Chelyabinsk meteor . . . Holy Carp!

Discussion in 'Fred's House of Pancakes' started by bwilson4web, Feb 15, 2013.

  1. tochatihu

    tochatihu Senior Member

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    Asteroid [email protected] Telescope and software automation of this process is is extremely impressive and productive. Not many years ago it was done individually, by individuals, more or less Clyde Tombaugh style.

    So why are things still showing up unannounced, as at Chelyabinsk? First note red region in graph @77 is growing slowly. Your common sense tells you (I hope) that there are many more small ones than large ones. Few smalls detected because even great current telescopes are not up to that task.

    More concerning, and sometimes mentioned, is that large ones can still be undetected if they are coming from 'sunny side' of sky. Some famous science talkers suggest that dinosaurs went extinct because they did not have telescopes. That has a 50% chance of being fundamentally wrong (because of sunny side).

    Humans do have telescopes and now use they well. However knowing of a high-probability bad event is not same as preventing it. This further weakens dinosaur story but I should stop flogging that corpse.

    It is arguably true that planning for and practicing asteroid nudging is a more important use of 'space money'' than, well, just about anything.

    Putting appropriate telescopes at Earth/Sun L4 and L5 could effectively address the sunny-side problem. Not currently a matter of serious discussion. A lucky civilization would get a 20-meter event, on land but not on big city, to stimulate that discussion.

    Feel lucky?
     
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  2. tochatihu

    tochatihu Senior Member

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    Lagrangian 3 is a better place for 'we're not dinosaurs' sentry telescope. Except it needs a relay to communicate with earth. There's a star in the way :)
     
  3. tochatihu

    tochatihu Senior Member

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    L3 also has high fuel requirement for long-term station keeping. Venus messes with that gravity well.
     
  4. ETC(SS)

    ETC(SS) The other One Percenter.....

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    Ion thruster - Wikipedia
    Either nucular or solar powered.

    All of the orbital mechanics classes that I never went to fail me here with calcuguessing an energy budget, but I'm thinking it's doable.
    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwib2ZGj3ZDhAhUym-AKHVvPAIAQFjAAegQIABAC&url=https%3A%2F%2Fntrs.nasa.gov%2Farchive%2Fnasa%2Fcasi.ntrs.nasa.gov%2F20040171140.pdf&usg=AOvVaw1i4ENZ0sy_YfnaaQC_H6p0

    There's even a company called L3 Technologies that makes the hardware.
    My favorite evil genius is going to be trying to loft another rocket big enough to get the job done.....on or about 7 April.


    ....that's 2019 in case this thread goes dormant for another 1.5 POTUS election cycles.....
     
  5. Skylis A

    Skylis A Senior Member

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    Did you get the pun?
     
  6. fuzzy1

    fuzzy1 Senior Member

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    Here are some discovery rate graphs showing a strong size shift trend of new discoveries. This trend suggests that the great bulk of the really big ones, >1km, have already been found, but that there are still far more medium-sized ones >140m awaiting discovery. The little ones keep getting found ever faster, so the search efforts haven't slacked off.

    The total discovery rate, all sizes, just keeps climbing. While the max was in 2017, I won't consider the slight dip in 2018 significant until it both continues for several more years and becomes much more pronounced. (2019 is obviously just YTD, meaningless until the 2020 bar gets started):
    upload_2019-3-20_11-26-35.png


    But discoveries of large rocks >1km peaked in 2000, and have dropped off by a factor of 10 since then. This clearly means that most of them have been found -- at least where we are looking for them. There could still be some rude surprises lurking in closets we haven't even opened yet.

    upload_2019-3-20_11-32-24.png

    Discoveries of medium rocks >140m are sort of plateaued. It is difficult to guesstimate how many more are left to discover, other than it is clear we are not yet getting close to having the full catalog:
    upload_2019-3-20_11-36-56.png
     
    #86 fuzzy1, Mar 20, 2019
    Last edited: Mar 20, 2019
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  7. tochatihu

    tochatihu Senior Member

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    To pick an arbitrary number, 100 cubic kilometers of angry asteroid will cause some level of planetary inconvenience. How often such things happen could be calculated, estimated, or guessed. Arrival speeds (which might be called anger) could range from few to >50 km/sec, which also matters a lot, but that will be another guess.

    Compare to a very different disruption from volcanoes right here at home. 100 cubic kilometers of volcanic ash emission event will cause some level of planetary inconvenience. If you guess that latter would be milder, I guess you're right. Here there is some basis for estimating frequency also. How happy I'd be if someone else took a shot at running those numbers!

    This are very different problems. They share 'hard to prevent' aspects. They call upon humans (faintly or strongly, take your pick) to make our Enterprise more fault tolerant. Best possible outcome would be if better fault tolerance also helped with respect to slow changes. I need not suggest what those might be :)

    ==
    Great minds have suggested that humans need to diversify from Earth as a way of mitigating risks here. Yeah, sure, I guess. However, as humans have not yet built even one 'habitation' on even most convenient (400,000-km-distant) moon, such diversification seems future-distant. Over shorter timescales, making Earth more robustly fault tolerant sure looks like a good money sink.
     
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  8. bisco

    bisco cookie crumbler

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    i think china should pay for it, they're the money bags these days. do a solid for the rest of us.
     
  9. tochatihu

    tochatihu Senior Member

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    Several entities could soft-land 6-ish tons on near side of moon with 3-ish tons of construction device and materials It's entirely open-source how to leverage that into habitat, including microwaving regolith.

    Bisco @88 hopes money (perhaps a billion $USD) should come from China. It surely could but they are not now talking about habitations. Nor is anyone else. So we wait (a big thing) and wonder if it will be some hate-able entity that makes habitations there first (perhaps a smaller thing?).

    After first whoever makes first off-earth habitation, there will be lots to talk about. But today, not so much.
     
  10. Merkey

    Merkey Member

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    Just wondering how long till I can get a senior coffee at a McDonalds on the moon.
     
  11. bisco

    bisco cookie crumbler

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    i thought we were chatting about blowing up asteroids. i don't think china needs to habituate the moon, they have plenty of land on earth
     
  12. bwilson4web

    bwilson4web i3 and Prime

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    We need a self-sustaining outpost to repopulate the earth. Call it a 'backup' for our species (and a few others!)

    Bob Wilson
     
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