Karl Gebhardt: Right now we have one of the greatest mysteries of our times. And as scientists, we have a responsibility to understand what that is.
That’s astronomer Karl Gebhardt of the University of Texas at Austin. He’s talking about dark energy. More than 70 percent of all energy in our universe is thought to be dark energy. But – though theoretical models say it should exist – astronomers have yet to detect dark energy.
Karl Gebhardt: What HETDEX is going to do, it’s going to look at an early time in the universe that has not been explored yet in terms of how fast the universe is expanding.
Gebhardt hopes to measure dark energy, through a project called HETDEX, the Hobby Eberly Telescope Dark Energy Experiment. The idea is that dark energy causes the expansion of the universe to speed up. HETDEX will peer at galaxies and supernovae over 10 billion light-years away, looking at the pattern of how they’re distributed.
Karl Gebhardt: Our universe is expanding, so that pattern’s expanding. So all you do, you measure that pattern at different times, and that tells you how fast the universe has expanded.
Astronomers expect that expansion rate to increase, due to dark energy.
Karl Gebhardt: And so when we have in our HETDEX survey a large sample of galaxies, we just make a map and we find the pattern. And we measure how large that pattern is, how large it appears to us, we compare it to what we know, and we’re done. That tells us how much our universe has expanded.
Gebhardt expects completion of the dark energy telescope by 2010.
The latest theory is that ever since the Big Bang, 13.7 billion years ago, our universe has expanded. Scientists expected that the gravity from all the universe’s matter created back then would cause that primal expansion to slow down. But measurements of supernovae suggest that the expansion is actually speeding up, fueled in a sense by dark energy.
Our thanks to:
Karl Gebhardt
Professor of Astronomy
University of Texas at Austin
Actually, most astronomers now believe that dark energy is a property of space itself. They are trying to make fine measurements of the expansion of the universe at various stages in its history. They believe that at first normal gravity was the primary force acting on the expansion of the universe—thus it was slowing down.
But as time went on, more and more space came into existence. That’s because it’s space itself that’s expanding. Each square inch of space has a tiny bit of dark energy associated with it. As the volume of space increases, more dark energy comes into existence. Dark energy has negative pressure and so it causes the universe to speed up its acceleration. The more space and thus the more dark energy there is, the faster the universe expands.
Ellen Jackson, author
THE MYSTEROUS UNIVERSE
How about this for a thought. There is no dark energy. Instead the universe has expanded to the point where gravity is no longer as large an influence as it was. Therefore the universes expansion is speeding up.
Assume outside the universe is a void. So there is no “force” stopping the universe from expanding in fact exactly like a balloon would expand in the vacuum of space, so the universe expands in the void.
Perhaps the forces astronomers think should slow down expansion are weaker then previously considered. Not as much matter?
I guess what I am formulating is a theory that the universe is not expanding due to the initial big bang (a theory in itself) but the expansion is due to the theory that given a void a single atom would expand to fill that void even if the void was the size of the universe itself. the only thing that keeps atoms and the electric charges around the atoms in check is the existence of other atoms and possibly the nature of space itself.
maybe?
But where is this dark energy coming from? Could there be other dimensions hidden from our view that act as dark energy ‘springs’?
Or is the term dark energy our best guess for some property of spacetime as yet understood? And what is the vacuum? Is it dark energy? A fluid like substance?
Rick, Chris is saying that imagine our universe is a bubble, all matter and energy contained in the bubble. Now imagine that outside the bubble is a pure vacuum with zero energy state. When the universe was small, the outer surface area of the bubble was low, therefore the amount of expansion was small. But as the universe’s bubble grew, so to does the area of the bubble. Since the bubble is bigger, the vacuum force has greater effect. Think of it like the universe is a sail and the wind as the vacuum energy outside our universe, a small sail does not gather much wind, so it wont move the ship. But if you make the sail larger, the wind has a greater effect. The vacuum effect of a small universe is low because it has less area for the zero energy vacuum outside the universe to act on it. As it expandes more area could be exposed to this outside vacuum force which would suck our universe outward even faster. I agree with Chris that this dark energy is pulling from outside rather than pushing from the inside.
