[Curious Cat (OP)]

.

[Just thinking]

They say that if U drilled a hole all the way thru the centre of the
Earth and dropped a weight/mass into it, then ignoring any friction,
like air resistance or rubbing against the side/s, that it would fall
right thru, in 42 minutes, and then oscillate, back and forth. They say
it would still take 42 min even if U missed the centre.

I believe that if we had a hole all the way through the earth and it was straight through the centre and the hole was sealed and void of any atmosphere/ vacuum the object would theoretically go back and forth forever each time reaching the surface. It would get from one side of the earth to the other very fast as a result of the vacuum zero friction.

[Bored chemist]

Unless the hole is also frictionless, you need to drill it from pole to pole.
Otherwise the thing hits the sides.

The theoretical "melt down" core would not get far because, as it fell, slowly through the molten rock, it would be dissolved and diluted.

[Just thinking]

Unless the hole is also frictionless, you need to drill it from pole to pole.
Otherwise the thing hits the sides.

Yes, I forgot about the earth rotation that would be like the Coriolis effect. I think?

[evan_au]

Why China?

It might be before your time: "The China Syndrome" movie was a box-office hit in 1979.

The title comes from the myth that if a nuclear reactor had a meltdown, it would melt its way all the way through the Earth, and come out on the other side (China being an exotic and distant location on "the other side of the Earth").
See trailer: https://www.imdb.com/title/tt0078966/

PS: This came up on another thread, talking about nuclear meltdowns.

[Petrochemicals]

Why China?

It might be before your time: "The China Syndrome" movie was a box-office hit in 1979.

The title comes from the myth that if a nuclear reactor had a meltdown, it would melt its way all the way through the Earth, and come out on the other side (China being an exotic and distant location on "the other side of the Earth").
See trailer: https://www.imdb.com/title/tt0078966/

PS: This came up on another thread, talking about nuclear meltdowns.

In the film The china syndrome, the term is where the nuclear fuel melts through to the ground water and then explodes in a dirty bomb, so for most areas where there are nuke plants the water table would be within a few metres of the surface. I have no doubt the cia where frustrated to learn that this was not a viable weapons delivery system.

[Petrochemicals]

Why China? Did the meltdown occur there? If not, it's not going to end up in China. The opposite side of Earth from China is the Pacific not far west of Peru/Chile, and you didn't say you were from there.

Because for around 2000 years China was a mystical place, as far away as you can get, hidden behind great walls on the other side of the world. Many phrases are linked to this, such as "row to China" "walk to china" etc as it was considered the farthest of the far.

[Bored chemist]

Why China?

They couldn't spell Timbuktu .

[Just thinking]

They couldn't spell Timbuktu .

They wouldn't let them have a nuclear reactor in New Zealand or they would have burnt through to Timbuktu.

[Eternal Student]

Hi.

How did the movie explain the nuclear stuff climbing back up on the other side?

  I saw the film.  It wasn't good.  I'm not sure it explained a lot.
   Also, it never actually happened.   There were people talking around a table but nothing actually did seem to happen.

[evan_au]

if we lower/ed that mass/weight slowly, why wouldn't it just stop at the point of max g?

If we lowered the mass 100m, stopped it, then lowered it another 100m....
- When the mass gets to the center of the Earth and we stop it - when we release it, it will just stay there.

[Just thinking]

If we lowered the mass 100m, stopped it, then lowered it another 100m....
- When the mass gets to the center of the Earth and we stop it - when we release it, it will just stay there.

That's right from the centre of the earth up is in all directions up up and away.

[evan_au]

if we lower/ed that mass/weight

Since we are in Physics Land, we assume that the rope has:
- zero mass (so it doesn't keep falling towards the center of the Earth, even after the central mass has come to rest),
- and is inextensible and inelastic (so that releasing and stopping the mass doesn't set up long-period oscillations)

[Just thinking]

Note that the slower you lower it, the less the effect of Coriolis force.

Yes, the Coriolis effect is what makes clouds and air craft drift of line I think it will also affect vertical movement as well . As B.C. stated this can only be avoided by a pole to pole drop.

[Just thinking]

A hole drilled straight through from where I am would come up not in China but right in your kitchen. You and I are effectively inverted relative to each other. We could exchange mail by strapping letters to bricks and throwing them through the (frictionless) hole.

That would work but Email is still faster.

[Halc]

We could exchange mail by strapping letters to bricks and throwing them through the (frictionless) hole.

That would work but Email is still faster.

Email conveys a different message. Imagine the local lynch mob trying to get you to leave town by sending an email requesting it. No, they use the note and the brick through the window. Such messages convey so much more... Doing through a hole all the way through Earth would scare even the lynch mob types. They'd never mess with you after that.

[evan_au]

The 2012 version of Total Recall imagined the working class living on the far side of the Earth, and commuting to work via an elevator drilled through the center of the Earth. 42 minute commute time isn't too bad (but not as good as working from home during lockdown).

They had the sensible idea that when you came out the far side, you would be upside-down, so the elevator turns upside down as it is passing through the center of the Earth - that way, gravity is pointing the right way when the elevator stops on the far side.

Someone obviously told them that there is a zone of weightlessness at the center of the Earth, and in this clip, you can see the star playing in zero gravity as they pass through the core of the Earth (they make use of it later in the film, too).

Of course, while the elevator is in free-fall, it would be weightless all the way through the Earth (until they stopped on the far side). And they had a funny idea about where the antipodes are, relative to London...

[Just thinking]

Email conveys a different message. Imagine the local lynch mob trying to get you to leave town by sending an email requesting it. No, they use the note and the brick through the window. Such messages convey so much more... Doing through a hole all the way through Earth would scare even the lynch mob types. They'd never mess with you after that.

I see what your saying ore better still strap the message to a horses head and drop it in.