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Author Topic: If the universe is expanding faster is more energy coming into it?  (Read 1191 times)

Offline acecharly

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If something travels through space at a certain velocity it will continue at that velocity in that direction until another force acts upon it.....sooo if the universe is expanding faster than before this must mean more energy is coming into the universe .....right or wrong?

Any thoughts

Cheers Ace


 

Offline imatfaal

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If something travels through space at a certain velocity it will continue at that velocity in that direction until another force acts upon it.....sooo if the universe is expanding faster than before this must mean more energy is coming into the universe .....right or wrong?

Any thoughts

Cheers Ace

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In physical cosmology and astronomy, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe.
 

http://en.wikipedia.org/wiki/Dark_energy

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...right or wrong? 
Too soon to tell.  This is the boundary of known physics - anyone expressing certainty in this area is chancing their arm.
 

Offline yor_on

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Define a universe :)

Closed?
Open?

Or maybe both? Closed to us, in what we can measure, but open in some other way, undefinable from our observations? If 'energy' is the coin of choice describing transformations, does it disappear?
 

Online evan_au

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To rephrase the question, if Dark Energy causes objects to increase their relative velocity, does this increase their kinetic energy, and can we turn this into "useful" energy?

Background: Normally, if you double the speed of an object, it's kinetic energy increases by a factor of 4: E=1/2Mv2
This energy can then be turned into "more useful" energy if moving air collides with something like a turbine blade (or into "less useful" energy, in the case of a car crash...)

Energy is neither created nor destroyed in this process, just changed from one form into another.

Dark Energy is still a new idea, but some of the challenges are:
  • The increased velocity comes from a stretching of the space between the objects
  • Is this transforming "Dark Energy" into "Kinetic Energy"?
  • Because already-distant objects are moving apart even faster, it is not obvious how to make them interact with each other to produce "useful" energy.
 

Offline yor_on

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Heh :)

Sweet idea, assume that you have two objects that move apart. Both defining the other as accelerating away, would that be a real acceleration?

Can one think of a way to disprove it as a acceleration? How about assuming that you have a 'sphere of objects' (planets/suns) surrounding you and you find them all accelerating away from you? Is it them or you? You decide it is them accelerating away and you call up one of them to ask 'what's up with all that acceleration, is it my smell or what'?

Now, if the answer you get is that he, same as you, finds all objects accelerating away from him, where is the acceleration? What degree of freedom, or dimension as they say, are all those objects 'accelerating' in? There is one point more to consider, in all accelerations there should be present a 'gravity/inertia' raising.

If we don't find gravity to raise, can it then be a acceleration?
In what degree of freedom?

 

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