• Captain Aggravated@sh.itjust.works
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    1 day ago

    The calculation of its speed was made by high speed camera, as you’ve probably seen the Mythbusters do. In this case the manhole cover was seen in flight in precisely one frame of high speed camera footage, and for it to go “installed, in flight, gone” in three frames means it would have had to be moving at mach jesus.

    It likely didn’t make it to space intact; it would have had ultrasonic compression heating on one side and a nuclear explosion on the other. It’s probably still here in the form of iron oxide dust scattered about the Northwestern hemisphere.

  • Valmond@lemmy.world
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    18 hours ago

    Maybe it desintegrated and thus vanished from the consecutive frame?

    Atomic blasts are kind of powerful versus an iron lid.

  • MonkderVierte@lemmy.ml
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    2 days ago

    Nope, it would just have bursted due to thermal schock and pressure. Escape velocity, what are you dreaming, is the lid made of tungsten?

    • logos@sh.itjust.works
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      1 day ago

      This is the origin apparently.

      RRB: “My calculations are irrelevant on this point. They are only valid in speaking of the shock reflection.” Ogle: “How fast did it go?” RRB: “Those numbers are meaningless. I have only a vacuum above the cap. No air, no gravity, no real material strengths in the iron cap. Effectively the cap is just loose, traveling through meaningless space.” Ogle: And how fast is it going?" This last question was more of a shout. Bill liked to have a direct answer to each one of his questions. RRB: “Six times the escape velocity from the earth.”

    • Comment105@lemm.ee
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      1 day ago

      Parker Solar Probe: 191 km per second.

      Nuclear Manhole Cover: 55 km per second

      Voyager 1: 17 km per second

      Voyager 2: 15 km per second

  • Professorozone@lemmy.world
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    2 days ago

    Ummm, not sure where they got these numbers from but Earth’s escape velocity is not 7000mph and escaping the sun’s gravitational pull (leaving the solar system from Earth) is not 30,000mph. Respectively the numbers are approximately 25,000mph and 94,000mph. You’re welcome.

    • stephen01king@lemmy.zip
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      15 hours ago

      94000mph is relative to the sun’s surface. Relative to the Earth’s surface, it is around 37000mph, which means they were still wrong.

    • Bosht@lemmy.world
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      2 days ago

      Gotta love Tumblr. Just massive amounts of disinformation and bullshit all the time.

    • merc@sh.itjust.works
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      1 day ago

      That’s 11.2 km/s and 42.1 km/s.

      Also, even if the manhole cover was going at above 12 km/s the trajectory has to be right for that to result in orbit. Most paths it would take would result in it going up and then coming back down again. Similarly, if somehow it did manage more than 50 km/s and wasn’t destroyed in the atmosphere, it might have the velocity to escape the sun’s gravity, but probably wouldn’t be on the right path to do it. Most likely it would fall into the sun.

      So, assuming the 125,000 mph (55 km/s) velocity is correct, the most likely outcome is that it was a reverse-meteor, something that burned up going up through the atmosphere, not down. And even if it did have enough speed to get out of the atmosphere, and there was enough of it left, it most likely fell right back down through the atmosphere somewhere else, either burning up on re-entry or hitting the ground (or the water) somewhere else.

      • druidjaidan@lemmy.world
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        22 hours ago

        Ignoring that it burned up and ignoring losses due to drag if it somehow didn’t. Isn’t the point of escape velocity that it explicitly won’t come back down.iar least not on earth. Your trajectory won’t matter as you have enough velocity to escape the gravity of earth and will orbit the sun. Further if you managed the solar system escape velocity you will end up orbiting the galactic core. Trajectory doesn’t matter if you have escape velocity. Correct trajectory just minimizes the delta v needed to reach that escape velocity.

        At least that’s all my recollection.

        • Maggoty@lemmy.world
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          20 hours ago

          Escape velocity means you could stay in orbit. It doesn’t guarantee anything if you launch at the wrong angle.

