Earth-Like Planet Around Proxima Centauri Discovered

Article written: 13 Aug , 2016
Updated: 26 Sep , 2016

The hunt for exoplanets has been heating up in recent years. Since it began its mission in 2009, over four thousand exoplanet candidates have been discovered by the Kepler mission, several hundred of which have been confirmed to be “Earth-like” (i.e. terrestrial). And of these, some 216 planets have been shown to be both terrestrial and located within their parent star’s habitable zone (aka. “Goldilocks zone”).

But in what may prove to be the most exciting find to date, the German weekly Der Spiegel announced recently that astronomers have discovered an Earth-like planet orbiting Proxima Centauri, just 4.25 light-years away. Yes, in what is an apparent trifecta, this newly-discovered exoplanet is Earth-like, orbits within its sun’s habitable zone, and is within our reach. But is this too good to be true?

For over a century, astronomers have known about Proxima Centauri and believed that it is likely to be part of a trinary star system (along with Alpha Centauri A and B). Located just 0.237 ± 0.011 light years from the binary pair, this low-mass red dwarf star is also 0.12 light years (~7590 AUs) closer to Earth, making it the closest star system to our own.

In the past, the Kepler mission has revealed several Earth-like exoplanets that were deemed to be likely habitable. And recently, an international team of researchers narrowed the number of potentially-habitable exoplanets in the Kepler catalog down to the 20 that are most likely to support life. However, in just about all cases, these planets are hundreds (if not thousands) of light years away from Earth.

Knowing that there is a habitable planet that a mission from Earth could reach within our own lifetimes is nothing short of amazing! But of course, there is reason to be cautiously optimistic. Citing anonymous sources, the magazine stated:

“The still nameless planet is believed to be Earth-like and orbits at a distance to Proxima Centauri that could allow it to have liquid water on its surface — an important requirement for the emergence of life. Never before have scientists discovered a second Earth that is so close by.”

In addition, they claim that the discovery was made by the European Southern Observatory (ESO) using the La Silla Observatory‘s reflecting telescope. Coincidentally, it was this same observatory that announced the discovery of Alpha Centauri Bb back in 2012, which was also declared to be “the closest exoplanet to Earth”. Unfortunately, subsequent analysis cast doubt on its existence, claiming it was a spurious artifact of the data analysis.

Artist's impression of the Earth-like exoplanet discovered orbiting Alpha Centauri B iby the European Southern Observatory on October 17, 2012. Credit: ESO

Artist’s impression of the Earth-like exoplanet discovered orbiting Alpha Centauri B by the European Southern Observatory on October 17, 2012. Credit: ESO

However, according to Der Spiegel’s unnamed source – whom they claim was involved with the La Silla team that made the find – this latest discovery is the real deal, and was the result of intensive work. “Finding small celestial bodies is a lot of hard work,” the source was quoted as saying. “We were moving at the technically feasible limit of measurement.”

The article goes on to state that the European Southern Observatory (ESO) will be announcing the finding at the end of August. But according to numerous sources, in response to a request for comment by AFP, ESO spokesman Richard Hook refused to confirm or deny the discovery of an exoplanet around Proxima Centauri. “We are not making any comment,” he is reported as saying.

What’s more, the folks at Project Starshot are certainly excited by the news. As part of Breakthrough Initiatives – a program founded by Russian billionaire Yuri Milner to search for intelligent life (with backing from Stephen Hawking and Mark Zuckerberg) – Starshot intends to send a laser-sail driven-nanocraft to Alpha Centauri in the coming years.

This craft, they claim, will be able to reach speeds of up to 20% the speed of light. At this speed, it will able to traverse the 4.37 light years that lie between Earth and Alpha Centauri in just 20 years. But with the possible discovery of an Earth-like planet orbiting Proxima Centauri, which lies even closer, they may want to rethink that objective.

Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity's first interstellar voyage. Credit:

Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity’s first interstellar voyage. Credit:

As Professor Phillip Lubin – a professor at the University of California, Santa Barbara, the brains behind Project Starshot, and a key advisor to NASA’s DEEP-IN program – told Universe Today via email:

“The discovery of possible planet around Proxima Centauri is very exciting. It makes the case of visiting nearby stellar systems even more compelling, though we know there are many exoplanets around other nearby stars and it is very likely that the Alpha Centauri system will also have planets.”

Naturally, there is the desire (especially amongst exoplanet enthusiasts) to interpret the ESO’s refusal to comment either way as a sort of tacit confirmation. And knowing that industry professionals are excited it about it does lend an air of legitimacy. But of course, assuming anything at this point would be premature.

If the statements made by the unnamed source, and quoted by Der Speigel, are to be taken at face value, then confirmation (or denial) will be coming shortly. In the meantime, we’ll all just need to be patient. Still, you have to admit, it’s an exciting prospect: an Earth-like planet that’s actually within reach! And with a mission that could make it there within our own lifetimes. This is the stuff good science fiction is made of, you know.

Further Reading: Der Speigel

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53 Responses

  1. ericsp28 says

    That’s fascinating if true! I just finished reading Stephen Baxter’s Proxima, which is largely about a habitable world around Proxima Centauri (the book actually about much more than that, but the planet around Proxima is a major part of the story).
    There’s been a lot of buzz recently about habitable planets around red dwarf stars like Proxima. The problem is that to be in the habitable zone around a red dwarf, the planet would have to be close enough to the star that it is probably tidally locked, which means that the sun would would never set one one hemisphere and never rise on the other. The average temperature on such a planet may be comparable to earth, the temperature extremes may make life impossible. It would be a very volatile atmosphere, probably much more so than our own (Baxter gets around this in his book by having the star go through cycles where it gives off more or less heat, which prevents the sun facing side of the planet from getting too hot for life).
    Having such a planet nearby means we could find out relatively quickly if live on such a planet would ever be possible.

  2. bcalvert9 says

    Yawn another maybe that has no proof. Another try to get funding.

    • Member
      Jeffrey Boerst says

      You obviously have no idea how science works, though you certainly believe you do.

      • dcdete says

        Science works by repeatable experiments and subjecting theories to peer review. This usually means that the researcher signs their name. None of that here.

      • JanQuadrantVincent16 says

        None of that here? This is a leak. Do you know what a leak is? Do you expect someone to put their name on it? lol.

    • whlanteigne says

      Don’t waste your time applying for a career in science.

  3. chumchingee says

    I suggest that iron/nickel core objects in space have to come from the Brown and Red Dwarf stars. The older the star the more combustion is available to start volcano type eruptions that end up as planets orbiting the star. Nobody says that such an old object is still active as a star. But the core of said object might still be hot.
    The gravity of such a Red Dwarf star even a light one is probably fairly high.
    That doesn’t mean in its old age it cannot have a surface and oceans.
    So where did we get all these iron/nickel core objects in our own solar system?
    We have two objects. The Earth and Venus with something like earth normal gravity and a third in a relatively large gas object in Neptune. But Neptune has a high core temperature. Is it solid or is it gas? No one really knows.
    Does it have a small solid core with continents and oceans? Again no one really knows. We get a bunch of garbage about the temperature of the atmosphere being about 300 degrees F. below zero instead. Yet we have a core that is at least 8,000 degrees F.
    How did it get that hot?
    And is there a goldilocks zone on Neptune where temperatures are above freezing yet not too hot for life?
    The core temperature of the earth-sized planet might be important towards whether or not it is capable of supporting life in alpha centuri system.
    Venus has an atmosphere 15 times thicker than the Earth. Is that an important factor in an Earth type twin? Is there a moon to keep it rotating

    • dcdete says

      Iron is the last fusion reaction generated by a main sequence star. Then it supernovas if it is large enough. There is really not much controversy among astronomers about that.

