this post was submitted on 28 May 2024
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Science Memes

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[–] [email protected] 194 points 6 months ago (4 children)

For anyone wondering it's because the bowling ball slightly pulls the earth faster toward itself. This amount is too small to possibly measure. But imagine if the bowling ball were the size of another Earth and it's easier to see why it happens.

[–] [email protected] 48 points 6 months ago

Thanks for the non-jargon version

[–] [email protected] 48 points 6 months ago (1 children)

This amount is too small to possibly measure

What the fuck did you say to me you little bitch? I'm going to go get $300 million in funding to create a device so complex and so sensitive that a butterfly sneezing 30 miles away will fuck it up and then I'm going to directly measure the the acceleration of the earth as a result of the mass of that bowling ball. You fucked up, kiddo.

  • Average metrologist, probably
[–] [email protected] 5 points 6 months ago

The issue isn't so much the sensitivity (although that is a significant issue), it's all the other crap going on. You'll probably be able to filter out the Mains Hum, but every anything moving in the same axis as the test will confount the data.

I'm thinking we might set up the instuments near counterweight energy storage or pumped hydro, and some on the exact opposite side of the planet, and try to measure the movement of the earth that way.

We can already see a change in the length of a day after big earthquakes and dam construction/destruction, but I don't think the acceleration has ever been measured directly.

[–] [email protected] 9 points 6 months ago (1 children)

When you drop them at the same time, it doesn't matter though.

[–] [email protected] 14 points 6 months ago

because of two bodies can not occupy the same space, the feather and the ball will be in different position when you drop them. And therefor gravitation will pull the earth slightly more toward the ball and slightly less toward the feather.

[–] [email protected] 5 points 6 months ago (2 children)

But being more massive means that due to inertia the ball will take just a tiny little wee bit longer to start moving no? So they end up falling at the same time.

Also, are these Newtonian mechanics? How do they compare to relativity at the "bowling ball and feather" scale?

Someone please correct me if I'm wrong. It's been a while since I read anything physics-related.

[–] [email protected] 17 points 6 months ago (1 children)

The acceleration from gravity would be the same no matter the object mass (~9.8m/s²).

[–] [email protected] 3 points 6 months ago (1 children)

Oh yes! I omitted that part, but what I meant to say is that mass and inertia balance each other, so that in the end the acceleration from gravity ends up the same for any object.

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[–] [email protected] 6 points 6 months ago

The above is just referring to the fact that the standard "feather vs. bowling ball" question assumes the earth/moon/ground is immovable. In that case, Newton says they fall the same.

The fact that the ground is not immovable is what's being referenced


in this picture, things don't "fall," they are each accelerated towards each other.

[–] [email protected] 111 points 6 months ago (3 children)

This is fascinating! Both of them accelerate toward the earth at the same rate, but because of the bowling ball's greater mass, the EARTH accelerates faster toward the bowling ball than it does toward the feather, so it's imperceptibly faster XD

[–] [email protected] 26 points 6 months ago (2 children)

But they are being dropped at the same time for dramatic effect, so the earth will also be accelerating towards the feather at bowling ball speeds because the feather is next to the bowling ball, therefore they still land at the same time.

[–] [email protected] 32 points 6 months ago (2 children)

That’s only be true if the feather was in the same position as the ball. Otherwise, the earth is moving ever so slightly more towards the ball.

[–] [email protected] 6 points 6 months ago

You are forgetting the sun. The earth turns in the direction of sun ever so slightly so if you align the feather next to the ball in the side of the sun, then probably the feather falls faster

[–] [email protected] 5 points 6 months ago (1 children)

So, what you're saying is, to do this experiment correctly, we have to stop the earth from moving. . I'm keen.

[–] [email protected] 4 points 6 months ago

🎵 I'll stop the world and melt with you 🎵

[–] [email protected] 10 points 6 months ago (1 children)

No, because the earth is accelerating towards the bowling ball and the feather is next to the bowling ball, the force vector is (ever so slightly) greater towards the bowling ball than the feather, thus the bowling ball drops faster

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[–] [email protected] 10 points 6 months ago (6 children)

Can someone explain how the Earth accelerates towards an object? Is this just because objects with mass attract things?

[–] [email protected] 15 points 6 months ago

You got it.

[–] [email protected] 2 points 6 months ago

In the same way that earth has gravity that attracts objects, the objects have gravity that attracts earth. See also Newton's third law, also known as "For every action, there is an equal and opposite reaction." - for the earth to attract something, the earth also has to be attracted with the same force. It's just that the earth has a lot more mass, so the force barely accelerates it.

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[–] [email protected] 49 points 6 months ago (1 children)
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[–] [email protected] 11 points 6 months ago (2 children)

There's a video of astronauts doing the heavy thing vs feather in vacuum experiment. I think it was a hammer rather than a bowling ball tho.

[–] [email protected] 10 points 6 months ago

I think the answer to this question changes based on your interpretation of 'falling faster'. I.e. whether that refers to the total time between the start and end of the fall or to the speed of the feather/ball to an outside observer.

[–] [email protected] 9 points 6 months ago (2 children)

I get that the heavier bowling ball affects the acceleration of the earth more than the lighter feather, but I don't see how that means it's falling faster as the meme is stating. The bowling ball would meet the earth first when dropped separately and from the same height because the earth is (imperceivably) accelerating toward it faster than it does the falling feather, but both the bowling ball and feather are falling at the same rate due to Earth's gravitational force.

Or am I missing something?

[–] [email protected] 13 points 6 months ago (2 children)

One definition for a "rate of falling" would comfortably be "the time it takes the surfaces of two free gravitational separated by some distance to meet." With this in mind, the imperceptible but very real difference in the acceleration of the earth towards the bowling ball would become part of that equation, as it shortens the distance between the two from the other side.

Think of it like a head on collision of two vehicles. You can do the math as two bodies colliding with opposite velocity vectors, or you can arrive at the same mathematical result (at least for some calculations) by considering one of them to be stationary and the other to have the sum of the two speeds in the direction of its original velocity. "Two cars colliding head on at 60mph is the same as one car hitting a brick wall at 120mph." It is rough and doesn't work for all calculations, but the idea is the same.

[–] [email protected] 2 points 6 months ago (1 children)

Mythbusters did this one and, surprisingly, the crash is way more fucked up at twice the speed on the wall

[–] [email protected] 3 points 6 months ago

Yeah, that's why I used the heavy caveats. The wall produces an inelastic collision which will do WAY more damage as all of the energy is arrested rather than an elastic collision of the two vehicles in which a good portion of energy is spread between the two bodies as they separate.

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[–] [email protected] 8 points 6 months ago

Balls fall faster because planets are more attracted to objects that are spherical shaped like them.

[–] [email protected] 7 points 6 months ago (13 children)

Does the bowling ball ever so slightly increase the gravitational constant because of it's greater mass? Is that what the right guy is getting at?

[–] [email protected] 24 points 6 months ago* (last edited 6 months ago) (2 children)

The gravitational constant G, no, the mutual gravitational force between the earth and the ball approximated as g, yes.

Edit: Since this is a little pedantic, G is used to calculate g.

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[–] [email protected] 4 points 6 months ago

Since we are in avaccum

That's where you're wrong kiddo

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