A large, rocky planet that\u2019s 289 trillion miles away is emerging as a top contender in the search for biological life outside of Earth \u2014 and it\u2019s a planet that a University of Colorado Boulder professor helped discover.<\/p>\n
For a planet to support life as we know it, it must be rocky, have an atmosphere and have the right temperature to support liquid water. Astronomers believe that a planet named LHS 1140b<\/a> likely has all three.<\/p>\n Zach Berta-Thompson, an astrophysical and planetary sciences professor at CU Boulder, helped discover this planet in 2017 as part of his doctoral thesis work at Harvard University. Berta-Thompson was part of the MEarth Project<\/a>, an astronomical survey where the team used small ground based telescopes to search for planets, specifically small, rocky planets near small stars. The survey began in 2008 and ran about 10 years. The team discovered three planets during the MEarth Project, including LHS 1140b in 2017.<\/p>\n \u201cThis has been a planet \u2014 since we found it and we were pretty geeked about it \u2014 that\u2019s one leading contender as a place outside the solar system that we might consider looking for life, for biology,\u201d Berta-Thompson said.<\/p>\n Data collected by astronomers and published in the journal Science<\/a> on July 16 provides evidence that LHS 1140b has an atmosphere. This latest discovery of the planet\u2019s atmosphere means LHS 1140b has all the pieces scientists believe are essential for life.<\/p>\n LHS 1140b, which is 49 light-years away from Earth, is about six times the mass of Earth and has a radius about 1.7 times that of Earth. Based on its mass and radius, it\u2019s likely a rocky planet, Berta-Thompson said. Scientists believe there are either high-density oceans on this planet with a lot of water, or a substantial atmosphere that\u2019s contributing to the radius of the planet. It\u2019s located at a distance from its star that falls within a temperature range known as the habitable zone, where it\u2019s warm enough for liquid water to exist but not too warm, where the water evaporates and is lost.<\/p>\n \u201cThis is probably about the biggest planet that we could imagine still being rocky,\u201d Berta-Thompson said. \u201cIf you have a planet that\u2019s much bigger than this, it looks like then that planet will inevitably have a really thick hydrogen helium envelope, and we would think of it more like Uranus and Neptune or Saturn and Jupiter.\u201d<\/p>\n While scientists have classified it as similar to Earth, LHS 1140b is different from Earth in a few ways. It completes a full orbit around its star in less than 25 days<\/a>, compared to 365 days for Earth. The planet is also in a state of tidal locking, where it always presents the same face to its host star, meaning there are no day and night cycles on the planet. Its atmosphere is also likely to be rich in helium, whereas Earth\u2019s is thick with nitrogen. While the exact percentage of helium in the planet\u2019s atmosphere remains unknown, Earth\u2019s atmosphere is composed of about 78% nitrogen.<\/p>\n LHS 1140b orbits a red dwarf star, a type of star that\u2019s much cooler than the sun and about a fifth of the size.\u00a0Red dwarf stars are quite common<\/a>, making up about 75% of all stars in the galaxy.<\/p>\n The planet is about 8.8 million miles away from its star. Earth\u2019s distance from the sun averages about 93 million miles. The sun is a yellow dwarf star, which is much hotter than a red dwarf star. The surface temperature of red dwarf stars ranges from 3,100 to 5,800 degrees Fahrenheit compared to the sun, which is 9,900 degrees Fahrenheit.<\/p>\n Researchers detecting helium escaping from the atmosphere revealed that the planet has an atmosphere at all, a critical component for the planet\u2019s ability to support life.<\/p>\n