silly hypothetical Q

silly hypothetical Q

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Pacman1978

Original Poster:

394 posts

110 months

Sunday 6th March 2016
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Hypothetically if I went to B&Q, bought a decent spade, went to my local park and proceeded to dig a hole, and kept on digging til I reached the opposite side of the Earth, would I fall out said hole or climb out?

I have googled, to no avail. Silly I know but something I have wondered ever since watching journey to the centre of the Earth..

(obviously the core and any other obstacle are hypothetically dealt with..)

Thank you ✌

Jakg

3,604 posts

175 months

Clickbait

2,324 posts

188 months

Sunday 6th March 2016
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TOTAL RECALL - THE FALL (Reel Physics)

https://www.youtube.com/watch?v=TmCmMmT7OX4


Simpo Two

87,101 posts

272 months

Sunday 6th March 2016
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Pacman1978 said:
Hypothetically if I went to B&Q, bought a decent spade, went to my local park and proceeded to dig a hole, and kept on digging til I reached the opposite side of the Earth, would I fall out said hole or climb out?
Well, if you fell out, what's holding the Ozzies on? It's not hard...

RobM77

35,349 posts

241 months

Monday 7th March 2016
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As per the link above, you'd die of the heat, plus of course the hole would probably collapse and you'd be bound to start ricocheting off the sides of the hole. However, here's an answer probably more aligned to what the OP was asking:

http://hyperphysics.phy-astr.gsu.edu/hbase/mechani...

Nimby

4,907 posts

157 months

Monday 7th March 2016
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If you hit seabed at the other end then the ocean would rush down the hole and eventually boil (depending on temp & pressure)so you'd get a spectacular superheated steam geyser in the park your end.

I wonder - would all the oceans boil away before the earth's core was quenched? I guess there would be a lot of rain as the steam condensed, so probably not.

ATG

21,370 posts

279 months

Monday 7th March 2016
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Forgetting the inconsequential practicality of digging a hole through the earth ... as if that really needs saying ... gravity pulls you towards the centre of the Earth. And when you're at the very centre itself, the Earth isn't exerting a net gravitational force on you at all. If you stopped at the centre, you'd float around weightless. If you assume the Earth's density is constant, then the gravitational force on you is greatest when you're at the surface and tails off the closer you get to the centre.

RobM77

35,349 posts

241 months

Monday 7th March 2016
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Gravity acts via an inverse square law, but inside a sphere of uniform density it simplifies to a linear relationship with zero at the centre and the standard F = Gm1m2/r^2 at the surface, where r is the radius of the sphere. Ergo, jumping down the hole would be like being attached to a giant bungee cord or spring mounted at the centre (i.e. F = kx): you'd gain enough speed to fly right through and pop up briefly at the other side before going back again. You would then oscillate back and forth being slowed by air resistance until you finally came to rest in the centre.

Edited by RobM77 on Monday 7th March 21:14

maffski

1,886 posts

166 months

Monday 7th March 2016
quotequote all
My vote for what would happen. You'd get arrested. And probably interviewed on local news. In about 30 years a low budget independent British film would be made about it. Likely with funding from Film4 and Canal+. Benedict Cumberbatch will play your grand dad. It will have only a limited box office release.





Toltec

7,167 posts

230 months

Monday 7th March 2016
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RobM77 said:
Gravity acts via an inverse square law, but inside a sphere of uniform density it simplifies to a linear relationship with zero at the centre and the standard F = Gm1m2/r^2 at the surface, where r is the radius of the sphere. Ergo, jumping down the whole would be like being attached to a giant bungee cord or spring mounted at the centre (i.e. F = kx): you'd gain enough speed to fly right through and pop up briefly at the other side before going back again. You would then oscillate back and forth being slowed by air resistance until you finally came to rest in the centre.

Edited by RobM77 on Monday 7th March 14:31
The air resistance alone would stop reaching the far end, don't forget air pressure will increase by one bar every 80Km or so.

Then you have the minor issue of the Earth's rotation...



RobM77

35,349 posts

241 months

Monday 7th March 2016
quotequote all
Toltec said:
RobM77 said:
Gravity acts via an inverse square law, but inside a sphere of uniform density it simplifies to a linear relationship with zero at the centre and the standard F = Gm1m2/r^2 at the surface, where r is the radius of the sphere. Ergo, jumping down the whole would be like being attached to a giant bungee cord or spring mounted at the centre (i.e. F = kx): you'd gain enough speed to fly right through and pop up briefly at the other side before going back again. You would then oscillate back and forth being slowed by air resistance until you finally came to rest in the centre.

Edited by RobM77 on Monday 7th March 14:31
The air resistance alone would stop reaching the far end, don't forget air pressure will increase by one bar every 80Km or so.

Then you have the minor issue of the Earth's rotation...
Sorry, yes, I completely forgot about the air pressure increase and yes, you're almost certainly right about it stopping one getting too far - even at typical skydiving altitude terminal velocity is very low compared to the theoretical speed in a vacuum for this hypothetical jump.

Monty Python

4,813 posts

204 months

Wednesday 9th March 2016
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You'd have to climb out.

Pacman1978

Original Poster:

394 posts

110 months

Wednesday 9th March 2016
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Monty Python said:
You'd have to climb out.
Thankyou for answering my question 😁

Derek Smith

46,506 posts

255 months

Thursday 10th March 2016
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Pacman1978 said:
Thankyou for answering my question ??
You'd have a lifetime of ease once you told B&Q about their wonderful spade.


s p a c e m a n

11,002 posts

155 months

Thursday 10th March 2016
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Phht, sod digging all that way. Just dig down as far as that machine they left bahind from making the channel tunnel and aim that downwards

anonymous-user

61 months

Thursday 10th March 2016
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Derek Smith said:
Pacman1978 said:
Thankyou for answering my question ??
You'd have a lifetime of ease once you told B&Q about their wonderful spade.
Hmm. I think the space would wear out in no time.

He'd need one of those little digging things Tom Hanks has in Shawshank. They're awesome.

Eric Mc

122,859 posts

272 months

Thursday 10th March 2016
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Greg66 said:
He'd need one of those little digging things Tom Hanks has in Shawshank
Tom Hanks?

wilfandrowlf

603 posts

219 months

Thursday 10th March 2016
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I think you would need quite a few skips to put all the soil and rock in.
That's not going to be cheap!

Just saying......

anonymous-user

61 months

Thursday 10th March 2016
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Eric Mc said:
Greg66 said:
He'd need one of those little digging things Tom Hanks has in Shawshank
Tom Hanks?
Well (appositely) bugger me. I could have sworn Tom Hanks was in that role. Tim Robbins.

Maybe the Tim Robbins version is a remake.

stinkspanner

701 posts

188 months

Thursday 10th March 2016
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What's the deepest anyone has gone so far I wonder