An Earth-like Planet Might Be Orbiting Proxima Centauri

By Carl Engelking | August 12, 2016 11:31 pm

Proxima Centauri shines brightly in the image from Hubble. (Credit: Hubble ESA)

Microsoft added the “Start” button to Windows in 1995, which was the same year scientists discovered the first exoplanet orbiting a star like ours – technically, astronomers found several terrestrial planets orbiting a pulsar in 1992.

But in 20 years, give or take, we’ve grown spoiled by the abundance of exoplanets in the universe. Kepler, the planet-hunter, has confirmed over 2,200 of them. Today, it’s safe to assume nearly every star has its companions.

The ante for hyping a new exoplanet discovery is a little higher these days, but if rumors are true, this one makes the grade: astrophysicists from the European Southern Observatory (ESO) plan to announce they’ve spotted an Earth-like exoplanet orbiting the nearest star, Proxima Centauri, in its habitable zone. This, according to an anonymous source quoted in a report that appeared Friday in Der Spiegel.

“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,” the source said.

And, for what it’s worth:


Big News, If It’s True

At just over 4 light-years from Earth, Proxima Centauri is our sun’s nearest neighbor, and it’s part of a triple-star system that includes the better known Alpha Centauri. The star’s proximity has made it an obvious target for many past exoplanet searches. All of them have come up short, which makes the most recent rumors all the more remarkable.

If the early reports ring true, scientists will announce this Earth-like planet near the end of August. Discover has reached out to an ESO spokesperson for comment.

Reason to Hold Our Breath

Although media reports say the rumored planet orbits in a region that’s potentially favorable for life, these smaller stars are less stable, and Proxima Centauri is known to have violent flares at times. Its occasional tantrums have made astronomers skeptical of finding life around red dwarf stars in the past.

However, skepticism has softened some in recent years, and SETI recently launched a major initiative to search for life around 20,000 red dwarfs, as these stars are the most common in the Milky Way galaxy.

Still, Proxima Centauri is only “close” on a cosmic scale. It would still take humans far too long to reach the planet with current technologies. Flying laser-sailing nanocraft to the yet-to-be-confirmed planet might be our next best bet, and that’s a pretty solid “plan b”.

Discover associate editor Eric Betz contributed to this report. 

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: exoplanets
  • CriticalDragon1177

    Wow! There could be one really close to home! I won’t hold my breath through. Remember not too long ago people thought that Venus and Mars were habitable, than when learned more realized just how wrong we were. Remember the claims in the early twentieth century about canals on Mars, and how people thought that Venus was a Lush tropical paradise? We don’t even know what any planets around Proxima Centauri look like, including this one.

    • Future Legend

      Curiously, it was just announced earlier this week that new simulations indicate Venus might have been habitable up until about 700 million years ago. Earth and Venus are thought to have formed with pretty much the same composition, but Venus has lost most of its water, boiled off into space as the planet’s runaway greenhouse turned its surface into a 900 degree inferno.

      Even if Venus started out with an ocean of liquid water before losing it, it had been thought the planet was too close to the sun to have been habitable for very long, if ever (the sun was much dimmer when it was younger but has slowly heated up as it ages).

      However, the new study indicated that – provided the planet’s rotation was about as slow as it is today (it pretty much always keeps the same face pointed toward the sun) – the dark side of the planet would have radiated enough heat out into space to potentially keep the planet’s surface temperature well below the boiling point of water for almost 4 billion years.

      So it’s possible that the habitable zone of stars could extend substantially closer to them than we’d previously thought, provided the planet is rotating slowly enough.

      Water vapor by the way is a very potent greenhouse gas, and another recent study indicated that planets with very thin atmospheres but lots of surface water might remain habitable much farther from their host stars than otherwise expected, because the thin atmosphere would allow water to boil at much lower temperatures, injecting a huge quantity of this powerful greenhouse gas into their atmospheres and keeping their surfaces much warmer than they would be with a thicker, drier atmosphere.

      We may ultimately discover the habitable zone is – at the extremes – much broader than we’d anticipated.

      I think not a lot of thought has been given to large exomoons, either. An exomoon the size of, say, Mars with a thin atmosphere and lots of surface water orbiting a gas giant twice the mass of Jupiter could be habitable far beyond what we’d normally consider the habitable zone. Large gas giants radiate a tremendous amount of heat, and would act like a giant heat lamp for moons in fairly close orbits, warming their surfaces enough to support life even far from the host star.

      • CriticalDragon1177

        I heard about Venus possibly being habitable for much longer than we thought, however, I find it a bit hard to imagine a gas giant radiating enough heat to make a difference.

