dark matter, a component of the universe whose presence is discerned from its gravitational attraction rather than its luminosity. Dark matter makes up 30.1 percent of the matter-energy composition of the universe; the rest is dark energy (69.4 percent) and “ordinary” visible matter (0.5 percent).

Dark matter is entirely invisible, emitting no light or energy, making it undetectable by conventional sensors and detectors.

Dark Energy is a mysterious force constituting approximately 68-70% of the universe that drives the accelerating expansion of space. Unlike gravity, which pulls matter together, dark energy acts as a repulsive, uniform, and persistent influence that stretches the fabric of the cosmos. It is distinct from dark matter and remains one of the greatest unsolved mysteries in physics.

What is matter? It’s not as basic as you’d think. Matter makes up nearly a third of the universe, but is still shrouded in secrets.

The reason it is so hard to define is because it’s an abstract notion. In physics, the concept of “energy” is really just a kind of shorthand, a tool to help balance the books. It is always conserved (or converted into mass) so is incredibly useful in working out the results of any kind of physical or chemical process. There is no physical “essence” of energy, and no such thing as “pure energy”. It is always carried by something, usually in the form of movement.

The Universe is all of space including everything that exists. Our planet, all other planets in existence, stars, and galaxies are all part of the universe. It was born more than thirteen billion years ago in the Big Bang. Scientists say that it is at least ten billion light-years in diameter. In this sense, the Universe means the Cosmos. The Universe is all time and space, i.e., spacetime. It includes all the galaxies, stars, planets, moons, and all other forms of energy and matter.

Science is the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.