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Hubble Discovers 'Planetary Graveyard' Around White Dwarf

Posted by Unknown on from the fate-of-man dept.

astroengine send this interesting excerpt from Discovery: "The Hubble Space Telescope has discovered rocky remains of planetary material 'polluting' the atmospheres of two white dwarfs — a sign that these stars likely have (or had) planetary systems and that asteroids are currently being shredded by extreme tidal forces. Although white dwarfs with polluted atmospheres have been observed before, this is the first time evidence of planetary systems have been discovered in stars belonging to a relatively young cluster of stars. 'We have identified chemical evidence for the building blocks of rocky planets,' said Jay Farihi of the University of Cambridge in a Hubble news release. 'When these stars were born, they built planets, and there's a good chance that they currently retain some of them. The signs of rocky debris we are seeing are evidence of this — it is at least as rocky as the most primitive terrestrial bodies in our Solar System.'"

26 comments

  1. don't get it by Anonymous Coward · · Score: 0

    They're white dwarfs so how can they be young. Maybe the planets are metallic like Mercury so after the stars went boom boom, some material survived without changing to dust.

    1. Re:don't get it by dreamchaser · · Score: 3, Interesting

      It says a relatively young cluster of stars. That doesn't mean that some members of the cluster aren't old enough to have gone nova. Also, larger hotter stars (than the Sun) don't stay in the main sequence nearly as long, so it's possible that some were just under the threshold to become neutron stars. There is no contradiction there.

    2. Re:don't get it by IndustrialComplex · · Score: 1

      Also, larger hotter stars (than the Sun) don't stay in the main sequence nearly as long, so it's possible that some were just under the threshold to become neutron stars. There is no contradiction there

      Very true. One of the things that always seemed counterintuitive, but obvious from a physics perspective, is that there are stars which have formed, burned insanely bright, and 'died', within the age of the Earth, let alone our Sun.

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  2. Re:Happy Thursday from The Golden Girls! by Anonymous Coward · · Score: 0

    I think it was supposed to be 'confidante', but I think I like cosmonaut better.

  3. poor science reporting by harperska · · Score: 1, Interesting

    The article doesn't explain why there is rocky material close enough to the white dwarfs to be tidally ripped apart. It makes a brief comment about the extreme tidal stresses ripping apart anything orbiting it. But superdense objects don't exert stronger gravity for their mass than less dense objects. If the sun spontaneously magically became a white dwarf, or even a black hole, the earth would continue in its orbit unperturbed. The only thing that would cause a former planet of this white dwarf to be tidally ripped apart is if the star gained magical mass (which it wouldn't as a white dwarf has less mass than the star it used to be, as the rest is now in the planetary nebula), or if the planet survived the red giant stage and was somehow pulled in to a closer orbit in the white dwarf stage. I could imagine an earth like planet being enveloped in the hazy outer atmosphere of the expanding red giant, and the star's atmosphere causing enough drag to slow the planet down and fall to a lower orbit. But that requires a planet survive passing through a star's atmosphere without being incinerated right there and receiving just enough drag to fall to a lower orbit but not plunge into the heart of the star. That is all pretty amazing stuff if true, and the article mentions none of it - choosing rather to go down the bad science "it's denser so it must magically suck harder because that's how gravity really works" route.

    1. Re:poor science reporting by osu-neko · · Score: 1

      ...choosing rather to go down the bad science "it's denser so it must magically suck harder because that's how gravity really works" route.

      Could you quote the passage in question? I read the article and didn't see anything saying that. They did say, "Any planetary system that was once in orbit around the star will be severely disrupted during the red giant phase...", which while less explicit is more or less what you said the article "mentions none of".

