Neil deGrasse Tyson - People at the equator would float

[FreakBoy]

According to Neil deGrasse Tyson's twitter feed:
http://twitter.com/neiltyson/status/12578210448

If the Earth spun 18 times faster he says that people at the equator would float....

I'm sure I'm missing something, but if they were floating, how would they retain the angular moment required to continue floating?

 

[Mark6]

They would be effectively in orbit

 

[Michael Redman]

Of course, if they're in the atmosphere, the local wind is going to effect them, and I would assume that the earth would tear itself apart pretty quickly if it were spinning that fast.

But ignore that and you've got ground level orbit, an interesting idea.

 

[macdoc]

There was a good sci-fi written on a rapidly rotating planet where life evolved near the poles and one "adventurer" had to cross the equator..

Mission of Gravity I think by Hal Clement.....well done as it took into account what the nature of the biology would be on a high mass planet that had high rotation...

 

[PixyMisa]

Great book, I got my copy autographed when he visited Sydney years ago.

 

[macdoc]

Don't think he wrote much...recall he was actually a working scientist.

 

[Skeptical Greg]

On a similar note, I recall a very entertaining short story, about a planet that had a small moon ( about softball size ( maybe a little smaller or bigger )) that orbited just a few feet above the ground ..

Lot's, of interesting implications..

 

[Bill Thompson]

would centrifugal force cancel gravity?

 

[Metullus]

On a similar note, I recall a very entertaining short story, about a planet that had a small moon ( about softball size ( maybe a little smaller or bigger )) that orbited just a few feet above the ground ..

Lot's, of interesting implications..

Wasn't that an Asimov story? I think that he called the moon "Bottomos".

 

[macdoc]

would centrifugal force cancel gravity?

Yep - been at amusement park...??

tho it might be centripetal....always get those tangled..

The astronauts are not really in gravity free environment....one force is cancelling the effect of the other..

 

[Skeptical Greg]

The astronauts are not really in gravity free environment....one force is cancelling the effect of the other.

Nothing is being canceled.
Astronauts are in free-fall . Gravity is very much at work ..

 

[macdoc]

From their standpoint one force is cancelling the effect of the other

Gravity is always in play and assumed to be...which is why I said effect

Just as a neutral buoyant diver has offset the effect on him of gravity

 

[Skeptical Greg]

From their standpoint one force is cancelling the effect of the other

What other force are you talking about ?

 

[shadron]

Don't think he wrote much...recall he was actually a working scientist.

Hal Clement is the pen name of Harry Clement Stubbs. Among other things, he was a B-24 pilot in WWII and retired as a colonel in the Air Force Reserve. He also painted astronomical artwork under the name of George Richard. His profession was teaching chemistry and astronomy at Milton Academy in Massachusetts. He died at age 81 in 2003.

His 20 or so full length novels are famous for the unusual physics, and his stories for their use of hard science as a plot device rather than window dressing.

 

[shadron]

What other force are you talking about ?

Balancing gravity against centripetal force. It's what being in a free-fall orbit is all about.

 

[Skeptical Greg]

They don't cancel each other out ..

For an object in orbit, gravity is the source of the centripetal force..

 

[icerat]

Wasn't that an Asimov story? I think that he called the moon "Bottomos".

Apparently it was a short story called "The Holes Around Mars" by Jerome Bixby, originally published in Galaxy, January 1954 but later included in a few anthologies including Asimov's Where do we go from here?

http://www.sfsite.com/vault/mail79.htm

 

[macdoc]

Centripetal force - Wikipedia, the free encyclopedia

Centripetal force is a force that makes a body follow a curved path: it is always directed orthogonal to the velocity of the body, toward the instantaneous ...

and do recall...."effect"..

 

[Skeptical Greg]

would centrifugal force cancel gravity?

Yep - been at amusement park...??

tho it might be centripetal....always get those tangled..

The astronauts are not really in gravity free environment....one force is cancelling the effect of the other..

Gravity and centripetal/centrifugal force do not cancel each other out ..
Their interaction does not produce the effect of weightlessness .

It doesn't begin to describe what's happening ..

It's bad science, if science at all, to offer it as an explanation ...

 

[Vorticity]

If the Earth spun 18 times faster he says that people at the equator would float....

I just ran the numbers. I get 17.0735 times faster as the minimum speedup required in order to float.