What Would Happen If You Drilled to the Other End of the Planet?

  • Thread starter sepa0202
  • Start date
  • Tags
    Planet
In summary: Plus, even if you somehow manage to jump out of the hole before it closes, you'll still be spinning around for a bit after you leave. So you'll be an easy target for any predator that's in the area.In summary, If you drilled a hole to the center of the Earth and jumped in, you would reach a velocity of 22,000 miles per hour and be displaced by 586 kilometers upon exiting.
  • #1
sepa0202
3
0
Hi guys,

(Have you ever asked yourself what would happen if you drill a hole into the Earth's surface that reaches to the other end of the planet and then jump in?)

It's a question that many pupils have asked me already. I bet you've thought about it at least once in your life...
I asked them that question, and there were silly but ingenious answers such as "once you've reached the other side of the Earth's crust, you go into space, like a rocket..." or "you get trapped in the middle of the earth".
The second one is not so silly though, but it's still not like that.
I am going to explain, for those who don't know, what would happen in the hypothetical case if you drill or dig a hole which reaches to the other end of the planet.
Okay, it seems quite stupid, because you get burned for sure... But let's imagine that we are wearing special and fireproof suits and it's possible to do it.

So, okay, we've drilled the hole. Now it's the time to jump in, and start to accelerate.
You would accelerate at 9.8 m/s to a velocity of around 38.000 km/h, or 22.000 miles per hour. That's a hell of a lot.
Anyway, once you've reached the centre of the earth, you will start decelerating, because gravity will act on you on the oppposite direction. And just when you reach the Earth's surface, your velocity would be 0. So there should be someone to pick you. If nobody grabs you, you will fall again...
By the way, it takes you 42 minutes exactly to reach the other side of the earth.
Eventually, and it might take you ages, you will end up trapped on the centre of the earth, yes, as there are air molecules which slowly slow you down because of friction, so theoretically, if you keep on traveling from side to side, you will end up trapped on the centre of the earth.

So, i hope I've helped those of you who didn't know it and were interested to find out the answer.
:smile:
 
Physics news on Phys.org
  • #2


sepa0202 said:
Hi guys,

(Have you ever asked yourself what would happen if you drill a hole into the Earth's surface that reaches to the other end of the planet and then jump in?)

It's a question that many pupils have asked me already. I bet you've thought about it at least once in your life...
I asked them that question, and there were silly but ingenious answers such as "once you've reached the other side of the Earth's crust, you go into space, like a rocket..." or "you get trapped in the middle of the earth".
The second one is not so silly though, but it's still not like that.
I am going to explain, for those who don't know, what would happen in the hypothetical case if you drill or dig a hole which reaches to the other end of the planet.
Okay, it seems quite stupid, because you get burned for sure... But let's imagine that we are wearing special and fireproof suits and it's possible to do it.

So, okay, we've drilled the hole. Now it's the time to jump in, and start to accelerate.
You would accelerate at 9.8 m/s to a velocity of around 38.000 km/h, or 22.000 miles per hour. That's a hell of a lot.
Anyway, once you've reached the centre of the earth, you will start decelerating, because gravity will act on you on the oppposite direction. And just when you reach the Earth's surface, your velocity would be 0. So there should be someone to pick you. If nobody grabs you, you will fall again...
By the way, it takes you 42 minutes exactly to reach the other side of the earth.
Eventually, and it might take you ages, you will end up trapped on the centre of the earth, yes, as there are air molecules which slowly slow you down because of friction, so theoretically, if you keep on traveling from side to side, you will end up trapped on the centre of the earth.

So, i hope I've helped those of you who didn't know it and were interested to find out the answer.
:smile:

Welcome to the PF.

This is actually a frequently asked question here on the PF. You have it mostly right, but you do not accelerate at 9.8m/s^2 all the way to the center of the Earth. Do you know why not?
 
  • #3


Also, would the rotation of the Earth affect your trajectory?
Let's say that the hole is on the equator and that it does take 21 minutes to travel Earth's radius, whatever velocity vector you had at top speed (at the Earth core) you might be displaced by 586km when you exit.
So this might mean that the hole would need to be 586km wide (long) at least.
 