      --
      "Convictions are more dangerous enemies of truth than lies."
  4. Too bad for any life by JoshuaZ · · Score: 2

    These white dwarfs are only 150 light years away. So if any life managed to get off planet and spread out we would have noticed the resulting civilization. We'll probably never know for sure if there was life or even intelligent life on any of these planets because they've been so torn apart by the tidal forces (and very likely anything left on them died out millions of years ago). I wonder if in a few billion years, there might be some other nearby just beginning race looking out to the remains of our solar system and reaching very similar conclusions.

    1. Re:Too bad for any life by iggymanz · · Score: 3, Interesting

      that's probably the answer to the Fermi Paradox. For billions of years the earth had life, but only in the last few decades the technology that *might* have detected or made a signal to another star. In less than 350 million years, the earth will be too hot to support multicellular life due to expansion of the sun. what if every billion years or so an intelligent species arises within 10,000 light-years of any other place that has the same thing happen once at some random time over the life of the universe? they find themselves alone...

    2. Re:Too bad for any life by Anonymous Coward · · Score: 3, Insightful

      You put too much faith in our ability to detect other civilizations.

      Who says they would be using technology noticeable to us?

      Who says we'd even notice them with a 150 year delay between their actions and our ability to perceive them?

      We know too little about how things work in space to draw any meaningful conclusions. Best to stop at, "Apparently, we saw nothing. Damn. Next section of the sky, please."

      The universe is too big for us to be completely alone. The only question is: are they in range for us to find them before we or they go extinct?

    3. Re:Too bad for any life by JoshuaZ · · Score: 1

      If there was life there that escaped the current destruction it had to have left millions (or billions) of years ago (since the star has been a white dwarf for a long time and has been being obnoxious to its inner planets for a long time also). That means they would have likely colonized near space (not at all limited to our own solar system). Keep in mind that even the Voyager probes, which aren't even designed to go to other stars will reach nearest stars on the order of 100,000 years. And systems using ion drives and deliberately timed gravity assists could put that in the range of 30,000 years for something to spread out, or a few hundred with nuclear drives of the right type. See for example the summary here http://www.universetoday.com/15403/how-long-would-it-take-to-travel-to-the-nearest-star/.But of course we see no sign of anyone from a nearby system doing much.

      Moreover, if they've had millions of years to spread out, that means that projects like Dyson spheres and ring worlds are obvious things to do. Systematic searches have been done and we're very certain we don't see any Dyson spheres in 300 parsecs (about 1000 light years) http://home.fnal.gov/~carrigan/infrared_astronomy/Fermilab_search.htm. While we can't be as certain, near ring worlds would likely have been noticed by Kepler. Other forms of engineering projects on that scale would be noticed, especially because this is in our back yard. This makes it unlikely.

      In this case, the extremely close nature of the system, and the system's current state means that we can make with a high confidence much higher than just "we saw nothing."

      Who says we'd even notice them with a 150 year delay between their actions and our ability to perceive them?

      I'm not sure what you mean by this. The presence of a delay doesn't interfere with noticing things. It isn't like it is 1 second goes by, wait a 150 years, and then another 1 second goes by. There's just a fixed 150 year delay (just as there's an 8 minute delay from the sun).

    4. Re:Too bad for any life by chris.alex.thomas · · Score: 1

      well it's actually a good point, our ability to detect something would depend on how much energy it expended, therefore crossed the galaxy in a way we could detect it.

      small scale example, a computer in the 50's took a whole building, generated a ton of heat and noise, people walking past easily could detect something was there, even if they didnt know what it was, standing inside the main room was hot and the air dry, all easy to detect.

      nowadays, computers use a tiny fraction of the power they used to and are thousands of times more capable, you'd have a hard time detecting a cellphone on standby in somebodies shirt pocket even if you were humping their leg, the power signature is practically non-existent apart from specialist technology that even then might not pin down exactly where or what it was.

      applying this idea to aliens and their possible futuristic technology, surely it's quite easy to suppose that their power signatures are not strong enough to reach us, or are absorbed/converted to other forms which don't appear identifiable from other normal or natural sources that at the end, they become invisible, yet they could be warping space time in some way and yet using the same power as it costs to turn on a television on our planet.

      you get the idea, but I think it's an interesting idea/point of view.

