Hey, now don’t get us wrong, we frickin’ loved Gravity. We even had a chance to chat with the movie’s science advisor – Kevin Grazier – not too long ago, so we know some of the work that went into it.

But what sort of space magazine would we be if we didn’t at least offer our critique of some of the science in the movie? So, without further ado, here’s what Alfonso Cuarón got right and wrong in Gravity.

And again there are, like, massive spoilers below. So don’t read on if you haven’t seen it yet and don’t want it ruined, or if you want to plead ignorance to science and stuff.

This list is by no means extensive though, so if you spot anything we missed then post it in the comments.

1. Clooney’s character is reckless to the point of being ridiculous

We understand the need for personalities in a movie like this, but really at times Clooney’s character suspended belief a bit too much. At the start he’s flying around the Space Shuttle at who knows what speed in his jetpack, mouthing off about random stuff and generally acting in a pretty dangerous manner while maintaining a complete lack of professionalism that wouldn’t suit any astronaut, let alone a veteran supposedly of his calibre. No astronaut would act like he did. Well, except that idiotic Indian astronaut who throws himself to the end of his tether, which would probably have cut him in two. Astronauts are supposed to be competent, highly trained professionals that work together for months. Which brings us to…

2. How did the astronauts not know anything about each other?

When astronauts find out who they’re going to be flying in space with, they begin training with them on a daily basis for several months. So why didn’t Clooney and Bullock know anything about each other? Clooney doesn’t even know where she’s from! Although judging by his earlier misdemeanours, we wouldn’t be surprised if he was allowed to just skip training altogether so he could brush up on the stories he was going to tell while in space.

3. All those communications satellites would’ve been fine

Houston tells the astronauts that the Russians have shot down a satellite in low Earth orbit (LEO), meaning a communications blackout is imminent. But why? Communications satellites orbit much, much higher in geostationary orbits (so they’re always above the same point on Earth). Like, 35,000 kilometres (22,000 miles) higher. We were trying to think of some scenario here where a satellite exploding in LEO might have affected geostationary orbit but nope, there isn’t one.

4. Sandra Bullock would have been screwed pretty early on

When Bullock’s character, Dr. Ryan Stone, gets flung from the Space Shuttle after the space junk impact, she appears to be moving at a pretty alarmingly quick speed. It’s a good 5 or 10 minutes before Clooney makes his way over to pick her up. Would he have found her, let alone catch up with her? Probably not. Although we guess this one isn’t that implausible.

5. There’s no way to get from Hubble to the ISS easily (especially not with a jetpack)

Yeah, this is the one everyone’s been talking about. The Hubble Space Telescope orbits at an altitude of 559 kilometres (347 miles); the ISS is at 424 kilometres (263 miles). It might not seem that different, but it is. There’s no feasible way to move from the higher orbit of Hubble to the ISS, and especially not in a space jetpack (spacepack? spacejet?) like Clooney does. However, we like to think that maybe, as this was a hypothetical future Shuttle mission that never happened (STS-157 if we remember correctly; the last was actually STS-135 in July 2011), then maybe, in this crazy future orbit-friendly timeline, NASA decided to try and move things like Hubble and the ISS closer together in Earth orbit. This is also absolute crap a good way to explain one of our later quibbles.

6. You can’t hit things at speed in space and expect to survive

Jesus, in the movie those astronauts don’t half like banging into things. The doomed Indian astronaut at the start flings himself to the end of his tether; Clooney smashes into Bullock in his jetpack; both Clooney and Bullock slam into the ISS; Bullock jumps into the Chinese Tiangong-1 space station in what we can only assume was a suicide attempt (more on that later). And what’s the common theme here? All the astronauts are unscathed, healthy and generally loving life (ish). In reality? Those bone crunching impacts would have been literally bone crunching. If you slam your body into a rigid object in Earth orbit, your body is going to be pretty much a goner thanks to the vacuum of space, the weightless environment and the lack of friction. But who wants to see a movie where Bullock’s crippled body is wedged into the ISS for two hours?

7. Sandra Bullock was a bit too, uh, scantily clad

When our how-old-is-she-again heroine gets out of her spacesuit in the ISS, we are treated subjected to an astronaut wearing what we don in the office most days: underwear and a tight fitting shirt. In reality she would have emerged from that suit a sweaty mess from the exertion of spacewalking, sporting a liquid cooling undergarment and an adult-sized nappy (seriously, just ask Chris Hadfield). But did we really want to see a sweaty, nappy-wearing Sandra Bullock emerge from that spacesuit? Uh, probably not. Good job, Hollywood.

8. Why did Clooney keep talking to Bullock when she was CLEARLY RUNNING OUT OF OXYGEN?

When Clooney and Bullock were drifting towards the ISS from Hubble, which we’ve already told you was ridiculous absolutely totally possible, she told him she had 2% of oxygen left. So, why the hell did he keep making her talk?! Did he want her to die? Perhaps. It’s a good thing she got her own back…

9. Clooney didn’t need to die (although we’re glad he did)

I heard someone say recently that this scene was an offense against science. A bit drastic, perhaps, but I’ll allow it. Here’s the moment in question:

What’s wrong here? Well, when Bullock is holding onto Clooney, they’re both stationary and have the same angular momentum. But he inexplicably tells her that she has to let go or they’ll both die, at which point he gains momentum from some invisible force and is thrown into space. Even if they weren’t stationary, why didn’t she just pull him towards her? He would have just drifted past, and then could’ve grabbed hold of the rope. Or she could have left him there, turned around, grabbed more of the rope, then turned round and picked him up again. And, even if all this failed, why did Clooney think it was such a stupid idea that she go get the Soyuz and come pick him up? Didn’t he do exactly the same thing but in his jetpack earlier on? Gah! Oh well, at least we got rid of the worst astronaut ever.

