Out of all the exoplanets found by Kepler, this distant world is most similar to Earth in size and estimated temperature and is a perfect candidate to host life as we know it on its surface.

There’s an alien world orbiting a star dubbed Kepler 1649. The world, however, was missed by scientists when they went through the data initially. But now, after scientists reanalyzed data gathered by the now-retired Kepler space telescope, they found the exoplanet and say that its of similar size compared to Earth and orbits its start in the so-called habitable zone.

NASA announces the discovery of an Earth-sized exoplanet orbiting its star's habitable zone using reanalyzed data from the Kepler Space Telescope. The habitable zone, also known as the Goldilocks zone, is the region of space surrounding a star where temperatures are just ideal for liquid water to exist on the surface of a planet.

Get to know Kepler-1649c.

The planet is formally known as Kepler-1649c, and it was discovered after scientists went through previous Kepler observations, a space telescope that NASA deactivated in 2018. Unfortunately, prior computer algorithm searches had overlooked the planets. Nonetheless, when experts reviewed Kepler's data and examined some of the signatures, they identified an object that turned out to be a planet.

This exoplanet is one-of-a-kind. According to NASA, this faraway alien world, located some 300 light-years away from Earth, is the most comparable to our own planet in size and projected temperatures of all the exoplanets discovered to date.

According to astronomers, Kepler-1649c is barely 1.06 times the size of our planet. Furthermore, the amount of brightness received by the planet from its host star is approximately 75% of the amount of light received by our planet from the Sun. This suggests that the temperature of the exoplanet is most likely fairly comparable to that of our planet.

Kepler-1649c, an improbable Earth, circles a red dwarf. These stars are notorious for stellar flare-ups, which could make the planet's surface difficult to support life.

An illustration of how Kepler-1649c would appear from the surface. Photographer: NASA/Ames Research Center/Daniel Rutter

“This intriguing, distant world gives us even greater hope that a second Earth lies among the stars, waiting to be found,” explained Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington.

“The data gathered by missions like Kepler and our Transiting Exoplanet Survey Satellite (TESS) will continue to yield amazing discoveries as the science community refines its abilities to look for promising planets year after year.”

It's still a mystery.

Despite Kepler-1649c's many parallels to Earth, the exoplanet is riddled with mysteries. The planet's atmosphere, which may have a critical influence in the planet's temperature, remains one of the greatest mysteries. Furthermore, as scientists have demonstrated, estimates of the planet's size have considerable margins of error for all values analysed in astronomy, particularly when looking at objects located at such great distances.

Nonetheless, rocky worlds orbiting Red Dwarfs have piqued astrobiological curiosity in recent years. Despite the high level of interest, specialists still require a large amount of evidence to determine whether the exoplanet is suitable for life as we know it. According to astronomers, "Kepler-1649c is highly exciting for scientists hunting for worlds with possibly habitable circumstances" based on what we know so far.

Although there are other exoplanets in the galaxy that are estimated to be closer to our planet in terms of size, such as TRAPPIST-1f and even Teegarden c, and other planets that are closer to Earth in terms of temperature, such as TRAPPIST-1d and TOI 700d, there are no other exoplanets that are considered to be closer to Earth in terms of temperature, size, and being located in the habitable zone of their respective star system.