The Race to Proxima Centauri (Part 1)

By Corey S. Powell | August 31, 2016 11:52 pm
An invisible planet beside the tiny dot of Proxima Centauri may be the key to understanding Earthlike planets across our galaxy. (Credit: Digitized Sky Survey 2)

An invisible planet orbiting the pale red dot of Proxima Centauri (seen here alongside its much brighter neighbors, Alpha Centauri A & B) may be the key to understanding Earthlike planets across our galaxy. (Credit: Digitized Sky Survey 2)

Sometimes it takes a while for the meaning of a new scientific discovery to really sink in. In the case of the planet Proxima Centauri b, announced last week, it may take decades or even centuries to fully grasp the importance of what we have found. You see, this is not just any planet: It is similar to Earth in mass, and it orbits its star in the “habitable zone,” where temperatures could potentially allow the existence of Earthlike bodies of liquid water. Proxima Centauri is not just any star, either: It is the very nearest one after the Sun, and it is a small red orb whose feeble light makes it relatively easy to study the planet close beside it.

The science at stake here is enormous. Proxima Centauri b will surely become the archetype for understanding more distant Earth-size, and possibly Earth-like, planets all across our galaxy. The effort needed to study it will be enormous, too, however. At present the planet cannot even be glimpsed directly through the mightiest telescopes on Earth. Nevertheless, the race is on–a thrilling but maddeningly slow-motion race to bring Proxima Centauri into view, to figure out if it could (or does!) support life, even to visit it with an interstellar probe.

That last goal is the most ambitious; some might call it the most absurd. But the discovery of Proxima Centauri b comes at a propitious time, just as a group of physicists and engineers have been thinking very realistically about how to send a space probe to another star, and to do it within a single human lifetime. The resulting Breakthrough Starshot concept would use an array of extremely high-power lasers to shoot a beam at a huge, extremely thin reflective sail. Energy from the beam would accelerate the sail (and a miniature probe attached to it) to  1/5 the speed of light, more than 1,000 times faster than anything humans have yet achieved.

Breakthrough Starshot concept would use a giant Earth-based laser array to accelerate a space sail to a significant fraction of the speed of light. Destination: Proxima Centauri b? (Credit: Breakthrough Initiatives)

Breakthrough Starshot concept would use a giant Earth-based laser array to accelerate a space sail to a significant fraction of the speed of light. Destination: Proxima Centauri b? (Credit: Breakthrough Initiatives)

I worked with Philip Lubin of the University of California at Santa Barbara to develop a popular-level summary of how the Starshot would work. You can read about it here. If you want to dig into the more technical details of the project, Lubin also has a much longer paper posted online. This proposal envisions technology beyond what is available today, but there are no science-fiction elements in it. No warp drive, no wormholes. It is a straight extrapolation from things we know and do right now, just executed on a vastly greater scale—which is broadly similar to where the idea of going to the moon was around 1950.

In other words, we don’t know how to build a Starshot yet, but at least we know where to start. If we invested seriously in the project—on the order of $20 billion total, more than the Large Hadron Collider but far less than the International Space Station—and got started right away, Lubin and other researchers guesstimate that we could have the technology ready in three decades. I’ll be more conservative and add another two decades to allow for all the full suite of components: In addition to the phased laser array you need the the energy-collecting sails, the probes themselves, and a “mothership” to carry them into orbit before interstellar launch. Just this week, a group of Starshot planners met at Moffett Field in California to hash out some of the details.

Lubin suggests that the a laser-accelerated lightsail could reach 0.25c (that is, 25 percent the speed of light). The Breakthrough Starshot announcement similarly suggests a target velocity of 0.2c. I’ll again be conservative–within this frame of crazy optimism, that is–and say that what is really possible is closer to 0.05c, or 5 percent the speed of light. That is still roughly 10,000 miles per second, a hugely ambitious goal. At that speed, sending probes to Proxima Centauri b would take approximately 85 years.