10. That 90 minutes thing? It’s sort of right, but mostly baloney

You’ll remember that Clooney mentions how the debris is going to come around every 90 minutes so he tells Bullock to set her watch to get ready for the impending disaster. We get the intention here; the ISS orbits the Earth every 90 minutes (actually it’s 92.91 minutes but whatever), so Hollywood are saying the astronauts will encounter the debris every 90 minutes. Well, they’re wrong. For one, the debris is in the same orbital plane and it’s not stationary, so they wouldn’t run into it every time they completed an orbit. In fact, they probably wouldn’t see it at all (Earth orbit is a big place). Even if the debris were moving directly towards them, it wouldn’t repeat at a regular 90 minutes; if anything it’d be less. Put this one in the ‘things they tried to get right but got wrong’ bin.

11. Tears don’t float in space so no cool 3D effects for you

Surface tension in space is a fickle business. Remember when Bullock is all weepy in the Soyuz spacecraft and her tear drifts out towards you in wonderful 3D? In actuality it would’ve just stuck to her face as it left her eye. But we’ll agree that’s pretty lame to see in 3D, and we probably wouldn’t shell out a few extra quid for ‘incredible surface tension effects’.

12. Getting to Tiangong-1 from the ISS? Yeah, not gonna happen

In the Gravity universe it seems, as we’ve mentioned earlier, future governments decided to move everything in space closer together. Because the ISS and Tiangong-1 are nowhere near each other, and there’s no way you’d see one from the other in the modern day, let alone travel between them. But we’ll forgive Hollywood in this orbit-friendly timeline and just assume that our future selves are idiots who think moving very sensitive equipment closer together in Earth orbit is a good idea.

13. What the hell was Bullock’s plan before she grabbed the fire extinguisher to recreate Wall-E, just jump?

Like, she’s about to jump out of the Soyuz and at the last second remembers the fire extinguisher. What the hell, was she just going to jump towards Tiangong-1 and hope for the best? Did she even read number 6 above?

14. Good luck swimming out of a flooded capsule when you’ve just returned from space

Yeah, so, when you’ve spent a prolonged amount of time in space, readjusting to Earth’s gravity isn’t easy. The chances that Bullock would’ve been able to swim out of that flooded Shenzhou capsule are pretty non-existent. Although, we suppose this may have all been set at the start of their mission before her bones and muscles had deteriorated in the weightlessness of Earth orbit. We suppose.

15. Yeah, yeah, like the person with months of astronaut training can’t pick the right spacesuit – COME ON

This is the biggest one of them all (maybe sarcasm, maybe not). When Bullock gets out of the Soyuz spacecraft to transfer to the Tiangong-1 station she is clearly wearing a Sokol re-entry suit and not an Orlan spacewalking suit, the latter of which would let her live in space and the former of which would probably see her die pretty quickly. What are we to believe, like this is some sort of magical xylophone or something? Oh wait, wrong Simpsons reference.

16. Coming in from a spacewalk isn’t that easy

On several occasions Bullock enters a spacecraft/space station, takes off her spacesuit and is immediately fine. In reality she’d need to spend a few hours breathing oxygen and nitrogen to avoid suffering the bends before she could actually do anything useful, like setting the ISS on fire.

But it’s not all bad. Here’s what they got right…

NASA did used to have a space jetpack (sort of)

So, the space jetpack spacepack space-flying-thing Clooney was using? Yeah, almost totally legit. It was tested in 1984 by NASA; we actually spoke to the guy who set the record for the furthest spacewalk in it last year. Sadly, though, they discontinued it pretty quickly. Guess they didn’t know how useful it would turn out to be in the future when a series of implausible events occurred simultaneously.

Space debris is a growing problem and we’re all gonna die (probably)

The Kessler syndrome is a very real threat. Go read about it. There have been several instances in the past where accidents or stupidity have drastically increased the amount of space debris in Earth orbit. Although not certain, some are convinced that there will come a point in future when Earth orbit is so crowded that a Kessler syndrome-like event will be guaranteed to occur. We’ll tell you when it’s time to panic.

Something something atmospheric drag

So, that Chinese space station burning up at the end was pretty unrealistic, right? Well, not so much actually. You see, atmospheric drag is a problem. In fact, even the ISS needs to be regularly boosted to prevent it falling into the atmosphere. If left untended, space stations like Tiangong-1 would indeed eventually burn up in the atmosphere. Now you know.

Bullock would’ve survived when imaginary Clooney opened the hatch

Sure, it was only in her imagination, but some people mentioned this to us; would Bullock really have survived if Clooney had opened the hatch to get into the Soyuz spacecraft while she wasn’t wearing her spacesuit? The answer is sort of yes; humans can survive for about 30 seconds in space unprotected, as long as they don’t breathe or anything. Most of our research comes from an incident where a test subject was *cough* accidentally *cough* exposed to a vacuum on Earth, and not totally on purpose because NASA wanted to know what would happen. However, she probably would’ve been sucked out into space by the sudden change in pressure. So there’s that.

All the buttons and modules and technology and things were spot on

Go ahead, pull up some schematic diagrams, pore over some technical drawings. You’ll be hard pressed to find any aesthetic errors on Hubble, the ISS or the Soyuz spacecraft. The layout, look and even the buttons of each object were meticulously recreated in CGI to ensure that, even if you couldn’t stand the science, you’d love the engineering aspect of the movie. Although we can’t say the same for the Chinese space station. Who knows what’s in there exactly? Hollywood’s guess was as good as ours.

You can follow Jonathan on Twitter @Astro_Jonny

Images courtesy of Warner Bros Pictures and NASA