The
Milky Way and Andromeda galaxy won’t collide for next 4 billion years. But but
a recent discovery of a massive halo of hot gas close to Andromeda Galaxy may
mean that our galaxies are already touching. Astrophysicist Nicholas Lehner from University of Notre Dame, led a group of scientists using the
Hubble Space Telescope to detect an enormous halo of hot, ionized gas about 2
million light years in diameter around the galaxy.
The
Andromeda Galaxy and Milky Way are the largest member of a ragtag group of some
54 galaxies, called the Local Group. Andromeda, with almost a trillion stars —
twice as many as the Milky Way — shines 25% brighter and can simply be seen
with the naked eye from outlying and rural skies.
If
the recently discovered halo spreads at least a million light years in our
direction, our two galaxies are way MUCH closer to touching than previously
thought.
Lehner
defines halos as the “gaseous atmospheres of galaxies”. Regardless of its huge size, Andromeda’s nimbus
is almost invisible. To observe and study the halo, the astronomer sought out
quasars, distant star-like objects that emit incredible amounts of energy as
matter is sucked into the supermassive black holes. The brightest quasar, 3C273
in Virgo, can be easily observed with in a 6-inch telescope!
Learn
more here.