An invisible form of matter that does not emit light but exerts gravitational pull, holding galaxies together.
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
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 Introduction to Cosmology
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.
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 An invisible form of matter that does not
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
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 Conclusion Cosmology shifts our perspective from the local
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.