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Space Science

Do 'Ultracool' Brown Dwarfs Surround Us? 224

Posted by CmdrTaco
from the itsatrap dept.
astroengine writes "The recent discovery of two very cool 'T-class' brown dwarfs in our cosmic neighborhood has prompted speculation that there may be many more ultracool 'failed stars' nearby (abstract). Not only are these objects themselves very interesting to study, should there be many such brown dwarfs spanning interstellar space. Perhaps they could be used as 'stepping stones' to the stars."
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Do 'Ultracool' Brown Dwarfs Surround Us?

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  • ... are 20% cooler than cool dwarves.
    • by poity (465672)

      As regular brown dwarfs would have you know, "ultracool" brown dwarfs are actually hipster poseurs.

    • Yes, but they've failed the Art of the Star. Maybe they can Giggle at the Gas Giants, but they're no more than Cupcakes compared to other stars who are At the Galactic mean size.

      Most importantly, what these brown dwarfs are are MACHOs (Massive Compact Halo Objects), which is a competitor to the WIMP (Weakly Interacting Massive Particle) theory of dark matter. So with this discovery we may begin a WIMPy Wrap-Up.

  • by Anonymous Coward on Monday July 18, 2011 @10:11AM (#36799618)

    Yeah, sure. Because when you're on a 100 year cruise to colonize Sirius the thing you really want to do
    with your intertia is slow down and stop at your local brown dwarf to pick up a pack of Coke and some cigs.

    • by TWX (665546)

      I speculate that it wold be worth the course. Depending on the design of one's spacecraft, one could pick up particles that are in orbit of the brown dwarf to use for fuel or other raw materials, and one could use gravity as an assist to accelerate further toward one's destination.

      • Depending on the design of one's spacecraft, one could pick up particles that are in orbit of the brown dwarf to use for fuel or other raw materials, and one could use gravity as an assist to accelerate further toward one's destination.

        If you're moving slowly enough that a gravity assist off a Brown Dwarf is worth doing, you're talking about interstellar voyages taking tens of thousands of years.

        And if you're taking tens of thousand of years to get to Alphacent, you're doing it wrong. Better to just wait

    • Q. What are the odds that 50 yrs of technological progress would slash the stellar travel time, so that a 100-yr trip would likely be pointless?

      • Not good. How did the last 50 years go? Oh I get it! By "Progress" you mean "Neglect" and by "Pointless" you mean "Imossible".
      • Well...we last went to the moon 42 years ago, so unless something amazing happens in the next eight years, I'd say...:

        Q. What are the odds that 50 yrs of technological progress would slash the stellar travel time, so that a 100-yr trip would likely be pointless?

        A. Not good.

    • If the Brown dwarf had some transverse velocity to the direction that you wanted to go,you could use it as a gravitational slingshot to gain speed and hence time with minimal or even possibly no fuel usage.

    • No you could establish colonies along the way on these brown dwarfs. They may be small enough that you could scoop up hydrogen from them for fueling and some may even have planets orbiting around them which would allow for colonization of them.

    • Everything is relative. It shouldn't be too difficult to find a brown dwarf heading somewhat in the correct direction. You'd have to spend some fuel to match the trajectory, but with judicious selection you could minimize that.

    • I find it amusing that everyone in this thread seems to think that we're anywhere *near* the technology for a propulsion system needed to journey to another solar system in a mere 100 years. The fastest we've ever accelerated any object in history (the New Horizons probe) would take more like 80,000 years (and that's just to get to the nearest one, our galactic next-door-neighbor at just 4.2 light years away). And that's not even factoring in added time for the deceleration you would need to actually stop o

  • Racist (Score:5, Funny)

    by Sedated2000 (1716470) on Monday July 18, 2011 @10:12AM (#36799634)
    I can't believe how racist slashdot has become. They may be ultra cool, but calling them brown is inciting hate. African American little people is the PC term.
    • Re: (Score:3, Insightful)

      by Rhaban (987410)

      I can't believe how racist slashdot has become. They may be ultra cool, but calling them brown is inciting hate. African American little people is the PC term.

      African American little people with sunglasses.
      You can't be ultracool without sunglasses.

