Neil deGrasse Tyson and astronaut Mike Massimino discuss the movie, Gravity
Neil deGrasse Tyson and astronaut Mike Massimino discuss the movie, Gravity

Cosmic Queries: Gravity, the Movie

Credit: © Warner Bros.

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About This Episode

To answer your questions about the movie Gravity, Neil deGrasse Tyson and Chuck Nice get a little help from 2-time Space Shuttle astronaut Mike Massimino. They explore the scientific inaccuracies in the movie – and how much Gravity got right. Mike gives it 2 thumbs up for the look and feel of being in space, from the spacesuits to the tools he actually used. He discusses how actual NASA astronauts train for emergencies, the time he tore his glove fixing the Hubble telescope, and the real rescue plans for his flights. @Astro_Mike (he was the first human to Tweet from space!) also describes impact of weightlessness on your inner ear and sense of balance, and how your brain adapts after a few days of zero-g. Neil explains why you’re weightless in space in the first place – it’s free fall, not lack of gravity – and describes an experiment you can do at home to prove it and amaze your friends and family.

NOTE: All-Access subscribers can listen to this entire episode commercial-free here: Cosmic Queries: Gravity, the Movie.

In This Episode

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  • I truly feel Apollo 13 was a far more effective “disaster in space” movie. It managed to be scientifically accurate and well-acted. It was also very emotionally engaging. I always cry at the end when the capsule splashes down.

  • kerry

    hi and thank you for taking my question. Sometimes when I’m out walking my dog and the night is quiet and calm I think about what would happen if gravity just ceased. Would I gradually float upwards and maybe becaome stuck in the tree tops or would it be a swifter and faster ascent to the stars?

  • Ted Daniel

    The first question I had when I watched the movie was: “Why do they keep coming across the same debris at great speed every 90 minutes? It seems to me that if the debris was orbiting the earth so much FASTER than they were that it was re-encountered every 90 minutes, it would spiral away from the earth so quickly that it would be far out into deep space in show order. However, if it were orbiting in the opposite direction, it would be going so slowly around the earth that it would re-enter the earth’s atmosphere in no time. Finally, if they were on totally different orbits, it would be highly unlikely that they would ever meet again.

  • Matt

    What a great show. I am so glad to hear from a real astronaut. Neal and Chuck are good too.

  • I thought the movie was great – very entertaining even though it has some (a few) discrepancies with reality. The only one that bothered me was Clooney at the end of the rope with Sandra Bullock entangled in the parachute strands. What on Earth (literally) would have been pulling George away from Sandra? after he had reached the end of his tether, so to speak, the laws of motion would have dictated that he drift back towards his attractive co-astronaut.

    • Jeff

      Absolutely right, Andrew.

  • Cameron

    “Acidosis” refers to when Sandra Bullock’s character was running low on oxygen. Because she was hyperventilating, she consumed the oxygen gas in her tank very quickly, resulting in a higher concentration of CO2 (and less oxygen). When this happens, her blood is overpopulated with CO2 and her blood pH goes down, which results in “acidemia” or acidic blood. The decrease in blood pH (increase in blood proton concentration) lowers hemoglobin’s affinity for oxygen, allowing any leftover oxygen to be released from her red blood cells into her tissues so they can use oxygen effectively, but further presents her red blood cells from picking up more oxygen, eventually depriving her body of the good stuff (oxygen, that is). Since her character is a doctor (since she is from a hospital, I would assume a medical doctor), I would think she would know to slow down her breathing, but, in her defense, I also would find that difficult to do if I were in her situation….

    • Jeff

      Thanks for clarifying that, Cameron!

  • Stuart Beresford

    This query will contain spoilers for the film Gravity.

    After the astronauts bounce across the ISS, Stone’s leg gets caught in cables, and she manages to grab the tether attached to Kowalski. He disconnects from the tether because “he’s pulling her down”. Surely, as they are in free fall, and stationary, there should be no force acting on Stone or Kowalski, so his mass should not be acting on her. As such surely she would just need to apply the gentlest of tugs on the tether to give him the impetus to reach either her or the ISS itself.

    • Jeff

      You are correct, Studart.

  • Henry Kwan

    Mr. Owl (Dr. Tyson), If I were in space and in free fall, and i farted, it should propel me forward, would it not?

    • Jeff

      Henry, as Mike says in the episode, only if the gas wasn’t trapped by your suit.

  • Valerie Wagner

    Gentlemen you amaze with your sense of fun and ability to explain without making me screw-up my face in a big question mark. Neil deGrasse Tyson, Mike Massimino, and Chuck Nice thanks for the good time! I’m gonna see ‘Gravity!’

