Introduction To Cosmology -

One of the most surprising realizations in cosmology is that the atoms that make up stars, planets, and people account for only about 5% of the universe. The rest is composed of two mysterious substances:

Evidence for this theory is overwhelming, most notably the radiation. Discovered in 1964, the CMB is the "afterglow" of the Big Bang—faint radio signals coming from every direction in the sky, representing the moment the universe cooled enough for light to travel freely. 3. The Composition of the Cosmos

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. Introduction to Cosmology

The study of cosmology is our attempt to understand the universe as a single, physical entity. While early humans looked at the stars and created myths to explain the heavens, modern cosmology uses the rigorous tools of physics and mathematics to answer the "big questions": Where did we come from, how is the universe structured, and how will it end? 1. The Expanding Universe

Cosmology shifts our perspective from the local to the infinite. It reveals a universe that is dynamic, evolving, and largely invisible. While we have mapped the history of the cosmos back to its earliest seconds, the nature of dark energy and the exact mechanism of the Big Bang remain the great frontiers of modern science. One of the most surprising realizations in cosmology

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

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 The study of cosmology is our attempt to

A repulsive force that appears to be accelerating the expansion of the universe, pushing galaxies apart at an increasing rate. 4. The Fate of the Universe