As we search for signs of extraterrestrial life, a potential threat to detection looms: the catastrophic collapse of megastructures like Dyson spheres. Can we detect the remnants of these massive structures orbiting distant stars?
In 1960s, physicist Freeman Dyson proposed that advanced alien civilizations could build enormous megastructures around a star to harness its energy. These structures, known as Dyson spheres, would allow a civilization to advance from a Type I to a Type II civilization on the Kardashev scale by directly harnessing the energy available from a star.
A Dyson sphere is a hypothetical megastructure that completely encloses a star, capturing its electromagnetic radiation.
Proposed by physicist Freeman Dyson in the 1960s, these structures are thought to be built by advanced civilizations to harness energy from their stars.
There are three types of Dyson spheres: Shell, Swarm, and Bubble.
Each design has its own advantages and disadvantages, with Shell being the most efficient but also the most difficult to build.
The concept of Dyson spheres raises questions about the search for extraterrestrial intelligence (SETI) and the possibility of detecting signs of advanced civilizations.
Dyson spheres could be giving off distinct technosignatures, making them observable from many light-years away. However, scientists have suggested that having satellite-like objects swarming around a star all at once could result in a disastrous, cascading effect in the case of a collision. As Brian Lacki, a scientist involved with the Breakthrough Listen Initiative, noted, ‘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?‘
This risk is already playing out in our own solar system. Scientists have warned that satellites circling the Earth could collide with each other or with space junk, potentially triggering a knock-on effect known as Kessler syndrome. Experts believe it’s only a matter of time until a collision could trigger a catastrophe.
Kessler syndrome is a hypothetical scenario where the accumulation of space debris in Earth's orbit leads to an exponential increase in collisions, resulting in a catastrophic cascade.
This phenomenon was first proposed by Donald Kessler in 1978.
The main concern is that once a significant amount of debris is present, it becomes increasingly difficult and expensive to launch new satellites due to the risk of collision.
According to NASA, there are over 500,000 pieces of debris larger than a marble in Earth's orbit, with many more smaller particles.
If left unchecked, Kessler syndrome could render space exploration and satellite deployment impractical.
To avoid this risk, aliens would need to be extremely careful in managing the orbits of their satellite-like objects. As Penn State astrophysics professor Jason Wright noted, ‘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.‘
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.
Researchers have previously found that building a Dyson sphere around our host star would require demolishing a Jupiter-sized planet, an enormous and likely risky endeavor. The feasibility of such a project remains uncertain, adding to the mystery surrounding these megastructures.
Despite the challenges, the idea of Dyson spheres remains a topic of interest in the search for extraterrestrial civilizations. As we continue to explore the universe, we may yet uncover evidence of these megastructures, or perhaps even their remnants, which could provide us with valuable insights into the presence and capabilities of alien life.
