New 'super-Earth' the best candidate yet for life beyond our solar system
A newly discovered "super-Earth" 39 light years away could be the best candidate yet for a world beyond the solar system that harbours life, say scientists.
The planet circles the faint dwarf star LHS 1140 in the constellation Cetus and lies at the heart of the habitable zone - the orbital band where temperatures are mild enough to allow liquid surface water.
Although it is 1.4 times the size of Earth, its mass is seven times greater, implying a dense world made of rock with an iron core.
Astronomers estimate the planet to be at least five billion years old - about the same age as the Earth and long enough for life to have evolved. Its star emits less radiation than many other red dwarfs, making it more likely to have preserved an atmosphere.
Lead scientist Dr Jason Dittmann, from the Harvard-Smithsonian Centre for Astrophysics in Cambridge, US, said: "This is the most exciting exoplanet I've seen in the past decade. We could hardly hope for a better target to perform one of the biggest quests in science - searching for evidence of life beyond Earth."
The discovery, reported in the journal 'Nature', was made using the MEarth-South telescope array in Cerro Tololo, Chile, which detected tell-tale dips in light as the planet passed in front of its star. Follow-up observations studied the star's 'wobble' caused by a gravitational tug of war with the planet and confirmed the presence of a super-Earth.
Meanwhile, an asteroid nicknamed 'The Rock' that could be big enough to devastate a country last night made its closest approach to Earth in 400 years.
The "potentially hazardous" asteroid 2014 JO25 flew past Earth at 33 metres per second at a distance of just over a million miles - far enough away to be safe but uncomfortably close in astronomical terms.
Experts put its size at between 650 metres and 1.4km in length. An asteroid a mile wide hitting the Earth would unleash as much energy as around 1,000 atom bombs like the one dropped on Hiroshima in 1945.