Notice, by the way, that I said probes. To make the Starshot work, you want to start with very small payloads, no larger than an iPhone and possibly a good deal smaller; the lighter the payload, the easier it is to accelerate to ultra-high velocity. A low-mass payload will necessarily have limited capabilities, probably a camera, a couple types of spectrometers, particle & magnetism detectors, and a laser communication system. When that probe reaches its destination, it will still be moving at 10,000 miles per second and will have no way to slow down. Your trip through the most interesting part of the Proxima Centauri system will happen very quickly, in a matter of hours, and you will have no way to steer toward planet b or any other specific targets.

Artist's impression of what Proxima Centauri b might look like. Nobody alive today will ever know if it is accurate, but a fast flyby view of the planet just might be possible within a human lifetime. (Credit: ESO/M. Kornmesser)

Artist’s impression of what Proxima Centauri b might look like. Nobody alive today will ever know if this scene is accurate, but a fast flyby view of the planet just might be possible within a human lifetime. (Credit: ESO/M. Kornmesser)

But there is a huge upside to the Starshot concept. Almost all of the cost goes into the laser system that launches your probe. The probe itself would be a tiny, solid-state device attached to a thin sail. If the probes were mass produced, the cost per launch might be just a few hundred thousand dollars. The Breakthrough Starshot team therefore envisions launching not one, but a swarm of thousands. Some of those probes would fail at launch; some would fail along the way; some would miss Proxima Centauri, or not pass close enough to interesting targets to get a good look. But it doesn’t matter; a 99 percent failure rate would still be a tremendous success. If you launch 1,000 probes, you need only a dozen to survive in order to achieve one of the most amazing missions of exploration in human history.

If you tally my numbers, you’ll see that I envision the first probes reaching Proxima Centauri in about 135 years (and then you have to allow another 4.3 years for their signal to get back home). Using much more aggressive assumptions, Lubin suggests that we could get start receiving our first up-close reports on Proxima Centauri b around 2070. Either way it is a very long wait time to make sense of a new discovery, and that assumes both a sustained, focused effort and the successful resolution of a vast number of technical challenges.

Fortunately, this race passes a lot of milestones that are much closer and easier to reach. Even in its early stages, laser-sail technology would be useful for high-speed exploration through the solar system, or for deflecting and maneuvering asteroids. More to the point, there is a whole other race to Proxima Centauri–one that does not require high-power lasers and interstellar travel, one that is underway right now. I’ll talk more about that in my next post.

For the latest science and technology news, follow me on Twitter: @coreyspowell

  • yaridanjo

    I hate to put it this way, but have you considered the possibility that there are sentient beings on Proxima Centauri b, and they have been visiting us for 4300 years or so? The most recent visit seems to be in December 2012.

    The worst of it is that they have left us with verifiable evidence about our own solar system 4300 years ago.

    They left us verifiable evidence about the masses of our Jovian Planets relative to our Sun. Also, they told us about a half Jupiter sizes planet in our outer solar system that our team has dubbed Vulcan.

    “A Jovian sized Vulcan was known to the ancient Akkadians of the third millennium B.C. Not only was it known, but they also knew of planets Neptune (that cannot be seen with the naked eye) and the barely visible Uranus. Figure 1 shows the Akkadian seal containing an image of Vulcan and the four Jovian planets, Jupiter, Saturn, Uranus and Neptune (courtesy of the seated god Ea – a Cenos astronaut from the Proxima Centauri star system). Note the size of Vulcan is between that of Saturn and Jupiter. Almost anyone can envision the Sun and these five solar bodies depicted in the Akkadian Seal.”

    Note Figure 2 that is a log/linear plot that proves this scientific relationship.

    Astronomers are now aware of this large planet and some call it Planet Ten.

    “In any case, the statistical and numerical evidence obtained by the authors, both through this and previous work, leads them to suggest that the most stable scenario is one in which there is not just one planet, but rather several more beyond Pluto, in mutual resonance, which best explains the results. “That is to say we believe that in addition to a Planet Nine, there could also be a Planet Ten and even more,” the Spanish astronomer points out.”

