Digging Through the Earth: What Happens?

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SUMMARY

This discussion centers on the theoretical implications of digging a hole straight through the Earth while avoiding the core. Participants assert that a vertical hole, defined as perpendicular to the surface, cannot miss the Earth's inner or outer core. The conversation explores the concept of gravity in relation to digging through celestial bodies, such as comets, and how two individuals digging from opposite ends would perceive their orientation. Ultimately, it is concluded that gravity would always pull towards the center of the planet, affecting the diggers' experiences as they approach the midpoint of their tunnel.

PREREQUISITES
  • Understanding of Earth's geological layers, including the crust, mantle, and core.
  • Basic knowledge of gravity and its effects on objects in different orientations.
  • Familiarity with the concept of verticality in relation to planetary bodies.
  • Awareness of celestial mechanics, particularly regarding small bodies like comets.
NEXT STEPS
  • Research the geological structure of the Earth, focusing on the mantle and core.
  • Study the effects of gravity in different environments, including microgravity scenarios.
  • Explore the physics of tunneling through various materials and celestial bodies.
  • Investigate the concept of orientation and perception of gravity in space travel.
USEFUL FOR

Students of geology, physics enthusiasts, and anyone interested in the theoretical implications of digging through planetary bodies and the effects of gravity in different contexts.

NewToThis
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Ok, I am sure similar questions have been asked but here it goes.

You start digging a hole with the intention of digging straight through the planet. Your hole will be straight but will only go through the mantle, missing the core and outer core, so you have avoided the weightlessness of the Earth's core. So what happens? you keep digging down and you get closer the surface on the other side of the world. Do you at some point fall back? when do you become upside down?
 
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depending on where you dig from and to, you may be digging sideways

consider this ...

upload_2016-9-30_9-11-51.png
you cannot drill at 90 deg to the surface and miss the inner or outer core
 
What do you think and why?
 
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davenn said:
depending on where you dig from and to, you may be digging sideways

consider this ...

View attachment 106703you cannot drill at 90 deg to the surface and miss the inner or outer core

So let's say you start about 2 thirds to the left or right of the YOUR DRILL HOLE point. That would mean your hole is vertical and misses the core.
 
NewToThis said:
So let's say you start about 2 thirds to the left or right of the YOUR DRILL HOLE point. That would mean your hole is vertical and misses the core.
I'm not getting any sense out of that. Draw it.
 
NewToThis said:
So let's say you start about 2 thirds to the left or right of the YOUR DRILL HOLE point. That would mean your hole is vertical and misses the core.

not sure what you mean
take my drawing and alter it to show me
 
phinds said:
What do you think and why?

I have no idea. Can't get my head around it.

The philae lander was held to a small comet by a small amount of gravity. Probably enough to hold a person. So if 2 people at each end of the comet started digging through it then eventually their feet would be touching. Like one is on the second floor and the other person on the ground is standing on the ceiling.

Weird
 
I saved your Earth image and altered it on paint. How do I upload it on here?
 
NewToThis said:
So let's say you start about 2 thirds to the left or right of the YOUR DRILL HOLE point. That would mean your hole is vertical and misses the core.
Do you mean like this?

upload_2016-9-30_9-11-51.png

You do realize that "vertical" means towards the centre of the Earth, not towards the bottom of the piece of paper you draw the diagram on?
 
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  • #10
DrGreg said:
Do you mean like this?

View attachment 106704
You do realize that "vertical" means towards the centre of the Earth, not towards the bottom of the piece of paper you draw the diagram on?

Yes, that's what i meant.
 
  • #11
NewToThis said:
Yes, that's what i meant.
So what about @DrGreg's question -- do you realize that drill hole is not vertical?
 
  • #12
jbriggs444 said:
So what about @DrGreg's question -- do you realize that drill hole is not vertical?

The point is to dig a hole that you could fall through without touching the sides, that is not at an angle and misses the core.

I could ask what would happened if you could dig a hole straight through the Earth's core but I think that question has been answered.
 
  • #13
NewToThis said:
that is not at an angle and misses the core.

but it is and has to be at an angle to the Earth's surface ( as I said earlier)
you cannot dig/drill a hole that is vertical (perpendicular) to the surface and not miss the core

look again at my drawings my original and the one Dr Greg rotated ... BOTH ends of the hole are at an angle to the surface

we just need you to get that sorted and understood, before tacking the gravity issueDave
 
  • #14
davenn said:
you cannot dig/drill a hole that is vertical (perpendicular) to the surface and not miss the core
Glad to see I'm not the only one who manages to say the opposite of what he means. :smile:
 
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  • #15
NewToThis said:
The point is to dig a hole that you could fall through without touching the sides, that is not at an angle and misses the core.
There is no such hole. If you can fall through it without touching the sides then the hole is vertical. If it is vertical then it points towards the core.
 
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  • #16
phinds said:
Glad to see I'm not the only one who manages to say the opposite of what he means. :smile:
?? ... did I err ?
 
  • #17
I think this is all going off topic a bit and too much is being discussed about my "vertical" hole, what I am interested in is what would happen to the person digging, he can be digging on anybody that has enough gravity to keep him grounded. So for example, he could be digging through the Rosetta comet, ad on the other side a person is also digging a hole. Eventually there holes will meet. From person A's POV person B is digging up and he is digging down. If they both jumped into the hole they'd land on each other's feet. Now if they are both lowered into the hole using a lift/elevator there feet will be on the floor of it, but as they get closer eventually they become upside down, so do they fall toe the ceilings of their lifts?
 
  • #18
NewToThis said:
what I am interested in is what would happen to the person digging
The person digging the hole shown in post 9 is not digging a hole per se, but rather they are digging a tunnel. That tunnel slopes downward at one end, is level in the middle, and slopes upwards at the other end. The digger could stand on one side the whole way, assuming they had enough traction at the ends.
 
  • #19
davenn said:
?? ... did I err ?
Well, maybe it's just that we interpret differently the use of too many negatives in the sentence. What I heard after removing the negatives was "if you dig a hole vertically, it will miss the core"

Convoluted language is MY job. Please be more straightforward in the future :smile:
 
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  • #20
phinds said:
What I heard after removing the negatives was "if you dig a hole vertically, it will miss the core"

you may be right :oops:

phinds said:
Please be more straightforward in the future

I will do better sir phinds :-p:-p
 
  • #21
NewToThis said:
If they both jumped into the hole they'd land on each other's feet. Now if they are both lowered into the hole using a lift/elevator there feet will be on the floor of it, but as they get closer eventually they become upside down, so do they fall toe the ceilings of their lifts?

No. At all times gravity pulls them towards the centre of the planet not the centre of their tunnel. So when they meet at the mid point they only experience a sideways force acting towards the middle of the planet. Neither would feel "upsidedown" they would feel like they were laying down on the sides of the tunnel.
 
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