Astronomy and Cosmology

While reading here, I saw someone say that the universe had a beginning called the Big Bang. I can't remember which thread. I have a problem with that. If there were to happen, then there must be some sort of matter. And if matter cannot be created or destroyed then matter must exist throughout all time making the universe infinite. If the universe were to have a starting point, then where would the matter come from?

I was sitting in physics class, and we were talking about orbiting objects, satellite's, and I thought to myself, what would it take to make my own satellite and put it into orbit. What will it do? Not much...maybe take a few pictures if its not hard to do, and then maybe just be like Sputnik and send back beeps every now and then. So, It would serve little to no purpose, and it would be extremely small. It's just the fun of building it and getting it up there. But what would the materials include? Estimated cost? Size of a rocket for a Sputnik if not smaller sized satellite? Are civilians even allowed to put their own satellites into orbit? It just seemed …

Why are we only able to see light that is traveling towards us? For example, if you look into a flashlight, you will see the light that is coming from it. However, if you look in the direction the light is going, you will not see the light going away from you. The only way you will see the light is if it comes back to you by reflecting off of another surface. In the same way, we are only able to see light coming towards Earth from distant objects. We are unable to see the light that is coming from Earth and going out into space. Would it be possible to somehow capture light that is leaving Earth and look at it? Could we create some type of telescope that can see…

Life must all be the same age, This I believe as the big bang happened at once. Development is at a different age...

We think that in an era some 300,000 years into the cosmic expansion, there was sufficient cooling that electrons joined protons in stable, neutral atoms. The other great change at this point is the decoupling of light which was previously caught in an interactive dance with the charged particles. I am looking at the possibility of fractional photons and they have a very different history. At earlier stages where states of higher energy (protons, etc.) condensed, there would have been the decoupling of the fractional part of the energies at those and higher levels. This is a much earlier freedom and is surely important to cosmic evolution at those earlier stages.

This is a question I came up with after I finished the book "Hyperspace" by Michio Kaku. Hypothetically, suppose humanity survives, prospers and actually explores space. Also suppose that we are able to survive for millions upon billions of years. Going through a few evolutions along the way we eventually become a class III civilization on the Kardashev scale. We master and are able to collect all energy from our galaxy. Now, suppose that we survive up until the universe begins to end. This is where either the universe contracts in on itself ending in a singularity (the big crunch) or the universe continues to expand ending in where everything hits absolute zero (…

Can anyone link me to a page showing detailed chemical analysises of iron-nickel meteorites, right down to the rare earths only occuring in a few ppm? I found some on the net a year back or so, but now I cant find the damned sites anymore! best regards, Michael

Hi everyone! Does anyone have any information about the current theories behind the why the CP violation occured? I am interested and I can't seem to find a lot of information on the subject. Cheers, Ryan Jones

Why is this so?????

Today in Earth Science me leaned about how our universe is heliocentric (duh) but still he had to teach it. He gave us a list of reasons why we know that the galaxy is not geocentric. One of the reasons he gave us was that the heliocentric model was a lot simpler than the geocentric model and simpler is usually right. Why? just because something is simple doesnt make it correct. I just thought that this was really dumb reasoning. Can anyone explain why if something is simpler it is more likely to be right?

http://physicsweb.org/articles/news/10/4/15/1?rss=2.0 It is an important question about solar system dynamics. The rotation axis of certain planets are tilted at unexplained angles. This guy has a theory. It might help understand some more of the history of formation of the planetary system.

I'm currently studying energy transfers e.g (very basically) chemical energy used for lifting something onto a shelf, which transfers to kinetic energy and once on the shelf has potential gravitational energy due to the height increase relative to the earth. No energy has been lost but conserved. Now if hypothetically a black hole appeared below the shelf...and the object fell into it...with the absence of a mass to transfer the energy from the object, wouldn't the gravity be applying constant work (constant acceleration) and obviously this would increase the kinetic energy...I can't fathom how the rules of energy convservation apply to black holes. Surely the ene…

If planets die and loose their water and life, become a barren planet. Were does the water go?? does it beak down into its atom state or what??

Just another thought... if a planet did die and the water turned back into its atom state, does that mean there are lots of hydrogen clouds in space??

Some believe that soon this universe will end (or begin…lol) with a big crunch. I just cannot understand how everything in the universe can just form into one single point. Here is my simple example: If I take a + and – magnet and throw them at each other, sometimes the will stick together and sometimes they will fly away from each other. The magnetism symbolizes gravity. Well, thanks if someone could answer this.

