Dyson spheres are believed to be megastructures built around a host star that uses energy from the star. Many people think this kind of advanced civilisation exists, and the search for these spheres began around the early 60’s.
Generally, when we observe an astronomical object like a star/galaxy, we get the light(Electro Magnetic Wave) from that object, which travels through space from the source object (star) to the primary lens of your telescope. We continuously monitor the amount of light received (flux) (The time series data of the received flux plotted over time is referred to as a light curve.) at different wavelengths, and we infer the physics from the data.
If a planet is orbiting a star, we should see the periodic dips in the star’s received flux. The interstellar medium plays an important role, but we were accurately able to detect the planets orbiting the stars (Transit Method). In the same way, we expect some abnormalities (like dips in the light curve) in the data if the Dyson sphere exists.
Several studies have been initiated searching for individual Dyson spheres in the optical and IR range, and no potential candidates have been found. Few have initiated searches for the partial Dyson spheres, which are in the process of building Dyson spheres.
Recent advancements in astronomy and technology have increased the number of telescopes(space and ground). A vast amount of data is collected from various missions like Gaia,2MASS, AllWISE, etc. With the latest data analysis techniques using neural networks and language models apart from traditional statistical analysis, the era paved the way to detect seven potential stars that could have a Dyson sphere.
The research proposed the following ideology: If a Dyson sphere exists, we expect optical dimming of the host star and waste-heat emission from the absorbing structure. That means the main starlight that is emitted will be obstructed by the Dyson sphere, so it gives a dip in the optical range, and the material the Dyson sphere is made of will emit the light in the Infrared Region due to which we must be able to see the excess flux in the infrared region.
This infrared excess can be caused if the host star is in a nebula environment or has a circumstellar disk. The researchers have carefully eliminated the risk of having a circumstellar disk by removing the sound stars where they mostly encounter a circumstellar disk, and they designed a neural network model to predict whether the star is in a nebula environment. This showcases the latest deployments in the Feld of ML/AL, which play a crucial role in the project.
This post is inspired by the recent publication ‘Project Hephaistos — II — Dyson sphere candidates from Gaia DR3, 2MASS, and WISE’ by Matías Suazo et al.
I am grateful to the authors and deeply interested in the research done. This post briefly gives the general audience an idea of the research conducted to find Extraterrestrial Intelligence by SETI.
Please refer to the paper for more scientific and accurate details https://arxiv.org/pdf/2405.02927.
Anumanchi Agastya Sai Ram Likhit