Cartwheel of Fortune
Explanation:
By chance, a collision of two galaxies has created a surprisingly
recognizable shape on a cosmic scale,
The
Cartwheel Galaxy.
The Cartwheel is part of a group of galaxies about 500 million
light years away in the constellation Sculptor.
Two smaller galaxies in the group are visible on the right.
The Cartwheel Galaxy's rim is an
immense
ring-like structure 150,000 light
years in diameter composed of newly formed,
extremely bright, massive stars.
When galaxies
collide they pass through each other,
their individual stars rarely coming into contact.
Still, the galaxies' gravitational fields are seriously
distorted by the collision.
In fact, the ring-like shape
is the result of the gravitational
disruption caused by a small intruder galaxy passing
through a large one,
compressing the interstellar gas and dust and
causing a a star formation wave to move out from
the impact point like a ripple across the surface of a pond.
In this case the large galaxy may have originally been a spiral,
not unlike our
own Milky Way, transformed
into the wheel shape by the collision.
But ...
what happened to the small intruder galaxy?
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
