If galaxies are moving away at ever increasing speed doesn't it violate law of conservation of momentum?

Answer 1

The "law of conservation of momentum" is a concept in Newtonian mechanics. In trying to understand galaxies on a large scale (that is to say, cosmology), it is best to apply the more modern theory of General Relativity. In General Relativity, the law of conservation of momentum changes, so that momentum becomes the "spatial" part of the "Stress-Energy Tensor". Loosely speaking, energy becomes the "temporal" or time part of the Stress-Energy Tensor. Stress-Energy is conserved in General Relativity, but to verify this, or to calculate its value, is more complex than in Newtonian mechanics. Basically, you must integrate the Stress-Energy tensor over a volume, taking into account the "arbitrary" nature of the coordinate systems that describe the space.

I'm sorry if this answer is complicated, but to try to understand these concepts correctly does require some complex mathematics. Don't be discouraged! It takes some effort to learn, but once you get through it, it leads to a much more satisfactory understanding.

The nature of the "Dark Energy" that is causing the acceleration of the universal expansion, is intimately tied up in the overall conservation of Stress-Energy. Dark Energy can only behave in certain ways (for example, the relation between its pressure and its density) and still conserve the overall Stress-Energy.

Answer 2

almintaka has the right answer. As far as macroscopic space, in which we live, is concerned, conservation of momentum is inviolate. However, once you start tweeking events at the boundaries of Heisenberg's uncertainty principle, things aren't as smooth, and what we consider "laws" are not necessarily true all the time. Any measurement over those intervals of time and distance is not possible by any means available to us because any measurement we would take would change the circumstances of what we're observing, and would FORCE it into the macroscopic world, where it is then forced to obey the laws of our world.

Answer 3

Law of conservation of momentum is applicable only for the Earthly objects.

Answer 4

Conservation of energy is the law not conservation of momentum.

Answer 5

The phenomenon you're asking about doesn't actually involve galaxies themselves moving >>through<< space. The observed increase in apparent velocity is actually due to the expansion of space and since galaxies, like eveything else, is embedded in space they appear to be rushing away from us. Exceptions are the local, internal movement of galaxies that are gravitationally bound in clusters.

Answer 6

No, since the -net- momentum of the Universe is what has to remain constant. The problem you're having is that you're looking at it from your own inertial reference frame.


Doug

Answer 7

braxton is right. the galaxies seem to be moving further away atr ever increasing speeds but it is actually the universe that is expanding away from us. not the galaxies moving through space away from us.

Answer 8

Not at all. According to the conservation of momentum.........................Well you would be knowing about it. Read it carefully and understand it. You'll get the answer yourself.

Answer 9

no as already said we have to consider only the net momentum not from ur frame of reference

Answer 10

Might be Who knows. By the way what is the law of conservation of momentum.???????????????????????????????????????????????????????????????????????