Comments on: The Centre of the Earth and Gravity http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/ Science at home from a science geek. Fri, 12 Oct 2007 02:15:57 +0000 http://wordpress.org/?v=2.9.1 hourly 1 By: The Homely Scientist » Taking a look back at 2006, my favourite posts http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-362 The Homely Scientist » Taking a look back at 2006, my favourite posts Thu, 11 Jan 2007 18:04:50 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-362 [...] I decided to pick a few of my favourite posts (it was hard, because I like a lot of them) to highlight.  The first up is the post that still holds the record for the most comments on any one post, a discussion of gravity and the centre of the Earth.  Never would have thought that a discussion of traveling through the centre of the Earth would generate such an interesting comment flow. [...] [...] I decided to pick a few of my favourite posts (it was hard, because I like a lot of them) to highlight.  The first up is the post that still holds the record for the most comments on any one post, a discussion of gravity and the centre of the Earth.  Never would have thought that a discussion of traveling through the centre of the Earth would generate such an interesting comment flow. [...]

]]> By: kat http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-258 kat Mon, 02 Oct 2006 14:55:39 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-258 Hello, Questions: as we exit the atmoshpere of the Earth, do we not experience less gravitational pull, even zero gravity? Or is it that we come closer to other celestial bodies that then attract us? Is there a black hole in the center of our galaxy that holds it together? Is the force of gravity equal thoughout the galaxy? Or stronger in the center of the galaxy? I know we are on the far edge of ours. Hello,

Questions: as we exit the atmoshpere of the Earth, do we not experience less gravitational pull, even zero gravity? Or is it that we come closer to other celestial bodies that then attract us?

Is there a black hole in the center of our galaxy that holds it together? Is the force of gravity equal thoughout the galaxy? Or stronger in the center of the galaxy? I know we are on the far edge of ours.

]]> By: Tris Hussey http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-90 Tris Hussey Sat, 06 May 2006 16:25:45 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-90 Floating, no, but you would be stuck. Since gravity pulls you towards the centre of the earth, that's where'd you be! Floating, no, but you would be stuck. Since gravity pulls you towards the centre of the earth, that’s where’d you be!

]]> By: Adam http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-89 Adam Sat, 06 May 2006 16:01:59 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-89 If I was to stand in the very center of the Earth, which way would gravity pull me? Or would I be just floating not being able to go any which way? If I was to stand in the very center of the Earth, which way would gravity pull me? Or would I be just floating not being able to go any which way?

]]> By: Paul Mernon http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-49 Paul Mernon Wed, 19 Apr 2006 06:45:55 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-49 #1: The earth rotational velocity at the equator is 465 meter/second (or 1 674 kilometer/hour). How do you think you don't notice such a speed? Because the earth's atmosphere rotates with the earth as well, with the same velocity. So, if you jump, atmosphere won't slow you down, as it <em>moves with the same velocity as you</em>. However, the rotation of the earth has some effects on the atmosphere. Did you know that cyclones rotate counterclockwise in the northern hemisphere, and clockwise in the southern hemisphere? This is due to Coriolis effect, which appears in any rotating object. #2: Why should the earth slow down if there is an empty space all around it? There is no friction between the earth and outside vacuum, so no slowing down. #1: The earth rotational velocity at the equator is 465 meter/second (or 1 674 kilometer/hour). How do you think you don’t notice such a speed? Because the earth’s atmosphere rotates with the earth as well, with the same velocity. So, if you jump, atmosphere won’t slow you down, as it moves with the same velocity as you. However, the rotation of the earth has some effects on the atmosphere. Did you know that cyclones rotate counterclockwise in the northern hemisphere, and clockwise in the southern hemisphere? This is due to Coriolis effect, which appears in any rotating object.

#2: Why should the earth slow down if there is an empty space all around it? There is no friction between the earth and outside vacuum, so no slowing down.

]]> By: Bald Man http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-44 Bald Man Tue, 18 Apr 2006 20:49:57 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-44 I know contact isn't relevant for gravity (except to the extent it is measures distance between the two bodies), but is it for friction. It's like standing on a stationary object that suddenly starts moving. Depending on the force of friction between me and the now moving object, I will either stick with the object or the object will slide out from under me. Now, let's assume I'm standing on an object that's already moving. If I jump, air friction will slow me down, and the object will move out from under me. Next step: Make this already moving object the earth. As I fall back and forth thru our imaginary hole, my lateral movement will eventually become different than the lateral movement of the hole on the earth surface. Air friction will slow me down, and my hole will rotate out from under me. Won't it? Follow up question #1: Why don't we feel a breeze as the earth rotates? Follow up question #2: What keeps the earth rotating? Why doesn't it slow down? I know contact isn’t relevant for gravity (except to the extent it is measures distance between the two bodies), but is it for friction. It’s like standing on a stationary object that suddenly starts moving. Depending on the force of friction between me and the now moving object, I will either stick with the object or the object will slide out from under me.

Now, let’s assume I’m standing on an object that’s already moving. If I jump, air friction will slow me down, and the object will move out from under me.

Next step: Make this already moving object the earth. As I fall back and forth thru our imaginary hole, my lateral movement will eventually become different than the lateral movement of the hole on the earth surface. Air friction will slow me down, and my hole will rotate out from under me. Won’t it?

Follow up question #1: Why don’t we feel a breeze as the earth rotates?

Follow up question #2: What keeps the earth rotating? Why doesn’t it slow down?

]]> By: Tris Hussey http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-42 Tris Hussey Tue, 18 Apr 2006 20:13:06 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-42 Nope ... since gravity is a force between bodies, no need for contact. The moon's gravity causes the tides on Earth and the Earth's gravity still affect planes in the sky. Gravity isn't like electricity where contact is optimal, it just is. Oooh how Zen is that! Nope … since gravity is a force between bodies, no need for contact. The moon’s gravity causes the tides on Earth and the Earth’s gravity still affect planes in the sky.

Gravity isn’t like electricity where contact is optimal, it just is. Oooh how Zen is that!

]]> By: Bald Man http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-40 Bald Man Tue, 18 Apr 2006 18:22:35 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-40 I figure gravity will be strong enough to keep the earth from speeding away as it revolves around the sun; but what about rotation on its axis? Won't you stop rotating with the earth? What force would pull you along if you aren't in physical contact with the surface? I suspect you might even bump into the sides of your hole. I figure gravity will be strong enough to keep the earth from speeding away as it revolves around the sun; but what about rotation on its axis? Won’t you stop rotating with the earth? What force would pull you along if you aren’t in physical contact with the surface? I suspect you might even bump into the sides of your hole.

]]> By: Deb L http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-38 Deb L Tue, 18 Apr 2006 18:02:53 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-38 Boy I can't wait for the kiddo to come home from school so I can read him the answer and all the comments too! *g* Boy I can’t wait for the kiddo to come home from school so I can read him the answer and all the comments too! *g*

]]> By: Paul Mernon http://www.homelyscientist.com/2006/04/the-centre-of-the-earth-and-gravity/comment-page-1/#comment-36 Paul Mernon Tue, 18 Apr 2006 17:37:59 +0000 http://homelyscientist.com/2006/04/13/the-centre-of-the-earth-and-gravity/#comment-36 No way, you will always have zero velocity at the surface and maximum velocity at the center, so it won't be risky in a sense of falling from the Earth. No way, you will always have zero velocity at the surface and maximum velocity at the center, so it won’t be risky in a sense of falling from the Earth.

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