As the Hubble and Webb telescopes discover more and more star systems, it was only a matter of time before systems with three or more stars that orbit each other or otherwise move in respect to each other were discovered. Now, the once obscure hypothesis known as the “three-body problem” is making the astrophysical news as the reality of such a possibility becomes clear. Here, we’ll look at the star system Gliese 667 as part of my exobiology research with a focus on Gliese 667 as a 3-body problem (三体)
This post also contains a review of Netflix’s 2024 television series called “3-Body Problem” (see column on right.)
Put in simple terms, the three-body problem is “a problem of mathematics and physics, as well as classical and quantum mechanics, regarding any three objects and the gravitational effects they may have on one another.” To understand this, think of the relationship between the Earth and our moon. According to Live Science,
. . . think about the way the moon’s gravity tugs on the Earth to produce the tides. Those tidal forces steal some energy from the interaction between the two bodies, and that changes the way each body moves.”
Yet, there is a relatively stable balance between the Earth and the moon as the moon revolves around the Earth and the Earth revolves around the sun. But the constant movement of the Earth in its orbit around the sun means that the moon must at times “move faster” to “catch up” to the Earth which is also moving. And the sun is moving, too. So, there is not a perfect precision between the Earth, the sun and the moon, but the system is balanced in some way and predictability is possible many millennia into the future. If you have a system with one sun and a planet (or eight planets), or even two suns and one or more planets, the system can establish a high degree of stability as the stars interact with each other, assuming certain things are true involving the mass of the respective “bodies,” their orbits, etc.
But, adding a third sun can destabilize the system and become unpredictable depending on the third star’s movement and its mass. Put in lay terms:
Since all three stars are exerting gravitational forces on each other, they end up throwing the solar system into chaos as they fling each other back and forth. For the Trisolarans, the name for these aliens [in the Netflix series], it means that when a sun is jettisoned far away, their planet freezes, and when a sun is thrown extremely close to their planet, it gets torched. Worse, because of the three-body problem, these movements are completely unpredictable.”
Even worse yet is when the planet approaches two suns at the same time.
Gliese 667
Gliese 667 is a system in the constellation Scorpius, some twenty-three light years from Earth. It is barely visible to the naked eye and appears as a blurry point of light if you can find it. In this system, the first two stars (667A and 667B) orbit each other while the third star orbits the first pair. Both 667A and 667B are K type stars. “Sun-like stars are classified as G-type stars; stars less massive and cooler than our Sun are K dwarfs,” according to NASA. The third star (667C) is a red (K) dwarf.
There are two known planets in this star system. One is a “super Earth” type planet, but not “Earth” are we know it. It orbits the red dwarf (667C) but too close to the star to harbor life (again, as we know it.) Also, it is tidally-locked like Mercury and our moon are. This means that the same half of the planet faces the sun and the other does not. This occurs when the rotation of a planet or moon on its axis equals its revolution around the sun or whatever body it revolves about. The second planet (cc), featured in movies such as “Alien v. Predator” also circles the red dwarf and is also tidally locked. It is currently thought to be too hot to support life, though there may be narrow zones near the planets terminator that can be more temperate temperature wise. There is almost as much daylight on cc as there is on Earth. I’ve discussed the possibility of life on planets circling red dwarfs here.
Gliese stars 667A and 667B and exoplanet. Star 667C is not in range. Photo credit: ESO/L. Calçada, CC BY 4.0 https://creativecommons.org /licenses/by/4.0, via Wikimedia Commons.
The Kepler Space Telescope revealed that the majority of exo-planets discovered that are somewhere between Earth and Neptune in size, have circular orbits. Furthermore,
astronomers have discovered some giant planets with moderate- to extremely-elongated orbits, resulting in brief, hot summers and long winters to cool off,”
according to Penn State Distinguished Professor of Astronomy and Astrophysics Eric Ford. Imagine a planet with a very hot summer that lasts for four Earth months and a winter that lasts for eighty years! What sort of life might develop there? Would life hibernate that long? This, is just one variable that may play into a triple star system. Or, flip this scenario around. Imagine a planet with a very cold winter that lasts four Earth months and a very hot summer that lasts eighty years. How could there be water on a planet’s surface exposed to heat, perhaps several hundred degrees F (or more?) Planet HR 5183b in the constellation Virgo is one such planet with an elongated orbit.
