Astronomy and Cosmology

I have always been told that there is mostly matter in the universe(compared to antimatter). How does anyone know? They say if there was, there would be buffer zones. I thought there are rediculous distances betwenn heavenly bodies, so why couldn't there be antimatter galaxies?

The recent pictures from the Hubble Deep Space Field got me wondering. They are from a time when the Universe was only 700 million years old, some 14 billion years ago. What I don't understand is this. At 700 mill years old, the maximum possible distance between the observed Galaxies and Earth is 1.4 bill LY. So if the Universe wasn't expanding, then the light would take 1.4 bill years to get here. The Universe is expanding of course, so, since the light has to travel further, then it takes longer to get here. 10 times as long. Now if we were at one "edge" of the Universe and the Galaxies at the other, moving away from each other either side of the "centra…

Maybe this will stir up *too much* debate, but I find it interesting...and not just limited to Cosmology. When scientific topics are brought into focus (Physics, Astronomy, Cosmology, Oceanography, etc.), shouldn't it also be brought into focus that *nothing* can be considered *truly* scientific that relates to pre-historic/first-matter creation? Science is based upon facts, and since man was not around to record the facts in pre-historic "time", then anything before man-made records cannot be considered a science, correct? Any religious belief (or lack of) (Christianity, Humanism, Darwinism, etc.) all require the same thing - faith. It does not take faith without phy…

http://pancake.uchicago.edu/%7Ecarroll/hawkingdublin.txt this is a transcript of the talk Hawking gave today wednesday 21 July at Dublin GR17 conference describing his idea of how to resolve the BH info puzzle

There is life there? Time ago, on a publication, apeared that 4 years (or 8?) after the explosion of Krakatoa with was the most powerfull of the modern times, an strange explosion apeared on Siberia (or Russia forest). So the author talked about that maybe "someone" at Alpha Centauri solar system got this manifestation tought that was a message and reply it. Well the above is not a must, but the point here is that with the current technology we can travel there?, even if we sent a sonde at 1/4 lightspeed we had to wait 4 years minim (depending on technology and after wait 16 years) to get reports about?

A good up-to-date introduction to cosmology. For undergraduates in the CERN Summer Students program Author Julien Lesgourges organizes it clearly and simply---with lots of diagrams. I added it to the A&C Reference library that Alexa has been organizing recently, a stickythread for useful links. This is a keeper, might even want to print it out. ---quote--- http://arxiv.org/abs/astro-ph/0409426 An overview of Cosmology Julien Lesgourgues Lecture notes for the Summer Students Programme of CERN (2002-2004). 62 pages, 30 figures. Very basic conceptual introduction to Cosmology, aimed at undergraduate students with no previous knowledge of General Relativity …

Recently here in the U.S. NASA has considered discontinuing shuttle missions for repairs to the Hubble Space Telescope. It's part of a plan that would discontinue all shuttle use in hopes of using a new method for space travel. To me this is sad news. The Hubble Space Telescope has captured some amazing images from the galaxy, and the universe. My understanding is that it is able to take the finely detailed photographs because it is in orbit, and does not receive interference from the Earths atmosphere. Could new ground based telescopes ever be as great as the Hubble? There's no real official word that the repair missions are being discontinued but the plan that…

It was only traveling at 100miles/hour So much planning and then the parachute doesn't work. Press conference in about 1 hour.

I've gotten into a discussion about this with a friend who is of the opinion that it is impossible for any Earth like planet to exist without divine intervention. Although I am a theist also I do not believe this is the case but when pressed I realised I can't actually back that opinion up (in hindsight it was probably bad scientific form to accept that view without prior evidence, oh well, live and let learn I suppose). Some Googling has found me the opinions of Dr. Charles H. Lineweaver and Professor Barrie Jones but it's all in the form of new reports and articles. Does anybody know where I can find their material online or at least a mathematical overview of their wor…

Hi! It is said that as we look deeper into space we look in the past...we see younger galaxies and objects, which formed at an early stage of development of our universe...and here is my question... Does it mean that we could see "ourselves", our own galaxy when it was young...or follow its formation back in time?

