This is a very interesting video that I want to finish watching.
Wednesday, April 30, 2008
Friday, April 11, 2008
Did pre-big bang universe leave its mark on the sky? - space - 10 April 2008 - New Scientist Space
This article might give us a way to check for a pre-big bang universe.
In cosmological models based on a theory called loop quantum gravity, our universe has a parent. Loop quantum gravity attempts to meld relativity with quantum mechanics by describing space-time as a constantly rearranging fabric of interconnections. On the smallest scales, around 10-35 meters, that fabric is a tangled mess, but on much larger scales the space and time of our universe look smooth.
The theory predicts that when this fabric is scrunched up, it becomes bouncy. So if the universe before ours was contracting, it would have reached a point of maximum density and then bounced out again in our big bang.
So what would this predecessor have been like? To find out, Parampreet Singh of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada, and Alejandro Corichi of the National Autonomous University of Mexico, Morelia, applied the equations of loop quantum gravity to a highly simplified model of the universe. They found that the properties of space, such as the quantity of matter and energy it contains, hardly change when the universe goes through the big bounce. "For the simple model considered, the universe is almost exactly the same on other side," says Singh.
It raises the possibility that we could see an imprint of the universe before ours. Singh suggests that the seeds of large-scale structures in our universe, such as superclusters of galaxies, would have been present on the pre-big-bang side. The pattern of those seeds might be preserved in the cosmic microwave background radiation - the relic radiation left behind by the big bang. "If this conclusion holds true, then it is possible that we are going to see signatures of the pre-big-bang universe," says Singh.
Did pre-big bang universe leave its mark on the sky? - space - 10 April 2008 - New Scientist Space
Technorati Tags: loop quantum gravity
Thursday, April 10, 2008
Ask Michio: If parallel universes exist, can they collide? - Michio Kaku
I have discovered Michio Kaku. He is a great explainer of science to the layman. Try the explanation below to see if it doesn't explain cosmology better than you knew it before.
This is the first time I have heard about the Big Splat. Michio Kaku's link is
mkaku.org
If parallel universes exist, can they collide?
Matthew
EnglandMichio: Probably. The latest cosmological data comes from the WMAP satellite currently orbiting the earth. The data is consistent with “inflation,” i.e. the idea that the universe began in a super turbo-charged expansion at the instant of the big bang. However, inflation is also a quantum theory, i.e. there is a finite probability that if inflation happened once, it can happen again, and again. In fact, big bangs may be happening all the time, even as you read this sentence. There may be a continual creation of universes.
In other words, our universe is probably a bubble of some sort which is expanding. But inflation theory seems to indicate that we may not be the only bubble/universe. Think of a bubble bath, in which there are innumerable soap bubbles floating, sometimes colliding, sometimes breaking in half, sometimes popping in and out of existence. This is the “multiverse” picture which seems to be emerging from inflation theory.
Inflation theory, however, cannot explain the dynamics of these bubble/universes. Inflation simply states that such a turbo-charged expansion took place, but inflation does not explain why inflation took place in the first place, or what drives it. For that, we need a higher theory, such as string theory (or its latest version, M-theory, where M stands for membrane).
In M-theory, there are innumerable membranes floating in a much larger arena (11 dimensional hyperspace). We live on the skin of one such bubble which lives in 3 dimensional space. However, there may be other “branes” floating in 11 dimensional hyperspace. The physicists at Princeton calculated what would happen if two such branes collided. Much to their surprise, they found that the two branes would merge and create a shock wave. By analyzing this shock wave, they found that it resembled the big bang itself. In fact, they were led to believe that this WAS the big bang. This theory is now called the Big Splat theory, and is one of the serious candidates for the underlying big bang theory.
Ask Michio: If parallel universes exist, can they collide? - Michio Kaku
Friday, March 28, 2008
Scientists to Fly Paper Plane From Space - AOL News
KASHIWA, Japan (March 27) - Japanese scientists and origami masters hope to launch a paper airplane from space and learn from its trip back to Earth.
In a test outside Tokyo in early February, a prototype about 2.8 inches long and 2 inches wide survived Mach 7 speeds and broiling temperatures up to 446 degrees Fahrenheit in a hypersonic wind tunnel - conditions meant to approximate what the plane would face entering Earth's atmosphere.
Friday, March 21, 2008
Flipping particle could explain missing antimatter - fundamentals - 18 March 2008 - New Scientist
It is one the biggest mysteries in physics - where did all the antimatter go? Now a team of physicists claims to have found the first ever hint of an answer in experimental data. The findings could signal a major crack in the standard model, the theoretical edifice that describes nature's fundamental particles and forces.
In its early days, the cosmos was a cauldron of radiation and equal amounts of matter and antimatter. As it cooled, all the antimatter annihilated in collisions with matter - but for some reason the proportions ended up lopsided, leaving some of the matter intact.
Physicists think the explanation for this lies with the weak nuclear force, which differs from the other fundamental forces in that it does not act equally on matter and antimatter. This asymmetry, called CP violation, could have allowed the matter to survive to form the elements, stars and galaxies we see today.
Flipping particle could explain missing antimatter - fundamentals - 18 March 2008 - New Scientist
Monday, March 10, 2008
Newborn Stars: Seeing Dark Filaments Inside A Molecular Cloud
ScienceDaily (Mar. 9, 2008) — Astronomers have measured the distribution of mass inside a dark filament in a molecular cloud with an amazing level of detail and to great depth. The measurement is based on a new method that looks at the scattered near-infrared light or 'cloudshine' and was made with ESO's New Technology Telescope. Associated with the forthcoming VISTA telescope, this new technique will allow astronomers to better understand the cradles of newborn stars.
While dark matter was not mentioned in this article, I will be watching to see if it is affected. This method will obviously tell us more about the birth of stars.
Newborn Stars: Seeing Dark Filaments Inside A Molecular Cloud
Technorati Tags: astronomy,dark matter
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