But on the other hand, the discovery opened a mystery the size of, well, the universe. The simplest explanation is that dark energy is Einstein’s famed “cosmological constant,” an energy that permeates space but does not interact with any type of matter. Today astronomers have homed in on the details of this scenario; if true, then the universe consists of 72 percent antigravity dark energy, 23 percent dark matter (unseen and uncharacterized, but susceptible to gravity), and 5 percent normal matter (protons, neutrons, electrons). We would be just a small part of totality, surrounded by perplexity.
“It could well be that there’s some big piece of reality that we don’t fully understand,” says astronomer Christopher Stubbs of Harvard University, who in a paper likened the new universe to “living in a bad episode of Star Trek.” Physicist Steven Weinberg of the University of Texas at Austin calls it simply “a bone in the throat of theoretical physics.”
Magic has not yet been proposed to explain the accelerating universe, but almost everything else has. In the past few years, physicists have widened their search beyond vacuum energy to include possible modifications to general relativity, spinless energy fields that vary with time and space, massive gravitons, brane worlds and extra dimensions. “All of them are so exciting, and any is going to rewrite the textbooks,” says Eric Linder, a cosmologist at Lawrence Berkeley and U.C. Berkeley. The hypothetical repulsive dark energy field may well not survive in the final explanation.
“It’s true the theorists right now are stuck,” Perlmutter says. “But from an experimentalist’s point of view, this is great: we have a mystery, and we have ways to get at it”—namely, in the form of new telescopes and satellites to look even farther across the universe (and, hence, farther back in time).
Ground-based projects are already gathering more data, looking for hundreds of type Ia events (instead of Perlmutter’s and Schmidt’s five dozen) to determine the relation between the pressure and density of the universe, akin to the ideal gas law. A galaxy like our Milky Way exhibits about one type Ia supernova every few hundred years, and its brightness fades in weeks, making the search for them quite a challenge. By observing the cosmic background radiation, the soon-to-launch Planck satellite will contribute more details about the universe’s expansion.
Dark energy aficionados look especially to the Joint Dark Energy Mission, now in the planning stages in the U.S. for a possible launch in 2014. The probe will host a device that could find thousands of supernovae a year and provide far smaller error bars than anything done so far. One candidate is the SuperNova Acceleration Probe (SNAP), for which Perlmutter is the lead scientist and Linder the head theorist. It would host a telescope about two meters wide and have a gigapixel camera.
The discovery of cosmic acceleration will assuredly win a Nobel Prize, and over the years there has been some dispute over which team deserves priority. Perlmutter’s SCP team announced the discovery first, but Schmidt’s High-Z team beat the SCP group in publishing the finding. Both Perlmutter and Schmidt shared one fourth of the 2007 Gruber Cosmology Prize, with the remaining fraction going to their two teams collectively.
Gregarious and talkative, Perlmutter attributes his success to being able to convey his excitement and convince other researchers to join his team. An amateur violinist who also teaches an undergraduate physics and music course, he draws an orchestral analogy. “As a violinist, I always love the moments when a group of people are creatively tuned in together.”
This article was originally published with the title Dark Forces at Work.
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Add CommentWhile matter may not travel faster than the speed of light, is it not possible that if the speed of light at some time in the long-distant past -- before the Big Bang maybe -- was significantly greater than it is currently, it may then have been able to travel just fractionally faster than the speed of light is now?
Reply | Report Abuse | Link to this(Yes, I know that the prevailing wisdom has it that there is no such thing as "before" the Big Bang. There is also a school of thought advocating be proposition that there is a constant sequence of Big Bangs, separated from each other by a period of expansion and contraction -- which leads to the next one...)
I know that's not regarded as remotely likely but, might it not allow that those objects at the furthest reaches of the universe as we perceive it now might not actually exist? If that fundamental proposition was valid, those objects might actually be images of galaxies etc. that were heading in this direction from most, if not all quarters, their journey culminating in the Big Bang. Because of the differing speeds of light, the whole pre-Big Bang process would be seen in reverse but because we are new developments on the planet, we haven't been able to observe the last 14 billion years of it! It also occurred to me that if that were the case, it would explain why everything at the far reaches of the universe appears to be leaving us at ever-increasing speed.
You'll have to excuse me -- I'm no scientist, so feel free to laugh!
One concept not encountered on these premises is that of gravity acting on photons from a position ahead of the photon.
Reply | Report Abuse | Link to thisFrom a position posterior to a photons path a black hole is known. Gravity sources laying alongside a photons path provides gravitational lensing.
What of gravity anterior to a photons path, would acceleration not effect the photon as well? Would that effect be, since the photon is traveling at velocity limits, the stretching of the photons wavelength? Would the dopler shift noted by Hubble be accounted for by gravitational acceleration just as well as expansion of the universe? Both are distance/time dependent.
Seems that gravitationl acceleration on the photon over time may be a better answer than shifting one universe, but then ...
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Edited by Arnie B. at 05/24/2008 1:26 PM
One concept not encountered on these premises is that of gravity acting on photons from a position ahead of the photon.
Reply | Report Abuse | Link to thisFrom a position posterior to a photons path a black hole is known. Gravity sources laying alongside a photons path provides gravitational lensing.
What of gravity anterior to a photons path, would acceleration not effect the photon as well? Would that effect be, since the photon is traveling at velocity limits, the stretching of the photons wavelength? Would the dopler shift noted by Hubble be accounted for by gravitational acceleration just as well as expansion of the universe?
Seems that gravitationl acceleration on the photon over time is a better answer than shifting one universe, but then ...
It is all very intriguing. Given the original view that gravity would put a brake on expansion would this not suggest a weakening of the force in the region of the 1a Supernova?
Reply | Report Abuse | Link to thisA better fit for all the "blacks" is "The Dynamic Ether" from Kunaki. One single assumption takes the mystery out all of the above and includes a proposal for a two fold type gravity, the tidal process, and even suggests a science based religion. Einstein could have been right for the wrong reasons, and Michelson/Moreley could have been wrong for the right reasons.
Reply | Report Abuse | Link to thisMichelson was taking readings in a closed system, Since the ether, according to the Dynamic Ether, converges on and travels with the earth.
Reply | Report Abuse | Link to this'Michelson could have been trying, as it were, "to find the drag of the air with a pitot tube in a balloon."
He was wrong to conclude there was no (measurable) ether, but was right to accept his readings for a nonexistent static ether.
I've seen you make a few posts about this "Dynamic Ether" by Kunaki. What is it exactly? All I found by on Google where more of your posts.
Reply | Report Abuse | Link to thisI am working on a link, sorry about that.
Reply | Report Abuse | Link to thisPerhaps the Solar Wind could be ingeniously harnessed for some solar sailing. After all the Earth's magnetic field interacts and diverts the flow, so why not figure out the why's and wherefores to allow the space boat to tack, run and close haul itself upwind towards the sun. Get Michio Kaku busy on the good ship "Sollipop"
Reply | Report Abuse | Link to thisThe expanding universe
Reply | Report Abuse | Link to thisquote -- "Perlmutter’s SCP team announced the discovery first, but Schmidt’s High-Z team beat the SCP group in publishing the finding."
High-Z made a big mistake by informing SCP of their discovery, who then hastily got into the act (it was probably unnoticed in their own data) and before High-Z could formally publish, Perlmutter did his sooner stuff.
-- Hitting all the media sources under the sun.
My guess is that SCP's poor science threw out any data that did not show the universe was slowing down, and only found the opposite motion when Schmidt told him to check his data.
Sorry for being meanish but there you are.