        • Future Legend

          Jupiter actually radiates more heat energy than it receives from the sun. More massive gas giants would radiate even more energy. And of course, tidal interactions would also generate heat.

          • CriticalDragon1177

            True, but would it be enough?

      • Chris Carlstrom

        I agree with your thoughts on exomoons, however, think tidal friction would be more likely to be the reason for sustainable heat, if the host star was too far to provide it. I would assume the life having arisen from an exomoon would most likely be aquatic having been protected by radiation from a thick layer of ice and sustained by geothermal activity closer to the core.

        • Future Legend

          It depends. There’s nothing to prevent an exomoon from having an atmosphere as thick as – or even thicker – than earth’s. There’s also nothing we know of to prevent an exomoon from having its own magnetic field. Both of these could shield its surface from radiation, especially if it orbited some distance from its host giant.

      • zlop

        “planet’s runaway greenhouse”
        surface pressure and incoming radiation accurately determine global average surface temperature.

        Pressure increased as all the water evaporated.
        CO2 out gassing further increased pressure.

        • Future Legend

          “surface pressure and incoming radiation accurately determine global average surface temperature”

          Not even close to being true. We’ve known since the 1800’s that CO2 and water vapor are both greenhouse gasses.

          • zlop

            “CO2 and water vapor are both greenhouse gasses”

            All gases warm the surface greenhouse or not. Even in intergalactic space, planet without a star, an atmosphere will warm below.

          • Small_Businessman

            And where is the heat going to come from? You defy the laws of physics.
            No, gasses don’t warm the surface. Some gasses help trap heat better than others, though. Carbon dioxide and water vapor are two of them. Nitrogen and oxygen don’t do much.

          • zlop

            “And where is the heat going to come from?”
            Microwave background and cosmic rays.
            At the microwave background, He3 has half a bar pressure.
            Lapse down to warmer below.

            “No, gasses don’t warm the surface.”?
            Look up Potential Temperature — which tends to equalize.
            There is a chart for Earth’s atmosphere, see at;
            “Potential Temperature | The Science of Doom”

            “Nitrogen and oxygen don’t do much.”?
            All atmospheres warm.

          • Small_Businessman

            Sorry, microwave background radiation and cosmic rays would be unable to generate anywhere near the required amount of head. If they were, all of the planets in our solar system would be much hotter then they are. Heck – MBR can only be detected by very sensitive instruments. And while cosmic rays are more energetic, there aren’t enough of them to heat a planet. If there were, the ionizing effect created by that many cosmic rays would sterilize the planet.
            And it’s too bad you can’t understand the science about which you are pontificating. However, that is the bane of the internet – everyone can think they are an expert, no matter how little they understand.
            And no, nitrogen and oxygen are not considered greenhouse gasses, and do little by themselves to hold the heat. If Earth were bererft of carbon dioxide, water vapor and methane (an even more important greenhouse gas), Earth would be much cooler.
            Just look at Venus as an example. Heavy in carbon dioxide and sulfur dioxide and containing a runaway greenhouse effect. With an atmosphere like Earths, it would still be hotter than Earth, but not almost 1,000 degrees C.

          • zlop

            Look up — pressure of He3 at the microwave background temperature.
            If there is an atmosphere, it will warm below (HE3 mist lapse to warmer below)

            “And no, nitrogen and oxygen are not considered greenhouse gasses, and do
            little by themselves to hold the heat.” — so what what — they can form a mist.
            Mists interact with radiation (radiative balance below a clouds — Miklos Zagoni)

            “Just look at Venus as an example …. containing a runaway greenhouse effect.”
            “physical nature of the so-called GH effect is a Pressure-induced Thermal
            Enhancement (PTE), which is independent of the atmospheric chemical
            composition. ” — See Nikolov and Zeller
            Thermodynamics interacts with and dominates radiation.

          • Small_Businessman

            You really should learn more about physics before continuing to make a bigger fool of yourself. Sure, mists interact with radiation. But heat loss is much higher than gain. If what you say were accurate, Neptune would be a hot desert. After all, it receives the CBR in addition to the heat from the sun.
            You are just proving that you pick up a few pieces of information off of the internet and espouse garbage because you don’t understand what you are talking about.
            Time for you to go back to third grade and LEARN something about thermodynamics.

      • William R. Cousert

        Venus has a day that’s more than 200 earth days long. Could life deal with that?

        • Future Legend

          I don’t see why not. Even complex life in the Arctic copes with weeks at a time without darkness. Simpler forms of life could certainly evolve in constant daylight – in fact, not having to cope with hours of darkness would presumably make things easier for simple forms of life.

