New Delhi, Jan 05: The Milky Way - our home galaxy - is rotating at a much faster rate, is much heavier and has
a much higher likelihood of colliding with neighbouring
galaxies than previously estimated, new findings presented
today suggest.
Astronomers have found that Milky Way - in which our
solar system is located - is moving at six lakh miles per hour
in the Galactic orbit which is higher by one lakh miles per
hour than previously estimated.
Scientists at the Harvard-Smithsonian Center for
Astrophysics, Massachusetts say that the present speed
increased the mass of Milky Way by 50 percent making it equal
to nearby Andromeda Galaxy.
"No longer will we think of the Milky Way as the little
sister of the Andromeda Galaxy in our Local Group family,"
said Mark Reid, one of the researchers.
The larger mass, in turn, means a greater gravitational
pull that increases the likelihood of collisions with the
Andromeda galaxy or smaller nearby galaxies, he said.
"Our Solar System is about 28,000 light-years from the
Milky Way`s centre. At that distance, the new observations
indicate, we`re moving at about 600,000 miles per hour in our
Galactic orbit, up from the previous estimate of 500,000 miles
per hour," Reid said while presenting findings at American
Astronomical Society`s meeting in California.
The researchers have used Very Long Baseline Array (VLBA)
radio telescope to redraw the map of Milky Way. The telescope,
known for its ability to make very detailed images of the
galaxy, is being used by scientists to measure distances and
motions taking place in it.
"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.
"These measurements use the traditional surveyor`s
method of triangulation and do not depend on any assumptions
based on other properties, such as brightness, unlike earlier
studies."
The astronomers found that their direct distance
measurements differed from earlier, indirect measurements,
sometimes by as much as a factor of two.
"These direct measurements are revising our
understanding of the structure and motions of our galaxy,"
Menten said.
"Because we`re inside it, it`s difficult for us to
determine the Milky Way`s structure. For other galaxies, we
can simply look at them and see their structure, but we can`t
do this to get an overall image of the Milky Way. We have to
deduce its structure by measuring and mapping," he added.
Bureau Report