          • druidjaidan@lemmy.world
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            2 hours ago

            That is not the definition of escape velocity. Escape velocity is the minimum velocity to escape a body’s gravity well entirely. Orbital is much lower

          • merc@sh.itjust.works
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            7 hours ago

            Exactly. It’s the minimum speed required to get into orbit assuming you get the direction correct. If you launch vertically, you’ll almost certainly come back down, no matter how far out into space you go. The only consideration is that if you go far enough out you might be influenced by the gravity of something else like the moon which could change your trajectory.

            • druidjaidan@lemmy.world
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              2 hours ago

              That is not the definition of escape velocity. Escape velocity is the minimum velocity to escape a body’s gravity well entirely. Orbital is much lower

    • SwordInStone@lemmy.world
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      2 days ago

      yeah, and it is not “research” to check it. They literally teach it in primary school physics.

    • CellarRat@sh.itjust.works
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      1 day ago

      I like how they are implying the speed of light is only 500000mph (as opposed to 671,000,000 mph or 1,080,000,000kph)

  • DaddleDew@lemmy.world
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    2 days ago

    This reminds me of that quote from Mass Effect:

    “This, recruits, is a 20-kilo ferrous slug. Feel the weight! Every five seconds, the main gun of an Everest-class Dreadnought accelerates one to 1.3 percent of light speed. It impacts with the force of a 38-kiloton bomb. That is three times the yield of the city buster dropped on Hiroshima back on Earth. That means: Sir Isaac Newton is the deadliest son-of-a-bitch in space! (…) I dare to assume you ignorant jackasses know that space is empty! Once you fire this hunk of metal, it keeps going 'till it hits something! That can be a ship, or the planet behind that ship. It might go off into deep space and hit somebody else in ten thousand years. If you pull the trigger on this, you are ruining someone’s day, somewhere and sometime!”

  • Zwiebel@feddit.org
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    2 days ago

    There is one detail wrong in the first post; that is not the lids speed but rather it’s minimum speed.

    • Klear@sh.itjust.works
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      2 days ago

      Unfortunately they got almost everything else wrong though. Mainly - the cover actually almost certainly just vaporiserd.

    • Reddfugee42@lemmy.world
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      2 days ago

      Notice, children, how the common apostrophe from lid’s migrated all the way to its.

      Isn’t nature amazing?

    • Victor@lemmy.world
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      2 days ago

      That’s assuming it crossed the image straight from edge to edge, though.

    • buddascrayon@lemmy.world
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      2 days ago

      The cover obtained all of its energy from the blast, it can only go slower than its initial speed unless acted upon by another force.

      • TheSlad@sh.itjust.works
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        2 days ago

        No no, because they only had one frame of it moving, they can only calculate and upper and lower bound on it’s speed. The number given was the lower bound is what theyre saying.

  • RememberTheApollo_@lemmy.world
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    2 days ago

    Ive seen this claim a dozen times. It’s a disc shape. How this thing isn’t going to start flipping and curving its trajectory, or just plain old running out of energy due to air resistance, and not making it out of earth’s atmosphere is beyond me.

            • CheeseNoodle@lemmy.world
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              1 day ago

              tbf the calculated speed is actually roughly the minnimum based on its starting position and the frame it appeared in. it could have actually been going even faster.

              • Victor@lemmy.world
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                2 days ago

                I don’t count having no visual indication of the object as “tracking” it, if we’re talking semantics. One frame could equal an even faster speed than what it would minimally take to cross the entire width of the image at some trajectory vector. For other vectors, it could be (much) less (like not passing straight through the image from on side to the opposite side, e.g.).

                It’s important to not hang too hard on this as the escape speed is dependent on air resistance, or rather lack thereof. Those escape speed numbers are defined along with the assumption of zero air resistance or other forces acting on the object.

                • finitebanjo@lemmy.world
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                  1 day ago

                  You can use the frame from before to calculate the MINIMUM speed. It could have been going even faster.

      • merc@sh.itjust.works
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        1 day ago

        Throw it into water or gelatin. At thousands of metres per second the air is going to seem much more dense.

      • RememberTheApollo_@lemmy.world
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        2 days ago

        If it’s like a frisbee, yeah, but it still curves. Now start it spinning like spinning a coin on edge. The curving will be much more dramatic.

