The M51 "Whirlpool
Galaxy" shines as one of the brightest spiral galaxies in the night sky.
Several
NASA space observatories combined to produce this composite image. The Chandra
X-ray Observatory shows purple, point-like sources that indicate black holes
and neutron stars in binary star systems, and also picks up on the glow of hot
gas lighting the space between the stars. The Hubble Space Telescope provides
optical data in green, while the Spitzer Space Telescope sees red infrared
emissions — both reflect lanes of stars, gas, and dust in the galaxy's spiral
arms. The Galaxy Evolution Explorer completes the image with views of hot,
young stars giving off ultraviolet energy in blue.
The spiral
shape may be a result of a galactic encounter when NGC 5195 passed through
M51's main disk about 500 million years ago. That gravitational tug-of-war likely
triggered a new round of starbirth, as gravitational forces condensed gas and
jump-started the process of star formation.
— NASA/JPL-Caltech and SPACE.com Staff
Credit: X-ray: NASA/CXC; UV:
NASA/JPL-Caltech; Optical: NASA/ESA/STScI/AURA; IR: NASA/JPL-Caltech/ Univ. of Ariz.
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