back to article A 73bn-kg, skyscraper-size chocolate creme egg spinning fast enough to eventually explode – it's asteroid Bennu

Scientists have compared asteroid Bennu to a chocolate creme egg – and say it may explode as it continues to spin at an ever-increasing rate. “You could imagine maybe in a million years or less the whole thing flying apart,” said Daniel Scheeres, coauthor of a study published in Science Advances on Thursday into the cosmic …

  1. redpawn

    How common is this?

    It seems like any object with some rotation perpendicular to its orbit would slowly spin up. More explanation of the YORP effect would have been helpful, especially why it prefers to spin an object up rather than down. I infer that the time in sunlight makes the sunset side of the asteroid hotter than the sunrise side so more heat energy is radiated.

    1. diodesign (Written by Reg staff) Silver badge

      Re: How common is this?

      I've added a link to an in-depth explanation of YORP by the probe's principal investigator. As you can see it goes on for quite a while, and in all honesty, we ran out of time to condense the effect's description down into an explanation that would satisfy everyone.

      Like any product, you have to draw a line at some point and ship it. Articles are no different -- otherwise, nothing would get published because we'd forever be trying to improve or add to them.

      I encourage you to read up on it and share here your best explanations of it.

      C.

    2. Tessier-Ashpool

      Re: How common is this?

      Objects can spin up or down from this effect, but it has negligible impact on large bodies because the amount of mass to be shifted increases with r-cubed whereas the surface area increases as r-squared. Also, larger bodies tend to have a less irregular shape.

    3. Little Mouse Silver badge

      Re: How common is this?

      Could the YORP effect be used to power a self-turning doner kebab grill or spit-roast?

      If I'm going to build one I guess I'll need a bigger heater, a colder atmosphere, and bearings with less friction than Disaster Area's stuntship, for starters.

      What else will I need?

      1. Chris G Silver badge

        Re: How common is this?

        "What else will I need?"

        Some yood quality Halal Doner meat, the extra hot chili sauce and some crisp salad.

        1. werdsmith Silver badge

          Re: How common is this?

          A yood quality elephant leg?

      2. ClockworkOwl
        Coat

        Re: How common is this?

        A very long piece of paper to write down all the other things you'll need...

    4. Anonymous Coward
      Anonymous Coward

      Re: How common is this?

      Presumably as it loses mass over time (as they all tend to do as they approach the sun) then the conservation of angular means its rotation increases as it shrinks?

  2. Kevin McMurtrie Silver badge

    73 billion kg of chocolate creme egg? I hope OSIRIS-REx brings back enough to share and doesn't melt it on re-entry.

    1. S4qFBxkFFg

      "73 billion kg of chocolate creme egg"

      Ah, an example dating from before Cadbury's resizing exercise.

      1. G R Goslin

        Was there ever....

        ... a time before the Cadbury re-sizing exercise? I thought that it had been going on since the beginning of time.

        1. Wellyboot Silver badge
          Unhappy

          Re: Was there ever....

          Cadbury creme eggs were unchanged for decades, as was Terry's chocolate orange.

          The chocolypse (Kraft buyouts of Cadbury & Terry's) ruined them.

          1. Anonymous Coward
            Anonymous Coward

            Re: Was there ever....

            Hmmmm.... chocolate......

            But agree with you that since the yanks have bought Cadbury the quality has gone down.

            Wife and I did visit the factory just after the buyout. Unfortunately we went on a maintenance day so the machines were all switched off. Anyway, part of the tour was the history of the place and how it built for the workers by the Cadbury family. Was kind of depressing seeing how the board sold the workers down the river

    2. HildyJ Silver badge
      Angel

      Toy inside?

      I remember chocolate creme eggs with toys inside that were banned here (across the pond) as a choking hazard.

      Maybe that's why the inside is less dense.

      1. Chris G Silver badge

        Re: Toy inside?

        I think that was Kinder eggs that were banned; Cadbury's creme eggs are creme all the way through, although including a toy in that would certainly be a choking hazard.

  3. Anonymous Coward
    Anonymous Coward

    Sooga! Sooga! Sooga!

    That's no moon....

    It's a mudhorn egg!

  4. Doctor Syntax Silver badge

    A new Register measure of mass - the Bennu?

  5. Paul Cooper
    Boffin

    Interesting thought

    Surely the fact that one of the first few asteroids that we have inspected up close is apparently close (in geological terms) to disruption has important implications.

    It implies that it is common for such bodies to be close to being disrupted, and hence places limits on the expected life-span of such bodies. Therefore, it also implies that such bodies must form at a rate to replace the loss by disruption. By form, I include entry into the inner solar system by perturbation of the Oort cloud.

    1. I ain't Spartacus Gold badge

      Re: Interesting thought

      Isn’t the Oort Cloud a bit far from the Sun for major YORP effects? Whereas Bennu is much closer in.

