i couldn't find!

http://www.arxiv.org/abs/astro-ph/0606266 Ellipsoidal Universe Can Solve The CMB Quadrupole Problem Campanelli, Cea, Tedesco Physical Review Letters, 29 September 2006 Physics News Update has an item about the Campanelli et al paper http://www.aip.org/pnu/2006/split/794-2.html?source=rsspnu would be very strange if it turned out right like Kepler for years everybody is assuming circular or spherical symmetry because that is almost right, and then some dude comes along and notices that it is not quite circular it is more like elliptical whoah! and this explains something about the CMB? maybe someone would like to discuss this.

this is not a puzzle in the sense of a game or riddle. It is a fact from astronomy that (if it is not already familiar) you might want to think about and get to understand In ordinary experience with earth-based geometry, the farther away something is the smaller it looks. That is true for short distance geometry done with metal rulers and yardsticks on the earth surface. But it is not true in space for very long distance geometry. In ordinary shortrange geometry there is even an approximate reciprocal relation between angularsize and distance that works for objects with small angular size. If it is TWICE AS FAR then it looks HALF AS BIG. If you double the dista…

can any one tell the formation of "white dwarf star"?

they haven't FOUND any habitable extrasolar planets the new NASA study just assesses the chances of eventually finding earthlike planets in systems with hot Jupiters http://news.bbc.co.uk/2/hi/science/nature/5325476.stm BBC: "Earth-like planets may be common" blog comment by astronomer (who partcipated in the new study) http://scienceblogs.com/catdynamics/2006/09/exotic_earths.php SEED magazing article: http://www.seedmagazine.com/news/2006/09/several_planetary_systems_may.php The main article got published in SCIENCE magazine, current issue 8 September. that is pretty good. Science magazine has decent editorial standards. Exotic Earths: Formi…

that "planette" bigger than Pluto, which Mike Brown of Caltech discovered and temporarily nicknamed "Xena" has now been given its official name, as has its little moon. As discoverer, Mike got to pick the names. It went into effect 13 September, yesterday. there was a circular sent out from the IAU Central Bureau of Astronomical Telegrams. As of today, the Wiki article has already been corrected http://en.wikipedia.org/wiki/136199_Eris Here is yesterday's announcement: scroll down to the dwarf planet section at http://cfa-www.harvard.edu/iau/Headlines.html or click directly on http://cfa-www.harvard.edu/iau/special/08747.pdf Eris is the Greek god…

How is the momentum of the expansion thought to be measured? Assuming there is enough matter present to create a "big crunch" is it assumed that space will "shrink" (or slow in expanding, stall, then shrink) to the same beat as would be consistent locally with a gravitational collapse "in" space?

Hi all, This might seem a silly question to you all, but what exactly determines the mass of an object, specifically the earth? Does the earth's mass include ALL its contents, i.e. does a new born baby contribute to the earth's overall mass? What about plants, cars, buildings etc. Are they all included?

It looks to me like the Schwarzschild metrics of a black hole (BH) yield a negative quantity for the square of light-speed for transverse waves inside the event horizon, and this says to me that they cannot propagate. Is this accepted understanding? Radially things are positive, at least.

Hi. I was reading a book recently, and it mentioned the Kuiper Belt, a big cloud of asteroids around the solar system, similar to the asteroid belt, but farther out. I was wondering what the difference was between this Kuiper Belt, and the Oort Cloud. There was a description in the book (Worlds Without End by John S. Lewis) but it didn't really explain much to me.

Hi all This weekend a man made satellite will crash on the moon surface and the flash created might be seen with a backyard telescope. Western united state are favored. http://sci.esa.int/science-e/www/area/index.cfm?fareaid=98 I think that may interest some people here !

http://www.guardian.co.uk/uklatest/story/0,,-6035526,00.html I think they made a mistake but I am glad they finally decided. The Prague conference of astronomers demoted Pluto

I read somewhere here (IIRC, I tried to search it but the search didn't work for some reason) that light intensity at astronomical distances stops falling off at the expected rate (I think it would be inverse squared combined with the redshift etc.) If I didn't dream this does anyone have an explanation or link?

a NASA press conference is scheduled for Monday 21 August (in about 4 days) to announce the first observations confirming that Dark Matter is real substance and not just a modified gravity effect Here are some pretty nice pictures. It is PDF of a talk Maxim Markevitch gave, scroll down to see the pictures. http://cxc.harvard.edu/symposium_2005/proceedings/files/markevitch_maxim.pdf the pictures show the two clusters of galaxies colliding, and the very hot ball of gas (ordinary matter) and then they show the LENSING BACKGROUND mapping the levelcurves of the dark matter density to show that the dark matter has passed through----and so has been spatially sepa…

Just something that I have been pondering for a while. Is it plausible that the big bang could be a localized phenomenon? Assumptions. 1)The universe is larger than we can imagine. 2)Gravity caused by the convergence of countless galaxies can create a very large unstable mass. (I don't know how this works so I'll ask below) 3)Big Crunches happen on a localized basis. 4)The unstable mass reaches it's critical stage and explodes. Existing galaxies in the region are pushed away if not destroyed. However, the event is localized. Does this sound plausible? Can Big Bangs be local phenomenon? It would explain the existence of galaxies/stars older than current sc…

I just received the latest copy of New Scientist and they had an article on the cyclic universe model (my favorite model). What I want to know is the percentage of scientists who believe in that model vs the other models. I've been reading about branes that collide every trillion years too and got to wondering about who believes in what.... Thanks Bettina