ensonik

I have read that it is an extension of herd or social behavior.....

I suspect it's something along those lines. I guess what I'm hearing is that there are no conclusive explanations for the phenomena.

If all the people are in the same room, they are most likely are all reacting to the same stuffy conditions in the room.

No, one yawn triggers the next. I'm curious what causes this.

As for yawns being 'transmitted' over the phone, my guess is that its probably just psychological.

(

Well it's not physical, so yeah. But I'm curious what psychology would account for an immediate involuntary reaction triggered by a sound over the phone.

It's a genuine phenomenon that everyone on the planet observes regularily. One person yawns, and then another person(s) immediately yawns thereafter. It happens over the phone as well. Is there a scientific explantaion for this?

basically' date=' it's the density of the object being spread across a greater volume, rendering the gravity as more diluted, yes?

 

Or more like spreading butter over bread, the more area you spread over the thinner it is. So the moon's gravity is not related to the earth's proximity.[/quote']

 

My original comment said it must be heavier/denser, which sounds like what you're saying. But then there's this talk of distance between two objects playing a role.

That's the best advice I've read in this thread so far.

It would depend on the mass of the object in question. The gravitational field, given by GM/r^{2[/sup'] is what you should look at.}

^{The objects in question are the Earth and Moon, right? While I appreciate you pointing me towards a fuller mathematical understanding of gravity, this thread is about two specific bodies and their relationship. So can I assume that my earlier remark about the moon deriving it's pull from the Earth was accurate, or not?}

Force of gravity = Gravitaional constant * mass of object 1 * mass of object 2 divided by the distance between the centers of the objects squared.

 

Objects that are further apart will have less gravitational attraction then objects that are closer together.

So basically without the Earth the moon would have an extremely weak gravitational pull. It's strong pull in relation to it's mass is essentially derived from object 2 (Earth)?

Because gravity depends on not just mass' date=' but distance.

 

[/quote']

 

Could you expand on what you mean here?

Good question. I don't know the answer other than to say the obvious thing, which is that it must be comprised of heavier materials.

Orphiolite, great answer. Very in depth and satisying. Can you elaborate on the variance in size and density of planetery bodies in relation to the sun? I understand why the gaseous planets are further away, etc, but am unclear on that lack of linearity in terms of size and gravitational pull of planets as they get further from the sun.

As the solar system formed, the gravity of the sun drew in the heavier, more dense chunks of planetary dust - that is why the inner planets, Mercury, Venus, Earth, and Mars, are rocky. And the outer ones are composed of gas.

So you're saying the planets are ordered outwards from the sun based on their density/heaviness? So Mercury is the second heaviest thing in the solar system next to the Sun, Venus the third, etc?

Martin, thanks for clearing that up. I guess I held a misconception about the term. So a Hubble volume is essentially a measured distance, and we have the capability to look beyond it. So how far past one H-volume can we see? Into a second or third, or farther?

I've heard this term, but am unclear on it's exact definition. I think it implies that the entire universe as we know it is just one "volume" inside of a larger universe. Is that an even remotely accurate definition?

I have to open and read text files larger than 10 zigabytes on a daily basis.

 

zigabytes?

Well, my guess would be that most of the dust has already "clumped up" and what is left probably is[/b'] clumping up but we ain't out there in space to observe a clump the size of a marble forming every thousand years or so.

lol

always thought that planets were made simply by the rings of dust from star formation colapseing under its own gravity to form a seed which could be built upon by collisions with other dust particles.

That makes sense as I could imagine a dust ring having areas denser then others. I suppose these dense areas could ultimately be drawn together, or collapse as you say.

The way it was explained to me is that in a cloud of dust, created by a (the) big bang, and in a vacume (or close enough) that two particles would be attracted to one another because of the attraction between masses. This would create a larger particle of dust which would in turn attract other particles and over a great deal of time, clumps of dust would be formed, which, upon comming close to each other would also tend to be attracted to each other, again, because of the attraction between masses, and that would form even bigger clumps.

 

Sounds a little like making a snowman, doesn't it?

So I guess my next question would be then, why is this process not continually occurring? If particles within a dust cload are naturally drawn together, should we not be seeing this clumping action take place right now all over the visible universe?

So you're saying the gravitational pull that 'hotspots' of dark matter produce could be the foundation on which planets are based? Interesting theory, I'm not sure if there's any truth to it or not. I guess the implication of that would be that planets, including Earth, reside on high concentrations of dark matter.

I posted this in another thread without response, so I'll try again:

What is the current explanation for why random particles within a nebula would in fact be drawn together towards an empty spot in space to eventually form a planet? What is the "motivation" so to speak for random particles to form together at some arbitrary point?

Thinking about this some more, and I can't help but imagine that particles attracted together by gravity within a nebula would form a uniform spherical surface. So is it off base to assume that prior to disruptions caused by plate techtonics and so forth, the earth was uniform?

And speaking of the creation of planets, what is the current explanation for why random particles within a nebula would in fact be drawn together towards an empty spot in space to eventually form a planet? What is the "motivation" so to speak for random particles to form together at some arbitrary point?

The USGS link is very informative, thanks.

So would the Eath's terrain have been uniform around the entire sphere prior to any natural disasters?

Aren't orbits due to the interplay between multiple forces? Your example cites only one.

Simple question: Why are large parts of the planet flat, while others are raised and mountainous? Is it related to climate and wind/rain errosion over enormous emounts of time, or was the planet just formed this way?