NASA’s talking about a mission called the Wide Field Infrared Survey Telescope or WFIRST. The mission is designed to search for planets outside our solar system where the majority of stars are. Studying the properties of these distant planets will help scientists to understand planetary systems throughout the galaxy and how planets form and evolve. Data gathered from WFIRST will be combined with data from Kepler and TESS missions to complete the first planet census that is sensitive to a wide range of planet masses and orbits.
The goal of the mission is to discover habitable Earth-like worlds beyond our world. Currently, most exoplanets are found when they pass in front of their host stars in an event called a transit that temporarily dims the star’s light. While WFIRST data can spot transits, it will primarily watch for the opposite effect. That effect is described as little surges radiance produced by a light-bending phenomenon called microlensing.
The team says that microlensing signals from small planets are rare and brief, but they are stronger than the signals gathered from other methods. Microlensing was one of the predictions of Einstein’s general theory of relativity and was confirmed in 1919. Scientists say that planets orbiting the foreground star could modify the lensed light and act as its own tiny lens.
The distortion created will allow astronomers to measure the planet’s mass and distance from its host star, and this is how WFIRST will use microlensing to discover new planets. So far, more than 4000 confirmed exoplanets have been found, but only 86 of them were discovered via microlensing. WFIRST’s microlensing survey will allow scientists to find analogs for every planet in the solar system except Mercury.
Planets the size of Mercury have a small orbit and low mass, making such planets out of the reach of WFIRST. The mission will also be able to find planets in other poorly studied categories. Microlensing is best suited to finding worlds and reaching out further to include ice giants like Uranus and Neptune.