NGC 6240 in 60 Seconds
Narrator (Joseph DePasquale, CXC): Two large galaxies are colliding and scientists have used Chandra to make a detailed study of an enormous cloud of hot gas that surrounds them. This unusually large reservoir of gas contains as much mass as about 10 billion Suns, spans about 300,000 light years, and radiates at a temperature of more than 7 million degrees. This giant gas cloud, which scientists call a "halo," is located in the system known as NGC 6240. As the galaxies - each about the size and shape of our Milky Way -- merge, the gas contained in individual galaxy has been violently stirred up. This caused a baby boom of new stars that has lasted for at least 200 million years. During this burst of stellar birth, some of the most massive stars raced through their evolution and exploded relatively quickly as supernovas. According to researchers, this created new hot gas enriched with important elements -- such as oxygen, neon, and magnesium -- that expanded into and mixed with cooler gas that was already there. In the future, the two spiral galaxies will probably form one young elliptical galaxy over the course of millions of years. It is unclear, however, how much of the hot gas can be retained by this newly formed galaxy, or if it will be lost to surrounding space. Regardless, the collision in NGC 6240 offers the opportunity to witness a relatively nearby version of an event that was common in the early Universe.