Research using SALT at the South African Astronomical Observatory has led the facility to important discoveries. By using the "Southern African Large Telescope", SAAO has the ability to take "snapshots" of stars in very quick succession. It is optimized for wavelengths and observing modes not available on other very large telescopes. As a result, astronomers can study rapidly changing properties of compact stars, primarily as they pull in gas from their companion stars or surroundings. The significance of this discovery allows us to detect black holes. The gravitational field of a compact star commonly pulls in gas from a companion star, thus radiation (especially X-ray) is emitted. Scientists used this as an indirect way to locate black holes. Another phenomenon that SALT has helped astronomers investigate is the way that masses build up on some compact stars until supernova explosions blow them apart, which gives scientists a "Type 1a" supernovae used to show that the expansion of the universe is speeding up.