I watched Alfonso Cuarón's Gravity today. It's spectacular, mesmerizing, well-acted, and even bringing up some real issues of space-faring. But I can't pass off the chance to nitpick some stuff...

SPOILER ALERT

I noticed two truly major violations of physics, not just for the sake of cinematics but the storyline:

1. When George Clooney's character sacrifices himself for Sandra Bullock's character by untangling himself. Pulled by... what force? They would have bungee-jumped back like correctly shown in all the other scenes. This was truly stupid considering that the script-writer could have created a realistic situation: if the two would hang on a rotating space station or a spaceship firing its rockets.

2. The uncontrolled Chinese space station burns up in the atmosphere. Within 24 hours of loss of control. The real time would be more like years.

Some minor stuff:

• The truly dangerous space derbis is (1) small, (2) spread out and (3) is in a circular orbit at a high angle relative to yours, meaning the relative speed is ultra-fast. A dozen screw-sized pieces coming in at 20 Mach would have devastated the ISS just as well, without making Sandra Bullock's survival so unbelieavable, but I submit it would be less spectacular.
  
• You'll meet space derbis again in 90 minutes if the hit satellite or you is orbiting in a slightly eccentric orbit with the same precession (rotation of the orbital plane) as yours. If it's a circular orbit, chances are you meet again in 45 minutes already: at the other side of the planet.
  
• Methinks anything entering the upper atmosphere would glow before doing any rattling reminiscent of subsonic motion in uneven or turbulent gas. This is hypersonic motion in extremely thin plasma.

On the other hand, this is the first time Hollywood discovers the possibility of Kessler syndrome: if there are too many satellites in low-earth orbit, debris from the destruction of one would result in more destructions and more debris until the Earth would be enveloped by a shell of space debris preventing the launch of any space vehicles for a few years (until the bulk of it spirals down and burns up in the atmosphere). And in contrast to the rope-untangling scene, real physics is shown when Sandra Bullock's character is unable to stop her rotation on her own. And while she is panicky for drama, George Clooney gets to show both of the two they characteristics sought for in an astronaut: not panicking in emergency and teamwork.

_{*Lunatic*, n.
One whose delusions are out of fashion.}