Nasa has announced the discovery of Kepler 452B by their Kepler space telescope - a planet very similar to Earth in the Milky Way. Here are the latest updates:
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The Kepler telescope, which was launched in March 2009, has previously discovered more than 1,000 planets in space - but Nasa's teasing announcement suggests that this discovery could be its most significant to date.
It would be an astounding achievement, considering the first star-orbiting planet outside the solar system was discovered in 1995.
In a statement, Nasa said: "Today, and thousands of discoveries later, astronomers are on the cusp of finding something people have dreamed about for thousands of years - another Earth."
Kepler works by monitoring hundreds of thousands of stars at once, and analysing the light levels that they give out.
When a planet passes between the star and the telescope, it obscures some of the light, and Kepler notices the dip in light levels.
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Using this method, it has been responsible for the vast majority of planet discoveries in the last few years.
Currently, Kepler's main mission is to detect earth-size planets within the habitable zone - the distance from a star where the temperature on the planet could allow liquid water to exist.
Nasa's announcement will be livestreamed online, in a conference beginning at 5pm.
