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if there are billions & billions of galaxies and stars, why is the space so empty where if you are inserted into space in random, the chances that you might find a galaxy is 10 to the power of 33.

2007-02-12 21:03:29 · 6 answers · asked by tarki 1 in Science & Mathematics Astronomy & Space

6 answers

In the beginning, there was not yet any matter. However, there was a lot of energy in the form of light, which comes in discrete packets called photons. When photons have enough energy, they can spontaneously decay into a particle and an antiparticle. (An antiparticle is the exact opposite of the corresponding particle--for example, a proton has charge +e, so an antiproton has charge -e.) This is easily observed today, as gamma rays have enough energy to create measurable electron-antielectron pairs (the antielectron is usually called a positron). It turns out that the photon is just one of a class of particles, called the bosons, that decay in this manner. Many of the bosons around just after the big bang were so energetic that they could decay into much more massive particles such as protons (remember, E=mc^2, so to make a particle with a large mass m, you need a boson with a high energy E). The mass in the universe came from such decays.

The next question to ask is: where did all the antimatter go? For each particle created in this fashion, there is exactly one antiparticle. In this case, there should have been exactly as much antimatter as there is matter. If that were true, when the universe had cooled somewhat each particle would have found an antiparticle and combined to form a boson (this process is called annihilation of the particles). Actually, this was the fate of most of these pairs--something like 10 billion particles annihilated for every one that survived. The survival of even such a small fraction was enough to form all of the matter in our universe. At some point during this process, something else must have happened to cause the survival of more particles than antiparticles (we call this the particle-antiparticle asymmetry).

There are many theories that try to explain this asymmetry. I will give a very brief description of one of them, called electroweak baryogenesis. (Understanding it requires a lot more background information than I have space for.) Protons and neutrons are particles called baryons, and baryogenesis means the creation of baryons. The current understanding of particle physics, called the standard model, dictates that nowadays the number of baryons is nearly constant, with only a small variation due to quantum mechanical tunneling. In the early universe, however, the temperature was much higher, so that this tunneling was commonplace and a large number of baryons could have been created. Electroweak refers to the time period in question, when the electromagnetic and weak forces were decoupling from a single force into 2 separate forces (between 10^-12 and 10^-6 seconds after the big bang--the asymmetry probably would have formed towards the end). An additional source of baryons is due to the fact that leptons (another type of particle, including electrons) can be converted into baryons at this epoch.

2007-02-12 21:39:53 · answer #1 · answered by Sporadic 3 · 0 0

I recommend that you look at Ian Ridpath's Book,
ASTRONOMY, DK Publishing, NY, NY. Page 48
begins a discussion of the ORIGINS and the Big Bang.
Many excellent drawings and color illustrations of the
possible scenario are presented there.It is the best
current model of how the universe began. About 13.7 Billion Years ago the universe came into being in a
violent explosion. To understand what might have occurred before that time and collected all that matter
together for such a possible explosion you must understand the life cycle of Stars. To do that, go to
the same book, ASTRONOMY, and you will see many
illustrations of the various kinds and sizes of Stars,
their life cycle from birth to one of three possible destinies: Black Dwarf, White Dwarf, or Supermova
Detonation and Black Hole. Red Giant and Blue Giant
Stars are the most massive stars of all and quite probably the universe as we know it originated from the detonation of one of these. Please study how stars burn and stay hot until they reach a point where there is insufficient fuel to continue the fusion process. At that point they begin to expand, and expand, and expand, consuming everything - everything into their center core. If they consume enough material into their core they will explode. There is your Big Bang.

There are many books on the subject which may be obtained at a library near you, but you must read and
study the concept at length because it is very complex.
Any theory that attempts to consider "all" of the matter within the universe is going to take an open mind and
comprehension of vast numbers to understand. I don't
think it is wise to glance at the idea and begin asking
questions...read more...study more and then possibly
you can grasp what is being suggested might have happened. 13.7 Billion Years ago is a very long time ago.
Certainly it was ages and ages before the first life forms developed, so no one knows for sure exactly what happened. And, more to the point of your question, who
is to suggest that there was not a universe of some kind prior to the Big Bang, and it all just collapsed one day??? In simple terms, you can look at what is happening today and reason backwards to some reasonable extent. Prior to that is only a guess, however intelligent the guesser is. Anyone, who suggests that all this gas, matter, heat and light came about out of nowhere, at the snap of a finger, has obviously not studied the universe at all. Please do not dwell on "before" the beginning and spend your time more effectively in understanding what is out there today that can be observed and measured, and even possibly photographed (if they ever get the Hubbel Space Telescope repaired and working again). Keep in mind that we still have two or three deep space probe sattelites far, far off into space sending data back to Earth. Pioneer I and Pioneer II have stopped working, but there are others out there. More discoveries are coming in each day.

2007-02-12 22:37:40 · answer #2 · answered by zahbudar 6 · 0 1

The space is empty as result of the Universe expansion. All matter and energy was created at the Big-Bang instant, and then the space suffered an huge inflation.
But actually it is not so empty as it seems. Now astronomers and cosmologists are realizing that almost 90 percent of the matter of the univers in dark, what means that it is there but it is cold enough for not emitting radiation, so we cannot see it.

Matter required for the beginning? Well, it is believed that the Big-Bang started as a quantum fluctuation in the vacuum. According to the indetermination principle of Heisemberg, energy and matter can sprout from nothing (from quantum vacuum, physically speaking).
I hope I made me understood, I am aware my english is poor.

2007-02-12 21:39:35 · answer #3 · answered by Jano 5 · 0 0

That is one of the main reasons why the Big Bang theory is wrong. The other is, what existed before the so-called big bang took place ? The only other theory which can accommodate both of these arguments is: "The Steady State Theory". At least this theory maintains there was no beginning or ending for our Universe, thereby eliminating the problems of what existed before the big bang and where were the materials required for the big bang to take place if there was no time and space !

2007-02-12 21:32:06 · answer #4 · answered by Anonymous · 0 3

The universe came from nothing.
This much easier to believe than that it was some primordial egg that sat somewhere,contained all the mass and space in the universe and then,some way exploded into what we experience to-day.
The single space-time pulse is much more plausible and easy to swallow.

2007-02-13 02:10:04 · answer #5 · answered by Billy Butthead 7 · 0 0

this is one of the limitation of the Big bang theory. there are some limitations with steady state theory also like how the universe has existed? so both of the theories have some limitations. but steady state theory has less limitations than big bang.

2007-02-12 22:35:47 · answer #6 · answered by Ray 2 · 0 1

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