      1. Paul Cooper

        Re: Interesting thought

        The disruptive effect would only happen after the asteroid reached the inner solar system. The mechanism by which they leave the Oort Cloud must be a different one - possibly even random gravitational encounters would be sufficient, though the possibility of there being a massive dark body (e.g. Planet X) can't be discounted.

    2. Doctor Syntax Silver badge

      Re: Interesting thought

      The alternative is that the fragments re-coalesce to form new asteroids.

      However, this is a sample of one...

    3. ThatOne Silver badge
      Unhappy

      Re: Interesting thought

      > the fact that one of the first few asteroids that we have inspected up close is apparently close [...] to disruption has important implications.

      Most of all as regards to the strategies to adopt if one tries to hit our planet! Obviously many if not most of those suggested so far wouldn't work on a floating heap of rubble: Push/hold one spot, and the rest of the asteroid just goes on unabated. And while we might dodge a bullet, we would still receive a load of buckshot, just as devastating.

      How can you stop/deviate a billion-ton loose heap of rubble?

      1. Version 1.0 Silver badge
        Joke

        Re: Interesting thought

        "How can you stop/deviate a billion-ton loose heap of rubble?"

        Vote against him in the election.

      2. Alan Brown Silver badge

        Re: Interesting thought

        "And while we might dodge a bullet, we would still receive a load of buckshot, just as devastating."

        more so. A series of airbursts fro a disintegrating comet is hypothesised as having near-sterilised North America and caused the Younger Dryas event

        https://craterhunter.wordpress.com/notes-on-ignimbrite-emplacement/part-two/

        If this guy is right (look at the rest of his site) then we should be worried about what we can't see coming

        1. ThatOne Silver badge
          Unhappy

          Re: Interesting thought

          > we should be worried about what we can't see coming

          Which actually spells "everything"! Especially if our sky is eventually obscured by sheets of Internet satellites, but even now we usually only spot those flying boulders at the very last moment. So, either we don't notice them until it's too late, or they are so big we won't be able to do anything about them anyway.

      3. Doctor Syntax Silver badge

        Re: Interesting thought

        The description suggests that it's spinning and the outer crust is sufficiently consolidated to hold the core in place against centrifugal force. If it were disrupted centrifugal force would disperse the core so what we'd get would be a fraction of it in separate chunks. The question then arises as to how big those chunks might be. Would they burn up on the atmosphere?

        As per earlier comment, this is a sample of one. Is it a common structure? How do you identify others without going to visit them?

  6. Anonymous Coward
    Anonymous Coward

    What is it with Septics using the smallest possible unit of measure?

    Is it the good ol' US "bigger is better"? How about tonnes, mega-tonnes?

    I've listened to podcasts where they reference things that are 150,000 lbs, or 2,000,000 cu. ft. WTaF!? It's less typing and much more relatable to say 75 ton or 74,000 cu. yds

    Do they measure cock size in thou'?

    1. ThatOne Silver badge

      Re: What is it with Septics using the smallest possible unit of measure?

      Using kilograms for stellar body masses is standard.

      Just check Wikipedia (https://en.wikipedia.org/wiki/Sun for instance) and look at the physical characteristics box on the right side: The sun's mass is given in kilograms.

      1. Anonymous Coward
        Anonymous Coward

        Re: ...stellar body masses is standard

        Original ac above, I didn't down vote you, but I'd rather not use wiki as an example of the truth.

        "is [a] standard" created by NASA perchance?

        1. ThatOne Silver badge

          Re: ...stellar body masses is standard

          > I'd rather not use wiki as an example of the truth

          True, but it's the easiest example to link to...

          No, that habit wasn't created by NASA (or even the USA) AFAIK. It seems to be quite old, I suppose from a time where SI units were still new.

          Anyway, using "tons" is dangerous since there are several units with that name, and in this context it is hardly better. And who would understand "teragrams" and "petagrams"?...

  7. Annihilator
    Boffin

    Cadbury's Creme Eggs

    I look forward to the updated 2021 marketing campaign of "How do you eat yours?".

    "I commission NASA to launch a $1 billion rocket to spend 7 years approaching and returning a tiny sample scraped off the top of it"

  8. Anonymous Coward
    Anonymous Coward

    It gets worse every year

    Halloweens not even over and already with the creme eggs.

  9. Dante Alighieri Bronze badge
    Joke

    Ooops...

    Unless OSIRIS-REx manages to find the catastrophically flawed weakspot on the surface and we get to see the yoke...

  10. Version 1.0 Silver badge

    Are aliens playing billiards?

    While the YORP effect is a factor, I wold have thought that it's only a minor one because it would take so long to be effective and it's probably more likely that another clump of rocks could either strike, or pass close, to Bennu to sprinkle both sets of rocks around. But the chances are that, while a few might wander into the solar system, most of the rocks would simply party with other clumps.

  11. Danny 2 Silver badge

    73bn-kg

    I don't understand without the standard simplified analogy. Is that higher or lower than the weight of Wales?

    1. Screwed

      Re: 73bn-kg

      Including the coal and copper that has been extracted?

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