    • Re:Racist (Score:5, Funny)

      by PvtVoid (1252388) on Monday July 18, 2011 @10:35AM (#36799848)

      I can't believe how racist slashdot has become. They may be ultra cool, but calling them brown is inciting hate. African American little people is the PC term.

      Mass disadvantaged stars of color.

    • Re: (Score:3, Funny)

      by hey! (33014)

      Face it, white man. Even our short guys get more than you do.

    • by sl3xd (111641)

      It's not just slashdot. It's the entire astrophysicist community.

      We should never forget "Black Holes" that destroy anything that come close enough - that's both racist and sexist.

  • Would these ultra cool brown dwarves serve in putting more fruit to dark matter theories?
    • by PvtVoid (1252388)

      Would these ultra cool brown dwarves serve in putting more fruit to dark matter theories?

      Almost certainly not. Dark matter made up of brown dwarfs was searched for in the gravitational microlensing experiments like the MACHO project [anu.edu.au]. They didn't find nearly enough to account for the dark matter.

    • by dido (9125)

      No. As much as it seems fashionable to bash (non-baryonic) dark matter here on Slashdot, our current astrophysical theories put constraints on how much baryonic dark matter (MACHOs) is possible. Our current theories on Big Bang nucleosynthesis place bounds [arxiv.org] on how much baryonic matter can remain dark. If there really were enough baryonic matter to account for all the dark matter that should be there based on indirect observations, then the abundances of various isotopes produced by Big Bang nucleosynthesis w

    • by HiThere (15173)

      No. Brown dwarf stars are made of baryonic matter, just like you and I. Dark matter must be non-baryonic, or physics needs to be totally redone. (A difficult job, as coming up with even one chunk of math that matched what we know of quantum behavior took lots of work.)

      Basically, current physics predicts the number of protons+neutrons created at the time of the "big bang", and thus the number of baryons in the universe. There aren't enough of them to account for the "dark matter". And all current altern

  • Yes there are (Score:3, Informative)

    by Cable (99315) on Monday July 18, 2011 @10:27AM (#36799756) Homepage

    In order to have elements beyond carbon one needs a bigger star than our yellow sun. Large stars tend to supernova and become brown dwarfs or black holes in some cases. Some stars fail and become brown dwarfs as well. But you can still get hydrogen from them from solar winds for spacecraft.

    It is hard to detect them because the brown dwarfs are Earth size and do not give off much heat or light. Our sun Sol is supposed to have a companion star nearby called Nemesis that is a brown dwarf and throws asteroids at our solar system.

    • Re:Yes there are (Score:5, Informative)

      by scharkalvin (72228) on Monday July 18, 2011 @10:42AM (#36799926) Homepage

      Large stars will never become brown dwarfs. They will end up as one of the following:
      White dwarf, neutron star, or black hole. A white dwarf will eventually cool and become a black dwarf. The chemical composition of a white dwarf is NOTHING like that of a brown dwarf. A brown dwarf is hydrogen and a few other elements. A white dwarf has very little hydrogen, it is the 'ash' of a star that once was and is made of mostly heavier elements that are the result of fusion.

    • by ceoyoyo (59147)

      Mods, this isn't informative.

      Large stars do not become brown dwarfs. Brown dwarfs don't have solar winds. Brown dwarfs aren't Earth size - they are many times larger than Jupiter. Nemesis is a piece of fiction - it hasn't been ruled out but there's no evidence at all for it's existence. If Nemesis did exist, it would be throwing comets at us, not asteroids, and they would come from within our solar system.

  • by kaizendojo (956951) on Monday July 18, 2011 @10:29AM (#36799764)
    Read this real quick and thought it was an advance report from Comicon...
  • All foam, no beer (Score:5, Interesting)

    by MonsterTrimble (1205334) <.moc.liamtoh. .ta. .elbmirtretsnom.> on Monday July 18, 2011 @10:41AM (#36799918)
    The idea of Y-class brown dwarf stars are neat and all, but this whole 'stepping stone' idea is not really explained. Why would we use these as stepping stones? Is there an advantage to it? I don't understand why we would use them is all.
    • Re: (Score:3, Interesting)

      by calderra (1034658)
      Random ideas off the top of my head: Rogue stars of any sort might carry clouds of hydrogen and/or other elements, possibly even rocky asteroids and protoplanets, with them. It might be possible to refuel in one of these systems. Gravitational slingshots become an interesting idea, possibly allowing for some really interesting maneuvers. A gravity source also makes orbiting possible, so we could send ahead robotic probes to orbit some big external fuel tanks to await a manned mission that will carry less ma
      • I understand that, however I wonder if a 'refueling' is possible within the constraints of near-future (100 or so years) technology.