  • sp3ctr4l@lemmy.zip
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    2 days ago

    Responding to the last comment in the image:

    You could literally just do reverse Starship Troopers, the movie at least.

    You’re a bunch of aliens and blam out of no where the nuclear launched manhole obliterates a holy site on your homeworld, your scientists track the trajectory back to Earth, conclude they must have launched it intentionally, and then launch an interstellar jihad against totally unaware Earthlings.

    • mindbleach@sh.itjust.works
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      1 day ago

      It is of course well known that careless talk costs lives, but the full scale of the problem is not always appreciated.

      For instance, at the very moment that Arthur said ”I seem to be having tremendous difficulty with my lifestyle,” a freak wormhole opened up in the fabric of the space-time continuum and carried his words far far back in time across almost infinite reaches of space to a distant Galaxy where strange and warlike beings were poised on the brink of frightful interstellar battle.

      The two opposing leaders were meeting for the last time.

      A dreadful silence fell across the conference table as the commander of the Vl’hurgs, resplendent in his black jewelled battle shorts, gazed levelly at the G’Gugvuntt leader squatting opposite him in a cloud of green sweet-smelling steam, and, with a million sleek and horribly beweaponed star cruisers poised to unleash electric death at his single word of command, challenged the vile creature to take back what it had said about his mother.

      The creature stirred in his sickly broiling vapour, and at that very moment the words I seem to be having tremendous difficulty with my lifestyle drifted across the conference table.

      Unfortunately, in the Vl’hurg tongue this was the most dreadful insult imaginable, and there was nothing for it but to wage terrible war for centuries.

      Eventually of course, after their Galaxy had been decimated over a few thousand years, it was realized that the whole thing had been a ghastly mistake, and so the two opposing battle fleets settled their few remaining differences in order to launch a joint attack on our own Galaxy – now positively identified as the source of the offending remark.

      For thousands more years the mighty ships tore across the empty wastes of space and finally dived screaming on to the first planet they came across – which happened to be the Earth – where due to a terrible miscalculation of scale the entire battle fleet was accidentally swallowed by a small dog.

      – Douglas Adams, The Hitchhiker’s Guide To The Galaxy

    • Dragon Rider (drag)@lemmy.nz
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      2 days ago

      That reminds drag of Halo, though significantly more silly.

      In Halo, the Covenant are on an interstellar crusade for holy artifacts left behind by the Forerunners. When they discovered the planet Harvest, inhabited by humans, they saw tons of artifacts on their scanners. So naturally, they landed on the planet and started blasting the humans to steal the artifacts. But the more humans they killed, the more artifacts disappeared from their monitors. The humans must be destroying the artifacts out of petty spite! What heresy!

      The Prophet of Truth is curious about what kind of artifacts the humans have, so he goes to talk to an ancient Forerunner AI they have in storage, Mendicant Bias. Truth shows Bias the symbol that they keep seeing on human worlds. Bias says “You fool, you’ve got it upside down. Turn it around, see? It says Reclaimer. It means a person the Forerunners have chosen to inherit their empire. You’ve just been killing these humans? No wonder the reclaimers keep disappearing, you’re the one who’s doing it!”

      So Truth realises that he’s been ordering his troops to kill what should rightfully be considered demigods by his religion, and who he should be worshipping. And he realises that if he reveals this information to the people, he and the other Prophets will lose all their political power since there are Actual Fucking Gods walking around. So naturally, Truth declares a Holy Genocide against humanity so that nobody will ever figure out that he’s guilty of Deicide and that their entire religious political structure is a lie.

    • zephorah@lemm.ee
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      2 days ago

      Or, you just decided on first contact, but, suddenly, ship goes boom after being struck in the propulsion system with a bullet like manhole cover.

  • Radioactive Butthole@reddthat.com
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    1 day ago

    Most likely it just evaporated, or disintegrated or something, but I think its pretty unlikely it survived that absolutely bonkers acceleration.

    • stephen01king@lemmy.zip
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      15 hours ago

      The escape velocity for the solar system and from Earth’s surface should not be the same. This is why you should always double check anything ChatGPT says.