Latest news with #FreemanDyson
Yahoo
17-05-2025
- Science
- Yahoo
What Are Alien Dyson Spheres, Why Are They So Janky, and Why Are They Doomed to Go Undetected?
In the 1960s, physicist Freeman Dyson proposed that advanced alien civilizations could be building enormous megastructures around a star to harness its energy. Such a move would allow a civilization to advance from a Type I to a Type II civilization on the Kardashev scale, harvesting the energy available from a star directly instead of from a given planet's surface. These shells, dubbed Dyson spheres, could be giving off distinct technosignatures, astronomers have suggested, making them observable, potentially, from many light-years away. But despite our best efforts, we have yet to make first contact, let alone with an alien-built megastructure siphoning off the energy released by a star. And, as New Scientist reports, there could be a good reason for that. According to Brian Lacki, a scientist involved with the Breakthrough Listen Initiative — which searches for evidence of extraterrestrial civilizations — Dyson spheres may destroy themselves long before we can encounter one. In a yet-to-be-peer-reviewed paper, Lacki proposed that having satellite-like objects swarming a star all at once could result in a disastrous, cascading effect in the case of a collision. "When you have a whole bunch of things moving together like that in a swarm, a natural question is going to be, do they sometimes bump into each other?" Lacki told New Scientist. "At their orbital speeds, that can be disastrous." In many ways, the risk of that kind of scenario is already playing out in the orbit of our own planet. Scientists have long warned that satellites circling the Earth could collide with each other or with one of the countless pieces of space junk, potentially triggering a knock-on effect, called Kessler syndrome. Experts have warned that it's only a matter of time until a collision could trigger a catastrophe. According to Lacki, aliens would have to tread very carefully to ensure that satellites aren't crossing each other's paths. "You just can't have that much material around a star without it colliding with itself and eventually shredding itself to pieces, unless each of those swarm components is careful about managing its orbit," Penn State astrophysics professor Jason Wright, who was not involved in the research, told New Scientist. Lacki's conclusion leaves an intriguing possibility: we may still be able to detect the signatures of already collapsed megastructures orbiting distant stars. However, without that visible technosignature, they would be incredibly difficult to spot. As far as harnessing the power of the Sun is concerned, researchers have previously found that we would need to demolish a Jupiter-sized planet to build a Dyson sphere around our host star, an enormous — and likely risky — endeavor. More on Dyson spheres: Scientists Identify Seven Star Systems That May Be Hosting Alien Megastructures
Yahoo
13-04-2025
- Science
- Yahoo
Alien Dyson spheres could really exist — but only in this 1 type of star system, new study hints
When you buy through links on our articles, Future and its syndication partners may earn a commission. Dyson spheres, the hypothetical mega-structures that advanced alien civilizations might use to enclose a star and harness its energy, suffer from a fatal flaw: They are catastrophically unstable. But now an engineer claims to have figured out a way to stabilize these structures — and all it takes is two stars. In the 1960s, physicist and polymath Freeman Dyson cooked up the idea of these eponymous spheres. He envisioned that a sufficiently advanced society would have an insatiable need for living space and energy. And if they were industrious enough, they could solve both challenges by taking apart a planet and turning it into an enormous spherical shell. This sphere would enclose a star, providing billions of planets' worth of surface area and capturing vast amounts of solar energy. Dyson calculated that a shell made from a planet with the mass of Jupiter could completely enclose the sun at roughly the orbit of Earth. But the gravity inside a hollow shell cancels out, which means there's nothing tethering the shell to the star. They are free to move in independent directions, which means that soon enough a star hosting a Dyson sphere will simply crash into the shell, destroying it. In a paper published Jan. 29 in the journal Monthly Notices of the Royal Astronomical Society, Colin McInnes, an engineer at the University of Glasgow, found a way to theoretically stabilize a Dyson sphere. The trick is that you need a system with at least two stars. McInnes started by searching for any points within a binary star system that could host a stable Dyson sphere arrangement, where the sphere could stay in place and the gravitational forces exerted on it would be uniform. He found one arrangement, where the sphere surrounds both stars. But that situation was only mildly stable and likely to suffer the same problem as the single-star case. Another stable point arises when the sphere orbits independently, surrounding neither star. While this might be useful for space station outposts, it doesn't provide the energy-capturing benefits of englobing a star. Related: 'Perhaps it's only a matter of time': Intelligent life may be much more likely than first thought, new model suggests But McInnes did find one stable — and useful — configuration. This only happens in binary systems in which one star is much smaller than the other. In that specific case, the Dyson sphere can enclose the smaller of the two stars. The motion of that smaller star acts like a gravitational anchor, keeping the Dyson sphere in motion with the same orbit around the larger star, preventing a catastrophic collision. There are several caveats to this. The smaller star has to be no bigger than around one tenth the mass of the larger companion, otherwise the gravitational stable point disappears. And the sphere has to be extremely light and thin compared with the two stars, otherwise its own gravitational influence mixes into the dynamics of the system and destroys the stability. RELATED STORIES —Alien 'Dyson sphere' megastructures could surround at least 7 stars in our galaxy, new studies suggest —First contact with aliens could easily end in genocide, scholars warn —12 strange reasons humans haven't found alien life yet And, of course, this analysis ignores any practical engineering considerations, like the stresses and tensions the sphere might experience, or how to build the thing in the first place. While it's unlikely humans will build a Dyson sphere in the distant future — if ever — this research does help inform searches for extraterrestrial civilizations. Presumably, a sufficiently advanced civilization would have made the same realization before building its own Dyson sphere, and so we shouldn't look for them around solitary stars. Instead, scientists could look for large, bright stars with a diffuse, infrared companion — the telltale sign of the heat leaking out of a Dyson sphere enclosing the smaller star of a larger companion.