        What I could see happening is setting up waypoints or space stations near the stars which are used much like the forts were during colonization of North America.

    • Survivable (with shielding) surface temperatures and an abundance of Hydrogen for one.

      If theres something that can function as a gas station in between us and Proxima Centauri the trip might become possible.

      • The article claims that they hope to find some with an exterior temperature below 225 C! For comparison, the earth's outer core ranges from 4400 C in the outer regions to 6100 C near the inner core, and the inner core is around 5400 C.

    • Re: (Score:3, Interesting)

      by david.given (6740)

      Instead of building a colony ship that can travel a minimum of 4 ly to the next star system, you can build one that only needs to go 0.1 ly (or so, depending on the density of these things). That's a vastly simpler job, requiring much less time and energy, and possibly only taking a decade or so --- well within a human lifespan. Once you get to the brown dwarf, you colonise. Even a small brown dwarf like Jupiter has an insane amount of resources. Sure, there's no starlight, but if you've got hydrogen you ca

    • by AJWM (19027)

      Unless there are a bunch of these closer than the nearest stars we can see, they'd make poor stepping stones. However, their existence suggests that other cold objects (icy, not pizza-oven hot like these things -- think Oort cloud or Kuiper belt objects like Sedna and Eris) may be more prevalent than previously thought. Those would make good stepping stones.

      The stepping-stone concept assumes we'll never have FTL transport or even significant-fraction-of-lightspeed transport. (Bussard ramjets may be harde

    • Refueling... Even with the best drive, you don't want to carry all your fuel with you. A quick circling stop there could boost speed and pick up more fuel, not to mention much needed gravity vacation.

      • Refueling... Even with the best drive, you don't want to carry all your fuel with you. A quick circling stop there could boost speed and pick up more fuel, not to mention much needed gravity vacation.

        You're aware that it takes fuel to stop there, right?

        And then it'll take the same amount of fuel you used when you left the Solar System to get back up to speed when you leave the Brown Dwarf, right?

        And the same amount of fuel to stop when you get where you're going ultimately as it took to stop at the Brown

  • by LordMyren (15499) on Monday July 18, 2011 @11:00AM (#36800116) Homepage

    Yet another place the JWST (James Webb Space Telescope) would be fantastically useful!

    Also, how seriously would the presence of previously undetectable ultra-cool stars affect the search for dark matter? Aren't we looking for energy/matter based off some energy level, and might that mass be tucked away in the form of ultra-cool stars, just to cool to detect?

    • by LordMyren (15499)

      Re: dark matter, apparently not. http://science.slashdot.org/comments.pl?sid=2332984&cid=36800042 [slashdot.org]

    • I agree whole-heartedly on the comment about JWST. It was an enormous eater of funds, but the science potential was even bigger.

      Regarding the dark matter issue, there is a small minority in the astrophysics community that believe these sorts of so-called Massive Compact Halo Objects (MACHOs, a name chosen to specifically counter Weakly Interacting Massive Particles or WIMPs) might make up the dark matter.

      The majority of the community is in pretty solid agreement that dark matter must be something more exot

  • I've suspected this since Gary Coleman and Emmanuel Lewis were first detected in the 1980s.

  • by wisebabo (638845) on Monday July 18, 2011 @11:22AM (#36800366) Journal

    So (like another poster) I'm not sure how useful these would be as refueling dumps (stepping stones). I mean, once you've gotten a starship up to speed then slowing it down to refuel just to speed up again just doesn't make sense. I guess the only use would be if there were consumables that could be obtained for "generation ships" or if some large piece of the ship needed repair material (as in the ice shield on the starship in Arthur C. Clarke's "The Songs of Distant Earth"). I guess they might make sense if they were power stations that could beam (lasers?) energy to a passing ship.

    Another (briefly discussed) issue is that of missing matter. I realize that the amount of planetary matter must be a negligible contribution but why couldn't there be 100s or 1000s of brown dwarfs for every sunlike star? Is it because we'd see a lot more microlensing events or our Oort cloud would be perturbed much more frequently? It would be kinda cool if there were much more of these things out there rather than stuff we can't interact with.

    Are there any "habitable zones" around them? Sure there wouldn't be any light but it'd be like being next to a nice campfire for some really close orbits. Would the orbits be too close and decay in a geologically insignificant amount of time?

    If we ever got fusion drives (but nothing better) maybe having lots of these things would allow galactic expansion as a long slow crawl at very small fractions of the speed of light. In which case setting up colonies of couple thousand AUs over many millennia could gradually establish a dark web between the brightly lit stars (so much for Star Trek). These bodies then wouldn't be waypoints. They would be our homes.

    • by wisebabo (638845) on Monday July 18, 2011 @12:07PM (#36800824) Journal

      So these brown dwarfs are essentially big balls of (mostly) hydrogen with the centers under tremendous pressures and temperatures but not quite hot enough to "light" (in a fusion sense). Well what would happen if you managed to drop a fusion bomb on it? (On or near the surface where the temperatures are low but the high gravity might still compress the hydrogen into the megabar range).

      While (probably) it would just fizzle, could the concentrated energy ignite just enough so the whole star went boom? (Like a Type I supernova?). I mean the "temperature" of an H-Bomb is in the hundreds of millions of degrees maybe it just requires one tiny (if an H-Bomb is "tiny") spark. Just like you can pour millions of gallons of gasoline on a barely sub-critical mass of Uranium and it won't go bang but one small neutron generator and you've got a mushroom cloud. While the impacts of asteroid and larger bodies could deliver a lot more energy, an H-Bomb could do so more INTENSELY.

      I guess this is what the first H-Bomb scientists were worried about when they feared the first H-Bomb *might* ignite the water vapor in the atmosphere and consume the entire world. Just how easy would it be to blow one of these things up? Could you do it with even smaller cooler less dense bodies, say Jupiter (as proposed by sci-fi writer Charles Sheffield) or Neptune? (Tried it on earth, nope doesn't work). Lastly, our sun is already alite, but the RATE of fusion reaction is very slow (each gram of the sun produces far less energy per time than, say, a live elephant). Could we speed it up? Could an H-Bomb (or a suitably powerful laser such as was used in one of the Man-Kzinti war sci-fi books) trigger a local (or maybe not so local) explosion?

      I guess this was the general idea behind the movie "Sunshine" (good movie). Seems they had some sort of very dense (causing a local gravitational field) fission bomb to re-ignite the sun. Wish they had a companion book to flesh out some of the details.

      Anyway I know these ideas are probably non-sensical to any physicist but don't have enough math and physics knowledge to calculate it for myself. If anyone of you is so inclined and it won't take much time or effort, I'd appreciate the debunking (or not!) of this idle speculation.

      (For even crazier speculation, how about igniting all that supposedly great fusion fuel Helium-3 that is just lying around on the lunar surface? Would it be enough to blow the moon out of orbit a la "Space 1999"?)

      • Thanks for the speculations, and I'd encourage you to try some back on an envelope order-of-magnitude calculations to see which might make sense. For example, get a figure for the energy of an atomic bomb in some unit, and then find out the energy the sun puts out in one second in the same unit, and compare them.

        Also, what may seem to make sense with today's physics might seem ludicrous with tomorrow's physics.

        Maybe the sun is indeed a ball of iron.
        http://www.thesunisiron.com/ [thesunisiron.com]

        Or maybe cold fu

        • by Fubari (196373)
          Nicely said; interesting speculation links.
          They remind a bit me of this book, which I think you'd like, by James Hogan:
          Kicking The Sacred Cow (Questioning the Unquestionable and Thinking the Impermissible) [amazon.com]

          Two excerpts from a review:

          In his introduction, "Engineering and the Truth Fairies," Hogan describes the ideal view of science, but points out that even scientists will accept findings in fields other than their own without skepticism. He states: "I used to say . . . that science was the only area of human activity in which it actually matters whether or not what one believes is true. . . . Today, I reserve that aphorism for engineering" (p. 9).
          He makes the point that since engineering deals directly with reality, it is a useful gauge to the truth of scientific theories.

