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Credit & Copyright: Mark Hanson
Explanation:
Can you see them?
This famous
Messier object
M89,
a seemingly simple
elliptical galaxy,
is surrounded by faint shells and plumes.
The cause of the shells is currently unknown, but possibly
tidal tails related to
debris left over from absorbing numerous small galaxies in the past billion years.
Alternatively the shells may be like ripples in a pond,
where a recent collision with another large galaxy created
density
waves that ripple through this galactic giant.
Regardless of the actual cause, the
featured image
highlights the increasing consensus that at least some elliptical
galaxies
have formed in the recent past, and that the outer halos of most
large galaxies are not really smooth
but have
complexities
induced by frequent interactions with -- and accretions of --
smaller nearby galaxies.
The halo of our own
Milky Way Galaxy
is one example of such
unexpected complexity.
M89 is a member of the nearby
Virgo cluster of
galaxies
which lies about 50 million
light
years distant.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Elliptical Galaxy
Publications with words: Elliptical Galaxy
See also: