Can “Warp Speed” Planets Zoom Through Interstellar Space?

[/caption]Nearly ten years ago, astronomers were stunned to discover a star that had been apparently flung from its own system and travelling at over a million kilometers per hour. Over the years, a question was brought up: If stars can be ejected at a high velocity, what about planets?

Avi Loeb (Harvard-Smithsonian Center for Astrophysics) states, “These warp-speed planets would be some of the fastest objects in our Galaxy. If you lived on one of them, you’d be in for a wild ride from the center of the galaxy to the Universe at large.”

Idan Ginsburg (Dartmouth College) adds, “Other than subatomic particles, I don’t know of anything leaving our galaxy as fast as these runaway planets.”

The mechanics responsible for the super-fast planets are similar to those responsible for “hypervelocity” stars. With stars, if a binary system drifts too closely to a supermassive black hole (such as the ones in the center of galaxies), the gravitational forces can separate the stars – sending one outward at incredible speeds, and the other in orbit around the black hole. Interestingly enough, “Warp Speed” planets can theoretically travel at a few percent of the speed of light – not quite as fast as Star Trek’s Enterprise, but you get the point.

The team, which includes Loeb and Ginsburg, created computer models to simulate the outcome if each star had planets orbiting it. The outcome of the model showed that the star shot into interstellar space would keep its planets, but the star “captured” into orbit around the black hole would have its planets stripped and sent outward at incredible speeds. Typical speeds for the planets range from 11-16 million kilometers per hour, but given the proper conditions could approach even higher velocities.

As of now, it’s impossible for astronomers to detect a wandering planet due to their small size, distance, and rarity. By detecting the dimming of light levels from a hypervelocity star as an orbiting planet crosses its face, astronomers could detect planets that orbit said star.

Ginsburg added, “With one-in-two odds of seeing a transit, if a hypervelocity star had a planet, it makes a lot of sense to watch for them.”

Loeb concluded with, “Travel agencies advertising journeys on hypervelocity planets might appeal to particularly adventurous individuals.”

If you’d like to learn more about hypervelocity planets, you can access a draft version of the upcoming paper at:

Source(s): Harvard-Smithsonian Center for Astrophysics , Hypervelocity Planets and Transits Around Hypervelocity Stars

30 Replies to “Can “Warp Speed” Planets Zoom Through Interstellar Space?”

  1. That picture makes me wonder… just how much volcanism or geothermal activity would a planet have to endure to keep it temperate while being so far from the nearest star?

    1. I think the press release made an unlucky choice for showcase of potential biosphere.

      More likely they were thinking of sustained plate tectonics making global (crustal) or local (hydrothermal vents) biospheres without the presence of temperate zones. Albeit superearths would likely have those for a long time with or without a star around.

      The more long lived and potentially larger type of biosphere would be ice moons orbiting an ejected gas giant, see Europa and Enceladus. They could keep a large, larger than Earth, biosphere for many billions of years.

      And now that we know orbiting planets survive the gravitational ejection unscathed, the ejected star of the binary system would be where the best tourist seats are bookable.

    1. Troll bait of course: the ejected stars, their velocity in that range and their heritage from our super massive black holes is both seen and their ejection mechanism tested (never “proven”) as mentioned in the article.

      And the existence of exoplanets is likewise both seen and their creation mechanism tested, as described elsewhere here on UT. Combining these are no different than noting that the same force pulling dropped objects to ground in my sight is responsible for, say, remains of rock avalanches.

  2. Warp speed?

    11-16 million kilometers per hour,is roughly 1% of the speed of light. Relativistic subatomic particles can go much faster.

    However, even if relativistic effects are still not strong for anyone on the surface of those planets, any impact with an asteroid(and planets suffer hundreds of them in billions of years) at 0.01c would be catastrophic.

    The main concern for these planets inhabitants would be of course not the speed of the planet, but the absence of the light and heat of a sun. Things would be very cold and dark there!

    I would call “warp speed” planets (still a sci-fi scenario) the result of a huge blob of negative energy around that planet, that would make the planet reach effectively superluminal “speed” (and if tidal forces do not break it into tiny pieces) without relativistic time dilation and space contraction. That would be a “warp speed” planet!

    1. I think the article was just indulging in some artistic licence:

      Interestingly enough, “Warp Speed” planets can theoretically travel at a few percent of the speed of light – not quite as fast as Star Trek’s Enterprise, but you get the point.

    2. I think, by “warp speed” the authors Ginsburg, Loeb, and Wegner just intended to say “relatively fast”. Authors of scientific articles should restrain from using science fiction language. They always get inappropriate connotations.

      1. “Warp speed” is no more just a science fiction term since physicist Alcubierre showed a solution of the General Relativity equation that describes a warped space bubble that can move arbitrarily fast (matter cannot go faster than light, but space is not matter). It’s called the “Alcubierre Warp Drive”.

        However, to create a warp bubble one needs an exotic form of energy, negative energy. And a lot of this stuff is needed, somewhere between the mass-energy of Jupiter and the Sun.

        We, as a civilization that still struggles to find energy sources that, unlike fossil fuels, do not deplete and do not pollute, are very far from this. But for a much more advanced civilization, this monumental task may be a possibility.

      2. I know Alcubierre’s approach very well, and have participated in discussions here and elsewhere. I would go as far as saying Alcubierre’s approach being a pipedream. The shortest explanation starts like this: Having a formal solution of a system of equations, without giving any good reasons why something like this would work in reality, and without the smallest experimental support, is research in a cloud of formulae, and only there; this gets us nowhere in reality — let me say: in non-fiction.

        Over and above that there are the pertinent unsurmountable problems, two of which you mentioned. Alcubierre’s approach does not violate the laws of relativity — that’s true — if you consider these laws as a set of formulae purely. But there are more physical laws, and the approach violates some of them.

        You bring the — I would say: notorious and hypothetical — “much more advanced civilization” into play. I don’t know any good reason — e.g. by extrapolating (how?) our current physical knowledge –, why there seriously “may be a possibility”.

        I insist: “warp speed” is science fiction — at most.

      3. “‘Warp speed’ is no more just a science fiction term since physicist Alcubierre …”

        I want to add — after having (again) looked into Alcubierre’s paper at (2000; originally published in Classical and Quantum Gravity, 1994) –, that Alcubierre did not use the term “warp speed” in his paper.

        Merriam-Webster tells about the origin of “warp speed”: “from the use in science fiction of space-time warps to allow faster-than-light travel”, and about the first known use: “1979”.

        It’s questionable whether Alcubierre himself used this term at all (correct me somebody, please; I would be interested). As far as I can tell, he does, at least, not need the term “warp speed” in the explications of his approach.

  3. Just a thought, but would the constant high speed collisions with galactic hydrogen produce enough heat to keep the planet warm?
    If the hydrogen heats up the leading side of such a planet, would it show up in infrared? Maybe we can see them. Torbjörn?
    A collision with anything much larger would probably be disastrous at these speeds, I would think.

    1. Perfect opportunity for a back-of-the-envelope calculation 😀

      The density of the interstellar medium is 10E-21 kg per cubic metre (I’m going to ignore precise values and just use orders of magnitude)

      3% of the speed of light is 10E7 meters per second

      So a planet with the same cross-section as Earth (10E14 square meters) travelling at that speed would draw out a volume of 10E21 cubic meters each second, soaking up 1kg of interstellar material (a surprisingly neat figure, orders-of-magnitude wise :))

      1kg of interstellar material travelling at 3% of the speed of light relative to the planet on average would have 10E14 joules of kinetic energy (ignoring relativistic effects), so assuming it all gets dissipated into heat, the planet (or its atmosphere at least) would receive 10E14 joules of heat each second.