    5. Re:Too bad for any life by Anonymous Coward · · Score: 0

      In less than 350 million years, the earth will be too hot to support multicellular life due to expansion of the sun.

      That is shorter than most estimates I've seen, which range typically from 800 to 1100 million years from now. It would not so much be the expansion but the increasing luminosity which increases by about 1% every 100 million years. There are expectations in the 500-800 million years from now time frame that some kinds of photosynthesis will not be possible as increasing weather and temperatures cause minerals to absorb CO2. But not all forms of photosynthesis would stop, only the kind that makes things like trees work, but not the kind that is in some human crops. It would take another couple hundred million years for the temperature to directly impact multicellular life.

    6. Re:Too bad for any life by Anonymous Coward · · Score: 1

      You made the erroneous assumption that species' survival is tied to the life of their home star.

    7. Re:Too bad for any life by Anonymous Coward · · Score: 0

      What part of your ass did you pull your figures from? Universe today says it has another 1.1 billion left, Wikipedia saysThe Sun is about halfway through its main-sequence stage, during which nuclear fusion reactions in its core fuse hydrogen into helium. Each second, more than four million tonnes of matter are converted into energy within the Sun's core, producing neutrinos and solar radiation. At this rate, the Sun has so far converted around 100 Earth-masses of matter into energy. The Sun will spend a total of approximately 10 billion years as a main-sequence star."

      Where did that 350 million years come from?

    8. Re:Too bad for any life by iggymanz · · Score: 1

      I made the logical conclusion that will be the case in most cases. any exceptions will be too far from us to matter.

    9. Re:Too bad for any life by iggymanz · · Score: 1

      nasa.gov says only a few million years for us or anything descended from us

      you make the mistake of seeing a time span for any kind of single cell extremophile life surviving, might still be possible in a billion years as the earth's temperature approaches boiling. But two and four legged land creatures will be long gone in half that time

  5. Re:Happy Thursday from The Golden Girls! by Anonymous Coward · · Score: 1

    whooosh

  6. Aw,... by maciarc · · Score: 4, Funny

    ... we've come out of hyperspace into a meteor shower. Some kind of asteroid collision. It's not on any of the charts.

    1. Re:Aw,... by Anonymous Coward · · Score: 0

      That's not a planet, it's a space station!

    2. Re:Aw,... by Ukab+the+Great · · Score: 1

      I have a bad feeling about this...

    3. Re:Aw,... by binarylarry · · Score: 1

      Kryten you smeg head! I said red dwarf, not white dwarf!

      --
      Mod me down, my New Earth Global Warmingist friends!
  7. Zombie planets by onyxruby · · Score: 1

    All I know is if they have zombie humans, cats, wolves and other such critters than they must inevitably also have zombie planets. Now one would assume that zombie planets munch on the brains of other planets, but the unfortunate thing is that this isn't covered in any of the zombie survival guides! Locking yourself in a nice zombie proof chamber isn't going to do any good when the planet next door comes gobbling away you know.

    Let's face it, your going to need a really, really big gun and how can you possibly put a planet killing gun in your back yard without having to explain things to the neighbors and or the United Nations? So many questions, so many scenarios and so few bad movies that have been made by Hollywood. Someone should get cracking on this.

    1. Re:Zombie planets by Anonymous Coward · · Score: 0

      never read Hellstar Remina did you?

      imagine a eldritch abomination that eats planets. brought to you by the same guy who created The Ringu

  8. Woo hoo! by PPH · · Score: 2

    Spare parts to keep our planet running longer!

    --
    Have gnu, will travel.
  9. Slashdotted by LeadSongDog · · Score: 0

    The site at http://linuxgizmos.com/linuxdevices-gone-but-not-forgotten.html seems to have been temporarily replaced by a static page. Bookmark and return later.

    --
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