ESO’s Wednesday Presser: Earth 2.0 at Proxima Centauri?

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.

Proxima Centauri Imaged by Hubble Space Telescope

German rocket pioneer Krafft Ehricke supposedly once said “if God had meant mankind to become a spacefaring species he would have given us a Moon.”

Based on that sentiment, tomorrow could be a bad day for atheists.

Last month, word began to come out that an Earth sized planet has been discovered in the habitable zone around our nearest neighbor, Proxima Centauri, the third (and closest) member of the trinary system most people know simply as “Alpha Centauri.”

The discovery, if that is indeed what it was, is likely to be the subject of a press conference being held tomorrow at the Headquarters of the European Southern Observatory. Given that a previous ESO finding regarding a possible planet around Centauri B has been largely refuted, the organization has perhaps been understandably reticent to come forward too quickly with the latest revelation.

And what a revelation it would be; an Earth sized planet potentially capable of holding liquid water on its surface, dangled before us in space only 4.25 light years away.

We should doubtlessly save the dramatic conclusions until the finding is confirmed, and even then we still won’t know all that much until more powerful, yet to be launched space-based instruments such as TESS or JWST can directly confirm the planet’s presence and characteristics, but even the possibility is beyond tantalizing.

As we are coming to think of solar systems not just in terms of the major planets they hold and the stars they orbit, but as reservoirs of vast resources, an Earth analog, even (and perhaps preferably) if it is a barren world done devoid of life, situated so agonizingly close would likely become as culturally compelling as Mars is today. The logical next step, and one that simply must be taken.

SpaceX after all, still needs a stretch goal.


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1 Comment on "ESO’s Wednesday Presser: Earth 2.0 at Proxima Centauri?"

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  1. Keith Pickering says:

    Of three worlds in Sol’s habitable zone (Earth, Mars, Luna) only one has life. So Proxima b is pretty cool, but it’s not necessarily something to pin your hopes on.

    Proxima is a flare star, meaning it is highly and irregularly variable, and spews out 400 times more x-rays than the Sun does. So even if Proxima b has an atmosphere and water, that may not be enough to make it a destination for colonists.

    I still think Alpha Cen (A & B) is a more likely choice to find something worthwhile.

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