Realized I screwed this up as I was writing it, it is what I get for doing this and my recipe blog at same time. Meant to so a teaspoon not an ounce. Was not trying to use a weight measurement.

Truth is that nobody has any idea what is in the center of the earth and therefore any theories on this subject are just that, theories.

Just to clarify, the mass of an object bends space-time and the amount of the bending communicates how much acceleration/gravity other objects experience when near that object. At least that's the general relativity explanation. On very tiny scales a new theory is needed.

Trust me, I have a PHD from the Greater Correspondence College of Tampa with a minor in VCR repair.

Speaking of black holes, when I was a kid, a friend and I rented a porno called "Hot Black Holes" on his mom's video card. When she saw the receipt she asked what it was and I got all all nervous and then my friend replied it was an educational movie about space. :1orglaugh

Gravity is an illusion and this existence is all a part of a simulation you willingly signed up and paid for.

If we give you all of the answers to how things work, that would destroy the entire purpose of it all, now wouldn't it?

Back to your regularly scheduled program...

I was just pondering a thought, I wonder where the center of gravity is for a torus shaped object?


it is kind of like a donut, a round shape with a hole in the middle, could one possibly exist in the universe of any substantial size or would gravity not be able to hold it together in that shape?

Electric Universe FTW

The center would be technically a vacuum and nature/physics hates vacuums. There is a big reason why matter likes to form spheres. So I would tend to think no it count not exist for any real amount of time.

I do think perhaps a tube vacuum could appear, potentially bend due to external forces and touch its other end. Still think it would collapse once it did into a sphere vacuum though.

Looks like a star in the middle or something else very dense and bright. Guessing maybe a cone shape more than a donut.

I really don't know much at all about them, but I was reading about how they are theorizing that some extremely massive black holes have a torus orbiting around them

pretty wild stuff to try to imagine

Ya that's getting into theoretical stuff that I can barely if ever wrap my head around when reading about it. I would be as lost as you when it comes down to it. I just know the basics, and that at same time nearly anything is almost possible as long as it only bends the rules and does not break them as we know it.

Plus 51 science talks.

What exactly is one looking at, when looking at the dark spot of a sunspot?

Is it the 'surface' of the sun, or the 'inside' of the sun?

Just a cooler and highly magnetic area on the sun.

Stupid fact, we (our body) radiates more heat per square inch than same area on the sun does.

ZOMFG I LOL"d for days looking at that :1orglaugh:1orglaugh:1orglaugh:1orglaugh:1orglaugh :1orglaugh:1orglaugh:1orglaugh:1orglaugh:1orglaugh

Not sure what you guys are talking about, but a torus shape can exist and does.

You'd probably die painfully....

When and where?
When it got to that we both said we think or gave opinions. Only time I have even heard of such is in a theory of the shape of the universe itself "doubtful but depends on who you follow" or in a 4-d or larger dimensional universe.

So please do share as I am highly curious now.

Nobody mentioned digging a hole to China yet? ;)

someone is intrigued after watching that "travel to the center of the earth" movie uh??

</lol>

We may be talking about different things and that's what is causing the confusion.

But a tire inner tube is a simple torus shape. Higher dimension torus shapes may or may not exist though if that is what you guys are referring to.

Talking about appearing naturally in space.

Aren't the electromagnetic waves encompassing the earth in the shape of a torus? Not sure about a physical structure but many components on the cellular level in the human body are torus shaped and they seem to do fine when replicating in the low gravity of space when astronauts spend months there.

No void in the field.
what in the human body is donut shaped with a hole in the center. Keep in mind the talk was about a true donut shape with a void in the center. I know say some parts of the blood are almost torus or donut shaped but they have a center still.

In the middle you would be torn apart and become hot sexy magma.

I'll have to check into it then. I seem to recall torus shapes during certain cellular divisions but I don't remember the specifics. I suppose that you could argue that it's not really naturally occurring (as defined here) as the membranes of the cells can exert their own forces even though it can happen in zero gravity.

What do you mean "nobody has any idea what is in the center of the earth"? Scientists have a very good idea about what is at the center and the middle of the earth for that matter based on extensive, albeit indirect evidence from a great many disciplines. It's solid metal and liquid metal respectively, not solid rock or magma like someone else in the thread suggested.