    Kind of check things out. We humans don’t have the best of reputations among our near by neighbors on other star systems.

    • Brian MCC

      Its ok to seek help for mental problems. Just do it.
      Bring this post (above) to the doctor. It will clarify things.

    • Lions Ground

      This account is spamming the same comments. Visit his account at and you see how active he really is..

    • coreyspowell

      I have just considered the possibility, and rejected it since there is no credible evidence to support it. A shame, since actual, documented evidence of alien life would be the greatest scientific discovery in history.

      • yaridanjo

        Then where did the Akkadians get the sizes of the Jovian planes compared to the Sun 4300 years ago?
        Neptune cannot even be seen with the unaided human eye. Uranus is barely visible.
        Your right, the discovery of a sentient space mobile species on our next nearest planet outside the solar system is the greatest discovery in human history and you are rejecting it as spam.
        Others are not so blind. But there are none so blind than those who will not see.
        Sent from my iPad

      • yaridanjo

        There is even another story here. That is that there is a half Jupiter mass body in our outer solar system that the Cenos aliens have pointed out. Up till now, astronomers were considering it to be ten to twenty Earth masses in size. Although the Spanish astronomers are considering it to have a semi major axis greater than 250 AU and a mass greater than Saturn.

        BTW, our half Jupiter mass body (that we call Vulcan) is one that only reaches about 448 AU from the Sun and comes in 134 AU. This is a stable orbits because it is less than 490 AU or 50 billion miles and would not be ejected from our solar system by a passing star.

        It’s not just technology that we can get from ET aliens, but it is astronomical information about our own solar system.

        • John C

          There’s already a planet Vulcan. It needs to pick a new name.

          • yaridanjo

            We followed procedures outlined by Madam Blavatsky to find the therotical orbital parameters of this body, and it should be (brown dwarf) star like. She called it Vulcan.


            George Forbes almost found it in 1880, but we got the complex set of orbital parameters. His and our parameters agree. However, we went on to verify its period by other independent measurements. We were 1.7 years different from Vulcan’s fherotical period up until astronomers recently refined 2000 CR 105 period (3:2 resonance). Now we are within 0.3 years of its therotical period.


            Astronomers did not read Blavatsky’s theory and miss named a hypothetical planet closer to the Sun than Mercury – Vulcan. It was Blavatsky that defined this astronomical body and Forbes who almost found it. We are honor bound to give it the name Blavatsky called it until it is officially recognized.

          • John C

            Please tell me you’re not voting in 2 months.

          • yaridanjo

            This discussion is about technical issues, not crooked, lying, genocidal psychopaths that go by the general name of politicians. There are lots of ET aliens that have visited Earth, but there is not an honest politician on the entire planet!

          • John C

            Now you’re making sense.

          • Ivar Ivarson

            Seems like an ideal libproggy voter to me.

        • coreyspowell

          The WISE survey would have easily seen a Saturn-mass planet out to 10,000 AU, and Jupiter-mass out to 25,000 AU. There is no evidence of such objects.

          • yaridanjo

            Absence of evidence is not evidence of absence. WISE could easily have missed this object if it is made of heavy elements and is not a gas giant.


            The aligned orbits of rocky bodies around Pluto hints at an unseen planet
            Spanish scientists claim this world would be 10 times the mass of Earth
            They believe this planet is moving in resonance with a much larger world
            They calculated this world would have a mass between that of Mars and Saturn and would orbit 200 times Earth’s distance from the sun

            The semi-major axis of our Vulcan is about 291 AU. These Spanish astronomers are estimating it to be 250 AU or more. The mass of our Vulcan is estimated to be 141 +/- 35 Earth masses from the data on the Akkadian Seal courtesy of the Cenos astronaut AKA the God Ea or Eiki or whatever it was called back then.


            Incidentally the log/linear plot was done on a NASA computer.