  • #4


The coriolis effect would be a factor unless your shaft passed from pole to pole. Another issue would be air resistance, which limits terminal velocity to about 58 meters/sec for a typical adult human. Yet another factor is the density of Earth increases with depth. The figure of 42 minutes for passing pole to pole is an idealized value that ignores air resistance and the density gradient.
 
  • #5


If you assume:

-Earth is not spinning
-Tunnel is frictionless
-No air resistance
-And probably something I'm missing

Then not only does it take "X" time to go from one end of the Earth to the other, but it also works out to take that same "X" time to go the full length of any straight tunnel though the Earth from any point on the Earth's surface to any other point on the surface... shallow tunnels like from DC to Boston, deeper ones like London to Paris, even deeper ones like Tokyo to Cairo... going between all surface points connected by straight tunnels through the Earth would take the same time...
 
  • #6


Is that true? If so it is quite an interesting fact, I like it!
 
  • #7


Yes, it does not matter what angle you drill the tunnel, it basically takes the same amount of time to 'fall' to the other side.
 
  • #8


If it would be possible to dig those tunnels, you could create a global network with an 1-hour schedule ;).

For connections between points which are not opposite to each other, there are quicker, curved paths.
 
  • #9


Unfortunately, air resistance would both significantly limit your maximum free fall velocity and prevent you from 'falling' all the way to the other end of the tunnel.
 
  • #10


Chronos said:
Unfortunately, air resistance would both significantly limit your maximum free fall velocity and prevent you from 'falling' all the way to the other end of the tunnel.

You could evacuate the hole, hold your breath and then jump into the entrance hole, so you'd "pop out" at the other end. :smile:
 
  • #11


In order to create the tunnel, you'd have to stop the flow of molten material at the Earth's core, thus interupting the Earth's magnetic field. So in order to conduct your experiment, you're killing an entire planet. Now that's an epic experiment.
 
  • #12


sepa0202 said:
It's a question that many pupils have asked me already. I bet you've thought about it at least once in your life...

So, okay, we've drilled the hole. Now it's the time to jump in, and start to accelerate.
You would accelerate at 9.8 m/s to a velocity of around 38.000 km/h, or 22.000 miles per hour. That's a hell of a lot...

By the way, it takes you 42 minutes exactly to reach the other side of the earth...

You obviously didn't do the calculation yourself, since if you accelerate at 9.8 m/sec^2 for 6.378 million meters, then decelerate at 9.8 m/sec^2 for 6.378 meters, it won't take 42 minutes to get to the other side.

And while your 22,000 mph is at least in the ball park for constant acceleration, your km/h looks like it was just pulled out of thin air. (Hint: If your speed is in meters/second, doubling the value gets you at least in the ballpark for miles per hour. Not a very accurate estimate, but accurate enough to get a feel for the range you're talking about.)


Your rate of acceleration has to decrease all the way down and your rate deceleration increases all the way up to get 42 minutes (42 minutes, 20 seconds would be a more accurate answer).
 
Last edited:
  • #13


sepa0202 said:
By the way, it takes you 42 minutes exactly to reach the other side of the earth.
Eventually, and it might take you ages, you will end up trapped on the centre of the earth, yes, as there are air molecules which slowly slow you down because of friction, so theoretically, if you keep on traveling from side to side, you will end up trapped on the centre of the earth.

Since it looks like we're assuming air resistance, not only will there be "air molecules" slowing you down, but there will be ALOT of air molecules slowing you sown. Much more than on the surface. Depending on what assumptions we make, it could even be liquid.

Either way, even if we assumed normal air resistance I'm guessing you probably wouldn't make it more than a meter past the center.
 
  • #14
BobG said:
You obviously didn't do the calculation yourself, since if you accelerate at 9.8 m/sec^2 for 6.378 million meters, then decelerate at 9.8 m/sec^2 for 6.378 meters, it won't take 42 minutes to get to the other side.

