The merger of the Milky Way and the Andromeda Galaxy will not happen for another four billion years, but the recent discovery of a massive halo of hot gas around the Andromeda probably means that our galaxy has reacted $ CUT $. A team of astrophysicists led Nicolas Lehner of the University of Notre Dame, using the Hubble Space Telescope have discovered a huge halo of hot ionized gas extending for at least two million light years around Andromeda.

The Andromeda Galaxy is the largest member of the local cluster, consisting of fifty-four galaxies, including the Milky Way. It is about a trillion stars that is about four times larger than the Milky Way, which shines 25% brighter, and can be easily detected by the naked eye in the sky in suburban and rural areas. Think about that for a moment - if the halo extends over at least a million light-years away in the direction of us, these two galaxies are located much closer to each other than previously thought, and now their molecules interact. Of course, in this case we are talking only about the interaction of the halo instead of the galaxies themselves. Lehner calls these ghosting "gaseous atmosphere of galaxies." Despite the huge size, the Andromeda halo is almost invisible. To find and study the aura, the team used quasars and distant stars, as objects that emit huge amounts of energy. For example, the bright quasar 3C273 in Virgo can be seen in a 6-inch telescope! Their brightest, pitting nature makes them an ideal tool.

"Before the light from quasars reach Hubble, he said, in part, will be absorbed by the gas halo of the galaxy, causing the quasar dim in a very small range of wavelengths," said study co-author

Christopher Hawke professor of physics at the University of Notre-Dame. "By measuring the drop in brightness of this quasar, we can judge the size of the halo around the M31." The astronomers studied the halo around another 44 galaxies, but none of them, it was not as massive as in Andromeda. Researchers estimate the mass of the halo, is a hot diffuse gas in half the mass of all the stars in the most M31. Computer models suggest that it was formed in the same period as the rest of the galaxy. Although the halo is mostly ionized hydrogen - protons and electrons - and it is also rich in heavy elements, probably supplied supernovae. Elements such as iron, silicon, oxygen during supernova explosions are thrown away from the visible part of the galaxy, deep space. During the entire existence of Andromeda, almost half of all heavy elements created by its stars were thrown far beyond the stellar disk of the galaxy (disc diameter about 200 000 light-years). The next time you look at Andromeda clear night, you should know that it is much closer than you think!