Diagram showing the size and scale of the Kepler-452 system compared with the Kepler-186 system and our Solar System. Kepler-186 is a mini planetary system that could fit inside Mercury's orbit. Credit: NASA/JPL-Caltech/R.Hurt
NASA’s Kepler mission has discovered an Earth-like planet in a system 1,400 lightyears away, marking a milestone in the journey to finding another habitable planet.
Kepler-452b is the smallest planet yet to have been discovered orbiting in the habitable zone, meaning it is the right distance from its star to enable water to pool on the planet’s surface.
The news brings the total number of confirmed planets in the habitable zone to 1,030.
"On the 20th anniversary year of the discovery that proved other suns host planets, the Kepler exoplanet explorer has discovered a planet and star which most closely resemble Earth and our Sun," says John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington.
“This exciting result brings us one step closer to finding an Earth 2.0."
Kepler-452b is 60 per cent larger in diameter than our own planet, making it a super-Earth size planet. Previous research suggests that planets this size could potentially be rocky.
Its orbit is 385 days, making its year just 5 per cent longer than our own, and it is 5 percent farther from its star Kepler-452 than Earth is from the Sun.
The star itself is 6 billion years old, 1.5 billion years older than our Sun, has a similar temperature, is 20 per cent brighter and has a diameter 10 per cent larger.
“We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth’s evolving environment," says Jon Jenkins, Kepler data analysis lead at NASA's Ames Research Center in Moffett Field, California, who led the team that discovered Kepler-452b.
"It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth.
That’s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.”
The information released by NASA was collected through ground-based observations at the University of Texas at Austin's McDonald Observatory, the Fred Lawrence Whipple Observatory on Mt. Hopkins, Arizona and the W. M. Keck Observatory atop Mauna Kea in Hawaii.