Try not to bubble over… Dive into this beautiful Hubble visualization of the Bubble Nebula, located about 7,100 light-years away in the constellation Cassiopeia. This “bubble” is actually seven light-years across! It’s being blown into space by a massive, super-hot star about 45 times the size of our Sun. Gas on the star gets so hot that it escapes into space as a "stellar wind" moving at over 4 million miles per hour. This outflow sweeps up the cold, interstellar gas in front of it, forming the