  4. tibi001 says

    “and is within our reach”
    Actually, that’s a (long) stretch.

    • William F. Maddock says

      a really, really, really looooooooooong stretch.

      We would have to achieve near relativistic speeds for that to be true. At such speeds, even a microscopic (or smaller) particle hitting your hull would act like a bomb going off, and, given the current rate at which small objects are being discovered in orbit around the sun beyond Neptune, I have ZERO confidence that such a mission would even succeed in making it out of our own solar system, much less all the way to another one.

    • Member
      Jeffrey Boerst says

      “Still, you have to admit, it’s an exciting prospect: an Earth-like planet that’s actually within reach! Should it prove to be true, I imagine Project Starshot will be reassessing its proposed mission to Alpha Centauri. Instead of sending their nanocraft to this system to have a look around, perhaps it should be going to Proxima Centauri to look specifically at this maybe-planet. Would certainly make for some interesting findings!”

      Starshot proposes to get nano-sats there in 20 years. Add 4 years data travel time and you’re well in the span of a few generations of humans. Try reading everything before you make uninformed statements to the contrary.

      • William F. Maddock says

        Starshot is nothing more than a proposal in an effort to get funded. It is not evidence of feasibility.

      • William F. Maddock says

        Starshot is nothing more than a proposal in an effort to get funded. It is not evidence of feasibility.

    • dcdete says

      Theoretically a baby born when the ship launches to Proxima Centauri would celebrate their eightieth birthday when they arrive there. Something they could witness in their lifetime, even though they’d have no memories of planet Earth, and wonder what the heck is that Earth-like planet out there! Are they supposed to go out of their ship-world to walk on that thing? No way.

  5. Torbjorn Larsson OM says

    So it is still a rumor without any media release.

  6. crocodilebomb says

    If true, very interesting. I wonder about the “habitable zone” around flare stars. I suppose it would work if your life form really likes intense x-rays.

    • William F. Maddock says

      That’s another problem with this claim. “Earth-like” implies that the planet is actually like earth, including that it rotates on its axis a LOT faster than it orbits its star, which, since Proxima is a red dwarf, is highly, highly, highly unlikely to say the least, because with a red dwarf, in order to be close enough to have an average temperature amenable to liquid water on the surface, the planet has to be so close to the star that it is inevitably tidally locked to the star, and that means scorching day side, solidly frozen night side. Beyond the perpetual terminator, you will NOT have liquid water on that surface.

      • crocodilebomb says

        Carl Sagan once said (in a private venue) that manned space exploration gives you 1/10 the science for 10x the cost, but that you need the manned program to drum up support for robotic missions. I think we’ve struck the motherlode though, searching for life in every light curve. Maybe we need to talk about terraforming Proxima to get the money for things like Cassini. In which case… Proxima to Stay! Who wants to go? Maybe you qualify, click here to take the online test for $40!

      • FarAwayLongAgo says

        Mercury is tidally locked to the Sun. But asynchronously so. It still has days and nights, more frequently than Venus, actually. An atmosphere could even out the temperature on a tidally locked world, like it does on Titan. And a planet can have a moon. The argument that a planet is uninhabitable because it is close to its dim star doesn’t hold.

      • William F. Maddock says

        Mercury is NOT tidally locked to the sun, having a length of day that does not equal the length of its orbit. All of its surface sees the sun eventually. It is thought that the highly elliptical, and variable, nature of its orbit (which varies in eccentricity from 0.000 all the way up to 0.45, where it has a small but significant chance of catastrophic interaction with Venus) is the cause of it not being tidally locked to the sun. A planet orbiting that close to its star does not have much of a chance of holding onto a moon for any astronomically significant length of time, because the star’s gravity will eventually distort that moon’s orbit to the point of either collision with the planet or escape from its gravity well. I’ve watched it happen many times, in simulation. Even at the distance of Mercury, a planet even as large as Jupiter eventually loses that moon. If it could hold that moon, however, the presence of a sizable moon, while it was there, would act to prevent tidal lock to the star, as you say.