Hey I think I've figured out 4th dimension speed. (speed of time) The big bang expanded the universe, throwing light in all directions, and also throwing the edge of the universe with it. So it must be conceived that the universe and all it's space are expanding at the same speed as that of light. So, c=u where "U" = the speed of the universe expanding, and "C" = the speed of light According to Einstien, space and time are the same thing. So, assuming the theories of Relativity and the Big Bang are accurate, the speeds of: light, the universe expanding, and time are all the same. C=U=T Where "C" = the speed of light, "U" = the speed of…

some people don't think so.... is this board.... like 99% geeks??

Why the planets are round ? Because they are revolving or because they are revolving inside some kind of walls(energy) walls?or because thing move in circular motion when they are inside something else?or some central force? MAB

http://education.guardian.co.uk/higher/sciences/story/0,12243,1302857,00.html The story says, in a nutshell, that both of the probes are experiencing identical change in trajectory not consistent with projections.

http://www.sky.com/skynews/article/0,,31500-13196489,00.html I read this a couple of minutes ago. pretty interesting, what does everyone think?

Severian mentioned this on another thread Very true. The 5th International Workshop on the Identification of Dark Matter[/url'] is on in Edinburgh next week. May be worth having a thread about current search going on for dark matter and efforts to map the presumed dark matter in clusters of galaxies by observing gravitational lensing of light coming from still further galaxies----from ones "behind" the cluster from our viewpoint. I went to the Edinburgh conference site and downloaded the programme. It did not mean a lot to me. there is obviously a huge amount of activity in observational astronomy around the dark matter thing. Also at Edinburgh they will be…

any good science experiments... that deal with space??? that don't require 2 billion dollars to do??? i need to do a science project...

Here it is The Great Internet Black Hole Survey; or a continuation of; which im sure will provide interest to many; (as taken from the book 'Black Holes a travellers guide') Please fill in your views 1.[Public or otherwise] Misconseptions [about black holes] 2.Public Fasination 3.Useful Function 4.Unsolved Problem [You would like to see found out] Thankyou

here`s a question asked by my wife, to which I have no answer. on the Moon Landing pictures and other manned pictures of space, there never seems to be any stars when looking at the black void of space, and yet here on a clear night we can see them? the Hubble provides pictures of mega distant galaxies, land based telescopes of many distant stars, and yet all manned space footage that we`ve seen seems to be without stars? is there any reason for this? Cheers

Just curious

A recent study conducted by Australian Astronomer Micheal Drinkwater at Siding Springs Observatory in NSW, has reveiled an unexpected abundance of Ultra Compact Dwarf Galxies (UCD's). These galaxies are tiny and had previously been misconcieved as stars in our own galaxy due to their minute size. However a detailed Spectroscopic analysis of the Fornax Cluster has shown that these objects are satellite galaxies, orbiting the Milky Way in intergalactic space. One of the suprising conclusions of the study has been that these UCD's may infact be more abundant than the more commonly known spiral galaxies and while they do not account for all the missing mass(each only con…

Acording to a science magazine, the people studing the cosmos finds the Andromeda`s Galaxy so similiar to ours that they think it is like a mirror. Maybe there are some kind of symetry on space, or that the galaxies form in the same way.

Hi all, this is my first post, and I hope you won't mind me taking the time to throw a fistful of questions out there concerning the effects of air loss aboard a spaceship. Though I am beginning to write a story that entails a Sci-fi setting, I can't claim to be a physics genius myself, but neither do I know if anyone has ever actually pondered what I ponder... I was wondering whether it would be catastrophic for a spacecraft to lose all or the vast majority of the air into space, not just in terms of what happens to the unfortunate passengers, but how that might affect the actual structure of the ship. Would it be something that destroyed the craft, or severly dama…

This is to be a true and false exam. The Moon... a mars like object crashed into us...and finally became the moon. Not only does the moon orbit us...be WE orbit it? The Moon, Jupiter, and Saturn may have all been instrumental in allowing complex life to exist, by warding off astroieds, meteorites? Passing Comets may have created our oceans? The Rare Earth theory is viable...cause we haven't found any complex life anywhere...yet? Are we the first? There is the Oort Cloud and Kuiper Belt..are they the same thing..and where are they located? While the might Zep has lots of passion, they aint got nothing on the Lad from Liverpo…

Second only to Nicole Kidman, I would pick Eta Caritinae. a relatively nearby star that could go nova at any time, I'd like it to be in my lifetime, but we shall see. http://www.space.com/scienceastronomy/astronomy/milan_eta_carinae_000307.html