This artist’s design illustrates a Jupiter-like a planet alone in the darkness of space, floating free with no parent star.
Exoplanet hunters have found thousands of planets, most orbiting near their host stars, but relatively few alien worlds have been detected floating freely through the galaxy as so-called rogue planets, unrelated to a star. Many astronomers believe these planets are more common than we think, but our planet-finding techniques have fallen short in locating them.
A planetary survey, called Microlensing Observations in Astrophysics (MOA), scanned the central bulge of our Milky Way galaxy from 2006 to 2007. He used a 5.9-foot (1.8-meter) telescope at Mount John University Observatory in New Zealand and a technique called gravitational microlensing. In this method, a planet-sized body is identified indirectly as it passes just in front of a more distant star, causing the star to glow. The effect looks like a cosmic mirror or magnifying glass – the background starlight is distorted and amplified, becoming brighter.
Using the latest technology, NASA’s Nancy Grace Roman Space Telescope will survey to discover many more exoplanets using powerful techniques available to a wide-field telescope.