Astronomers first discovered a hint of this cometlike ball of gas careering through a distant cluster of galaxies called Abell 3266 two years ago, but they didn't know what to make of it. It doesn't emit visible light. But now astrophysicists have mapped its thermodynamics using X-ray data caught by the European Space Agency's XMM-Newton satellite
in a high-speed camera chase. And as it turns out, this fireball is full of surprises.
In this image, the "comet" is confined to the red-orange regions. As it moves from the top left to the bottom right, its tail fans out across the green galaxy cluster. The fireball and its tail measure 6 million light-years long (one light-year is about 6 trillion miles). So the gas ball is big enough to engulf our entire solar system 5 billion times over, making it the largest of its kind ever discovered.
The comet is hotter than the center of the sun, measuring a scorching 83 million degrees Fahrenheit. The red-orange region in the middle represents the fireball's charged gas, or plasma, and has lower entropy—that is, it has more order—than the even hotter green galaxy cluster it moves through.
And boy, is it moving. The gas ball travels at 1.8 million miles an hour—600 times faster than a speeding bullet—through the galaxy cluster, giving researchers clues as to how such clusters grow. As the comet hurtles along, gas is stripped away from the edges, leaving mass behind.
Don't panic—it's traveling in the opposite direction from Earth. And it's already 864 million light-years away. This map includes hundreds of galaxies. Here, some appear as little white dots.
5 And Out of Control
The fireball probably entered the galaxy cluster at an angle and now follows an eccentric path. The image shows the ball plowing straight into the cluster after taking the plunge. Now it's veering off to its left.
6 But Also Nice
The great ball of fire is actually a creative force, not a destructive one. The gas ball's sloughing fuels galactic growth. A sun's worth of mass spins off every hour, and that scattered matter may eventually seed new stars and galaxies.