Astronomers announced Wednesday they have discovered the smallest known planet. Dubbed Kepler-37b, the planet, roughly the size of Earth’s moon, was discovered outside of our solar system and is the smallest ever found in space.
Although tiny and relatively similar in size to Earth, experts say the planet likely does not have the ability to hold life. The temperature of the tiny planet is estimated to be 700 degrees Fahrenheit as it sits very close to its sun-like star. The small planet is also missing an atmosphere and there are no signs of a source of water. According to NASA, the tiny planet almost certainly is rocky in composition.
It was found in the constellation Lyra and is the third planet to be discovered in that area. It is roughly 210 light-years away from Earth and has been named Kepley-37b by NASA.
Over a year ago, Thomas Barclay of the NASA Ames Research Center in Northern California, discovered the tiny planet, which he immediately knew was not a moon. However, scientists weren’t so quick to agree with him as it took a year and an international team of researchers to announce that it was, indeed, a planet.
Still, the announcement has the astronomy community buzzing. One of the most famous planet-hunters, astronomer Geoff Marcy of the University of California, Berkeley, said Wednesday’s discovery is “absolutely mind-boggling.” Marcy, who did not participate in the discovery said it is the latest indication that the universe contains a diverse set of planets that seem to come in all shapes and sizes.
“This new discovery raises the specter that the universe is jam packed, like jelly beans in a jar, with planets even smaller than Earth,” he said.
Astronomers have long posited that planets smaller than Earth must exist, but until now they have not have any definitive proof evidence. The tiny planet is far smaller than our solar system’s tiny planet, Mercury, which is about two-fifths the size of Earth. The small planet is estimated to be one-third the size of our planet, according to NASA.
Thanks technology developed by NASA, there has been an overwhelming number of new planet discoveries outside of our solar system in recent months. The space agency developed the Kepler Space Telescope in 2009 in hopes of discovering Earth-like planets. The telescope keeps track of over 150,000 stars, searching for planets similar to Earth. According to NASA, there have been 861 planets outside of our solar system discovered and the Kepler Space Telescope has had a hand in discovering a large majority of them.
NASA’s Kepler Space Telescope searches for planet candidates orbiting distant suns, or exoplanets, by continuously measuring the brightness of each star. When a planet candidate passes, or transits, in front of the star from the telescope’s vantage point, light from the star is blocked, producing a dimming effect. Different sized planets block different amounts of starlight. The amount of starlight blocked by a planet reveals its size relative to its star.
Even though the small planet is not habitable, Alan Boss of the Carnegie Institution for Science in Washington, who did not participate in the study, says the planet is a major milestone for NASA scientists and astronomers around the world.
“It does not detract from the fact that this is yet another mile marker along the way to habitable Earth-like planets,” he said.
The discovery comes as NASA announced late last year that the successful completion of the Kepler Space Telescope’s three-year prime mission and the beginning of an extended mission that could last as long as four years. The extended mission is set to focus on using the data collected over the past three years to begin discovering true sun-Earth analogs — Earth-size planets with a one-year orbit around stars similar to the sun.
Details of the discovery are slated for publishing in this month’s issue of Nature.