        • Handsome Jack

          Maybe in the twilight regions

      • ilduderino

        There are unique situations and exceptions to every generalization.

    • TroganFileDotGen

      Actually, Mars is in a way habitable, It’s on the very edge of the habitable zone, so it IS to cold, but technically, its in the habitable zone. Just to far in it to harbor life.

      • CriticalDragon1177

        Mars may technically be in the habitable zone, but Mars isn’t habitable right now, that is why I said it isn’t habitable. At the moment it isn’t capable of supporting life as we know it, except maybe microbes, and even those would be some pretty intense Extremophiles. There are also some people who think there maybe microbial life in the clouds of Venus, but the planet still wouldn’t be habitable for anything that wasn’t a microbe, even if that turned out to be the case.

        • Handsome Jack

          Mars lacks a strong enough magnetosphere to hold onto an atmosphere that can support life. The sun blew away most of the martian atmosphere, leaving mars in an almost vacuum state. Currently we have no evidence of microbial alien life on either planet.

      • brycly

        Mars would be habitable if it was the size of Earth/Venus. If that was the case, the core would be hotter and more geologically active, and the atmosphere would be thicker due to that and the increased gravity. It’s a shame Jupiter didn’t wind up a little further out.

        • MidasMike

          With all these findings, we can all see that there’s a Supreme Being, God Almighty, who is gracious to us all by stationing us on earth. We’ve, however, been busy f**king up our safe abode through our acts and inaction, then hoping to elope to another habitable place to live before the disastrous consequences of our activities get back at us. My advice: WAKEUP! Stop destroying our planet, forthwith. Let the culprits of global warming begin (with immediate alacrity) mitigation and stop their incessant ozone ‘killing’. This planet belongs to us all, it shouldn’t be destroyed by some with consequent implications on all…….
          PS: Atheists, pls don’t bother commenting, there are certain truths your minds can’t comprehend…

          • Small_Businessman

            Yes, and there are certain truths YOUR mind can’t comprehend, either. And I’m saying this as a Christian.

          • brycly

            I’m an atheist and I don’t appreciate your condescending tone. I already explained why Mars could have been habitable. It has nothing to do with God and everything to do with science. Regardless, Earth will be uninhabitable for large lifeforms in 500 million years and Earth’s own oceans will boil off in a billion years which sorta kills the theory that God is protecting the Earth. The grim truth is that Earth has been habitable for a long time, long enough for us to develop, but it will not remain hospitable for all that much longer because the Sun has become middle aged and it’s starting to slowly fall apart and heat up as a result. If a God was watching out for us, it would have made Mars bigger to serve as a lifeboat for Earth’s plants and animals. Instead, it left them all to die. If humans leave the solar system, we may be able to save some of them but only a very tiny fraction. Everything else: gone.

          • GORT

            @MidasMike:disqus , your personal religious beliefs have nothing to do with this conversation. Please save your pompous foolishness for a Sunday conversation with your preacher. Given your arrogance toward atheists (and who knows how many other groups of people), you obviously need to be saved… from yourself.

            Regarding the article, we will continue to find many more planets as our equipment gets better. The question is, what will we do with this information? For those planets that are “close”, we have the technology right now to explore them, but we need to realize that it can only be done with a multi-generational commitment. Sure, a space ark may actually be built and launched in a few hundred years – but in the interim we need to first explore any potential candidates for occupation. The best way to accomplish this using existing technology is with robotics, on ships powered by a combination of ion drives, solar sails, and small chemical engines for navigation. Even still, this would be a multi-generational effort, as it would take many decades, if not hundreds of years, for a ship to travel a mere 4 light years, and once there, communications will be on an 8-year round-trip.

            Regarding Mars, before we attempt to send humans there (which is a goal I disagree with), we need to establish a permanent moon base and develop the technology to launch deep-space exploratory craft without fighting Earth’s gravity. To do that, we need to learn how to mine and manufacture on the moon using only the moon’s resources. Unfortunately, Mars will never be like Earth; it will never be inhabited by any more than a handful of highly skilled specialists sent to Mars at a cost of at least tens of billions of dollars per person. The first person to die on Mars will also probably be the last. Furthermore, without a magnetosphere, the only place to go on Mars is underground. It’s a grand experiment, and worthy of entry into the ranks of greatest human achievements, but Mars will never be a temperate planet with a breathable atmosphere, ample water, fertile soil, and a magnetosphere to protect human beings. So the question is, why do we really want to send people to Mars? To look for life? Robotic craft can do that. To occupy the planet and prepare it for an influx of human occupants? Get real. If nothing changes, Mars will continue to soak up space agency resources and distract us from more practical – and useful – goals.