And while your 22,000 mph is at least in the ball park for constant acceleration, your km/h looks like it was just pulled out of thin air. (Hint: If your speed is in meters/second, doubling the value gets you at least in the ballpark for miles per hour. Not a very accurate estimate, but accurate enough to get a feel for the range you're talking about.)


Your rate of acceleration has to decrease all the way down and your rate deceleration increases all the way up to get 42 minutes (42 minutes, 20 seconds would be a more accurate answer).

That seems accurate. Gravity train - wiki
 
  • #15


Well of course, assuming it's an isolated system from the universe.
But if we had to carry this experiment out, we should take in account more things, such as air resistance.
 
  • #16


Lsos said:
Since it looks like we're assuming air resistance, not only will there be "air molecules" slowing you down, but there will be ALOT of air molecules slowing you sown. Much more than on the surface. Depending on what assumptions we make, it could even be liquid.

True. At thr surface you've got a 50 mile or so column of air on top of you. By the time you got to the center youd be under a 4000+ mile column of air.
 
  • #17


Lsos said:
Since it looks like we're assuming air resistance, not only will there be "air molecules" slowing you down, but there will be ALOT of air molecules slowing you sown. Much more than on the surface. Depending on what assumptions we make, it could even be liquid.

The temperature would be above the critical temperature for both oxygen and nitrogen, so the air could not be liquified no matter how high the pressure got.
 
  • #18


Chestermiller said:
The temperature would be above the critical temperature for both oxygen and nitrogen, so the air could not be liquified no matter how high the pressure got.

Right...depending on what assumptions we make (about the temperature).
 
  • #19


The gravity component is an excellent calculus problem...
There's a bit of thermo...some fluid mechanics...a bunch of free body diagrams...several chapters of a good physics book...and a lot of educated guesses.
This is a 3 pizza problem.
I'm going to Dominos.
 

1. How deep would you have to drill to reach the other end of the planet?

The depth at which you would have to drill to reach the other end of the planet would vary depending on where you are drilling from and the location of the other end. However, on average, the Earth's radius is about 6,371 kilometers, so you would need to drill at least that deep to reach the other end.

2. Would it be possible to drill all the way through the Earth?

While it may seem like a feasible idea, drilling all the way through the Earth is currently not possible with our technology. The extreme temperatures and pressures at the Earth's core would make it difficult for any drilling equipment to withstand, and it would also be extremely expensive and time-consuming.

3. What would happen to the temperature and pressure as you drill deeper into the Earth?

The temperature and pressure would increase as you drill deeper into the Earth. This is because the Earth's core is made up of extremely hot molten rock and metal, and the weight of the layers above it puts immense pressure on the core. At the Earth's core, the temperature can reach up to 5,400 degrees Celsius and the pressure can be over 360 GPa (gigapascals).

4. Would it be possible to survive a trip to the other end of the planet?

No, it would not be possible for a human to survive a trip to the other end of the planet through drilling. The extreme temperatures and pressures, as well as the lack of oxygen and other essential resources, would make it impossible for a human to survive that journey.

5. What would happen if we drilled to the other end of the planet?

If somehow, we were able to drill all the way through the Earth to the other end, the first thing we would encounter is the Earth's molten core. The intense heat and pressure would likely destroy any drilling equipment, and it would be impossible for humans to survive. Additionally, the Earth's rotation and gravity would also be affected, causing massive disruptions to the planet's ecosystem and climate.

Similar threads

Replies
5
Views
294
  • Other Physics Topics
Replies
15
Views
2K
  • Other Physics Topics
Replies
6
Views
865
  • Special and General Relativity
Replies
11
Views
171
  • Sci-Fi Writing and World Building
Replies
13
Views
1K
  • Classical Physics
Replies
5
Views
741
  • Sci-Fi Writing and World Building
3
Replies
87
Views
4K
  • Other Physics Topics
Replies
20
Views
2K
Replies
10
Views
1K
  • Mechanics
2
Replies
37
Views
2K
Back
Top