How big is the universe? What are the dimensions of our galaxy? Are there other planets like Earth out there among the stars? We have asked these questions around campfires and in the halls of universities for centuries. Today, we know that the answers lie hidden in the positions and distances of the stars and galaxies. And each time scientists have measured these positions and distances with greater accuracy, they have gained a wealth of new understanding.
SIM PlanetQuest (formerly called Space Interferometry Mission), currently under development, will determine the positions and distances of stars several hundred times more accurately than any previous
program. This accuracy will allow SIM to determine the distances to stars throughout the galaxy and to probe nearby stars for Earth-sized planets. SIM will open a window to a new world of discoveries.
This breakthrough in capabilities is possible because SIM will use optical interferometry. Pioneered by Albert Michelson, who became the first American to win the Nobel Prize in physics in 1907, optical interferometry can fulfill its full potential only outside the distorting effects of Earth's atmosphere. There, it can combine light from two or more telescopes as if they were pieces of a single, gigantic telescope mirror. Developed for use in space with SIM, this technique will eventually lead to the development of telescopes powerful enough to take images of Earth-like planets orbiting distant stars and to determine whether these planets sustain life as we know it.
SIM is being developed by the Jet Propulsion Laboratory under contract with NASA and in close collaboration with industry partner Northrop Grumman in Redondo Beach, California.