          • John Cherish

            Did it ever occur to you it might just be a brown star that is not very luminous and not a planet. The Alpha Centuari star system has 2 stars, and a another red dwarf star nearby, Proxima Centuari a short distance away. It is only our arrogance that precludes this possibility that our solar system might be a binary system as well. It has been discovered in observations that many star system are binary more so that they first estimated.

          • yaridanjo

            That possibility is worth considering. Proxima Centauri cannot be bound to the Alpha Centauri star system. It is too far away. Alpha Centauri A is about Sun size and if a planet or brown dwarf star were bound to it, it would have to be closer than 50 billion miles (Hynek) or 490 AU (Van Flanderen)

            If Proxima Centauri b is inhabited by a space mobil sentient species, I think a reasonable upper bound for it is 46 Earth masses. That is a pretty small brown dwarf, and I am proposing that our Vulcan is a brown dwarf at 141 Earth masses. I am reasonably sure I would be critisized in either case.

            But if sentient life is really there as it seems to be, there must be a star like object close by. Alpha Centauri A & B are pretty far away.

            Proxima Centauri b is most likely not a brown dwarf, but there could be one within 100 AU (WAG) of Proxima Centauri. There are damn few stellar systems that are not binary, especially when one is willing to consider brown dwarfs.

  • OWilson

    There’s a cost/benefit analysis required before grossly adding to our unpaid debt.

    Particularly while our inner cities suffer.

    But spending billions, then waiting 200 years to find out that there’s no alien life, not only in our own solar system, but in the closest one too, is not likely to inspire.

    This latest ape has indeed met his cosmological limit.

    • coreyspowell

      Let’s see. $20 billion over 20 years (with lots of technological spinoffs along the way, but never mind). Half of that would be done with international partners and/or private funding. So figure about $500 million/year devoted to this project. Such lavish support would equal 0.01% of current federal spending. If devoting 0.01% of the budget to the inner cities would relieve their suffering, why are we not doing it now?

      I’m not being flip here. The purpose of a project like this is not to pour away money and wait 200 years. It is to develop new technologies, test new ideas, inspire new scientists and engineers, and open up the human imagination all along the way. Compared to most of the other things we spend money on, I think it’s a really smart investment.

      • John C

        True, government sponsored research, especially by the Defense Dept., the fruits of which are then leveraged in the private sector into com satellites, GPS, iPhones, the Internet, etc. has given the best return on investment of any taxpayer money in history.

      • OWilson

        First things first :)

        Getting to our own Space station, without having to buy a ticket from Vladimir Putin, would be “a really smart investment”.

        If you weren’t some $20 billion in debt, it might be different.

        Face it, your space program ended with the safe return of your astronauts in 1969.

        A few circa 1970’s Radio Shack robots since then is has not produced any notable spin offs since the 60s. Not even another reliable rocket!

        The action has all been in biological research, and that is mostly private money.

        • John Cherish

          You are so wrong about all the spin-offs its amazing. However first lets deal with the mis-information you provided on the national debt. The national debt is not $20 Billion, if it were it could be be paid off in a year its 1000 times more than that at $20 trillion.

          But as far as the spin offs go. Here are a few. Computers, currently what you hold in your hand as a cell phone has more computer power than the computer had on board the Apollo space craft. Advances in quantum physics made this possible with ever smaller electronics circuitry these advances wouldn’t have occurred without the technology we used to go to the moon.
          They are now working on propulsion systems that don’t need fuel and use microwaves to accelerate IONS found in space. Space isn’t exactly empty there are Ions in space and likely will be usable as fuel for the ION drive without having to launch all the fuel into orbit.

          This is not circa 1970 electronics at work, this is advanced quantum physics and such devices you can’t make with radio shack components or from hardware of the 70’s

          There have also been numerous advances in the material sciences as well directly as a result of space research. One of which is in the area of superconductive materials that will give us better ways to generate energy and transmit it as well as providing us with the necessary research into quantum physics and containment of high energy particles

          It’s not that we can’t afford it it is that we lack the focus and the will power invest in new technologies that could propel us to the planets of our solar system and its moons efficiently and further still into interstellar space. There was a time when people said manned flight couldn’t be done. Then that we could never travel faster than the speed of sound. These are only temporary barriers. probably in a hundred years we might even discover how to travel faster than light

          • OWilson

            Funny, I just edited that billion/trillion stuff that before I read yours. I frequently refer to the National Debt correctly here so regulars will give me a pass.

