What model of the origin of the universe believes that the universe expands?

Answer 1

Obviously, there are many theories of how the universe formed, but personally, the universe formed from the result of a black hole, that sucks in matter, and that matter has to empty out somewhere, and it does, as a "white" hole, and that explosion is known as "The Big Bang".

Answer 2

well you could go with god creating it or there the bid bang theory which happened almost 14 billion years ago.

According to the scientific community, all the matter in the universe, as we know it today, began in a very tiny, hot and compacted point.At the moment of the big bang, the point began expanding like a balloon, versus the long-held misconception of an actual explosion. As the point of matter expands, which it continues to do today, it cools, contracts and forms stars and galaxies.

Answer 3

Stars themselves may expand or contract; usually, they remain at more or less the same diameter for a long time.

Perhaps you were confusing this: mainly, what is expanding is the Universe - the distance between galaxies is inreasing.

Answer 4

It's all due to hydrostatic equilibrium. [See related question] As a star looses mass due to nuclear fusion, the pressure gradient increases against the loss of mass. Thus expanding the outer shell.

Answer 5

Good question, although for most questions about astronomy and cosmology we don't have very many answers to the question "Why... " We observe facts, and then we generate explanations; then we look for more facts to either refute or reinforce our explanations.

We believe that the universe began in a titanic explosion called the "big bang" about 14 billion years ago. (Estimates vary; it could have been a billion years more or less ago.) We can see, based on the red shift of distant galaxies, that very distant galaxies are going away from us, and with increasing speeds depending on the distance. We have no way of knowing of those distant galaxies are STILL moving away from us; based on the speed of light, when we see very distant objects, we're actually looking at the objects as they WERE when their light was emitted from them.

Answer 6

The term dark energy is an unknown force that was invented to try to explain the acceleration in the expansion of the Universe.

In the traditional model the universe expanded hugely in the so called inflationary period. It was then thought that the expansion should be slowing down due to gravity. Studies of type 1a supernovae however seemed to contradict this.

A type 1a supernovae occurs when a white dwarf becomes more massive that 1.38 solar masses (the Chandraskhar limit) and becomes a neutron star. Since this is the same through out the universe we can quite accurately determine how far one is away from us by how bright the supernovae is.

When the red shift of various supernovae was examined it showed that instead of slowing down the universe started to accelerate about 3-4 billion years ago. The only explanation is some yet unseen force pushing the galaxies apart. Dark energy was theorised as a result.

Answer 7

A star is in a delicate and fragile balance between gravity, which would collapse the star to a point, and its internal pressure caused by the energy of the nuclear fusion reaction in the core. A star begins to collapse when the energy output decreases, and expands when the energy generated increases. It's a balance.

An "average" star such as our Sun will begin to shrink somewhat in about 3 billion years or so, when the hydrogen "fuel" begins to be depleted. The REAL problem isn't that there isn't enough hydrogen; it will be that there is so much helium, the "ash" left over from hydrogen fusion, that it will begin to interfere with normal fusion reactions.

The Sun will begin to shrink, as gravity starts to win the "tug of war" between gravity and energy. As the Sun shrinks, the internal pressure and temperature will increase. At some point, when the core temperature increases to about 35 million degrees, a new reaction will start happening, as the helium begins to fuse into carbon and other heavier elements. This will provide an ENORMOUS boost of energy to the Sun, which will then expand greatly - into a red giant.

Answer 8

Although we know that the universe is expanding, finding the central point of it would be almost impossible because such an expansion began fromthe condition of a singularity. You would expect that if you were to stand on this point everything would be speeding away from you. From our Milkyway this is true, we see all the other galaxies speeding away from us but that doesn't mean that we are the centre. If we traveled to any other galaxy in the universe, the galaxies including the Milkyway would be seeming to be traveling away from that galaxy.
Youmight find the centre if you knew where the edges of the universe were in relartionship to its beginning asa singularity. We only inhabit a small portion of the universe and have trouble seeing beyond the fog of the CMB. Sizewise, remember that there are millions of galaxies out there and even the smallest are several hundred thousand time the size of our sun.

Note: There is no known shape, size, or age for the complete universe; rather we only have the observable universe from which to make conjectures about the more complete universe. Subsequently there is also no real center to the universe, as it is expanding in all directions; rather the expanding universe isonly the unfolding of SpaceTime into varying evolutionary conditions. It is not a center which can be viewed, or even measured, as its very reality is subject of debate. It is this persistence that purports, in our dimensional measure of being, a flow of influence to and from center. Thus the notion of a universal singularity is derived, not from its focus of centricity, but from within its ambit of containment in Time. So it is not a fixed location in Space, but rather a fixed condition in Time. These are the conditions of our creation and termination. As you can imagine, our current interpretations for shape, size and age of the universe will forever remain a mystery and a constant miracle of discovery as we continue to further our knowledge.
As demonstrative of this concept, from the perspective of an inflationary universe, an analogous measure of these spatial sections can be abstracted as many balloons all inflating at the same rate of expansion within an infinite unknown void or abyss (rather than ust one balloon, as per previous visualization). To further expound upon this abstraction, imagine that all balloons are touching and that in the center of each inflating balloon there are observers. Subsequently each of these observers could then observe that every other observer was moving away from them as the balloons equally and simultaneously inflated their spacial sections. Noted in this analogy is that only the spacial sections are growing in size and not the observers; for if everything is expanding at the same rate, then nothing is measurable expanding. To this end there has been ascribed a commencement force for this expansion, explained as that hot dense plasma whose heat fueled its prevailing motivation for inflation within the medium of some unknown void. An analogous representation would also be akin to boiling rice, in which each spatial section was uniformly expanded due to this commencement force.

Answer 9

Unfortunately, nobody knows. The one thing restraining us from knowing is the distance and size of our GINORMOUS universe. Albert Einstein, the smartest man ever known, once said that it is impossible to travel faster than the speed of light. In our future generations, we will hopefully be able to prove Einstein wrong and discover the rest of the universe with the ability of traveling at the speed of light.

Answer 10

A star is a constant conflict between two forces, the explosive force of the nuclear reactions (think zillions of nuclear bombs) in it's core, and the force of it's gravitational field holding it all back.

As it's hydrogen "fuel" is gradually converted into energy and given off in the form of heat and radiation (the only form in which it can escape) the sun's mass diminishes, and it's gravitational force weakens, until in it's later phases it begins to expand and contract wildly, eventually either collapsing in or exploding out, or sometimes (if the star is big enough) exploding, then contracting in on itself and forming a black hole.