This planet spends most of its time loitering in the outer part of its star’s planetary system in this highly eccentric orbit, then it starts to accelerate in and does a slingshot around its star . . .”
Andrew W. Howard, a Caltech astronomer who leads the California Planet Search noted. “We detected this slingshot motion.”
The planet HR 5183b carries the nickname of the “Slingshot Planet.”
And extreme heat seems to be the rule rather than the exception. Of the 5,000 known exoplanets, eighty percent are closer to their sun than Mercury is to ours.
Ford also mentions that “solar systems very similar to own are not typical. But still, we don’t know if they’re rare.” (ibid.) If it is true that our solar system and particularly our planet are the life-embracing exceptions in our universe, it would be a boost to the Rare Earth hypothesis.
There is nothing at present to suggest that Gliese 667 presents a three-body problem, though it is just a matter of time before one is found. The movie review (right) mentions some specific problems that life might encounter on a planet in a three-body system.
The Netflix review
The Netflix series called 3-Body Problem was released in March of this year. It was based on the book 三体 (“Three Body”) written by Cixin Liu and published in 2008. The premise of the book is that there is intelligent life in a solar system (in this case, Alpha Centauri) that has three suns, which move in a way that repeatedly demolish the surface of the planet. One minute, inhabitants of the planet are being burnt to a crisp, and on another occasion, millions of people, animals, objects and structures are being pulled up off the ground headed towards space as a passing body containg much more mass overpowers the gravitational field of their planet.
How can a society evolve when it is utterly destroyed repeatedly? It might happen once every ten thousand Earth years or perhaps twice in a short space of two-decades. And there is no warning.
David Benioff, D.B. Weiss and Alexander Woo join forces to produce the eight episodes that comprise Season One. Production for a second season was announced only in the last week.
Many of the actors are necessarily Chinese, including the star Ye Wenjie (variously played by Zine Tseng and Rosalind Chao.) She is a product of Mao’s Cultural Revolution of the sixties and she is recruited by the regime to search for alien life in space because of her training in Astrophysics. She receives an intelligent reply to her radio telescope message which has been broadcast repeatedly into space. The message warns her that there are evil entities in space that will hone in on her reply and then attack Earth. Accordingly, she should not under any circum-stances acknowledge the message she received. But because she is so bitter about life under present constraints, she does anyway, and now the planet is in mortal danger (though it will take several centuries for the invaders to arrive.)
Approaching doom? “3 Body Problem” Eiza Gonzalez. For editorial use only. Copyright of Netflix and/or the Photographer assigned by the Movie or Production Company. A Mandatory Credit to the movie company is required. Strictly for use for the promotion of the above film unless written authority gained via the movie company is obtained by the end-user.
Other co-stars include Vedette Lim, Jess Hong and various non-asian actors which were not in the book. This has led some to criticize the production for “race bending” or substituting Asian characters with characters of other races. Perhaps this was done just to make the plot easier for Western audiences to follow.
Even though it will take centuries for the enemy fleet of ships to arrive, somehow, using those extra dimensons that we can only hypothesize about, the aliens are able to contact and brainwash selected humans to do their bidding. This involves the murder of the best scientists on this planet and the distribution of virtual reality type headsets that explain the alien dilemma by presenting gaming scenarios in order to “hook” unsuspecting but talented Earthlings to work for their cause and help them with the transition and eventual invasion. Obviously, recalcitrant recruits are quickly done away with, often in bloody or brutal ways. In fact, the series carries many warnings such as gore, nudity, language, horror, violence and so forth. But whatever objectional material appears (at least in the first eight episodes) is brief and hardly gratuitous.
Already on several online platforms, reviews are literally stellar and it is very possible that a cult-like following will develop between now and when the second season is released. Many of the first seasons episodes were focused on human relationships, sci-fi concepts and gaming, so there is something for everyone. There are also new concepts introduced such as social and culture norms among alien civilizations.
The talent and type-casting is excellent and most of the jargon is explained so that anyone can understand it. The series is worth watching.
