What Is A Dyson Sphere?
A Dyson Sphere, also known as a Dyson shell, is a hypothetical megastructure that would be constructed by aliens with advanced intelligence and sophisticated technology in order to collect a significant amount or all of the energy emitted by their star.
An alien civilization that wishes to capture the energy of an entire star would use such a structure to do it. In our case, only a tiny fraction of the total energy emitted by the Sun reaches Earth. If we wanted to collect and use all of the sun’s energy, we would use a Dyson sphere to harvest the sun’s energy.
A Dyson Sphere is like a massive solar power plant erected in space around a star like the sun. It is a shell the size of Earth’s orbit around the sun.
The amounts of material required to construct such a shell is enormous and the technology super-advanced. The idea is quite farfetched for us.
How Did the Concept of a Dyson Sphere Come About?
The concept was proposed by Freeman J. Dyson, a brilliant physicist, in 1960. It started as a thought experiment.
Before this, the concept was the stuff of science fiction novels. In fact, Dyson Freeman admitted that his imagination was inspired by The Star Maker written in 1937 by Olaf Stapledon.
He visualized a gigantic solar power collection system the size of a solar system. He didn’t imagine it as a source of power that we could use on Earth. He imagined it as something super intelligent aliens living in other parts of our galaxy would create.
He suggested that we could search for aliens in our galaxy by looking for signs of such structures in the galaxy. So he offered as another way to search for aliens residing in other parts of our galaxy.
You can listen to Dyson speak about his ideas on Tedtalk here.
How Would A Real Dyson Sphere Look Like?
Dyson visualized an artificial hollow sphere of matter around a star. In his imagination, he saw a Dyson sphere that looked like a shell. According to SentientDevelopment.com, it would consist of a shell of orbiting solar collectors or habitats around the star of an advanced civilization where all or a significant amount of the energy of the star would hit a receiving surface where it can be used.
A real Dyson Sphere would be so massive that it would be the size of a planetary orbit. If we had one on Earth, it would be a giant artificial sphere whose radius would equal the distance from the Earth to the sun. This shell would surround our sun so sunlight would fall on it.
A supercivilization might build a giant sphere around a star that was so large that it had a radius equal to the distance from the Earth to the sun.
Why Would Aliens Construct a Dyson Sphere?
A Dyson Sphere is an aggregation of star orbiting solar collectors or space habitats. It would create a huge living space and gather enormous amounts of energy.
An advanced civilization would create such a structure to use all of the energy from its star, meet its rising energy needs or store it for future use in case their star’s energy were to be depleted.
As stars orbit the center of their galaxy, they pass through galactic potholes in form of clouds of gases and dust. These clouds can dim a star causing it to emit less energy. A civilization could create a Dyson shell as insurance in case of climate change.
Since a Dyson Sphere also has artificial living space, a civilization in search of an alternative habitat for the survival of their kind in case their planet were to end up in destruction or living space were to be limited due to overpopulation would create such a structure to act as an artificial habitat.
What Are Cosmologists Looking for In The Search for Dyson Spheres?
Scientists have been searching for aliens by listening for radio signals for years without getting any results. They welcomed this new SETI (Search for Extraterrestrial Civilizations) strategy fully.
Several groups of astronomers are currently looking for signs of Dyson spheres in our Milky Way galaxy. The search for these alien megastructures began this year (2013). So what exactly are they looking for and how will they know they have found it?
Everything that absorbs energy reradiates it ultimately. A system of solar power collectors around a star would alter the star’s light as seen from Earth. The collectors would absorb and reradiate energy from the star. It is the reradiated energy that astronomers are looking for.
For now, no one has ever seen a Dyson Sphere and we are not even sure they exist. This may change soon if the search yields positive results. If we find these massive structures, it will be a major step in finding out whether aliens exist.