            As I said nothing really new, in Space, since 1970. :)

            But biology and chemistry, Wow!

    • bwana

      Put a little bit of the totally insane military budget to projects like this might result in something worthwhile other than death and destruction!

    • Rigel54

      OWilson has met that limit, apparently. As a deficient ape, he cannot speak for the others.

    • Ivar Ivarson

      If I have a choice of furthering your social experiment in funding self-destructive lifestyles and launching probes to the stars, I will choose the latter. The poor we will always have with us.

  • Mark Sugrue

    Its worth considering that the technology needed to go to proxima Centauri will have massive commercial benefits closer to home.

    A ground based laser array of that power would dual use as a tool for cleaning up space junk in Earth Orbit.

    And space mining would benefit from fast survey probes. Current tech needs up to 10 years to do a flyby of an asteroid. A Starchip could reach any point in the solar system in a few hours – and vastly more cheaply too.

  • KMGuru

    Comments sound like people talking from 18th century…may be these folks (us) will soon get advanced…think about UFOs..and just wait…

  • Antonio Urbizu

    Kind of stupid concept. If you reach your destination, how are you going to talk to earth with such a small device.

  • Arttai

    Cute, but I think that right now we need to focus on building giant space telescope that is strong enough to identify all the planet in our neighborhood say in the vicinity of 500 year light away and learn basic parameters about them like composition atmosphere and mass. We can get the big picture about what is around so later when we have better means know where to send probes to. It can be done by building a modular telescope that more and and more mirrors can be added to it over time with different sensors that can be added and replaced that can capture different types of light wavelength and radiation.

  • Nixak*77*

    It’s probably going to cost a lot more than $20 billion. I’ll would NOT be a bit surprised if it ended up costing well over $200+ billion.

    To build a laser w that kind of power, range & pin-point accuracy is no trivial matter. IMO such effort is better spent of building laser arrays to make a break-thru re commercially viable fusion reactors- for which lasers would NOT need to be nearly as precise, & likely would NOT need to be nearly as powerful either.
    -PS: IMO w a laser that powerful & precise, you might as well use it as a deep-space probe-scanner & point it directly at Proxima-Centauri, & then analyze the light’s that reflected back to Earth.

    Plus we can already estimate w hi-confidence that Proxima-Centauri-B is most likely life-less & almost certainly is devoid of any complex life-forms. Why? Because Proxima-Centauri’s a red dwarf star, to which PC-B orbits so close, it’s tidally-locked; & also is continually blasted by the PC star’s powerful solar-flares; plus its estimated average sun-lit side temps is -36*F to as frigid as -100*F. This all adds up to a harsh environment totally inhospitable for complex life-forms as we know it.

    IMO The Rare Earth Principle is likely correct- which would fully explain ‘Fermi’s Paradox’. IMO there’s like just a few or perhaps only one truly Earth-like planet orbiting a/a few Sun-like star(s) w a/a few solar-system(s) like ours- per galaxy or maybe even per group of galaxies. So tho there MAY Be billions of earth-like planets inhabited by ET type civilizations in the entire Universe [maybe], IMO for our Galaxy there are likely just a handful of ‘earth-like’ exo-planets w ET type civilizations- In fact we may even be unique re this Galaxy.


Out There

Notes from the far edge of space, astronomy, and physics.

About Corey S. Powell

Corey S. Powell is DISCOVER's Editor at Large and former Editor in Chief. Previously he has sat on the board of editors of Scientific American, taught science journalism at NYU, and been fired from NASA. Corey is the author of "20 Ways the World Could End," one of the first doomsday manuals, and "God in the Equation," an examination of the spiritual impulse in modern cosmology. He lives in Brooklyn, under nearly starless skies.


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