Furthermore, a theory when used by a serious scientist is not some willy nilly half-assed guess, but an educated hypothesis based on a lot of evidence. So don't dismiss it that quickly unless you have something better to offer in it's place.

aren't red blood cells torus shaped?


I guess we had in mind a planetoid of solid matter in the shape of a torus

Haven't read the rest of this thread yet... because I am lazy, but...

Assuming no air resistance, you would oscillate about the center of the Earth. The gravitational force acts like a Hooke's Law force, since the force you feel is proportional to your position: (distance from center, i.e. r)

If there were air resistance, look up damped oscillators. In one damped oscillator situation, you would oscillate about the center with progressively smaller amplitudes, until you stopped altogether at the center (amplitude 0). In another damped oscillator situation, where the air resistance is really strong, you may not even make it past the center once, you'd just come to a stop. But that all depends on the strength of the air resistance, which I don't think in this situation would be that strong.

BUTTTTT Lets take air resistance into the equation..

You would fall, with the maximum acceleration being at the start of your fall. The acceleration would zero out at the centre of the planet, but your velocity by then would cause you to continue through, with gravity now trying to pull you in the opposite direction (back to the centre) and with its power increasing the further you went. If we neglect air resistance, your velocity would be *just* sufficient to get you to the surface on the other side of the planet, at which point you would then start falling back down. If we don't neglect air resistance, there will be a damping effect on your yo-yo'ing, causing you to 'stop' further from each surface on every oscillation.

First off... think of forces.

The force pulling you down is gravity F(g) = Gm1m2/r

Drag force is proportional to the velocity^2 (double velocity, quadruple drag).

Now, you will accelerate as you move down, but the force will become increasingly smaller as you approach the center (the summation of all the forces from all the mass particles is decreasing).

What will happen is you will accelerate downwards until you reach terminal velocity within your fluid (air likely). This will slowly decrease as the force will decrease.

You will decelerate as terminal velocity drops (your drag force is greater than your gravity force).

Then once you reach the center, you will start to decelerate even further until you stop and switch direction.

With aerodynamic drag acting as a damper (this is a 2nd order diff eqn), you will likely only get a fraction of the distance past the center and slightly oscillate around that until you stop in the center. The damping is actually greater than you would think (on a large scale)

Without drag, you would actually just oscillate back and forth forever.

Make sense?

That's what you get for trying to be helpful!

Thanks people been fun this evening, my muscle relaxers and pain pills are kicking in.
Enjoyed it d-null, jim, fucksakes, other jim, everyone. (except kandah :winkwink: )

Annnnnndddd, one last post, although my other posts should be pretty responsive: Assuming the usual optimal conditions, no friction etc., you would oscillate and have your maximum speed obviously in the center with over 17000miles/hour.
http://hyperphysics.phy-astr.gsu.edu.../earthole.html

If you won?t loss speed you will continue to exchange from one side of the hole to the other.

awesome, thanks for the calculation


curious what the frequency of the oscillation would be ie. how long it would take for you to fall from this hemisphere to the surface of China, and then back again (hypothetically speaking with no air involved etc :P )

BBC Space has a spectacular series on space.

Here is Black Holes, it touches lots on gravity, and has one of the most current theories on black holes.

http://www.veoh.com/videos/v257653TN...8436&rank= 10

The entire series is awe inspiring.

Had to this up one more time:

All objects are attracted to the center of the Earth.

If the hole runs through the center it will be rather like pulling a pendulum to one side and allowing it to settle, the pendulum oscillating back and forth. Thus you would fall in a straight line accelerating towards the center then deccelerating away from the centre until you, almost reach the other side of the earth and your velocity is zero. Then you will be drawn back, accelerating and deccelerating again, to almost where you originally fell. Each journey back and forth like the pendulum gets shorter and shorter until you settle stationery at the center of the earth. This is due to the fact that there is air in the hole which provides friction or drag. Such motion is called Damped Harmonic Motion (if the hole was in vacuum then your would not settle at the centre but would continue to execute a full simple harmonic motion)

Holes not going through the center have similar effects but you would fall in a curve and bump the side of the hole half way down, as the earth trys to attract you to its centre. You will again end up half way down the hole but stuck to the side which is closest to the earth's center.

http://www.physlink.com/education/askexperts/ae52.cfm

Well I hear there is a penalty if you run into any Chinese people on your way though.