Astronomy and Cosmology

While trying to help someone else in another thread I posted a Link for them to go to. They were trying to draw a map. What intrigued me is the Great Wall of galaxy cluster shown. I started this new thread to see if anyone has any theories about it. This is the map http://www.astro.princeton.edu/~mjuric/universe/ This is more info about the Sloan Great Wall http://emystics.org/newscienceparadigms/astro/great_wall.htm

this is a lively ongoing line of research in LQG a new paper by Bojowald et al just came out this month http://arxiv.org/gr-qc/0503041 A black hole mass threshold from non-singular quantum gravitational collapse Martin Bojowald, Rituparno Goswami, Roy Maartens, Parampreet Singh 4 pages, 3 figures Report-no: AEI-2005-020,IGPG-05/3-3 "Quantum gravity is expected to remove the classical singularity that arises as the end-state of gravitational collapse. To investigate this, we work with a simple toy model of a collapsing homogeneous scalar field. We show that non-perturbative semi-classical effects of Loop Quantum Gravity cause a bounce and remove the classical…

Hi all, i'm not sure if this is the right forum for this but i think its more of an astrophysics question. Can somebody please give me the gist of dark matter/ dark energy? Is it like antimatter or what? Thanks in advance ~Scott

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Just a personal possible theory here. But what if instead of out of nothing came the Big Bang, that the Universe was just one Big Solid Mass with no Space. Then at some point a fracture occured. So therefore all the Mass we see has always been. The Space inbetween is what's new. Sorry for the lack of scientific terminology here.

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If not what is a planetary body? What do we consider a plantery body?

http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Riemann.html to be accorded the right to lecture at the university Riemann had to present a talk on something he prepared 3 lectures, two on electricity and one on geometry, and he let Gauss choose which he should give Gauss chose the one on geometry this talk was on the foundations of geometry and it showed how a space can have shape and curvature and all that good stuff without living in any larger surrounding space and without having any boundaries this talk was given in 1854 Georg Friedrich Bernhard Riemann lived 1826-1866. He was extraordinary creative, like Mozart, except it was in math ins…

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This might be the hardest question ever because it's questioning the size and dimensions of the universe. If the universe is infinite (space-time is flat and Euclidean), this simply means there never was a big bang at all. But if the universe is finite (space-time is curved and elliptic) but unbound (eternal but not infinite in size) then we, as 3D creatures, will never be able to see what lies beyond. A NewScientist article implies that the universe is finite but unbound.

Earth years - is this true or false.

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Does anyone know; were the Dinos the first walking animals on this planet? I believe they survived about 50 million years is that right? And I'm really confused to as how long have we've been around... some say only a million years yet fossils say we've been around for about 4 million years does anyone out-there know for sure?...us.2u

measusing changes in the apparent wavelength of lines in their stras spectrum (the radial velocity method) True or False?

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Take a look at these pictures. I hope everyone can access them, they came off the AOL home page. http://rl.channel.aol.com/space/hubblegallery Edited: I checked it from the Foxfire browser and it seems that you will need an AOL screen name--sorry.

Why can we not use the direction of other galaxies that are moving away from us and the speed they are traveling to triangulate the origin of the Big Bang. I mean all galaxies are most likely to still be moving away from the Big Bang which means if we can identify only a few galaxies to our so called Northe south east and west, and the speed and direction from us and us from them, We should be able to determine which direction all of them are going and triangulate the origin of the Big Bang. Right? We need to clone Einstein. \ . . . . / \ . . . / …

The standard big-bang cosmology is based on the cosmological principle, which assumes that the universe is homogenous and isotropic on large distances. We use the FRW metric. Since cosmic inflation is getting slight support, why do cosmologists estimate that the acceleration began roughly 5 billion years ago? If so, what hapanned before that which caused the universe to decelerate?

hi im currently studying physics in grade 12. I have an assignment due at the end of the week which asks for the most important discoveries to the model of the solar system/universe. The major events in history i am aware of i.e. the invention of the telescope and Keplers 3 Laws of Astrophysics, but i am unsure of the importance of the lesser contributions to the model. I would appreciate any contribution to the importance of the developments in the model of the solar system/universe.

i know about the expanding universe, and does that relate to the big bang? is the big bang still going on? is the 'expanding universe' just the big bang still continuing? + i heard that when the big bang began it exploded faster than the speed of light. And if the big bang is still happening, that means the 'end' of the universe has no light, is that possible?

First Nasa decided they don't have the money to keep the Hubble up and running and now Nasa is looking to scarp their currently operating unmanned missions. It's discussed here in this article. I think it's very sad that we could loose these probes right when the data they are returning is coming so close to fruitarian. We have the Voyager probes, which already have proved useful in finding error in classical Newtonian gravity, and are just now approaching the heliopause. Considering it's taken 30 years of funding to get them this far, why not wait until after we know how thick the heliopause is before we cut off all communications? The Ulysses is a sola…

I posted this in another thread without response, so I'll try again: What is the current explanation for why random particles within a nebula would in fact be drawn together towards an empty spot in space to eventually form a planet? What is the "motivation" so to speak for random particles to form together at some arbitrary point?

I want to know whether or not the universe has a center of mass. Is there any experimental fact that dictates that the universe must have one? Thank you

The universe is expanding in all directions. It is not the galaxies that moves away from each other, but space itself who is expanding. Space is created between the galaxies. What was a million light years long is a million and one light year long. (You can use Hubble constant to know how long it takes) Here on earth we don't feel this expansion and we have no clue that this expansion is happening in our galaxy. Why ? Is it possible that is because the earth and all other masses in the milkyway "eat up" that space created by the expansion ? Let suppose that's the case: The universe is expanding and all masses eat up that space. The bigger the mass the more it ca…

The March '05 issue of Scientific American has an interesting article about misconceptions regarding the Big Bang and the expanding universe. The full article is now available on their web site at: http://www.sciam.com/article.cfm?chanID=sa006&colID=1&articleID=0009F0CA-C523-1213-852383414B7F0147 Here are some of the more interesting bits: Question: What kind of explosion was the Big Bang? Wrong Answer: The Big Bang was like a bomb going off at a certain location in previously empty space. Right Answer: It was an explosion in space itself. The space we inhabit is itself expanding. There was no center to the explosion; it happened everywhere. T…