Articles about "Universal Expansion"
Table of Contents
Universal expansion refers to the idea that the universe is continuously growing over time. This concept suggests that all galaxies and cosmic structures are moving away from each other, which is observed through the redshift of light from distant objects.
Key Concepts
The Big Bang
The universe began as a small, hot point about 13.8 billion years ago in an event called the Big Bang. From that moment, it started expanding, and this expansion has not stopped.
Bouncing Universe
Some theories propose that instead of starting with a Big Bang, the universe could have experienced a "bounce." This means it could have contracted to a certain point before expanding again. This idea helps avoid certain problems, like singularities, which are points where normal laws of physics break down.
Modified Gravity Theories
Scientists have different theories about how gravity works, especially when considering the universe's expansion. Modified gravity theories aim to explain behavior that standard gravity cannot, particularly under extreme conditions. Some of these theories suggest that the universe doesn't always have to face problems related to singularities and can have more stable expansion patterns.
Thermal Equilibrium
In some scenarios, it is important for the universe to maintain a sort of balance, or thermal equilibrium, where temperatures remain constant. This stability helps ensure that the universe can continue expanding without sudden changes.
Conclusion
Universal expansion is a central idea in cosmology, helping us understand how the universe has changed over time and the forces that drive its growth. Different theories about gravity and the universe's beginning provide various insights into what this expansion means for the future.