Is the science far out in space movies?

Don’t Look Up is an apocalyptic black comedy where humanity finds itself in the headlights of a planet destroying comet. NASA astronomer Amy Mainzer worked as the science advisor for the film and spoke to Otis Kingsman…

Amy - The director originally wanted the object to be a much larger asteroid, something in the range of about 60 kilometers across and he wanted it to be an asteroid. So we had to come to a compromise on that. I had suggested that instead of an asteroid of that size, which is so big that it really would be absolutely hopeless to try to stop such an object, that we really wanted something that was smaller. Still plenty large enough to cause a lot of damage, but small enough that we would have a reasonable chance of doing something about it. Basically anything that's in that size range, something larger than say about a kilometer across is big enough to cause what we would call global damage. And then also switching from an asteroid to a comet, there were a couple of reasons for this one we have really, at this point now mapped out most of where asteroids that get close to the earth in that size range are. The really truly big ones we know where most of these are now. But comets on the other hand come from much further away. This particular class long period comments can come from out of the blue. We sometimes find them with only a few months of notice; Just like comet Neowise, which we discovered in 2020. That object we found within a few months of its closest approach to the earth and the sun. So, that's quite realistic.

Otis - I suppose the temptation is to think that bigger is better, but as you've just explained, that's not always the case.

Amy - That's one of the important things I think about interacting with a movie crew as a scientist, you want to bring enough scientific realism to the production that it doesn't pop you out of the story. In this case, of course, the comet in this movie is really an allegory for a lot of different kinds of global problems that we face as a society like climate change, loss of biodiversity and even the pandemic. But you know, in this case, we wanted to make the point that if everybody works together as a society, we actually can do something about these big global problems. It's not hopeless.

Otis - Yeah. I didn't really question any of the science when watching it; I was too hooked. Take, for example, when Jennifer Lawrence's character first discovered the comet, I assume the maths and the formula were accurate?

Amy - In this case, in the movie what you're seeing is a group of astronomers who actually don't study comets as their primary science objectives, they study something else. I think these are characters who in their day-to-day lives, wouldn't calculate asteroid or comet orbits. Leonardo DeCaprio, he's a professor, he's got a bunch of students with him. He's trying to teach them and use the discovery of the comet as a teachable moment and he's gotta go look up in a textbook how to actually do this kind of math. It's not something he would do every day. That's pretty realistic.

Otis - If we actually had one of these comets heading towards earth, would it be possible to redirect it as discussed in the movie?

Amy - The single most important thing that we need is time. If we don't have a lot of time, it's much harder. What you see in the movie is there's this huge worldwide scrambled to launch spacecraft equipped with explosives that can push the comet out of the way. That task is made considerably more complex in real life, because it's very hard for us to build a spacecraft in less than a year, realistically. Not only that, it's not just the time that it takes to build a spacecraft capable of deflecting the object, but the energy that you require for your task actually gets considerably easier if you have more time. In other words, it takes less energy to push it out of the way if you can find it years to decades in advance, instead of just 6 months in advance. If you can even do such a deflection mission at all within 6 months. Time is really the most important thing.

Otis - Sure. The closer to the earth the comet the bigger the deflection we would require. I mean, this all sounds rather well thought. In your unbiased opinion, how scientifically accurate is Don't Look Up?

Amy - I would say this movie is about an 8 out of 10. It's pretty good in terms of the presentation of the scientists in doing their best to discover the object and track it, figure out where it's going, and then let everybody know that there is a large and imminent danger out there to society and to the planet. That's very realistic.