      Which is about as much as it would receive from the Sun at Saturn’s distance, and about a thousand times less than what Earth receives from the Sun (10E17).

      Hmm… given it’s “only” 3 orders of magnitude difference, I think a more precise calculation may be warranted, but I wouldn’t bet money on a rogue hyper-velocity planet being balmy.

      1. Well, and this supposes that these particles will reach the atmosphere to impart their thermal energy. If the planet maintains any sort of magnetic field due to internal dynamism, wouldn’t that deflect the particles before they got close?

      2. Well, and this supposes that these particles will reach the atmosphere to impart their thermal energy. If the planet maintains any sort of magnetic field due to internal dynamism, wouldn’t that deflect the particles before they got close?

      3. Or conversely, a magnetic field might channel them into the planet… I’m not too hot on magnetics so I can’t say for sure either way.

      4. Squidgeny did the heavy lifting for any sort of contemplation of heating effects.

        What magnetic fields does is trapping particles in the Van Allen belts, where they either bleed into the atmosphere, or as recently discovered is purged from time to time by CMEs (IIRC) and what not.

        Yes, it would diminish the direct heating effect on the atmosphere. How much seems not amenable to back-of-envelope calculations, despite having a decent estimate of the generic heating effect.

      5. Thanks for your precise ‘back of the envelope’ calculation!
        While I didn’t really expect ‘balmy’, this does change the equation a little. Of course it all depends on if there really are such planets, but makes for interesting thought exercises.

  4. There may be planets inside star clusters cannoning around like pinballs, and if I got some time on a supercomputer I could work out their probable paths and publish it as a paper. As TL said I’m not quite sure what applying known gravity laws to postulate sci-fi scenarios achieves, beyond good headlines and the miniscule possibility of frozen alien life speeding towards us over the aeons. Pray God anything planet size travelling towards us would be subject to enough tidal forces to eventually render it into rubble and the encounter would be as asteroid/meteorite. Finding one of these would be much more news-worthy and it makes me wonder how would you establish extra-solar orgin? Stable isotope ratios?

    1. Did I say that?

      The possibility of these ejects of the galaxy is IMO, if observable, as everything else observable, it helps sorting things out.

      As for planets traveling towards us, it is much more likely the normal population of stray exoplanets ejected out of solar systems will meet us.

      They are currently estimated to be twice as many as the number of stars. But if only planetary scientists can come up with ideas how they originate, those rogues may well be up to ~ 100 000 per star! IIRC I recently had to estimate the frequency of encounters as they strain observation: ~ 1 rogue would pass within the solar system every thousand year or so.

      I’m sure something has to give here. However, it points to that our system has survived meeting many of these rogues. There have been papers on how they can be picked up by a system, kept for several orbits, and then ejected again.

    2. — “Pray God anything planet size travelling towards us would be subject to enough tidal forces to eventually render it into rubble and the encounter would be as asteroid/meteorite.” —

      Can you clarify this?
      What are the tidal forces you are referring to? Tidal forces of this rough planet on the solar planets? Or tidal forces that this rough planet experiences when it gets accelerated?

  5. Seems the extreme gravitational forces in a black hole environment would tear apart a star, let alone a planet before it could reach such hyper speeds. Perhaps the existence of such objects indicates scientific understanding of gravitational force is once again ripe for change.

    1. The gravitational forces would, to a point, tear a planet or star apart. I think (assuming I’m envisioning it correctly) that the star would have ‘boomeranged’ around the black hole’s event horizon. By not getting close enough to be eaten, it would be accellerated to the point that it is racing through space.

  6. I’d like to see simulations of a hypervelocity earth-sized planet colliding with different sized planets, asteroids, stars, etc. (^_^)

  7. Shades of “When Worlds Collide” an interesting book and movie from the 50’s.

    1. “Melancholia” was my thought. I just saw it. Not a great movie IMO, but have become intrigued by the idea of rogue planets. Up til now I’d mostly thought about asteroids as our biggest danger.

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