The Milky Way galaxy is on a collision course with the Andromeda galaxy. When the two impact, the earth will cease to exist.
However, this probably won't happen for a few billion years.
"I recommend you don't lose sleep about this since 4.5 billion years is a long time," said Margaret Geller, senior astronomer at the Smithsonian Astrophysical Observatory.
Geller spoke about the collision of galaxies to a packed auditorium during a recent visit to the U. Her talk was part of the Frontiers of Science lecture series sponsored by the College of Science.
Geller and her fellow scientists are using Hubble's Law to pioneer the construction of a cosmic map of the universe. Their studies have helped revolutionize astronomers' knowledge of the structure of the universe.
Hubble's Law, proposed by American astronomer Edwin Hubble in the 1920s, is the theory that the distance between galaxies is continuously increasing, and as a consequence, the universe is expanding. This theory also supports the idea that the universe began with an explosive "big bang."
Addressing a pitch-black auditorium, Geller used a projected computer simulation to demonstrate the process that leads to the collision of galaxies.
She showed how the galaxies merge in a process that can take 100 million years or more. What happens is that the galaxies are traveling at a speed of around 40,000 miles per hour when they collide. Over time, they will either merge to form one galaxy or pass through each other. In the aftermath of the collisions, planets and stars are formed.
Geller's cosmic map will act as a history book of space as it traces the evolution of galaxies.
"When you look out into space, you essentially see the history of the universe,"Geller said.
jgoldsmith@chronicle.utah.edu
