Explanation:
Spanning the sky toward the majestic Clouds of Magellan is an unusual stream of gas: the Magellanic Stream.
The origin of this gas remains unknown but likely holds a clue to the origin and fate of our
Milky Way's
most famous satellite galaxies: the
LMC and the
SMC.
Until recently, two leading genesis hypotheses have been considered: that
the stream
was created by gas stripped off these galaxies as they passed through the
halo of our
Milky Way, or that the stream was created by the
differential gravitational tug
of the Milky Way.
Recently, however, wide angle radio images -- including those from the
Byrd Green Bank Telescope -- have shown that the
Magellanic Stream
is longer and older than previously thought, perhaps as old as 2.5 billion years.
These observations bolster a third possible origin for
the stream -- that the
Large and Small Magellanic Cloud
galaxies once passed so close to each other that
gravitational tides
triggered a burst of star formation that left the stream.
Pictured above digitally superposed on a recently-completed all-sky image in visible light, the
radio emission of Magellanic stream is shown in false color pink extending across the sky and ending at the
two Magellanic galaxies on the lower right.
digg_url = 'http://apod.nasa.gov/apod/ap100125.html'; digg_skin = 'compact';
New Mirror:
APOD now available in Hebrew from Israel