      • William F. Maddock says

        Interesting! At its most eccentric orbit, Mercury stands a chance of a catastrophic encounter with Venus, and Mercury’s length of day is almost precisely a 1/2 match to that of Venus. Hmmm…

        Could there have been such an encounter in the past, with a brief coupling of the two planets in the same orbital space, as a temporary double planet?

        It’s just speculation, mind you, but interesting nevertheless.

      • William F. Maddock says

        More interesting!! OK.
        Mercury’s day almost exactly 1/2 of Venus’ day.
        Venus’ day is almost exactly 1/2 its orbit.
        Venus’ orbital inclination is almost exactly 1/2 of Mercury’s.

        What are the odds?

        Folks, it’s starting to look like something’s going on, here.

      • dcdete says

        What’s going on is bs. Mercury’s day is roughly 1/4 Venus day.
        Venus day is approximately 19 days longer than its year. Not half its year!
        Though Mercury’s inclination is about twice that of Venus.

      • FarAwayLongAgo says

        It’s called asynchronous tidal locking, 2:3 instead of 1:1 because of the eccentricity. With circular orbit it would show the same side to the Sun always. Together with an atmosphere that evens out temperature, and the short “year” in the HZ of a red dwarf gives short day and night cycles. A moon would of course not be tidally locked to the Sun even if its planet is, and could be habitable. Wouldn’t even a Jupiter sized planet in the HZ of a red dwarf keep its moons? Here’s a SETI Talk about the temperature distribution of synchronously locked atmospheric planets, at 29:30 for example:

      • spaceartuk says

        By ‘earthlike’ it means ‘terrestrial’ — ie. a smallish, rocky world with an atmosphere containing oxygen, and able to sustain liquid water. To do this, as in my 1972 painting!Proxima1972/zoom/cye0/image_17qj it would need to orbit its star in about 10 days.

      • Member

        Saw that. Lovely work, btw!

  7. BlackWolfStanding says

    Project Starshot will 100% be able to examine the planet from afar. The problem will be directing the micro-probes close enough to get any detailed information. The target planet revolves around those stars. How long does that take? Will a relativistic micro-probe be able to be targeted that well? We still have our motion and the motion of Proxima Centauri around the Milky Way to worry about. Too many if’s. Let’s worry about getting a probe to pass through the system them we can worry about targets within the system.

    • William F. Maddock says

      First, let’s get it safely out of our own system before we worry about anything regarding the target system.

  8. Member
  9. spaceartuk says

    Here is a painting I did of an earthlike planet of Proxima back in 1972! (For ‘Challenge of the Stars’ with Patrick Moore)!Proxima 1972/zoom/cye0/image_17qj
    Stephen Baxter and Arthur C. Clarke also described tis scene in their book ‘Light of Other Days’.

    • crocodilebomb says

      Kudos! I was not familiar with your work. Your conception of Pluto was not far off. Have you tried your hand at Haumea?

      • spaceartuk says

        Really? I’ve been doing it for longer than anyone else now around (see my website). No, I haven’t yet painted Haumea specifically, but there are several Kuiper Belt Objects under the ‘Space Debris’ gallery, inc some binaries.

  10. FarAwayLongAgo says

    ESO. So it is not based on the Gaia data to be released in a month or so?

  11. BigAtheist says

    Will the James Web telescope be able to see the planet when it is built?

    • FarAwayLongAgo says

      If it is not transiting, any atmosphere will be hard to detect anyway. It depends on JWST’s choranograph if it can image the planet. It is difficult so close to the star, as a planet in HZ of a red dwarf must be.

    • Member

      Most likely, and many people are now saying this is where we should aim it (pending confirmation, of course).

  12. lostindub says

    A space probe apparently travels at about 17km/s. It would take a probe 74601 years to travel 4.25 light years. How is it that you think this planet is within our reach?

