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A new study has discovered a powerful force that is now driving evolution on Earth.

A possible third planet has been discovered in the vicinity of Proxima Centauri, our Sun's nearest neighbour star.

Proxima d might be a fourth the size of Earth, making it one of the tiniest worlds identified beyond our solar system.


According to recent research, the sun's closest neighbour may really be home to three worlds.

Astronomers have discovered evidence of a third planet surrounding Proxima Centauri, a red dwarf star 4.2 light-years away from our solar system. The candidate world, known as Proxima d, is believed to be only 25% the mass of Earth, making it one of the lightest known exoplanets if verified.

The finding demonstrates that our nearest star neighbour appears to be teeming with intriguing new worlds, many of which are within reach of additional investigation and future exploration.

Proxima Centauri is known to have only one planet—the about Earth-sized Proxima b, which orbits once every 11 Earth days. This places Proxima b in the star's "habitable zone," the ideal range of orbital distances for liquid water to exist on a planet's surface.

In 2016, Proxima b was discovered. Three years later, astronomers revealed the discovery of a probable second world in the system, Proxima c, which is at least six times the mass of Earth. If Proxima c exists, it is most likely too cold to support life as we know it on its surface; the hypothetical planet takes 5.2 years to complete one circle around Proxima Centauri, which is considerably smaller and brighter than the sun.

Proxima d, which orbits Proxima Centauri once every five Earth days. If Proxima d exists, its orbit implies that it is too hot to support Earth-like surface life (though the habitable zone is a squishy and tricky concept that should not be taken as gospel). (Proxima d, like Proxima c, has to be validated by more observations.)

ESPRESSO ("Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations"), an instrument built on the European Southern Observatory's (ESO) Very Large Telescope in Chile, detected Proxima d.

In 2020, ESPRESSO discovered the first evidence of a probable third world in the Proxima Centauri system, while also confirming the existence of Proxima b. Follow-up observations indicated that the new signal was produced by a planet rather than by other variables such as changeable star activity.

ESPRESSO discovers planets using the radial velocity approach, which detects small wobbles in a star's motion caused by the gravitational tug of an orbiting globe. These pulls were quite mild in the case of Proxima d, equivalent to a planet with a minimum mass of one-quarter that of Earth. Proxima d would be the lightest planet ever discovered using the radial velocity approach.

This accomplishment is incredibly significant because it demonstrates that the radial velocity approach has the potential to reveal a population of light planets similar to our own that is believed to be the most prevalent in our galaxy and capable of supporting life as we know it.

This discovery definitely demonstrates what ESPRESSO is capable of, and it makes us wonder what it will be able to discover in the future.


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