            Knowledge is the greatest of human achievements, but we as a species often lack the clarity to know what should really be done with it. If our goal is to perpetuate the human species beyond the life expectancy of our current solar system, occupying Mars is a waste of time and resources. My recommendation is to set aside sending humans to Mars and instead focus on the moon for now. Once we have a moon base and the ability to mine it and manufacture spacecraft, we should head straight to Europa, and develop true terraforming there. Once we have that knowledge, then and only then will be be able to have a real conversation about actually traveling to other planetary systems with occupation as the goal.


          • brycly

            you’re very misguided if you believe Europa is a better candidate for terraforming than Mars. Europa is an ice world, it’s ocean is only sustainable because of the ice on top of it. Without that ice, any life in its ocean would be fried by Jupiter’s intense radiation, which is strong enough on Europa to kill you in days. And of course, being low gravity it would eventually lose its ocean to space where it would be consumed by Jupiter. And there’s the fact that there would be no land so we would be building on top of an ocean that’s miles deeper than anything on Earth and due to Jupiter would probably have waves half a mile high. Mars is a far, far better choice for terraforming. It would never look like the Amazon but it has all the water and gases that are needed to replace spacesuits with oxygen masks and give us a source of water for hundreds of millions of years at least. And let’s not forget that SpaceX has made it their mission to make affordable large scale Mars colonization possible. There may be no need for our space agencies to get involved.

          • HERB.SYSTEMS

            If you think the radiation environment on the surface of Mars is bad (which is roughly equivalent to LEO), then you won’t like Europa.

    • Chris Carlstrom

      It is difficult to compare scientific claims from “the early twentieth century” to those of today. The degree that science has advanced, just in the past 20 years greatly transcends any other period in human history.

      Keep in mind, that when we use the term “earth like” it is based considerably on composition and distance to its host star, not on biological factors or life. The baseline for the statement is merely a way for us to partition newly found exo planets into groups. Earth like doesn’t imply or suggest life has arisen, merely that it is a “rocky” planet (opposed to a gaseous planet) with an astronomical position that could theoretically contain the building blocks humans consider necessary for biological life. IE; liquid water, stable orbit, and so on. Being so far away, we can only use the information we gather to make hypothetical but educated conclusions in regards to these exo planets. I think “earth like” is often and very easily misinterpreted as “like earth” and a distinction that has to be addressed and understood so people don’t prematurely jump to the wrong conclusions.

      PS. If an exact duplicate of mars was found orbiting a star, it would fall under the “earth like” umbrella immediately, and rightfully so. Had the core of mars not stopped protecting the atmosphere there is a strong possibility that we would have some biological neighbors. (in my personal opinion)

      • CriticalDragon1177

        We still haven’t seen this planet’s atmosphere, so we can’t be sure exactly how “earth like” it is. That was my point.

        • Handsome Jack

          I’m not sure about the composition of the specific planet this article is talking about. Still we can tell the composition of an exoplanet’s atmosphere through light spectrometry. Each element on the periodic table absorbs a specific pattern of light. This is the same technology used to determine the composition of a star.

      • JR Horsting

        well said.


        Was getting ready to write essentially that. You saved me the effort.

    • William R. Cousert

      Having another Venus or Mars would be a great start. Maybe by the time we have the ability to visit it, we’ll also be able to teraform it as well.


    Vulcan? Also it occurs to me that P.Centauri was in the right ballpark in 1977 for the “Wow!” signal, if the beam was being deflected by a very large object nearby (eg a neutron star) to get around the energy usage problems.

    • tekkiguy


      • Small_Businessman

        Not necessarily a hit by another object. Gravitational drag from the Sun could have slowed it way down (similar to Earth”s effect on our Moon). The lack of its own moon would mean there is nothing to encourage rotation other than inertia (conservation of angular rotation).

    • okiejoe

      If there were a neutron star between us and P Centauri I think we would have noticed it by now, gravitationally if nothing else.

  • Uncle Al

    1) Was there ever a Dark Ages’ day when some visual manifestation of One True Church dogma did not poke the stinking starving faithful with a sharp stick?

    2) Conversely, are they good to eat?

    • CriticalDragon1177

      Huh? What?

      • John C

        I think it’s a Zen riddle.

  • John C

    Now to do a detailed analysis of the atmospheric spectra for possible biological signatures. Once the tech improves, that is.

  • zlop

    For life, need a fluid and appropriate temperature. Planet without
    a star, in intergalactic space, could have a warm enough fluid.
    Even without internal radioactivity, an atmosphere could exist.

