Proxima B

It’s been an exciting week for the scientific community.

On the 24th of August, scientists announced the discovery of our nearest exoplanet, Proxima B.  The planet was detected by observers at the European Southern Observatory in Chile.

What’s so special about a new exoplanet?  Well, there are a couple of exciting things about this one: Proxima B is only 4.2 light years away, AND, it’s in the habitable zone of Proxima Centauri.

Habitable zone?

Also known as the Goldilocks zone, the habitable zone is that space between a planet and its star where the temperature is ‘just right’, so right that there is the very real possibility stable liquid water could have formed on the surface of that world.

Shining brightly in this Hubble image is our closest stellar neighbour: Proxima Centauri. Proxima Centauri lies in the constellation of Centaurus (The Centaur), just over four light-years from Earth. Although it looks bright through the eye of Hubble, as you might expect from the nearest star to the Solar System, Proxima Centauri is not visible to the naked eye. Its average luminosity is very low, and it is quite small compared to other stars, at only about an eighth of the mass of the Sun. However, on occasion, its brightness increases. Proxima is what is known as a “flare star”, meaning that convection processes within the star’s body make it prone to random and dramatic changes in brightness. The convection processes not only trigger brilliant bursts of starlight but, combined with other factors, mean that Proxima Centauri is in for a very long life. Astronomers predict that this star will remain middle-aged — or a “main sequence” star in astronomical terms — for another four trillion years, some 300 times the age of the current Universe. These observations were taken using Hubble’s Wide Field and Planetary Camera 2 (WFPC2). Proxima Centauri is actually part of a triple star system — its two companions, Alpha Centauri A and B, lie out of frame. Although by cosmic standards it is a close neighbour, Proxima Centauri remains a point-like object even using Hubble’s eagle-eyed vision, hinting at the vast scale of the Universe around us.

While both Proxima B and our very own Earth are within the habitable zones of their respective stars (ours is Sol, and Proxima B’s is Proxima Centauri), the similarities seem to end there.

Proxima B is 1.3 times larger than our planet, which means it is most likely tidally locked (one side always faces the sun), and due to it’s size is probably a very rocky world.

Could it sustain life?  Or already be sustaining life?  Does it have water?

No one can answer those questions just yet, but something Space 2049 reported on a few months ago might be able to in the not too distant future.

Breakthrough Initiatives, with their Breakthrough Starshot project, may send some of their solar sail powered nanocraft to the Proxima system when they launch the amazing devices on a voyage of discovery to the Alpha Centauri system in about a decade.

While the Breakthrough Initiatives team continues to explore the possibility of diverting some of their nanocraft to Proxima, numerous observatories around the world will continue to give the Proxima star system the focus it deserves as we seek to learn more about this new world.

Will humans be able to visit Proxima B any time soon?  Using current technology… no.  It would take about 70,000 years for a manned spacecraft or even a conventional unmanned probe to make that journey.

If Breakthrough Starshot is able to launch its fleet of nanocraft as anticipated, the journey could be made in decades, but putting humans on Proxima B anytime soon is slightly beyond our reach.  For now.

If you’d like to read more about this discovery, visit space.com here.

If you’d like to read more about the Breakthrough Starshot project, visit Breakthrough Initiatives here.

Even with nanocraft zooming off to visit Proxima B in a decade or less, it will be some time before we know anything much about that world beyond what we can observe here on Earth.  Despite that, this news is remarkable, and to have discovered a world like Proxima B so close to our own makes you wonder… just what else will science reveal to us about our closest neighbours in the coming years?