Separating science fact from fiction in Netflix’s 3 Body Problems

Note to those who haven’t seen it yet: Spoilers ahead.

What is the three-body problem in physics?

For two objects orbiting each other, scientists can accurately predict the location and speed of these objects in the future. But for three or more rotating objects, the motion can be chaotic. This means that the results depend so sensitively on the initial locations and velocities of the three objects that the future is unpredictable (SN: 4/6/20).

IN 3 Problem with the bodya race of aliens called the San-Ti inhabit a planet in a triple star system four light years from Earth. The unpredictable orbits of the stars lead to both stable and chaotic periods. Chaotic epochs wreak havoc on planets’ climates, destroying entire civilizations.

In reality, the sun’s nearest neighboring star system, Alpha Centauri, hosts three stars, and even planets, about four light-years from Earth.SN: 24.8.16). But this system is not chaotic. Two larger stars orbit close together, and a less massive star orbits them, further away. This particular system has a solution that is quite stable, Delabruille says.

For a hypothetical system in which three stars rotate chaotically, however, the planet probably wouldn’t survive long, Delabruille says. Most likely what would happen very quickly is that the planet would either crash into one of the stars or simply be thrown away.

Does quantum entanglement allow instantaneous communication?

In the show, the San-Ti are able to manipulate events on Earth, controlling video screens and particle physics experiments from afar and even making stars appear to twinkle. These powers are explained through sophons, which the series describes as supercomputers the size of a proton.

A single proton can become a supercomputer, the show explains, because San-Ti uses extra dimensions. Extra dimensions are a real idea of ​​physics: In string theory, for example, scientists propose that there are 10 or more dimensions, instead of just the three spatial and temporal dimensions we know. But, Delabruille points out, those extra dimensions must be small (SN: 10/5/18). In the series, the extra dimensions unfold to a size large enough to allow a computer to be carved into the proton. This is complete science fiction, says Delabruille.

Another head-scratcher: San-Ti speeds up the Sophons to send them to Earth, but it’s not explained how the Sophons slow down and arrive unscathed in Earth’s atmosphere. High-velocity protons from space hit the Earth’s atmosphere regularly; are called cosmic rays (SN: 23.11.23). When those cosmic rays arrive, they are hidden in bottles of particles. Likewise, the sophon would hit the atmosphere and disintegrate, Delabruille says.

Additionally, phones can transmit information to and from San-Ti faster than the speed of light. This is explained in the show by quantum entanglement, a real feature of physics often abused by science fiction authors (SN: 10/4/22). Entangled particles have properties that are related. Take a measurement of an entangled particle and you know what its partner would give, even if the two particles are light years apart.

But physicists are clear about one thing: quantum entanglement cannot transmit information. Each measurement of an entangled particle gives a random result. So, says Delabruille, the best we could do is take measurements, get random numbers, and then in turn they would get random numbers as well.

Could nuclear explosions power a space probe?

With San-Ti heading towards Earth, expected to arrive in 400 years, the humans send a probe to meet them. To increase the probe’s speed to about 1 percent of the speed of light, the team deploys a series of nuclear explosions, carefully timed to intercept the probe’s drifting radiation as it passes.

The numbers might work, Delabruille says, but the efficiency of each explosion would be small, most of the energy of each explosion would be lost to space and not go into propelling the probe. I think that’s a little optimistic, he says.

There were many other moments in the show that, while based on real science, end up not being believable, Delabruille says. Nanofibers can make impressively strong materials, for example (SN: 1/10/18). But individual ones could not pass on a ship. And scientists have tried to send messages to aliens, but the sun wouldn’t amplify a radio signal that humans transmit (SN: 24.2.23). And no, Delabrouille says, an army wouldn’t sail off San-Ti’s planet if the three stars aligned with each other. Raising the army would require tremendous tidal forces that would tear the entire planet apart.

Despite the science jumps, Delabruille says he enjoyed both the show and the novel it was based on. It’s wildly imaginative, and I like that, he says. It makes me think: Is this believable? Is this possible? And then you have to think why it’s not possible, so it’s also interesting in that respect.