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NeedBranes
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When our universe first started to expand, is it safe to assume that the energy inside of the expanding universe was traveling at the speed of light?
NeedBranes said:When our universe first started to expand, is it safe to assume that the energy inside of the expanding universe was traveling at the speed of light?
than your original post..energy right after the expansion of space
When our universe first started to expand...
NeedBranes said:The energy (or matter) of our universe, which is not presumed to have negative pressure or of any relation to inflationary energy, can all be traced back to a point in time, in our universe, in which it was massless. So it would be moving at the speed of light. Right?
osxraider said:I would say that the Universe expanded ridiculously fast (just like galaxies receding) but they were not exceeding the velocity of light but that space being created between them was causing them to move apart faster than light that might be able to travel between them However, in the early Universe, light could only begin traveling after the Universe became transparent enough for photons to travel long mean free paths.
osxraider said:I think the rate was different. Isn't that why inflation was put in? I believe that the rate has slowed?
I was confused myself but apparently, inflation (the ridiculously crazy expansion that flattened the Universe into uniformity said to be caused due to "reverse gravity") is a little different that the current expansion due to dark energy.
osxraider said:Yes, you are absolutely correct! but in an early universe, there was a point at which the distance might not have been big enough to cause a recession velocity that was faster than the speed of light. KEYWORD: MAY OR MAY NOT
osxraider said:That is very dangerous because it could imply infinite recession velocity. That means in a Universe that is been around for a finite amount of time, something has managed to appear to go away from us at infinite speed?
Richard Feynman,Quote by NeedBranes
The energy (or matter) of our universe, which is not presumed to have negative pressure or of any relation to inflationary energy, can all be traced back to a point in time, in our universe, in which it was massless. So it would be moving at the speed of light. Right?
It is important to realize that in physics today, we have no knowledge what energy is. We do not have a picture that energy comes in little blobs of a definite amount.
Could inflationary energy and dark energy be two aspects of the same energy?
A most basic fact is that the universe evolves: We do not live in a static cosmos. Total energy in the universe is constant, but its form is steadily evolving from a low entropy to a high entropy form. All forms of energy, such as matter, fission, fusion, and kinetic and potential energy are precisely offset by the negative gravitational potential of everything. All energy is contained either in matter or force fields and the theoretical Higgs field which imparts mass to certain particles (as protons, neutrons and electrons). The universe ... began from a very high energy, high temperature, unstable state. It evolves towards a more stable lower temperature state and might eventually reach absolute zero in the big bang model. Inflationary energy created exponential expansion just after the big bang and such energy decays into radiation via quantum mechanical processes. ...
In the beginning it’s believed most energy was in the form of heat radiation and inflationary (vacuum) energy from which space, time, and matter evolved. As the universe expands, the total vacuum energy increases and its repulsive nature causes space to expand even faster…in a run away exponential expansion. In the big bang model, dark energy [the cosmological constant] powers an accelerated expansion after 9B years as it overpowers the gravitational attraction of matter.
Matter energy density decreases as volume grows and causes matter to spread out; radiation energy density not only decreases but its wavelength is stretched further by expansion depleting its energy faster, so radiation density falls faster than the energy density of matter. Dark matter energy density remains nearly constant. Dark matter dominated the past; dark energy will dominate the future. Dark matter has nearly three times the energy density of dark energy.
Dark matter and dark energy are related by name only, they are distinctively different. We infer the existence of dark matter by its gravitational effects. We have no idea about the properties of DM particles. It does, however, appear to be 'cold' - i.e., generally not moving at relativistic speeds. The existence of DE is inferred strictly from its effect on expansion of the universe.
The Big Bang theory is the leading scientific explanation for the beginning of the universe. It states that about 13.8 billion years ago, all matter and energy in the universe was compressed into a single point, known as a singularity. This singularity then expanded and continues to expand, creating the universe as we know it.
Scientists have observed that galaxies are moving away from each other at increasing speeds. This indicates that the universe is expanding. Additionally, the leftover radiation from the Big Bang, known as the cosmic microwave background, shows a pattern of tiny variations that support the expansion of the universe.
The concept of "before" the Big Bang is difficult to understand, as time and space as we know it did not exist until the Big Bang. Some theories suggest that the singularity was always present, while others propose the idea of a multiverse, where multiple universes exist simultaneously.
Dark matter and dark energy are two mysterious substances that make up a majority of the universe. While we cannot directly observe them, their presence can be detected through their effects on visible matter. Dark matter is thought to have played a crucial role in the formation of galaxies and other structures in the early universe, while dark energy is believed to be responsible for the current accelerated expansion of the universe.
There are various theories about the ultimate fate of the universe. Some suggest that the expansion of the universe will continue indefinitely, leading to a cold and dark death known as the "Big Freeze". Others propose the idea of a "Big Crunch" where the universe will eventually collapse back into a singularity. It is also possible that the universe will continue to expand at a slower rate, resulting in a steady state of existence.