The SIM Lite Astrometric Observatory is 6-meter baseline Michelson interferometer capable of positional accuracies of 4 microarcseconds all over the sky and 1 microarcsecond for selected targets. SIM Lite addresses foundational problems across all of astrophysics:
SIM Lite will identify terrestrial planets in the habitable zones of their stars, as well as hundreds of other planets.
SIM Lite will determine masses and luminosities of stars at their extremes, including brown dwarfs, neutron stars, and black holes, permitting tests of models of stellar evolution.
SIM Lite will determine the age of the Milky Way, its formation history, the Sun’s place in it, the distribution of dark matter in the Milky Way and Local Group, and place limits on the mass of the dark matter particle.
SIM Lite will investigate the sources and mechanisms of energy release and jets from stellar masses to mega-solar-mass galactic nuclei.
SIM Lite will establish an optical astrometric grid accurate to 4 microarcseconds over the whole sky.
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.
The SIM Lite Astrometric Observatory (formerly called the 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 Lite 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 from planets around nearby stars to the behavior of quasars billions of light years away.
Displacement of the Sun over 45-year period caused by Jupiter, as observed from 33 light-years away. To download a copy, click here.
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.
The SIM Lite Astrometric Observatory 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.
