The Race to Find an Earthlike Planet

Professor Geoffrey Marcy has been searching for extrasolar planets since the last century. He is a leader in the field and is head of the Center for Integrative Planetary Science at the University of California at Berkeley. According to the Center, the first terrestrial planet (outside the solar system) was recently discovered orbiting GJ 876, a star about 15 light years away. The planet, called Gleise 876 d, was discovered by E. Rivera and his team and announced in 2005.

Temperature on Gleise 876 d is listed at a balmy 642 Kelvin (695 Fahrenheit) in The Guide to Extrasolar Planets. Scientists are still searching for a more Earth-like planet that has more moderate temperatures. To date, the search has been limited to only a small patch in the Milky Way near the solar system.

The Automated Planet Finder Telescope is being designed with the hope of answering some great questions in science: "Are other Earth-like planets common? Do they exist at all? If so, where are they?" The answer for now remains mysterious: "No one knows." Details on the specific technology to be used are sketchy, but as of 2008 the goal was to automate the search for terrestrial planets by using a computerized telescope to scan stars within 100 light years of Earth. It will include a spectrograph for the type of light analysis used in the search for extrasolar planets, and it will be fully automated.

The Kepler mission, launched in March, 2009, is another effort to find Earth-like exoplanets or extrasolar planets. It has a tremendous capacity for collecting information: In only ten days it took pictures of over 52,000 stars. Basically, the Kepler Telescope is a photometer that senses slight changes in light from a star. When an extrasolar planet passes in front of a star, some of the light from the star is blocked. The Kepler Telescope can sense the change in light emission.

Another method of finding extrasolar planets is to measure the effects on the parent star as the planet orbits. The gravity of the planet will cause the star's mass to wobble slightly, and by observing the wobbling mass of the star physicists infer the presence of an orbiting planet.

The NASA/JPL Space Interferometry Mission is a project to launch a space-based interferometry telescope to be used in the search for extrasolar planets. It will utilize data from the Kepler mission.

NASA's Terrestrial Planet Finder Mission is another mission that is currently in the planning phase.