A filament of hydrogen gas connecting the Triangulum Galaxy,
M33, with the giant Andromeda Galaxy, M31, indicates a close
encounter probably occurred billions of years ago between our
two galactic neighbors. Using the National Science Foundation’s
Green Bank Telescope (GBT), U.S. astronomers have established
the existence of a hydrogen “bridge” that was first spotted in
2004 with six dense clumps of gas revealed. “The properties of
this gas indicate that these two galaxies may have passed close
together in the distant past,” said Jay Lockman at the National
Radio Astronomy Observatory (NRAO) in a press release. “Studying
what may be a gaseous link between the two can give us a new key
to understanding the evolution of both galaxies.” The two
galaxies belong to the Local Group, which comprises about 30
galaxies including the Milky Way. They are about 2.6 and 3
million light-years away from Earth respectively. Extended
regions of stars and interstellar gas can form between galaxies
when they interact due to gal