Kepler Telescope Discovers First Earth-Size Planet in 'Habitable Zone'

NASA | APRIL 19, 2014

Using NASA's Kepler Space Telescope, astronomers have discovered the first Earth-size planet orbiting a star in the "habitable zone" -- the range of distance from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun.

Kepler-186f, the First Earth-size Planet in the Habitable Zone (Artist's Concept) Credit: NASA/Ames/SETI Institute/JPL-Caltech

While planets have previously been found in the habitable zone, they are all at least 40 percent larger in size than Earth, and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth.

Although the size of Kepler-186f is known, its mass and composition are not. Previous research, however, suggests that a planet the size of Kepler-186f is likely to be rocky.

Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets, which orbit a star half the size and mass of our sun.

The star is classified as an M dwarf, or red dwarf, a class of stars that makes up 70 percent of the stars in the Milky Way galaxy.

Kepler-186f orbits its star once every 130 days and receives one-third the energy from its star that Earth gets from the sun, placing it nearer the outer edge of the habitable zone. On the surface of Kepler-186f, the brightness of its star at high noon is only as bright as our sun appears to us about an hour before sunset.

YOU MAY ALSO LIKE

Does Mars Have Rings? Not Right Now, But Maybe One Day

Saturn has rings, but it's possible that one of our closest neighbors also had rings at one point and may have them again someday.

Cassini Finds Saturn Moon Has 'Sea Level' Like Earth

Saturn's moon Titan may be nearly a billion miles away from Earth, but a recently published paper based on data from NASA's Cassini spacecraft reveals a new way this distant world and our own are eerily similar.

Dust Storms Linked to Gas Escape from Mars Atmosphere

A study published this week based on observations by NASA's Mars Reconnaissance Orbiter during the most recent Martian global dust storm suggests such storms play a role in the ongoing process of gas escaping from the top of Mars' atmosphere.

Dark Matter Less Influential in Galaxies in Early Universe

New observations indicate that massive, star-forming galaxies during the peak epoch of galaxy formation, 10 billion years ago, were dominated by baryonic or “normal” matter.

NASA airborne research focuses on Andean volcanoes

A NASA-developed airborne imager called a synthetic aperture radar took a detailed look at volcanoes in Central and South America during an Earth science study in late April and early May 2014.

On Second Thought, the Moon's Water May Be Widespread and Immobile

A new analysis of data from two lunar missions finds evidence that the Moon’s water is widely distributed across the surface and is not confined to a particular region or type of terrain. The water appears to be present day and night, though it’s not necessarily easily accessible.