In a galaxy far, far away, about 60 million light years from Earth, a huge cloud of unfathomably hot gas spotted by NASA's Chandra X-Ray Observatory tipped astronomers towards an amazing cosmic spectacle -- the collision of a dwarf galaxy and one of its much larger brethren.
While more observation is needed before astronomers can officially confirm what they think they see, the discovery represents the first time such a collision of galaxies has been detected using only X-rays, a feat which could prove to be a significant learning experience which could have implications for understanding how galaxies grow through such collisions.
The dwarf galaxy appears to be crashing into the much larger galaxy NGC 1232. The collision most likely caused a cosmic shock wave -- something like a sonic boom on Earth -- that generated temperatures around 6 million degrees Fahrenheit.
Chanda's X-ray data (evinced by the purple haze in the photo) plus optical light data created the spectacular composite image above. The gas cloud's comet-like appearance is caused by the motion of the dwarf galaxy.
A cluster of very bright stars are at the head of the gas emission. Astronomers suggest the shock wave was so powerful it may have triggered star formation.
At this point astronomers are unable to determine the mass of the entire gas cloud. The cloud could be thin like a pancake or have a spherical shape and thus a larger mass, but the two-dimensional image is not detailed enough for astronomers to make a definitive conclusion. Best estimates place the pancake-flat gas cloud at the mass equivalent of 40,000 Suns, while a more voluminous gas cloud could have the mass three million times that of the Sun.