Featured Research

from universities, journals, and other organizations

Physicists Say Universe Evolution Favored Three And Seven Dimensions

Date:
October 4, 2005
Source:
University of Washington
Summary:
Physicists who work with a concept called string theory envision our universe as an eerie place with at least nine spatial dimensions, six of them hidden from us, perhaps curled up in some way so they are undetectable. The big question is why we experience the universe in only three spatial dimensions instead of four, or six, or nine.

Physicists who work with a concept called string theoryenvision our universe as an eerie place with at least nine spatialdimensions, six of them hidden from us, perhaps curled up in some wayso they are undetectable. The big question is why we experience theuniverse in only three spatial dimensions instead of four, or six, ornine.

Two theoretical researchers from the University ofWashington and Harvard University think they might have found theanswer. They believe the way our universe started and then diluted asit expanded -- what they call the relaxation principle -- favoredformation of three- and seven-dimensional realities. The one we happento experience has three dimensions.

"That's what comes out whenyou do the math," said Andreas Karch, a University of Washingtonassistant professor of physics and lead author of a new paper thatdetails the theory.

Karch and his collaborator, Lisa Randall, aphysics professor at Harvard, set out to model how the universe wasarranged right after it began in the big bang, and then watch how thecosmos evolved as it expanded and diluted. The only assumptions werethat it started with a generally smooth configuration, with numerousstructures -- called membranes, or "branes" -- that existed in variousspatial dimensions from one to nine, all of them large and none curledup.

The researchers allowed the cosmos to evolve naturally,without making any additional assumptions. They found that as thebranes diluted, the ones that survived displayed three dimensions orseven dimensions. In our universe, everything we see and experience isstuck to one of those branes, and for it to result in athree-dimensional universe the brane must be three-dimensional.

Other realities, either three- or seven-dimensional, could be hidden from our perception in the universe, Karch said.

"Thereare regions that feel 3D. There are regions that feel 5D. There areregions that feel 9D. These extra dimensions are infinitely large. Wejust happen to be in a place that feels 3D to us," he said.

Inour world, forces such as electromagnetism only recognize threedimensions and behave according to our laws of physics, their strengthdiminishing with distance. Gravity, however, cuts across alldimensions, even those not recognized in our world, Karch and Randallsay. But they theorize that the force of gravity is localized and, withseven branes, gravity would diminish far more quickly with distancethan it does in our three-dimensional world.

"We know there arepeople in our three-brane existence. In this case we will assume thereare people somewhere nearby in a seven-brane existence. The people inthe three-brane would have a far more interesting world, with morecomplex structures," Karch said.

With gravity diminishing rapidlywith distance, a seven-dimensional existence would not have planetswith stable orbits around their sun, Karch said.

"I am notprecisely sure what a universe with such a short-range gravity wouldlook like, mostly because it is always difficult to imagine how lifewould develop under completely different circumstances," he said. "Butin any case, planetary systems as we know them wouldn't form. Thepossibility of stable orbits is what makes the three-dimensional worldmore interesting."

Karch and Randall detail their work in theOctober edition of Physical Review Letters, published by the AmericanPhysical Society. The research was supported by grants from the U.S.Department of Energy and the National Science Foundation.

Karchsaid they hope the work will spark extensive scientific exploration ofmany other questions involving string theory, extra dimensions and theevolution of the cosmos.


Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University of Washington. "Physicists Say Universe Evolution Favored Three And Seven Dimensions." ScienceDaily. ScienceDaily, 4 October 2005. <www.sciencedaily.com/releases/2005/10/051003233431.htm>.
University of Washington. (2005, October 4). Physicists Say Universe Evolution Favored Three And Seven Dimensions. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2005/10/051003233431.htm
University of Washington. "Physicists Say Universe Evolution Favored Three And Seven Dimensions." ScienceDaily. www.sciencedaily.com/releases/2005/10/051003233431.htm (accessed September 18, 2014).

Share This



More Matter & Energy News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) Video provided by AP
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

Newsy (Sep. 16, 2014) MIT developed a robot modeled after a cheetah. It can run up to speeds of 10 mph, though researchers estimate it will eventually reach 30 mph. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins