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posted by martyb on Thursday August 20 2020, @12:09PM   Printer-friendly
from the Chelyabinsk-wannabe dept.

Astronomers spot closest Earth-buzzing asteroid ever recorded :

Astronomers have identified an asteroid that's just made the closest pass to Earth ever recorded – and it was only spotted after it had passed. The object skimmed Earth's atmosphere over the weekend, close enough to have its orbit changed by the planet's gravity.

On August 16, an asteroid designated 2020 QG whizzed past our planet at a distance of only 2,950 km (1,830 mi) above the surface. That's well within the altitude of many satellites, and almost twice as close as the previous record-holder, an asteroid called 2011 CQ1. Of course, this record is about the closest pass to Earth, and doesn't include objects that have impacted the planet.

That said, even if it had hit, asteroid 2020 QG wouldn't have caused any damage. It measures about 3 to 6 m (10 to 20 ft) wide, meaning it would have just burned up in the atmosphere.

Also at phys.org and JPL.

Perhaps the Monolith was doing a fly-by.


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  • (Score: 2) by Immerman on Friday August 21 2020, @01:38PM (5 children)

    by Immerman (3985) on Friday August 21 2020, @01:38PM (#1039864)

    100km, 62 miles, 330,000 feet: https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line [wikipedia.org]

    And not everyone agrees on that definition for the edge of space.

    Your definition is also a little off. Wings work at any altitude that has any air, you just need to travel faster to get the same amount of lift.

    The Kármán line is the altitude where the speed necessary to aerodynamically support the airplane's full weight equals orbital velocity (assuming typical wing loading and lift coefficient for an airplane). In practice, supporting full weight wouldn't be necessary to maintain altitude because the curvature of the Earth adds centrifugal lift as the airplane reaches orbital speed.

    Taking that second sentence into account, it's a fairly arbitrary line in the real world - the height at which a typical aircraft would need to travel at orbital speeds to maintain sufficient lift, if the Earth were flat and orbiting was impossible. In practice most of a plane's weight would be supported by "centrifugal lift" well before reaching the Karman line, and so suborbital aircraft could fly at considerably higher altitudes.

    In practice though, the Karman line so is deep in the no-man's land where neither normal aircraft nor normal orbital vehicles would be able to operate effectively, that one definition is pretty much as good as another.

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  • (Score: 2) by FatPhil on Friday August 21 2020, @03:57PM (4 children)

    by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Friday August 21 2020, @03:57PM (#1039941) Homepage
    The GGPP was talking about a tangible physical property, one defined by solving equations based on masses, distances, and densities, not the regulatory arbitrary definition defined by lawyers with rubber stamps.

    So I cited the number you get from the equations, from that same article.
    --
    Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
    • (Score: 2) by Immerman on Friday August 21 2020, @04:51PM (3 children)

      by Immerman (3985) on Friday August 21 2020, @04:51PM (#1039972)

      What makes you think that? All the mentioned was that 2950km was "about 30 Karman lines away" - using the original equation solution, rather than Karman's subsequent suggestion of 100km actually makes that statement less accurate.

      Besides, as I already pointed out Karman's calculations completely ignores vital aspects of reality anyway - which means it's still just an arbitrary value with no actual relevance to the real world.

      • (Score: 2) by FatPhil on Friday August 21 2020, @11:35PM

        by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Friday August 21 2020, @11:35PM (#1040161) Homepage
        > What makes you think that?

        Facts.
        --
        Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
      • (Score: 2) by FatPhil on Saturday August 22 2020, @09:18AM (1 child)

        by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Saturday August 22 2020, @09:18AM (#1040305) Homepage
        Are you not able to read the subject line of the very posts you are responding to?
        --
        Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
        • (Score: 2) by Immerman on Saturday August 22 2020, @02:28PM

          by Immerman (3985) on Saturday August 22 2020, @02:28PM (#1040380)

          You mean "definitely not buzzing the Earth"? That has even less to do with what definition of the Karman line was being used.