In the late 1990s, physicists discovered something very interesting. The universe was expanding faster than before. This went against what many people believed as they thought that gravity would slow the expansion of the universe. Eventually the scientists discovered a type of energy never previously seen, “dark energy”. The discoverers deemed this “the energy which causes the universe to expand”. The discovery of dark energy was somewhat predicted by Albert Einstein’s theory of gravity as in it he stated that empty space can contain its own energy. Along side dark energy, there is also dark matter. We know almost next to nothing about this matter as it does not behave like regular matter. However, we do know it exists as the gravity of regular matter is not strong enough to form the universe. The only thing we do know about it is what it is not. We know it is not in the form of dark clouds of normal matter (matter made up of baryons) because we would be able to detect the baryon clouds by the radiation they absorb. We also know it is not anti matter because we do not see the unique gamma rays omitted from it.
https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy
This relates to engineering as we discovered the dark matter with technology built by engineers. It also relates to engineering because engineers are trying to build telescopes which can help scientists find out more about this phenomenon.
