Milky Way has become a faster spinner, making it more massive

January 6th, 2009 - 12:50 pm ICT by ANI  

Washington, Jan 6 (ANI): In a new research, a team of scientists has determined that the Milky Way Galaxy is rotating about 100,000 miles per hour faster than previously understood, making it more massive with time.

According to Mark Reid, of the Harvard-Smithsonian Center for Astrophysics, that increase in speed increases the Milky Ways mass by 50 percent, bringing it even with the Andromeda Galaxy.

No longer will we think of the Milky Way as the little sister of the Andromeda Galaxy in our Local Group family, he said.

The larger mass, in turn, means a greater gravitational pull that increases the likelihood of collisions with the Andromeda galaxy or smaller nearby galaxies.

Our Solar System is about 28,000 light-years from the Milky Ways center.

At that distance, the new observations indicate, our galaxy is moving at about 600,000 miles per hour in our Galactic orbit, up from the previous estimate of 500,000 miles per hour.

The scientists are using the National Science Foundations Very Long Baseline Array (VLBA) radio telescope to remake the map of the Milky Way.

Taking advantage of the VLBAs unparalleled ability to make extremely detailed images, the team is conducting a long-term program to measure distances and motions in our Galaxy.

The scientists observed regions of prolific star formation across the Galaxy.

In areas within these regions, gas molecules are strengthening naturally-occuring radio emission in the same way that lasers strengthen light beams.

These areas, called cosmic masers, serve as bright landmarks for the sharp radio vision of the VLBA.

By observing these regions repeatedly at times when the Earth is at opposite sides of its orbit around the Sun, the astronomers can measure the slight apparent shift of the objects position against the background of more-distant objects.

The new VLBA observations of the Milky Way are producing highly-accurate direct measurements of distances and motions, said Karl Menten of the Max Planck Institute for Radio Astronomy in Germany, a member of the team.

The star-forming regions harboring the cosmic masers define the spiral arms of the Galaxy, according to Reid.

Measuring the distances to these regions thus provides a yardstick for mapping the Galaxys spiral structure.

These direct measurements are revising our understanding of the structure and motions of our Galaxy, Menten said. (ANI)

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