    • postman1 says

      Google Project Starshot

      • dcdete says

        Mere conjecture. They don’t explain if a mere dust particle such as found in meteor showers hits a satellite at just 30,000 miles an hour and can obliterate it (as seen in the movie Gravity), then what would happen if a ship traveling at 20% of the speed of light would hit the same dust particle?

      • FarAwayLongAgo says

        If thin as a circuit board it has very small area to hit. It doesn’t need the sail after acceleration. The interplanetary dust might maybe still be a big problem during acceleration as it has some decimeter large sail area. If couple of gram hit the atmosphere at 25 speed of light, it would cause a tens of kilotons explosion, like a meter sized asteroid at normal speed. But maybe a dust grain would only make a tiny hole in the thin sail.

    • Member

      Follow the link for Project Starshot.

  13. dcdete says

    So basically this has been unconfirmed, and is just a rumor.
    As for the Starshot ship reaching 20% of the speed of light? You kidding? That is somewhere around 134 million miles an hour! So far either New Horizons or the Juno probe reached the fastest man made speeds of just over 100,000 miles an hour. Starshot will be going 1,340 times that speed. Would have saved Juno a lot of travel time if they could have gone that fast!

    • FarAwayLongAgo says

      Three hours to Jupiter! With SLS a Europa Clipper could get there in 2 years.

    • Member

      No, it is based on a source claiming to be from the ESO. As for the Starshot ship, that’s no joke. Its a proposed nanocraft that would be towed by a laser sail, not a space probe or anything comparable in size to Juno or NH.

  14. chumchingee says

    The speed of light travel is a tricky thing. It might take many years to get to this solar system neighbor in Earth years. But on board the ship the time slows down so that only about 20 years passes.
    At least that is how I understand it works.
    Meaning a round trip might take 40 years onboard time. But it might take 700 years total in relative time to the Earth.
    Has anyone else seen a piece of straw embedded in a telephone pole? What happens with higher speeds is the object gets incredibly hard relative to the objects it is running into.
    It has been suggested that the ship cast water in front of it at high speeds thus giving it a slightly shielded nature. Whether or not that would work or not is anyone’s guess.

  15. forj says

    Please stop calling these “earth-like” or “habitable”. You are going to mislead a lot of people. I am pretty certain a scientist would not label such a prospective planet as such. And we are reporting on these before we even have a confirmed source now? At least you admitted that part. Very exciting news of true but we need to talk about these things in realistic terms, not conjecture and assumption. Could have waited until there was a confirmed source instead of sticking your necks out there hoping Der Speigel has good information

    • Member

      There was no conjecture or assumption. The report cited the source verbatim, and we made no claims that aren’t substantiated at this point. Also, the use of the words “Earth-like” and habitable come directly from the Kepler science team and the Observatories making the discoveries.

  16. jearley says

    Something that no one has mentioned here is the fact that Proxima is a flare star, like many red dwarfs. Red dwarfs are fully convective, and that produces a strong set of magnetic effects in the chromosphere. Proxima is no exception. Its quiescent X-ray flux is the same as our Sun, despite its far smaller size. I can not do any calculations right now due to the lack of information as to the orbit of this reported planet but I think, based on the location of the habitable zone, that we are looking at a background X-ray flux two orders of magnitude greater than the Earth. As others have pointed out, it is possible that Proxima b, if it exists, would be tidally locked, or at least in a rotational period similar to Mercury, so describing this as Earthlike is an exaggeration. I suspect that we will find that it is a rocky planet, what used to be called a Terrestrial planet (as opposed to gas giant) when I was a kid. That means that it could be Mercury like, or Mars like, or even Venus like. In any event, I am content to wait for a few weeks for some real data. As to the discussions here about getting there, you might look at the old project Longshot papers, and see what was being talked about 30 years ago or so. Given the advances in Z axis fusion drive research by the University of Washington, Longshot is now possible. ( says that the paper about this discovery should be released at the end of this month)

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