Highlights Scientists have discovered more than 5,000 planets outside of the Solar System, or “exoplanets”. Most stars in our galaxy have at least one exoplanet, and many are unlike any of the worlds in the Solar System. Some exoplanets could be habitable and are prime targets in the search for life beyond Earth.

Astrometry is the oldest method used to search for extrasolar planets. As early as 1943 astronomer Kaj Strand, working at the Sproul Observatory at Swarthmore College announced that his astrometric measurements revealed the presence of a planet orbiting the star 61 Cygni. Although the announcement was greeted with enthusiasm at the time, the claim has remained …

Advantages Transit photometry is currently the most effective and sensitive method for detecting extrasolar planets. It is a particularly advantageous method for space-based observatories that can stare continuously at stars for weeks or months.

Advantages Microlensing is capable of finding the most distant and the smallest planets of any currently available method for detecting extrasolar planets. In January 2006 scientists announced the discovery through microlensing of a planet of only five Earth masses, orbiting a star near the center of our galaxy, 22,000 light-years away! It was the lowest mass planet detected up to …

At a glance: Exoplanets are planets that orbit other stars. Some look like planets in our own solar system, while others are dramatically different. Exoplanets seem to follow the same general rules as the planets in our solar system: Small planets are rocky, big planets are gassy, and the ones in between may be watery. There are other rocky worlds orbiting stars at the right distance to …

Transit Timing Variations Many extrasolar planets have been discovered by watching them transit (cross in front of) their stars. Although we can’t see the planet itself, we can see the dip in brightness of the star as the planet blocks some of it from Earth’s view.

This is a serious problem for planet hunters, because mass is the leading criterion for distinguishing between planets and small stars. Some astronomers believe that at least some of the "planets" detected by the radial-velocity method are not planets at all but very low-mass stars.

This makes it complementary to the radial velocity method, which is most effective for planetary systems positioned edge-on to Earth and planets orbiting close to their parent star.

2023年10月11日 · One of humanity’s biggest questions remains: “ Are we alone?” For nearly half a century, astronomers have looked for messages from extraterrestrial intelligences that might reach Earth. Many other astronomers hope to answer this question by taking detailed observations of exoplanets: planets orbiting distant stars. But how can astronomers hope to …

2007年11月6日 · There was a big extrasolar planet announcement today. I'm young enough that, for me, it's always been the Space Age. But there have been some major revolutions in space science in the time I've been around, and one of those is extrasolar planets. I had a Time-Life series of books on science that I read and reread growing up, and I remember reading about …