ANDROMEDA GALAXY Frontal collision with the Milky Way

Science and techno world topic: Space

Our neighboring Andromeda galaxy will collide in about four billion years ago, probably head-on with the Milky Way. This resulted in an analysis presented yesterday by detailed observations of the Hubble Space Telescope. After another two billion years of the two galaxies, then new, elliptical galaxies have been formed.

This could look like in our night sky around 3.75 billion years ago.The collision with the Andromeda galaxy is then imminent. Picture:NASA, ESA, Z. Levay, R. van der Marel (STScI) and A. Mellinger

"Our results indicate statistically indicate a head-on collision between the Milky Way and the Andromeda galaxy," says Roeland van der Marel together at the Space Telescope Science Institute (STScI) yesterday introduced the study. It is based on detailed observations with the Hubble Space Telescope, with which the motion of the Andromeda galaxy could be measured more accurately than ever before. Also known as Messier 31 (M31) galaxy is known at present from about 2.5 million light-years more of us. Milky Way and M31, however, draw on each other, so that they come closer to unstoppable.

That the Milky Way and Andromeda collide and merge again be, astronomers have long suspected. What will happen but just in a few billion years, you might not know yet. "After nearly a century of  speculation about the future fate of Andromeda and Milky Way, we finally have a clear idea of what will happen in the next few billion years," said Tony Sangmo son of STScI.

The new measurements from Hubble were used in computer simulations that the processes were modeled in our local group, our home galaxy clusters. They showed that it will take after the collision in four billion years ago, some two billion years before the two galaxies have merged completely and a new elliptical galaxy is formed.

Although galaxy collisions often appear dramatic, the individual stars in the galaxy happen while relatively little: The space between the stars of a galaxy is so large that direct collisions of stars do not occur in practice. The stars, however, come in a collision on a new cars and it is very likely that our solar system at the end of the merger process much further from the galactic center is new as it is today from the galactic center.

For additional complications should also provide the Triangulum Galaxy (M33), a smaller companion galaxy of Andromeda. Also, this system will be, involved in the collision and would later merge with the pair of Milky Way and Andromeda Galaxy. There is even a slim chance that the M33 galaxy first strikes.

Although the universe as a whole continues to expand, but be everywhere observed collisions of galaxies and even clusters of galaxies. The reason for this is that these galaxies are bound together by their gravitational force. We know, for many decades that the Andromeda galaxy is moving at a speed of 400,000 kilometers per hour on the Milky Way.

From this information alone could be deduced, however, is not whether Andromeda will collide head-on with one of the Milky Way, or perhaps they just touches, or even just missed. This requires also data on the tangential velocity component of Andromeda, so their movement "to the side." Just now these traditional observations of the Hubble Space Telescope, "This, we have observed repeatedly succeeded by certain selected regions of the galaxy over a period of five to seven years," said Jay Anderson from the STScI.

"In the worst case of the M31 meets head-on simulation of the Milky Way and all the stars are scattered throughout this whole new orbit," said Gurtina Besla from Columbia University in New York. "The stellar populations of the two galaxies merge, the galaxy loses its flat pancake-like appearance. The cores of the galaxies merge, and the stars are reflected in random orbits, forming an elliptical galaxy."

The results of the astronomers are described in three scientific articles that appear in the journal The Astrophysical Journal.