In 1929 Edwin Hubble made the assumption that space could be expanding in some way, because in distant planets the light began to shift . Even before that Albert Einstein discovered something called the cosmological constant.He considered the constant a source for Vacuum energy. This source turned out to be something called Dark Energy & Matter.Dark energy is a complicated concept to learn, as there isn’t really a clear answer to where it came from. Dark energy is very important to outer space, as it takes up most of space. Cosmological Constant is the expansion of space, it is a product of dark energy. The expansion of the universe is a dynamic field of dark energy that create some type of static that alters the force of gravity. As much as the size Dark Energy is also responsible for the shape of the universe. Dark energy is one of the biggest wonders in the physics world. Physicist just can’t quite pinpoint the what it exactly is. But they have a very faint understanding of the concept. Dark energy causes the acceleration of cosmic forces. It basically makes space expand making it larger in size. Dark energy is a property of space that grows by itself causing the expansion of the space. It was predicted that when acceleration of the expansion of space gets faster it soon collapse on itself due to the force of gravity.We live in the visible also the tiniest part of the universe Dark energy and matter take up most of the universe.Dark energy makes up 68% of outer space, while dark matter makes up 27% , and the visible parts of space ( stars, planets, moon) make up about 5%. Dark energy is invisible explaining why you can’t see the rest of the universe. The only way we can see dark energy is if there is a vast quantity surrounding something, it bends the light around it make itself vaguely noticeable. As the universe expands the wavelength of light stretches. Dark energy is a very mysterious wonder of space , maybe we’ll never find the source.