Sharma | Spring 24 1
BYRNE SEMINAR SPRING 2024 | WHAT IS THE UNIVERSE?
The universe, as understood by physics, is the entirety of space, time, matter, and energy,
encompassing all known forms of existence, from the smallest particles to the largest galaxies
and everything in between. Physics seeks to understand the fundamental laws and principles
that govern the behaviour and evolution of the universe.
At its core, the universe is governed by the four fundamental forces: gravity, electromagnetism,
the weak nuclear force, and the strong nuclear force. These forces dictate the interactions
between particles and the behaviour of matter and energy on both the cosmic and quantum
scales.
One of the most fundamental concepts in physics is the theory of general relativity, proposed by
Albert Einstein in the early 20th century. General relativity describes how matter and energy
curve the fabric of spacetime, giving rise to the force of gravity. According to this theory, massive
objects like stars and galaxies warp spacetime, causing smaller objects to move along curved
paths in their vicinity.
On the other hand, quantum mechanics, developed in the early 20th century, describes the
behaviour of matter and energy at the smallest scales, such as atoms and subatomic particles.
Quantum mechanics introduces concepts such as wave-particle duality, uncertainty principle,
and quantum entanglement, challenging our intuitive understanding of reality.
The universe began around 13.8 billion years ago in an event known as the Big Bang. At this
moment, the universe was incredibly hot and dense, and it has been expanding and cooling
ever since. The Big Bang theory is supported by a wealth of observational evidence, including