    • Small_Businessman

      And where is that heat going to come from?

  • Chris H

    If and when we are able to, how do we send our first Soloarnaughts to this new world, armed or unarmed.
    I can’t any politician voting for something that will not happen in their life time.

  • JR Horsting

    Finding life would be amazingly cool. Finding intelligent life would magnificent. We can find whale, octopus, pigs, birds, dogs, cats, and primates…etc, right here on earth. They are all intelligent. Finding a more advanced race on another planet is a matter of timing. Did the last long enough to save themselves from the cosmos? Or from themselves? Would they want to talk to us? They need nothing we have. If they talk to us it would astounding.

    • Handsome Jack

      Statistically, due the vast size of the milkway galaxy, it would very unlikely that humanity would ever come in contact with an alien civilization. There might be several advances civilizations in the milkyway alone and none of them have any awareness of one another. The galaxy is just too big. Radio signals would have to be incredibly powerful to maintain their message across space. I think the sci-fi genre causes us to perceive the galaxy as smaller than it really is. The odds are simply against us ever meeting another civilization.

      • Small_Businessman

        Maybe, maybe not.
        First of all, radio signals can be heard by sensitive receivers many light years away. And as for travel, our knowledge of physics is far from complete. For instance, it is theoretically possible to create a “warp field” a la Star Trek and effectively travel faster than light. It’s just no one knows how to generate the negative energy needed to create such a field – yet.

        • zlop

          Like Jesus Christ, Hollywood movies and Superbowl shows, Space Spock is a psychological, distraction, operation.

          • Small_Businessman

            YOU are the psychological, distraction, operation. But once again you show your ignorance.

          • zlop

            “But once again you show your ignorance.”?

            Your annoyance allowance has been exceeded
            and I will block you in a few minutes.

          • Small_Businessman

            No skin off of my back.
            The difference between ignorance and stupidity is that ignorance can be corrected. You are just stupid.

      • zlop

        “galaxy is just too big. Radio signals would have to be incredibly powerful”

        Radio is the way to go. There are lots of photos to work with.
        A solar system sized synthetic array needs to be deployed.
        For practice, use several satellites in similar to Earth’s orbit.

    • Small_Businessman

      Before finding intelligent life on other planets, we should concentrate on finding it here.

  • Sev

    I have been waiting for this news my entire life. It is hard not not jump up and down in excitement but I will wait til more in depth findings are released. For all we know it could be in the habitable zone with an atmosphere of primarily HCN.

  • Billie Mudry Spaight

    WoW. It makes sense that in our vast and limitless universe, there has to be other lifeforms besides us. We cannot be alone; that’s just illogical.

    • zlop

      Life likely exits on unexpected planets. However, like dolphins, space travel would be difficult, unless helped by other creatures or robots.

  • MidasMike

    With all these findings, we can all see that there’s a Supreme Being, God Almighty, who is gracious to us all by stationing us on earth. We’ve, however, been busy f**king up our ‘safe abode’ through our acts and inactions, then hoping to elope one day to another habitable place before the disastrous consequences of our activities get back at us. My advice to the comity of nations: WAKEUP! Stop destroying our planet, forthwith. Let the culprits of global warming begin (with immediate alacrity) mitigation and stop their incessant ozone ‘killing’. This planet belongs to us all, it shouldn’t be destroyed by some, with consequent implications on all…….
    PS: Atheists, pls don’t bother commenting, there are certain truths your minds can’t comprehend…

    • zlop

      I will block you, if you nnoy once more.

  • GS Chandy

    It’s wonderful that science has discovered that Earth has a twin in our ‘near-neighbourhood’. But isn’t it about time that science thinks of ways to ensure that we humans do not further make our own planet uninhabitable in the near future?

  • Episteme

    Regardless of whether signs of life are detectable on any terrestrial Centauri exoplanet, a confirmed rocky planet there in its habitable zone strikes me as a key target for some sort of probe (even knowing that it would take decades to arrive). Given that all of our studies-by-probe to date are of material that came from the same early disc, having a planet constructed from the formation of another star (especially one whose structure is more similar to that which we understand) so ‘close’ would be incredibly helpful; to better understand the possibility of life beyond Earth, any new data sources on the composition and elemental consistency of alien worlds is the very definition of what science requires for better predictions. We’ll certainly see incredible advances in telescopic imaging over the next years, but having an exoplanet to probe directly (even if needing to plan decades ahead of time) is just the sort of experimental data (versus Earth’s ‘control’) in determining how to more deeply explore the universe around us.


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar