Introduction To Cosmology -

An invisible form of matter that does not emit light but exerts gravitational pull, holding galaxies together.

The foundation of modern cosmology was laid in the early 20th century. Before this, most scientists—including Albert Einstein—assumed the universe was static and eternal. However, in 1929, Edwin Hubble observed that distant galaxies are moving away from us. More importantly, the further away a galaxy is, the faster it recedes. This discovery of proved that the universe is expanding, implying it must have had a beginning. 2. The Big Bang Theory Introduction to Cosmology

If the universe is expanding today, it must have been smaller and denser in the past. The suggests that approximately 13.8 billion years ago, the entire observable universe was concentrated in a state of infinite density and heat called a singularity. An invisible form of matter that does not

The ultimate fate of the cosmos depends on the battle between gravity and dark energy. Current data suggests we live in a "flat" universe dominated by dark energy, leading to a scenario known as the In this future, galaxies will move so far apart they become invisible to one other, stars will run out of fuel, and the universe will eventually become a cold, dark, and empty void. Conclusion However, in 1929, Edwin Hubble observed that distant