Hi,could u explain to me exactly what dark energy is because to me it seems you have the best understanding of it all. Thank you
The whole mass of the Universe was contained in a single body almost infinitely small. It just exploded, like a house with closed doors and windows would in the path of a tornado. If you think in terms of pressure differential, at the beginning, there was an infinite pressure on the Universe original elements that caused them to remain into a single almost infinitely small object. The pressure suddenly dropped to none(within a very small fraction of a second) and the effect of that release in a vacuum – a real void with no matter..a state of nothingness…- has caused a very rapid expansion which created a very turmoiled Universe giving rise to many vortexes. Dark matter is a fluid which vehicles photons. Heavier elements compounded into gases were trapped into this twirling dark matter and formed cluster of galaxies here and there, black holes and other universal objects.
It is very hard to demonstrate this phenomenon because the density difference between the gases and dark matter does not have an equivalent density differential between two bodies here on Earth. But if such an experiment could be set up, we may recreate a miniature big bang. The key is to create a tiny, extremely heavy body of elements under pressure in a void. I doubt this can be done but it is certainly worth a try.
For light to expand and travel, it needs a medium (dark matter). AT teh beginning, dark matter either existed for light to travel through it or it had to expand faster than the speed of light or may be at the same speed but not slower. Thoughts?
The truth is that for every answer that scientists develop, another question is raised. This will continue until the end of all of our lives. We should be able to undertstand what gravity is, but nobody really does. There are fancy theories9Gravitons, strings, etc.), but nobody knows for sure. In order to understand why the universe is speeding up, we would need to understand this most basic of all questions.
What does a quark look like in its natural state? What does any sub-atomic particle look like in a natural state? All we see is what they do when we beat the dog snot out of them. The harder we look, the less we see, because the more we alter the true nature. There is a built in mechanism in nature that prevents man from seeing or understanding the absolute nature of things; both at the micro, as well as the macro scale. Ask who made that rule, and study the simple miracle of a right angle. Will this stop man from trying to undertstand? No, and he will always develop a better weapon in the process.
Perhaps we are life’s attempt to stop the next major extinction on this planet. After 3 great extinctions, perhaps life recognized that the next heavenly body to strike the earth may put it out of the game permanently, with nothing left to re-evolve. We then are the answer to life’s problem. Poor little trilobites, poor t.rex, maybe we are the solution to a big problem, and in the process of creating the necessary technology, we will end up destoying life ourselves. Life’s major screw up.
Anyhow, all of the theories regarding the topic, although interesting ultimately explain nothing. These things will be pondered for decades to come, and many Ph.D. degrees will be awarded, but even 40 years from now, not one of those Ph.D. holders will be able to accurately answer why while standing in a field, if one lets go of a ball, it falls to the ground. Anything further from me would involve religion, and I know that won’t go over well.
Again: Dark Energy And Dark Matter YOK
A. From “Ancient dawn’s early light refines age of universe
Satellite images reveal new aspects of Big Bang’s relic radiation.”
http://www.sciencenews.org/view/generic/id/55957/title/Ancient_dawns_early_light_refines_age_of_universe
- “The ancient light, known as the cosmic microwave background, is peppered with hot and cold spots, signs of the tiny primordial lumps from which galaxies grew”, And “(It is suggested) that theorists will have to revise their understanding of galaxy clusters”.
- The “universal composition” mantra is displayed, again, as 4.5% ordinary matter, 22.7% dark matter and 72.8% dark energy.
B. From “No Dark Matter, No Maybe”
http://www.the-scientist.com/community/posts/list/240/122.page#4545
- Enough is enough. Humanity has been hallucinating about dark energy and dark matter for circa 100 years.
- The “tiny primordial lumps” grew NOT into galaxies, but into galaxy clusters.
- “Galaxy Clusters Evolved By Dispersion, Not By Conglomeration”.
- “There’s No Dark Energy Nor Dark Matter”. All the initial singularity energy and matter is still there in space-distance, accounted for by E=Total[m(1 + D)] .
C. And “Cosmic Evolution Simplified” accounts for the origin and nature of evolutionary biology via the cosmic gravity monotheism.
Dov Henis
(Comments From The 22nd Century)
Dark energy is only theoretical.
I have a blog against the expansion of the universe, with arguments that show this is impossible.
How the people consider there are evidences for the Big Bang I study these evidences.
I have arguments and Hypotheses in: http://bigbangno.wordpress.com
Thanks.
the discpoveries of galaxies nine to twelve billion light years would suggest that their light left those bodies that long ago,is it to assume that these objects are no longer in existence,and we are only seeing what was there from their birth.