- Netflix’s “3 Body Problem” is based on a sci-fi trilogy and follows a group of physicists.
- We asked an astronomer and an aerospace engineer to explain some of the show’s scientific concepts.
- It might help to have a little background on the Fermi Paradox and Wow! signal before watching.
The upcoming Netflix show “3 Body Problem” is a sci-fi story about a group of physicists struggling to discover an alien civilization.
Taking its name from a complex piece of orbital mechanics – three celestial bodies moving around each other – the show is based on the sci-fi trilogy “Remembrance of Earth’s Past” by Liu Cixin.
In the series, several of the main characters studied physics at Oxford University. Fortunately, you don’t need to have the same experience to enjoy the show.
However, there are a few scientific concepts that might be helpful to know before you tune in on March 21.
The three-body problem is intractable and chaotic
Part of the action of the series takes place in a virtual world around which three suns revolve. The celestial mechanics of such a planet have long baffled scientists in the real world.
“This is an age-old problem,” Shane Ross, professor of aerospace and ocean engineering at Virginia Tech, told Business Insider.
Isaac Newton was able to understand the two-body problem, how a pair of massive objects such as stars or planets move when they are affected by each other’s gravity.
“The two-body problem is kind of a paradigm of stability,” Ross said. However, adding a third body turns everything upside down.
Mathematically, “it’s unsolvable,” Ross said of the three-body problem. “You can’t write the all-time solution as some algebraic formula.”
It’s a bit like the butterfly effect: a small change can make a big difference to the outcome. “Any uncertainty we have in the initial conditions grows exponentially to the point where the future state of the system is essentially unpredictable.”
Alpha Centauri is the closest star system to Earth
The three-body system in the story is based on a real neighboring star system called Alpha Centauri.
About 4 light-years from Earth, it is the closest to our star system and contains three stars: Alpha Centauri A, Alpha Centauri B and Proxima Centauri, which has two planets orbiting it.
“We’re talking about something super close to us,” said Frank Marchis, a senior planetary astronomer at the SETI Institute. “It’s basically like watching the neighbors’ backyard.”
However, special conditions would be required for life, at least as we know it, to survive on the two planets around Proxima Centauri. “Living conditions are extremely rare,” Ross said. “I think Earth is a very special planet,” adding that “there could be life that takes some other form that we don’t know about.”
If a civilization from Alpha Centauri evolved at rates similar to ours, then “they’re probably more advanced than us,” Marchis said, since the system is estimated to be between 5 and 7 billion years old, while Earth’s solar system formed 4.5 billion years ago.
Fermi’s Paradox asks where are all the aliens?
If there are advanced beings on other planets, why haven’t they made contact? That’s the question astrophysicist Ye Wenjie asks when he brings up the Fermi paradox on the show.
In 1950, Nobel Prize-winning physicist Enrico Fermi wondered where all the aliens were. Decades later, other scientists raised the issue. If other civilizations existed, they must have left some evidence.
For Marchis, what has come to be known as Fermi’s paradox is an outdated way of thinking. “The idea is that because we’re a civilization that’s technologically advanced, the first thing we do is travel through the galaxy, kind of like Star Trek,” he said.
Instead, he favors the “zoo hypothesis.”
If they are truly advanced, he said, “they probably have reached a certain level of sensitivity or consciousness that makes them respect other civilizations that are advancing more.”
In short, they purposefully avoid contact with our planet.
Aliens could communicate through Wow! signal
One of the most mysterious communications with potential aliens is known as Wow! signal. In the show, Clarence (Benedict Wong) describes how the strange signal was picked up in Ohio and China.
In the 1970s, Ohio State University researchers were indeed involved in the search for extraterrestrial intelligence, or SETI. They used a radio observatory nicknamed “The Big Ear” to try to pick up alien communications.
In 1977, volunteer Jerry Ehman was looking at a computer printout of a signal that the Big Ear had picked up three days earlier. He circled the numbers and wrote “Wow!” past them. The 72-second signal was strong and located at a frequency known as the hydrogen line.
At the time, researchers thought aliens would communicate through this frequency “because it’s the easiest way to send signals across the galaxy,” Marchis said.
The signal was never repeated or detected again, Marchis said. (And no other observatory reported picking up the signal, in China or anywhere else.)
Because the signal itself wasn’t saved, there’s no way to know if it contained a message, Marchis said. Some more mundane explanations for the signal have been suggested, such as a radio transmission reflected from a passing comet.
SETI has come a long way since the 1970s, with many researchers using newer technology and a wider range of signals, Marchis said. “We assume that if aliens are communicating with us,” he said, “they are a little more advanced than humans in the 1970s.”
Occam’s Razor suggests that simple explanations are often better
Like many other sci-fi movies and shows before it, including Contact and Fringe, 3 Body Problem makes reference to Occam’s Razor.
In 1852, the philosopher Sir William Hamilton coined the term “Ockam’s Razor,” attributing the idea to the 14th-century theologian William of Ockham.
William of Ockham had written, “Numquam ponenda est pluralitas sine necessitate,” or “Plurality should never be posited without necessity.” This is an idea that Aristotle and Ptolemy also state.
Today, the well-known concept is usually phrased as “the simplest solution is usually the right one”. An often-cited example is that if you hear the sound of hooves, think horses, not zebras (provided you’re not in the savannah).
Neutrino detectors are built deep underground
The trailer for the show includes a dramatic shot of one of the characters stepping into what looks like a neutrino detector and falling, presumably to his death.
Neutrinos, also known as ghost particles, are subatomic particles that the sun and supernovae I create. Billions pass through your body at any given moment.
Like particle accelerators, the devices could help unlock some of the universe’s secrets. They are often built underground to protect them from cosmic rays that can interfere with data.
Three celestial bodies aligned in a line is known as a syzygy
During the show’s third episode, the three suns in the virtual world line up in a triple eclipse.
Ross pointed out that the show debuted around a “cosmically significant day,” the vernal equinox. “It is the day when, throughout the world, daylight and night are equal,” he said.
It’s also close to the upcoming solar eclipse, which is passing through much of North America.
“It’s the sun, the moon and the Earth in one line,” Ross said. “It is called a syzygy when three celestial bodies are exactly in a line.”