          In his afterword, "Gothic Cathedrals and the Stars," he notes that many of the most important findings in science over the past several centuries were actually made by outsiders, from Leonardo da Vinci (who was trained as a painter) to Albert Einstein (who was working as a patent clerk when he made many of his most important findings). He observes: "While most research today depends ultimately on government funding . . . history shows that bureaucratic stifling and an inherent commitment to linear thinking makes officially inaugurated programs the least productive in terms of true creativity" (p. 466).
          It is a scathing analysis of modern science, but one that is not undeserved.

      • by xigxag (167441)

        A meteoroid with enough impact power to equal the largest nuclear bomb we have ever made impacts the earth roughly every thousand years or so. So, any brown dwarf that could be ignited by a bomb would be ignited already by stray impactors.

        I suppose one could set up a scenario where a bd had, over the eons, been heating up little by little due to external forces and was now only one bomb away from ignition. But again, if it were that close to going stellar, then any ol' starquake, or maybe even tidal force

      • by holmstar (1388267)
        Even on a successful star, no fusion occurs in the outer layers. So If I had to venture a guess, I'd say the the "surface" of a brown dwarf would be far too diffuse to support a fusion chain reaction even with an ultra powerful fusion bomb as an "spark". So to have any chance, you would need to get your big fusion bomb much closer to the core, which would be an impressive feat given the intense pressures that it would have to withstand. I'm not saying it would be impossible, but we'd be talking about pre
      • by erice (13380)

        So these brown dwarfs are essentially big balls of (mostly) hydrogen with the centers under tremendous pressures and temperatures but not quite hot enough to "light" (in a fusion sense). Well what would happen if you managed to drop a fusion bomb on it?

        "Fusion" bombs fuse Deuterium and Tritium. Brown dwarfs already fuse Deuterium and Tritium for the part of their life cycle. That's what makes them brown dwarfs and not planets.

        http://cronodon.com/SpaceTech/BrownDwarf.html [cronodon.com]

        In order to create a real star, you need proton fusion. But that requires maintaining necessary heat and pressure for millions of years. If the gravity of the brown dwarf and the native deuterium and tritium couldn't do it then it is unlikely that your puny little H-bomb is going to

    • by xigxag (167441)

      Refueling wouldn't incur slowing the ship down...it would involve sending an automated factory out to the brown dwarf in advance, which would gather matter and launch it at high speed into the flight path of the refueling vessel. If necessary, rockets on the payload could be used to match the exact velocity.

  • I have presented to several of my friends/coworkers/family the idea that interstellar space IS NOT the great void we seem to have been assuming for so long, but instead may well be filled with all manor of significant objects, including brown dwarfs, rogue planets, etc. We don't have to make some multi-lightyear jump across nothingness to reach the stars; we can jump from world to world to world, like a great migration wave-front, gathering resources and establishing waypoints as we go. It was an article

    • And further, maybe someday we'll also be able to tap zero-point energy and create matter and energy in the middle of apparently empty space.
      http://en.wikipedia.org/wiki/Zero-point_energy [wikipedia.org]

      I can wonder if planets and asteroid orbiting brown dwarfs far away from the turmoil of the galaxy and other stars might be and ideal place for life, same as there is a lot of variety of life in the rarely disturbed deep ocean. The closer you live to a galactic core, the bigger the chance for periodic supernov

  • star formation results in a range of star sizes. some sizes are below ignition threshold. we don't see them, simply because they're dark. but, statistically speaking, there should be a lot more failed stars than ignited stars. so take a random section of space, count the number of stars you can see in that, and there should be a mathematical relationship between the number of visible stars, and the number of invisible unignited smaller "stars". and this relationship should be proportional by orders of magni

  • ...these objects represent some of the "dark matter" we are searching for?

The meta-Turing test counts a thing as intelligent if it seeks to devise and apply Turing tests to objects of its own creation. -- Lew Mammel, Jr.

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