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Selasa, 10 Juli 2012

Solar system moving 100000 mph faster than thought; 15% speed increase translates to doubling of mass of Milky Way

Solar system moving 100000 mph faster than thought; 15% speed increase translates to doubling of mass of Milky Way

By WcP.System.Thinker 

our solar system

It turns out that our solar system is moving nearly 100,000 m.p.h. faster than previously thought — revolving around the center of the Milky Way at 568,000 m.p.h., announced Mark Reid of the Harvard-Smithsonian Center for Astrophysics on Monday at the American Astronomical Society's conference in Long Beach, Calif. Since velocity is related to mass, the 15% increase in solar-system speed translates into a near doubling of mass of the Milky Way, according to Reid's group — and all of that newfound bulk is composed of dark matter.

the Milky Way 

Original estimates of the solar system's speed were based on what Reid calls "one- dimensional velocity" obtained solely from Doppler shifts. "Now," he says, "we have three-dimensional velocity and more exact measurements" — a huge advancement in the field. The findings debunk the notion that the Milky Way is a little-sister galaxy to her neighbor Andromeda. "They're more like fraternal twins," Reid says. And the fact that they are of equal size increases the likelihood that the two will someday collide.
But humans needn't flee the galaxy anytime soon. First, there's so much room between stars that Earth likely wouldn't feel any effects of a galactic collision, though our constellations would certainly change. And second, a crash is still about 3 billion to 5 billion years away, by which time our sun will have transformed into a red giant and turned the Earth into a smidgen of charred dust.

the solar system; the relative size of the planets is indicated but the Sun is very much larger than shown 

A flurry of recent findings has provided a clearer understanding of the Milky Way than ever before. Just a few weeks before Reid's announcement, Martin Pohl, an associate professor of physics and astronomy at Iowa State University, revealed the most detailed map to date of the galaxy's spiral arms. Pohl's map establishes that there are two symmetric arms in the inner part of the galaxy that branch off into four — answering a question that astrophysicists have grappled with for 50 years. (According to Pohl, our solar system is located near one of the branching-off points, about 28,000 light-years — or 168 quadrillion miles — from the galactic center.)

Photos courtesy of scienceclass.ning.com, lns.mit.edu, and gcsescience.com
Original Source: Time

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