  • Blaed Hutchinson

    Loved this episode! reminds me of this song:

    • Jeff

      Blaed, the song wasn’t there.

  • Alexander

    some questions that bug me. Would we need to have the same orbiting speed to stay in orbit over other planets that have either a higher gravity well or a lower gravity well? would we also need to be in higher orbit or lower orbit for planets that have diffrent gravity wells that earth? Lastly, can Mr. Tyson theorize of a method to create a counter gravity device.

    just a few things to kicking around in my head.

    • I think this question is easy to answer, even without proper physics calculation: if we need to move fast enough to continue falling towards the Earth and the sideways at the same time, there is a velocity in which orbit becomes stable, related to the size of our planet. If the planet gets bigger, we need to move faster and faster to keep falling relative to its gravity and radius. I’m not sure of that. Maybe to answer it better, you could search for the orbit speed of bigger planets’ moons, like Saturn.

  • Allen

    In the movie, there is a crucial scene where our heroes are barely hanging on, with one character’s foot wrapped up in some lines, and a tether between the two of them. The scene goes on for more than just a few seconds, and yet there is a constant force pulling them away. There doesn’t seem to be any explanation for this. Their momentum should have stopped. There didn’t appear to be any rotation applying a push away. This looked like one scene where the physics fell to the needs of the drama.

  • Niall

    I really like Chuck Nice as a co-host! He’s funny and intelligent, and is sensitive to the conversations; he doesn’t butt in or derail right when things get interesting.

  • Tracey

    Dr. Tyson,

    You had offered a fact about suction cups on this show that I found interesting, but didn’t fully think about until I was lying in bed that night (when most great ideas attack!), trying to fall asleep. Forgive my challenge in advance, I am a mere art school drop-out/ bookstore employee. But since you’re my personal astrophysicist, I feel inclined to ask questions.

    Your explanation for how suction cups work is the pressure bearing down on the outside, and that there is no suction involved; that suction cups are titled a lie!

    My idea is that suction cups DO suck. They are made of a soft rubbery material that is concave in its relaxed state. When you push it to a flat surface, the memory in the material tries to return to its previous form. It’s flattened out, trying to become a concave again, against a surface that is not allowing air to pass through. Is this NOT suction?

    On that note, I have a follow up question…

    If you had a glass (since the glass is solid and won’t change shape) with a rubber seal to make an air-tight suction on a flat surface, and you were able to create a vacuum in this glass, would that be a better example of the external pressure holding the glass to the surface as you described on this episode? Would it then stay attached to the surface regardless of trying to pull it off?

    I would SO MUCH appreciate a response. I’m sure you understand how those thoughts that enter your mind as you’re trying to drift off to sleep can haunt you. 🙂 And thank you endlessly for all you do to make science exciting and humorous.

    Much love from Nashville, Tracey

    • it’s not suction. suction is a steady flow of negative pressure. a suction cup isn’t flowing air. its just negative pressure inside forcing the outside air to put pressure onto it trying to get to the inside negative pressure, thus. holding it in place and retaining in place for a long time.

  • Jim

    @Henry…First off….if your in a space suit and you fart I dont think your going anywhere. Your butt would have to be exposed to space to have a chance to act as a thruster provided that is even possible.

  • Karen_Tiede

    Gentlemen–I’m horrified!! Acidosis is the key player in …. Andromeda Strain! Surely you’ve seen that….

  • Eugene

    I feel somewhat confused about explanation of weightlessness in orbit. You talk about the speed the Earth’s surface curves away from an astronaut. As far as I remember, to get an orbit you need the masses and distance between centers of mass. The Earth could be very small and of random shape, or huge, round and just ten meters below the astronaut, if the masses are the same the speed is the same, and curvature is not in play. Am i right?

  • Angela Dunne

    I finally saw this movie the other day in theaters (in Japan!) and was glad to finally be able to listen to this episode. But I am surprised no one went over the “death scene” of George Clooney’s character. It made no sense, for sure, and me and my friend were debating the various reasons why, though we’re only amateurs. Care to shed some light on it?

  • Ricardo Magalhães Ribeiro

    talking about free-fall, watch one of those metal springs in slow motion. the upper portion falls, but since it’s pulling the reast, the bottom keeps completely steady. very cool

  • Stephen Bates

    There’s quite a bit of discussion about how it would be impossible to open the hatch of the Soyuz in space. I think that inaccuracy might be excused by the fact that the whole sequence is an hallucination!

  • Lemonia Maris

    Lol Dr Tyson I am 19 years old and I know what acidosis is….you weren’t paying attention in anatomy/physiology!! Its when your blood is has low pH. You’re welcome

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