Is the universe expanding accelerative ?

reply to post by redbore

thanks, very interesting. now, i wonder what a repulsive force is and how empty space can create it.

reply to post by icepack


prob. something to do with dark matter or dark energy or both?

reply to post by sunspot0

according to the article redbore posted, this energy is created from empty space. empty space does not have matter, so dark matter seems off. dark energy ? maybe, the repulsive energy is kind of a dark energy, because empty space is dark ?

Originally posted by icepack
reply to post by sunspot0

 

according to the article redbore posted, this energy is created from empty space. empty space does not have matter, so dark matter seems off. dark energy ? maybe, the repulsive energy is kind of a dark energy, because empty space is dark ?

Dark energy/matter just refers to an as-yet undiscovered type of one or the other to account for gravitational anomalies, unexplained effects like this, and various other things we've observed but can't otherwise explain with our understanding of physics - just wanted to clarify for the unclear, and sorry if I mistook your post here.

Now, for a counter theory on this - what if the universe is actually staying the same size, and everything in it is actually just shrinking?!



Take care.

reply to post by Praetorius

Now, for a counter theory on this - what if the universe is actually staying the same size, and everything in it is actually just shrinking?!

well, i don't believe this theory.
what about this: if you would travel fast enough for the "border" of this universal "bubble", you will never be able to reach the edge. not because you are slower than the expanding, but because you think you fly straight towards the edge, but in reality you fly a "curve", because the space is bended.

reply to post by icepack

well, i don't believe this theory.

Well - I think you're a meat popsicle. So we're even.

And I'm sure there's some very good argument against it, but given the issues with the prevailing theory, I'd have to say either is every bit as likely. And perhaps that's why the energy and matter are dark, because we're looking the wrong way to try to explain an accelerating/expanding universe, instead of expecting shrinking groups of mass/matter.

Hmm...

what about this: if you would travel fast enough for the "border" of this universal "bubble", you will never be able to reach the edge. not because you are slower than the expanding, but because you think you fly straight towards the edge, but in reality you fly a "curve", because the space is bended.

Sometimes, I have to think that scientists just sit around in their private clubs laughing with one another, arguing over who can come up with the craziest stuff to tell the masses next and see who can fool the most people.

Either that, or reality just doesn't seem to make a whole lot of sense sometimes! If you have yet, you might as well go ahead and look into the dual-slit experiment to add to this one, for your collection of head scratchers.

Take care.

reply to post by Praetorius

which definition do you mean ?
www.urbandictionary.com...

It appears to be accelerating due to the perceived "red shift" of objects increasing with the distance from earth, making it seem like the more distant and object is the faster it is moving away from us.

As I understand it, the concept of using red-shift to determine an object's speed of retreat from us depends upon time and the speed of light. However, if one considers the concept of "hyper-inflation", where the Universe expanded at super-luminal (faster than light) speeds early on in its development, and expansion slowed over time, the apparent increase in red-shift as distances increase could be an artifact of this hyper-inflation and thus not truly indicative of true acceleration and thus not true indication of distance and time.

Einstein developed a concept of a cosmological constant to solve his calculations for a static or constant Universe. But he dismissed it as an anomaly after integrating the concept of red-shift in to his works. Even though E=MC(squared) works well, the cosmological constant has received revived attention since the late '90s due to exactly what you're asking about: an accelerating, expanding Universe.

It is worth noting though that some are pondering the idea that the constant isn't really a constant but more a variable whose value has changed over time. Meaning, early in the Universe, the speed of light was faster than it is now, and localized space expanded faster than it sems to now... or the properties of space were different then so as to make it seem so.

Summary:
If the properties of space, time and the speed of light were the same then as they are now it would appear the Universe is expanding at an increasing rate, thus necessitating the concepts of dark energy and matter. If the properties of said were different in some way, it would appear the Universe is expanding at an increasing rate but it would in fact not be.

And to throw another wrench in the machine: Great Attractor, and Dark flow

Happy hunting!

Originally posted by icepack
reply to post by redbore

 

thanks, very interesting. now, i wonder what a repulsive force is and how empty space can create it.

You don't actually need a repulsive force if the properties of space, time and light changed since the beginning of the Universe.

Originally posted by icepack
thanks, very interesting. now, i wonder what a repulsive force is and how empty space can create it.

Imagination.

That's the force. You see, when you imagine something, you're literally creating something from nothing -- an image from the void. And you wouldn't think that would add anything to the universe, but what it actually does is collapse a quantum wave function and make something real out of potential non-existent virtualities. Energy. Light. Motion. Both forward and backward in time. It's extremely small, but it adds up!

And we might not be the only ones doing it. If there are aliens out there with consciousnesses and imagination, aliens as tiny as bacteria or with brains the size of planets, they could be filling the universe with their thoughts, too, and they might have much larger and energetic thoughts than ours. And the universe has to get bigger to make room for the thoughts.

And speaking of Einstein, he himself said that imagination was more important than knowledge.