Pendulum Gravity

a reply to: greenreflections


So what would the earth look like if it stopped spinning?

The following is not a futuristic scenario. It is not science fiction. It is a demonstration of the capabilities of GIS to model the results of an extremely unlikely, yet intellectually fascinating query: What would happen if the earth stopped spinning? ArcGIS was used to perform complex raster analysis and volumetric computations and generate maps that visualize these results.

www.esri.com...

a reply to: Kashai

great find Kashai..

although as for me personally, it is little of interest. Sometimes I look at, say, Earth Moon system as if stationary, but that is just for simplicity..this is also a proof that gravity is not generated by physical object spin...If you stop Earth Moon rotation, both will still experience tidal effect of each other.

I know you support rotating hull of space ship to generate artificial gravity on board...and let it be. I am not going to argue with any one any more on this.
Time will tell if this is a correct approach... But I think it will never work for a reason I gave in my last dozen of posts in this thread.


cheers)

a reply to: Kashai

I think you and Phage are thinking of gravity as something having to do with centripetal force. I think gravity is more sophisticated mechanism than that. It is geometrical by cause and it's degree of effect is govern by inertia of physical bodies.

Centripetal force or for that matter Centrifugal force is not gravity but it will allow Astronauts to arrive on Mars and start walking, the moment they arrive their.


As to if we are arguing that is debatable.


Now for something completely different...

a reply to: Kashai

..it will allow Astronauts to arrive on Mars and start walking, the moment they arrive their.

yup..it probably will, while the occupants are in fixed position attached to rotating hull...something like stasis chambers with the crew.

But it wont be usable artificial gravity, where the crew can walk freely inside space ship as if they were on planets surface.

a reply to: Phage

A tethered object in a lower orbit would have less than orbital velocity so would not be in freefall

Not really. The spatial space metric gradient inside gravity well can make lighter object to have greater weight depending on proximity to gravity source.

No?

a reply to: greenreflections

That's what I said. Not be in freefall.

Why does a hot air balloon go up, with gravity pulling down on everything?

originally posted by: BakedCrusader
Why does a hot air balloon go up, with gravity pulling down on everything?

Something evil, called buoyant force, the bane of second semester freshmen in physics and engineering the world around.

a reply to: Bedlam

It's also a pain in the neck when SCUBA diving with a wet suit.

a reply to: Bedlam

But gravity is pulling down on everything.

a reply to: greenreflections


Initially yeah but with some of the theoretical propulsion theories out their not necessarily in subsequent missions.


Generating artificial gravity alternatively could be the result of finding a way to increase the density of an object like a plate of steel, without increasing its mass. Like taking an object that weights 10 million tons and increasing its density to the point where its generating 1g, for the sake of discussion.

Like building a space ship that is designed around a micro-black hole large enough to sustain a 1g environment on the vessel.

Some way to stop it from consuming the vessel would have to be understood.


Actually its something that is plausible though it would probably take about 1000 years to develop.

This is really cool stuff to talk about; thanks for responding.

originally posted by: Phage
a reply to: greenreflections

That's what I said. Not be in freefall.

Yes, ok. In free fall will be the spot in the middle of tether, some where between my space ship and weight at the end. This orbit will balance out my space ship, which will retain same orbit but going much faster then what Newtonian mechanics would suggest.

originally posted by: Bedlam

originally posted by: BakedCrusader
Why does a hot air balloon go up, with gravity pulling down on everything?

Something evil, called buoyant force, the bane of second semester freshmen in physics and engineering the world around.

Can you explain the concept of buoyancy and density? Freshmen terms will do.

It's also pulling down on the air.

a reply to: Bedlam

The air is moving down around the balloon as it goes "up"? The Earth itself too?

originally posted by: BakedCrusader

originally posted by: Bedlam

originally posted by: BakedCrusader
Why does a hot air balloon go up, with gravity pulling down on everything?

Something evil, called buoyant force, the bane of second semester freshmen in physics and engineering the world around.

Can you explain the concept of buoyancy and density? Freshmen terms will do.

I can, but in about four minutes I'm off to work. Google 'buoyant force', there's lots of video tutorials.

But in a somewhat uninformative nutshell, there's more pressure at the bottom of the balloon than the top, and that's where the lift comes from. And that happens because there's an air pressure gradient due to gravity.

originally posted by: BakedCrusader
a reply to: Bedlam

The air is moving down around the balloon as it goes up? The Earth itself too?

No, but the air isn't the same pressure at the bottom of the balloon as at the top, because gravity creates a pressure gradient in a working fluid.

You could google for "ascent velocity formula" and look for a force diagram?
There doesn't seem to be any difference with a theoretical "vacuum balloon" if that is what you were thinking.

It is obviously all about buoyancy and density. Matter with a high density goes down, and matter with a lower density goes up.

That is the Law we see in reality.

If you are denser than air you fall down, if a gas is less dense than air it goes up.

So why are we talking about a force that is pulling everything down to the center of the Earth?

It only serves one purpose.