Is the total amount of energy in the universe constantly changing??
594714
No, the amount is constant. It can change between different states though. Particles with some mass can change into energy in interactions and vice versa and there are many many different ways of energy changing from one to another.\n\nOn a school level you can think of "chemical energy" changing to kinetic energy in a car for example. At a higher level you need to consider more in-depth things like an electron loosing potential energy by moving down a level in orbit around an atom and emitting a photon with that energy so it is conserved.
1181994
I believe in a comparitively new but very popular theory that Universe creation and destruction are cyclic in nature. Its like the BIG BANG, then BIG CRUNCH, then BIG BANG again and so on.... The energy for the newest big bang event (the one studied by Edwin Hubble), came from the previous big crunch.  The Cosmic Microwave Background, when studied suggests that the radiation at the denser parts of the universe are heavily red shifted. This is an evidence in support of energy being 'old'.
930423
All energy eventually ends up as heat.  It's a consequence of the second law of thermodynamics
1057782
If all matter is over 90% empty space, then there should theoretically be small vacuums throughout the entire universe.  However, such a vacuum would be impossible to detect, contain, or sustain.\n\nPerhaps beyond the edge of the universe, a perfect vacuum exists.  All the matter/energy ever can only take up so much space.  However, there is no way to observe or reach that vacuum either.\n\nMmmm... uncertainty!
803811
You have progressed to a higher energy level.\nYour quanta is exponentially growing.\nBe aware a large mass may effect space time.\nIf your Dark Sucker. (Incandecent bulb) goes out you may have reached event horizon.\nI don't think there is a grey iffy area here. Chaos will not prevail in the face of large amounts of energy.\n\nLay off the donuts while your reading! 8^)
1182405
I don't really believe in this God-particle everybody is talking about here....\n\nThe scientific theory is that the Universe started as a fluctuation of the vacuum. Such vacuum fluctuations make appear a small amount of energy, for a small time. This phenomenon is responsible for the existence of forces, that hold the Universe and matter together.\n\nNormally the bigger the energy fluctuation, the smaller the time it is in existence.\n\nNot so the Big Bang. That was a HUGE fluctuation. So big that a lot of energy came to appearance in the form of mass, elementary particles. These particles started expanding, before the vacuum could reclaim the energy.\n\nAnd it is still expanding today. 14 billion years later.
472392
"Matter can be neither created or destroyed" is an old saw from pre-Einstein physics.  Matter is continually being transformed into energy in every star in the sky in accordance with E = mc^2, so in that sense, there is certainly less matter in the universe now than when I started typing.  However, (I think) the equation is reversible, so the energy can be transformed back into matter, so maybe the answer is there has always been a constant amount of matter/energy in the universe.
980485
The number of atoms in the universe is not decreasing...\nThey are spreading out as the Universe expands...
955705
If the theory is indeed correct, the only possibility is that matter/energy pre-existed the "big bang", and all that the "big bang" accomplished was rearranging things.  This is perhaps an interesting theory on how things were formed from pre-existent matter, but hardly a good explanation of the origin of matter.  It has been fairly well established that matter and energy are somehow the same thing.  According to the law of entropy, if energy always existed, it would inevitably (after an infinite period of time) be evenly distributed by the actions of random process.  Since this is not the case (stars are obviously hot spots in the soup of matter), matter cannot possibly be infinitely old.  So we find ourselves coming back to the question of origin, again...
799758
This is not an either/or situation.  The Universe as seen by physics is a trend for ordered sub-systems to become more chaotic over time.  This is the Second Law of Thermodynamics which states "The entropy of an isolated system not at equilibrium will tend to increase over time, approaching a maximum value."  However NO sub-system is ever really isolated.\n\nLiving systems tend to reverse the "normal flow" toward higher entropy.  One might say that life runs counter to the Second Law of Thermodynamics.  Living systems tend to induce order to random elements of the Universe over time.\n\nThe best answer to your question is that the Universe is both Ordered and Chaotic, depending upon what localized portion of the space-time continuum one is observing.
436081
There you have the 2nd (I think) law od thermodynamics.\n\nLook it up, but it's the commonly quoted one about entropy always increasing in a closed system.\n\nIn laymans terms, the amount of disorder always increases, as things naturally seek a lower energy state.  Eventually, when the universe is 'run down' it will consist only of a uniform soup of particles.\n\nFortunately we don't have to worry about that quite yet!"
578190
I think you are confusing homogenous with constant. The fact that the universe consists of packs of matter separated by tremendous amounts of empty space makes it exactly inhomogeneous! However, because of conservation of energy, there is a constant interrelationship to the universe.
15241
Well yes and no. According the the principal of conservation of energy there is a set amount of energy and it can only be converted, not created or destroyed. But as we look into more complicated realms of physics, we understand that matter can be converted  into energy, and vice-versa.
809521
E=MC2, so universe = infintie mass, Energy= infinite times. \n\nSpeed of light squared is will power.
889920
Yes, if it's converted to energy.  E=mc^2
275638
- All of the above\n\nThe 1st Law of Thermodynamics tells us that energy is neither created nor destroyed, thus the energy of the universe is a constant. However, energy can certainly be transferred from one part of the universe to another. To work out thermodynamic problems we will need to isolate a certain portion of the universe (the system) from the remainder of the universe (the surroundings).
1165052
all the energy that is in the universe came from the Big Bang and the universe today is expanding, though a lot slower than before.\n\nHow do we know this? Astronomers have been using spectrometers to chart the temperature from the center of the universe onwards. As you may already know, the farther we look into space, the farther back in time we are looking. What we found, astonishingly, is that the temperature of the universe was hotter before and is slowly reducing. \n\nRight now the temperature is 3 Kelvin (-270 degrees Celsius) in deep space (deep space defined as one atom per cubic kilometer). It shows that energy is continually dissipating, leading to the expansion of the universe, which is leading to a slow decrease in temperature. So there is overwhelming evidence stating that all energy in universe came from the Big Bang and is contained.