Universe Is Expanding – Quickly, Says Harvard Prof
COLLEGE STATION —
The universe is expanding, and it is doing so in a rapid manner, believes renowned astronomer Robert Kirshner of Harvard University.
His remarks were part of Mitchell Symposium on Observational Cosmology being presented this week at Texas A&M University. The conference features 40 of the world’s top astronomers and physicists commenting on a wide variety dealing with the universe.
Kirshner, speaking Monday “The Extravagant Universe,” said up until about 1917 it was believed the Earth and or the sun were the center of the universe.
| Robert Kirshner, Professor of Astronomy, Harvard University |
“We know now they aren’t even the center of our own galaxy, the Milky Way, and that our own galaxy is not the center of the universe,” he adds.
Kirshner said our sun is one of 100 billion stars in the Milky Way, and there are at least 100 billion galaxies in the universe.
Astronomer Edwin Hubble showed the Milky Way was not the whole universe, Kirshner said, which was a revolutionary idea 80 years ago. “He showed we live in a universe of galaxies, each equivalent to the Milky Way,” Kirshner noted.
Hubble, for whom the well-known space telescope is named for, was able to use the brightness of stars in galaxies to judge distances. From that, we learned of supernovas – super stars going through tremendous explosions.
“When we see the universe, we see it as it was, not as it is,” Kirshner said.
“Most of the light we see came from stars from two billion light years ago, although we’ve been able to detect light from as long as 14 billion years ago. It is this evidence that shows that our universe is expanding, and this expansion is speeding up over time.”
Kirshner said recent studies show that the universe is made up of 73 percent “dark energy” and 23 percent cold, dark matter. Atoms comprise only four percent of the universe, he says.
The conference concludes on Friday when John Kormendy of the University of Texas at Austin speaks about “Supermassive Black Holes.”
For more information about the conference and individual speakers, visit: http://cosmology.tamu.edu or contact Roland Allen, Professor of Physics.
-aTm-
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