Movie: Gravity

If you get a chance to see the new Sandra Bullock/George Clooney movie in 3D IMAX don't pass it up.  I'm pretty hard to impress... and I was impressed.  The technical details were masterful.

Okay, a little research his morning turned up one technical detail the movie got spectacularly wrong.  The Hubble is orbiting 120 miles higher than the ISS, and thus at a much slower speed.

I didn't question it at the time.

Later: Well now wait a minute. Orbital velocities are fixed, they must be fixed to counterbalance gravity. That's why the ISS has to orbit faster than the Hubble. But that also means the debris field which impacts Clooney and Bullock every 90 minutes makes no sense. It would have to be orbiting at the same speed as them, if they're at the same height. Else wise it would either be flung off into space or fall from orbit.

Make that TWO spectacular errors.

Isn't it necessary to take into account the mass of the orbiting body?
How would that affect your concerns about the movie's inaccuracies?

_Howard wrote:

Isn't it necessary to take into account the mass of the orbiting body?

No.  Gravity is a constant.  All that is required is to balance the angular momentum against the pull of gravity, so the object is forever falling over the horizon.  The mass cancels out.

_Howard wrote:

How would that affect your concerns about the movie's inaccuracies?

Well if you've seen the movie you know that the sequence of events depicted is unlikely to the point of impossibility, so one can only critique the science in it, not the logic.

But the director had me totally buying into it at the time.

NoCoPilot wrote:

The mass cancels out.

Are you sure about that?
I have never previously given this matter any thought at all (and I remember lying in the yard at night trying to see Sputnik right after it was launched), but it seems reasonable that with a constant gravitational force, the mass of the satellite must be considered as well as its velocity. I could be wrong.

_Howard wrote:

NoCoPilot wrote:

The mass cancels out.

Are you sure about that?
I have never previously given this matter any thought at all (and I remember lying in the yard at night trying to see Sputnik right after it was launched), but it seems reasonable that with a constant gravitational force, the mass of the satellite must be considered as well as its velocity. I could be wrong.

Yup.  From the article you linked:

Quote :

•The equation is independent of mass. If the moon rather than the artificial satellite orbited at 400 miles and you could ignore air friction and collisions with the Earth, it would have to go at the same speed as the satellite in order to preserve its close orbit (which would make for some pretty spectacular moonrises).

Although this explanation conveniently ignores the gravitational effect of a body the size of the moon orbiting at 400 miles....

Yeah. I didn't read the whole article. mea freakin' culpa.

It still doesn't seem right, though. But then very little that involves gravity seems logically correct.

Think of it as a curvature in space rather than a force, and you'll be alright.

Nope. Can't do that. Won't do that. Don't buy that.

Awesome film regardless of it's few inaccuracies. They got the physics right. The silence in space while exploding debris surrounding the astronauts flies in all directions was just haunting and spine tingling. It's taken hollywood a long time to recognize that silence in space is more effective than sound effects.

Bullock's performance really impressed me too. In fact I fell in love with her, so I suppose that clouded my judgement.

The sheer beauty and intricate detail in the film was reminiscent of Kubrick's 2001 ASO (...and he accomplished that in 1968 without the aid of digital effects).

I have to agree with Cameron on this. One of the best hard-sci-fi-set-in-space films ever made. Must see in 3D too. It's an experience that has to be felt viscerally to be believed.

11 out of 10. No contest.

Hey SAI2, long time no hear.

Yeah, I'm willing to cut Gravity a couple of get out of jail free cards on technicalities in the interest of a really great story and some jaw-dropping visuals.

Thanks for your review.

And don't feel bad, I've been in love with Sandy since Demolition Man.

Hmmm. I may have to see this one.

Not usually crazy about disaster-in-space movies, but the comparison to Kubrick intrigues me.
Then again, I saw 2001 ASO in 1969 when I was really stoned, so it may not have the same impression on me.

_Howard wrote:

Hmmm. I may have to see this one.

Do it. I'm not easily impressed and I was gobsmacked.

I may have to reconsider taking recommendations from someone who says "gobsmacked."
I'm not sure I even have a gob, and if I do, I don't recall it ever being smacked hard enough to disturb me.

It's worth the extra effort to see it in 3D on IMAX if you can.

Where I live, that's not an option.
In fact, the stupid damn digital theaters fall far behind my home setup as far as picture quality and sound are concerned. I'll wait for the DVD.

Too bad man -- what planet are you on?

Planet Boondocks.

Bummer dude. Harshes your buzz. Might even smack your gob a bit.

It's "Harsh my mellow" and "Kill (or wreck) my buzz."
You kids will never learn.

As far as gobs go, I looked on Amazon and they have gobs of stuff, but they don't have gobs. I guess I must remain unsmacked.

Does your porcupine need whacking?

Thanks for the kind offer, but I've got it.

NoCoPilot wrote:

Cool.

Found it online last night, it's okay. Nothing that special. Can't explain why it's being considered for all sorts of awards.