Dyson Spheres

Dyson spheres are hypothetical devices that would allow for large amounts of energy to be harnessed from a solar system's parent star, with minimal energy wastage. In today's world, the sun emits more energy in one hour than all of Earth uses in one entire year! This really puts into perspective the sheer potential the sun has. But why can't we use all of this energy? The sun splays energy in all directions, and in earth's orbit, we can only receive a certain amount of raw energy. Even from the energy we do receive, we cannot harness it with 100% efficiency as energy always dissipates when converting it into other forms. This stems from the first law of thermodynamics, which states that energy cannot be created nor destroyed, only transferred from one form to another. 

Fig. 1

In the far future, as civilization progresses and technology leads humankind into a new era, our energy consumption will increase by a ten-fold. To meet these energy demands, a Dyson sphere can be created to encompass the sun in a casing of sorts, which would cover each square meter of the sun and capture all of the energy it gives out. This energy would then be sent back to Earth, for our consumption and usage. In the present, a device like this cannot be built due to obvious engineering incapabilities, but perhaps in a few million years, a Dyson sphere may be the norm for interplanetary and intergalactic travel. 

Here is how a Dyson sphere would most probably be constructed if we were to develop one in the future:

many (relatively) small satellites would orbit the sun, making a semi-solid structure. It would not be something like a box entirely covering the sun, as that would result in various complications such as the box collapsing in on itself and falling into the sun. Thus, many satellites orbiting the sun would work best for all other factors considered. 

Constructing said satellite would be an engineering challenge, as the sun is very, very large. To completely surround the sun, we would need about 3x10^16 satellites of 1 square kilometer each. This would use a vast amount of resources currently not available to us on Earth. Next, actually constructing and putting these satellites into orbit around the sun would take up large amounts of work and energy, and infrastructure to help get the satellites to their destination as soon as possible. All of these limitations are based upon the fact that our civilization is not yet advanced enough, as the problem of resources and getting the satellites to the sun can only be confronted when space travel is a norm. For example, the resources needed to build these satellites would likely be found in other planets and terrestrial objects, and so we would need to find a way to mine these planets.

As you can probably tell by now, constructing a Dyson sphere is no easy task, but as humanity progresses and becomes increasingly intelligent, we can hope to see one in at least the next million years. On another note, in an interesting theory, some futurists believe that extremely intelligent alien life forms whos civilizations are millions of years ahead of ours may have already constructed these spheres, so if you happen to see one, run away as fast as you can.

Here's a great video explaining the concept - https://www.youtube.com/watch?v=pP44EPBMb8A