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Дата изменения: Unknown Дата индексирования: Sat Dec 22 01:32:12 2007 Кодировка: Поисковые слова: coma |
Astronomy Picture of the Day |
APOD: 2004 November 21 - Spiral Galaxies in Collision
Explanation:
Billions of years from now, only one of these two galaxies will remain.
Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart,
creating tides of matter, sheets of
shocked gas, lanes of
dark dust, bursts of
star formation, and streams of
cast-away stars.
Astronomers predict that NGC 2207, the larger galaxy on the left, will
eventually incorporate IC 2163, the smaller galaxy on the right.
In the most
recent encounter that peaked 40 million years ago,
the smaller galaxy is swinging around counter-clockwise,
and is now slightly behind the larger galaxy.
The space between stars is so vast that when
galaxies collide,
the stars in them usually do not collide.
APOD: 2004 June 12 - NGC 4676: When Mice Collide
Explanation:
These two mighty galaxies are pulling each other apart.
Known as "The Mice" because they have such long tails, each
spiral galaxy
has likely already passed through the other.
They will probably collide again and again until they coalesce.
The long
tails are created by the relative
difference between gravitational pulls
on the near and far parts of each galaxy.
Because the distances are so large,
the cosmic interaction takes place in slow motion --
over hundreds of millions of years.
NGC 4676
lies about 300 million
light-years away toward the constellation of
Coma Berenices and are
likely members
of the Coma Cluster of Galaxies.
The above picture was taken with the
Hubble Space Telescope's
Advanced Camera for Surveys
which is more sensitive and images a larger field than
previous Hubble cameras.
The camera's increased sensitivity has imaged, serendipitously,
galaxies far
in the distance scattered about the frame.
APOD: 2005 April 4 - NGC 1316: After Galaxies Collide
Explanation:
How did this strange-looking galaxy form?
Astronomers turn detectives when trying to
figure out the cause of unusual jumbles of stars, gas, and
dust like
NGC 1316.
A preliminary inspection indicates that
NGC 1316 is an enormous
elliptical galaxy
that includes dark dust lanes usually found in a spiral.
The above image taken by the
Hubble Space Telescope
shows details, however, that help in
reconstructing the history of this gigantic jumble.
Close inspection finds fewer low mass
globular clusters
of stars toward NGC 1316's center.
Such an effect is expected in galaxies that have undergone
collisions or
merging with other galaxies in the past few billion years.
After such collisions, many
star clusters would be
destroyed in the dense galactic center.
The dark knots and lanes of dust
indicate that one or more of the devoured galaxies were
spiral galaxies.
NGC 1316
spans about 60,000 light years and lies about 75 million
light years away toward the constellation of the Furnace.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
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Disclaimers
NASA Official: Jay Norris.
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A service of:
EUD at
NASA /
GSFC
& Michigan Tech. U.