How do you explain that not only is our universe expanding, it is accelerating as well?
- ?Lv 61 decade agoFavorite Answer
draw 2 dots on a balloon, and then blow it up.
- oldprofLv 71 decade ago
There are several theories on this: dark stuff (matter and energy) is one of them. According to this theory, there is dark matter, which may account for why galaxies do not fly apart under centrifugal force, and dark energy, which may be propelling the expansion of our universe. These darkies are called dark because, up unitl very recently, no one has actually detected either one.
Dark matter, which accounts for the extra gravitational pull to keep galaxies from flying apart, has just recently been observered in two colliding galaxies. Here the energy released by this enormous collision has set the dark matter surrounding each galaxy into glowing. Thus, it is no longer dark. And, thus, it is no longer a theory; it is an experimentally proved thing. [See source.]
Dark energy is a horse of a different color. It has not yet been observed; so its existance is still speculative. However, the acceleration of the universe is not...it has been measured (observed). The universe is in fact expanding at an ever increasing rate. Thus, to explain it, the astro guys invented dark energy to push the expansion along.
In the mechanical world KE = work = Fd; where KE is kinetic energy (like the expansion, dark energy), F is a force pushing a mass (like the universe) some distance d (like an expanding diameter). Thus KE = Mad; so that KE/(Md) = a; where M is the universal mass (including dark matter) and a is the acceleration. This is a rather simplistic model (it overlooks, for example, the gravitational forces pulling inward), but you get the point. Where there is sufficient energy, a body will expand with acceleration.
Couple the energy inside our known universe with the total lack of energy in the universe outside our known universe, and you have an enormous pressure (force over area) differential pushing our known universe outward. Our known universe has a background temperature of about 3 deg Kelvin, one can speculate that outside our known universe, the expanse our universe is expanding into, is at a much lower temperature than that...given that it has not yet received energy from our big bang. One might even guess that the outside universe, which I call a null universe, is at zero deg Kelvin (absolute zero). Therefore, the outside universe has no energy whatsoever, dark or otherwise.
So there we have it...some energy (our universe) creating a force pushing into absolute nothing (the null universe) and, thus, you have acceleration.
ONE FINAL POINT: It's the universe itself that is expanding and accelerating, not necessaritly the stuff inside the universe...like planets, stars, and galaxies. In fact, contrary to intuition, the galaxies remain pretty much the same size even though the universe is expanding. Even so, the galaxies, on average, are getting farther and farther apart from each other. Go figure....Source(s): http://today.slac.stanford.edu/feature/darkmatter.... for dark matter observation, plus a great photo showing dark matter
- 1 decade ago
There are several observations that support the idea that the universe's expansion may be accelerating: "In the late 1990s, observations of Type Ia supernovae suggested that the expansion of the universe is accelerating. In the past few years, these observations have been corroborated by several independent sources: the cosmic microwave background, gravitational lensing, age of the universe and large scale structure, as well as improved measurements of the supernovae."
- 3 years ago
The universe's fee of boom is accelerating. the quantity of darkish count number is possibly turning out to be. The universe would or received't have boarders. we do not understand. the quantity of functional count number (dirt clouds, which enable the beginning of suns) will run out. No new count number functional mater will come. we do not understand some thing about darkish count number or darkish power, extremely. all of us understand that is there, and that it messes with our calculations. at the same time as the universe began, all the functional count number replaced into actual close at the same time. Now, that is spreading out. The galaxies are shifting faraway from one yet another, for the most section, yet we do not understand why. How do all of us understand this? The Doppler result. The Doppler result may be utilized if all of us understand what colour a galaxy might want to seem, interior the most elementary experience, because if a galaxy is shifting faraway from us, that is "pink-shifted." the colour spectrum is going from Blue to pink. The blue issues are coming in course of us, and the pink issues are going away. there replaced right into a study that the speed of boom replaced into actual turning out to be, even although we once concept it replaced into going to initiate retracting. i'm hoping I helped The universe has no boarders The universe is understanding of issues to artwork with definite, there is extra darkish count number.
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- campbelp2002Lv 71 decade ago
I don't explain it, but others explain it as the result of "dark energy". What is dark energy? Nobody knows. It is just some unknown thing that is assumed to cause the acceleration.
- genericman1998Lv 51 decade ago
This is one of the most pressing questions among professional astrophysicists today. Meaning, it is not really understood yet. Something called "dark energy" is the proposed reason for the acceleration, but nobody yet knows just what this dark energy is exactly.
- ThermoLv 61 decade ago
This is absolute nonsense with even more peculiar explanations.
The expansion is an illusion caused by presuming redshift is only caused by the Doppler effect. Most astronomers ignore Compton effect.