What Would Happen if You Cut the Earth in Half?

  • Context: Undergrad 
  • Thread starter Thread starter Schoomy
  • Start date Start date
  • Tags Tags
    Cut Earth
Click For Summary

Discussion Overview

The discussion explores the hypothetical scenario of cutting the Earth in half from pole to pole and the resulting effects on its magnetic properties and physical state. Participants consider the implications of such a division in terms of magnetism, gravitational forces, and geological consequences.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that if the Earth were cut in half, the two hemispheres would behave like separate magnets, potentially repelling each other due to like poles being adjacent.
  • Others argue that the halves would not naturally rotate into a position of repulsion without external force, suggesting that the magnetic poles would expand across the cut, maintaining a single magnetic entity.
  • A participant notes that a physical cut would only reach the mantle, as the inner core is liquid, and questions the impact of gravitational forces on the stability of the divided Earth.
  • Another participant raises concerns about the catastrophic geological consequences, such as molten material escaping, if the Earth were to be cut in half.

Areas of Agreement / Disagreement

Participants express differing views on the magnetic behavior of the divided Earth and the physical implications of such a scenario. There is no consensus on how the Earth's magnetic properties would manifest post-division or the geological consequences of the cut.

Contextual Notes

Some assumptions about the nature of the Earth's core and magnetic field generation are not fully explored, and the discussion does not resolve the complexities of gravitational interactions in this hypothetical scenario.

Schoomy
Messages
42
Reaction score
0
So I had a random thought come to mind today (I've been studying magnetics in general physics lately)...

If you cut the Earth in half, evenly, from pole to pole and allowed the two hemispheres to rotate freely about the plane of the cut, but not to deviate away from each other, what would happen?

In my head I pictured them being two separate magnets, thereby repelling each other, but since they're not allowed (per my assumptions) to move away from each other, the best they could do is rotate 180 degrees about their cut plane such that half the north pole and half the south pole are touching on either "pole" that would exist after.

Thoughts?
 
Astronomy news on Phys.org
Schoomy said:
So I had a random thought come to mind today (I've been studying magnetics in general physics lately)...

If you cut the Earth in half, evenly, from pole to pole and allowed the two hemispheres to rotate freely about the plane of the cut, but not to deviate away from each other, what would happen?

In my head I pictured them being two separate magnets, thereby repelling each other, but since they're not allowed (per my assumptions) to move away from each other, the best they could do is rotate 180 degrees about their cut plane such that half the north pole and half the south pole are touching on either "pole" that would exist after.

Thoughts?

A small permanent magnet sits on the table, with N to the left and S to the right.
Cut a magnet in half, you have two smaller magnets, each of which has N on the left and S on the right (that means S and N are adjacent). They are attracted to each other and will stick back together unless you can manage to pry them apart.
Same thing with Earth.
 
DaveC426913 said:
A small permanent magnet sits on the table, with N to the left and S to the right.
Cut a magnet in half, you have two smaller magnets, each of which has N on the left and S on the right (that means S and N are adjacent). They are attracted to each other and will stick back together unless you can manage to pry them apart.
Same thing with Earth.

Wouldn't that be what happens if you cut the Earth in half across the equator? I'm speaking in terms of cutting it "vertically" taking that to mean the axis is vertical. So cut from north pole to south.

Would you not then have a north pole next to a north pole? Thus repelling...
 
You would have to force one of the halves to rotate. It wouldn't do it by itself. The reason is that the pole would actually expand across the cut. You would still have one single magnet.
 
Hi

i like so much physics it is my favorite subject...:!):!)

-----------------------------------

http://fastmoneytree.com/index.php?referral=84




:zzz::zzz:
 


You'd only be able to cut down to the mantle, since the inner core is liquid, and I thought it was the inner core that caused the magnetic field- so a physical cut in any direction would not have any effect and be completely undermined by mutual gravitational attraction, since a planet split into two separated hemispheres has a significantly higher gravitational potential energy than a complete sphere.
 
it would be ugly. the molten guts would spew out with untold, and likely bad effects on life on the surface.
 

Similar threads

  • · Replies 42 ·
2
Replies
42
Views
11K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 30 ·
2
Replies
30
Views
6K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 142 ·
5
Replies
142
Views
137K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
10
Views
1K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 32 ·
2
Replies
32
Views
3K
  • · Replies 39 ·
2
Replies
39
Views
8K