I was looking around for information on Universe finite/no boundary theory and got this site. http://www.ians.org/big-bang-infinity-expanding-space.html It seems some what valid to me since I know nothing much about physics..period, well comparatively I guess. "The Big Bang So we've established that the universe must have a definite starting point. Could that have been an explosion of some kind, like the big bang theory suggests? It seems possible, but unlikely. As the theory goes the expanding energy from the initial conflagration eventually cooled and matter formed. Sounds simple enough, maybe too simple? As the universe expanded and matter condensed out…

I'm trying to get a layman's understanding by what is meant by "Space Time is curved or flat" From my readings, space time has 10 dimensions; from my perceptions, it has 4 dimensions. I'm gravitating toward conceptualizing space time curvature and flatness in the following way: A 2-dimensional object such as a sheet of paper (ignoring its thickness) becomes curved if it is distorted in the 3rd dimension. A 3-dimensional object becomes curved if distorted in the 4th dimension (leading to things like a Klein bottle). Thus, an n-dimensional object becomes curved by its distortion in the (n+1)-dimension. Similarly, an n-dimensional object is said to be flat …

If for example a star that you want to travel to is 28 million light years away. From the perspective of the people travelling on the ship, travelling at 99.99% the speed of light. Would it take 28 million light years to get there or a much shorted time. It would be 28 million years for those of us on earth not travelling though right? Thanks

What with the recent support for the neutrino mass, even if it is very very small, I was wondering if this gives us enough mass in the universe to close it. I think closed is the right term, when there is enough mass in the universe to have the expansion of the universe slow down and reverse because of the pull of gravity. I thought we had like, 85% of the mass necessary to have such a universe. Does the neutrino mass give us any?

I would like to add a couple of things that popped into my head stemming from the cosmic microwave background. When the BB expanded there was a period of time when the mass was opague to radiation. When hydrogen finally forms a transparency appears. I am fine with this. Some additional considerations are connected to the outer surface of the expansion. When everything was small, yet expanding, the matter of the universe had a maximized surface area/volume ratio. Although I can see the volume being opague for the early expansion, shouldn't the outer surface area, but seeing empty space, have radiated energy into empty space. The amount would have decreased as the surf…

The earth's magnetic field is assumed to stem from convection in the molten or liquid iron (nickel) that surrounds the solid iron (nickel) core. This is actually a very reasonable theory. A logical side affect would be the solid iron core becoming polarized magnetically within the magnetic field direction created by the eddies, just as a piece of iron will become a magnet if it spends enough time in a magnetic field. The electrons within the iron will line up with the magnetic field. The earth has been shown to reverse its magnetic field with north pole becoming south and vise versa. Based on the logic of the first paragraph this would imply the convection somehow re…

I would like to show how it is possbile to create a red shift without requiring relativistic speeds. If we took a balloon of nitrogen gas into space, that is heat to give off a certain IR signiture, and then popped the balloon, the expansion into space will be endothermic, due to the entropy expansion, and the IR wavelength signature would expand to reflect the lowering in temperature. Even nitrogen gas heading toward us would appear pseduo-red shifted. If we use superheated water vapor instead and popped the balloon, the expansion will also show a pseudo-red shift. If there was enough water, the hydrogen bonding would cause a smaller scale enthalpy contraction into …

http://news.yahoo.com/s/afp/20060404/sc_afp/spaceastronomyoffbeat_060404000657

The CMB is generally is considered a remanant of the eariest expansion of the universe. There is another explanation for the CMB. In simplest terms, it stemmed and is still stemming from the stars and the galaxies. This would also explain why it is everywhere, with irregularities being due to the distribution of stars and galaxies within the universe. Below is a microwave image of a galaxy. Microwaves work similar to electron fields and affect charged atoms, molecules, ions, and particles. When we microwave water, the dipole charges (oxygen and water) cause the water molecules to rotate in the microwave field creating friction heating. If we look at our sun, the…

I read that people can measure stars using paralax , but only if the stars are within 400 light years away. But How do we measure stuff further away. Is there more then one method to measure far away objects? Reason i am asking is that a guy i was talking to told me, that scientists can only measure stars accurately using the parallax method, and anything further then that are just "guesses". I knew he was wrong, but i didnt know how to reply to him. So yeh i would really like to know some info. ps Does redshift have much to do with it?