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  • (Score: 3, Interesting) by c0lo on Friday July 27 2018, @03:50AM (5 children)

    by c0lo (156) on Friday July 27 2018, @03:50AM (#713547) Journal

    and then controlling its descent. Possibly into a desert instead of an ocean.

    I propose the Washington DC instead - not too many jobs in manufacturing around, cheap minerals available near the surface may change that.
    Additionally, the heat of reentry may dry that swamp.

    (grin)

    --
    https://www.youtube.com/watch?v=aoFiw2jMy-0
    • (Score: 2) by realDonaldTrump on Friday July 27 2018, @04:20AM (3 children)

      by realDonaldTrump (6614) on Friday July 27 2018, @04:20AM (#713549) Homepage Journal

      Our economy is growing tremendously -- new numbers coming out Friday at 8:30am ET. So we need all the beautiful Clean Coal we can get. Whether it comes from outer space or right here on Earth!

      • (Score: 0) by Anonymous Coward on Friday July 27 2018, @04:27AM

        by Anonymous Coward on Friday July 27 2018, @04:27AM (#713550)

        So we need all the beautiful Clean Coal we can get.

        Well, buy some from China, I hear everything coming from there is cheap.

      • (Score: 3, Funny) by martyb on Friday July 27 2018, @03:32PM (1 child)

        by martyb (76) Subscriber Badge on Friday July 27 2018, @03:32PM (#713709) Journal

        So we need all the beautiful Clean Coal we can get. Whether it comes from outer space or right here on Earth!

        That got me to thinking. What if this asteroid was composed entirely of anthracite coal and it was plummeting straight to Earth?

        TFA mentions "a near-Earth asteroid about 30 feet in diameter"; let's call that 10 meters in diameter, or 5 meters in radius.

        The volume of a sphere is: 4/3 * Π * r^3

        Given a radius of 5 meters, that comes to approximate 523 cubic meters.

        The density of coal [reference.com] varies; for anthracite coal it's 800-929 kg/m^3.

        Let's choose a round number of 900kg/m^3. With 523 cubic meters of coal, that works out to about 471,000 kg.

        Now let's have some fun...

        The energy density of coal [wikipedia.org] "is roughly 24 megajoules per kilogram".

        That puts us at 11.3 million MJ or 11.3 terajoules.

        The energy content of TNT [wikipedia.org]: "The energy density of TNT is used as a reference-point for many other explosives, including nuclear weapons, the energy content of which is measured in equivalent kilotons (~4.184 terajoules)".

        So, we're looking at about 2.7 kilotons of TNT. (By comparison, the bombs dropped on Hiroshima and Nagasaki were about 16 and 21 kilotons, respectively).

        So, it's on the small size for a thermonuclear device, but I still would not want to be anywhere near its approach!

        [Please feel free to verify the math and provide corrections... that was a quick pass through and I need to hurry to get ready for work, so don't have time to double check everything.]

        Thanks for the thought experiment!

        --
        Wit is intellect, dancing.
        • (Score: 2) by martyb on Friday July 27 2018, @03:42PM

          by martyb (76) Subscriber Badge on Friday July 27 2018, @03:42PM (#713713) Journal

          Doh! I completely forgot about the kinetic energy involved in dropping a 471 metric ton rock from outer space; the above calculation only made use of the intrinsic energy of a chunk of coal of that size.

          I would imagine the kinetic energy would be vastly greater.

          --
          Wit is intellect, dancing.
    • (Score: 2) by VLM on Friday July 27 2018, @04:15PM

      by VLM (445) Subscriber Badge on Friday July 27 2018, @04:15PM (#713723)

      From what I understand of recent Chinese politics and economy they're almost certainly talking about crashing it into Africa.

  • (Score: 3, Insightful) by MichaelDavidCrawford on Friday July 27 2018, @04:37AM (1 child)

    ... to cover the entire land surface of the Earth multiple meters deep.

    But Seriously Folks:

    The real value in asteroid and lunar mining is that it's already in space. Even with the lunar gravity the energy required to get it into Earth's orbit is dramatically less than what it would be to launch it from Cape Canaveral.

    And it happens that gold really is crucial to satellite design, not just for its electronics but also to reflect infrared. Aluminum doesn't reflect it as well.

    --
    Yes I Have No Bananas. [gofundme.com]
  • (Score: 2) by takyon on Friday July 27 2018, @04:52AM (2 children)

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday July 27 2018, @04:52AM (#713558) Journal

    https://en.wikipedia.org/wiki/BFR_(rocket) [wikipedia.org]

    50 metric tons returned. Let's say the mission costs $50 million. $1 million per ton (1,000 kg).

    1 ton of platinum = about $26.6 million
    1 ton of gold = $39 million

    That's great and all, but good luck extracting that much pure gold/platinum/etc. in space, especially from a smaller asteroid. There is lots of cheap iron, cobalt, nickel, water, etc. that should probably stay up there because it is so cheap down here.

    Instead, if one rocket launch could deploy the bag + heat shield around a 10 meter diameter asteroid, you could crash land about 1500 tons without needing to do any processing. The hardest part could be carefully nudging that asteroid into Earth orbit, probably requiring a separate mission. Luckily, it would just burn up in the atmosphere [wikipedia.org] if you make a mistake.

    Still likely to cost many millions of dollars and return a lot of unneeded iron, nickel, water, etc.

    --
    [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 0) by Anonymous Coward on Friday July 27 2018, @05:12AM (1 child)

      by Anonymous Coward on Friday July 27 2018, @05:12AM (#713564)

      The Chelyabinsk meteor [wikipedia.org] was around 12,000 or 13,000 tons; the explosion was around 400 to 500 kilotons TNT equivalent. You want to bring down a 1,500-ton asteroid. Linear extrapolation gives roughly 54 kilotons TNT for the explosive yield (~3-4 Hiroshima units).

      • (Score: 0) by Anonymous Coward on Friday July 27 2018, @06:02AM

        by Anonymous Coward on Friday July 27 2018, @06:02AM (#713567)

        Linear extrapolation gives roughly 54 kilotons TNT for the explosive yield (~3-4 Hiroshima units).

        Good... how about Florida?

  • (Score: 0) by Anonymous Coward on Friday July 27 2018, @06:05AM (1 child)

    by Anonymous Coward on Friday July 27 2018, @06:05AM (#713571)

    ... into Earth orbit and then controlling its descent. Possibly into a desert instead of an ocean.

    And who does that asteroid belong to once it lands in the desert? Presumably the country whose desert it lands in.

    The Good News: against all odds, you have captured an asteroid containing several tons of gold and successfully landed it on Earth.

    The Bad News: it now sits in the middle of a desert in a country that is corrupt, but thanks you for your generous gift.

  • (Score: 4, Informative) by Arik on Friday July 27 2018, @07:36AM (1 child)

    by Arik (4543) on Friday July 27 2018, @07:36AM (#713584) Journal
    You don't mine asteroids to bring them to Earth. You mine asteroids for materials to be used in space, so you don't have to boost them up there *from* Earth.
    --
    If laughter is the best medicine, who are the best doctors?
    • (Score: 0) by Anonymous Coward on Friday July 27 2018, @08:33AM

      by Anonymous Coward on Friday July 27 2018, @08:33AM (#713591)

      Depends.
      Sure the gold and platinum are better used down, but those rod from gods have strategical value only when up.

  • (Score: 0) by Anonymous Coward on Friday July 27 2018, @10:16PM

    by Anonymous Coward on Friday July 27 2018, @10:16PM (#713854)

    until you nuke a city because somebody made a typo in deorbital navigation code.

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