this post was submitted on 02 Dec 2024

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submitted 2 days ago by fossilesque@mander.xyz to c/science_memes@mander.xyz

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[–] captain_aggravated@sh.itjust.works 24 points 1 day ago (2 children)

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.

[–] Idontevenknowanymore@mander.xyz 10 points 1 day ago (1 children)

In my head I know you're right but my heart wants this.

[–] Iheartcheese@lemmy.world 7 points 1 day ago (1 children)

If we kill him he never will have said it and the manhole cover will be in space.

[–] Idontevenknowanymore@mander.xyz 4 points 1 day ago (2 children)

I like the energy.

[–] marker2002@lemmy.world 2 points 23 hours ago (1 children)

As much energy to put a manhole in space?

[–] tetris11@lemmy.ml 1 points 13 hours ago

As much energy to put a man, whole, in space

[–] captain_aggravated@sh.itjust.works 1 points 23 hours ago (1 children)

You'll have to kill Kyle Hill too.

[–] Idontevenknowanymore@mander.xyz 1 points 23 hours ago

That I'd do for free.

[–] dogma11@lemmy.world 3 points 23 hours ago (2 children)

I'd like to think that it's possible that it was launched fast enough that it escaped the blast and Earth's atmosphere and made its way to a neighboring galaxy where it's now living lodged in some far off asteroid or some comet or planet.

Manhole cover first man made object in Andromeda.

[–] anothercatgirl@lemmy.blahaj.zone 2 points 19 hours ago

It's not going fast enough to escape the Milky Way Galaxy.

[–] captain_aggravated@sh.itjust.works 3 points 23 hours ago

This was in what? the 50's? So it would have had to travel ~2 million light years in 70 years, so it would have had to hit several hundred thousand times the speed of light?

[–] Sam_Bass@lemmy.world 12 points 1 day ago (2 children)

RIP jpgd to death

[–] Venator@lemmy.nz 12 points 1 day ago (1 children)

Slightly less recompressed version: https://imgur.com/2UHiL4r

[–] Sam_Bass@lemmy.world 3 points 1 day ago

Definitely easier to read thx

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[–] Valmond@lemmy.world 1 points 17 hours ago

Maybe it desintegrated and thus vanished from the consecutive frame?

Atomic blasts are kind of powerful versus an iron lid.

[–] pineapplelover@lemm.ee 1 points 19 hours ago

Man. I haven't seen an ifunny logo in so long. Are people still on it?

[–] MonkderVierte@lemmy.ml 23 points 1 day ago* (last edited 1 day ago) (1 children)

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 10 points 1 day ago* (last edited 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."

[–] glibg@lemmy.ca 6 points 1 day ago (1 children)

The Parker Solar Probe moves 120 miles per second as it passes around the Sun. That's nearly half a million miles per hour!

https://en.wikipedia.org/wiki/Parker_Solar_Probe

[–] Comment105@lemm.ee 3 points 23 hours 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 64 points 1 day ago (10 children)

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 1 points 13 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 23 points 1 day ago

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

[–] merc@sh.itjust.works 3 points 1 day ago (1 children)

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 2 points 21 hours ago (1 children)

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 2 points 18 hours ago (2 children)

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

[–] druidjaidan@lemmy.world 1 points 32 minutes 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 2 points 5 hours ago (1 children)

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 1 points 32 minutes 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

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[–] OrnateLuna@lemmy.blahaj.zone 15 points 1 day ago

Surprised no one has posted this but Kyle hill made a video on it

[–] DaddleDew@lemmy.world 138 points 2 days ago (7 children)

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!"

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[–] Zwiebel@feddit.org 106 points 2 days ago (6 children)

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 16 points 1 day ago

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

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