Entropy did not go down when the universe expanded, even though gravity did clump stuff together. To understand the entropy of a system, you have to look at everything that happened-- when galaxies and stars form, they do so by sending a significant amount of energy outward into the reaches of space, often in the form of light. That energy experiences large regions where it can enter into a great many number of states, even though the material left behind gets access to fewer states. So the net is more states, not fewer-- entropy increases.nard said:How can we explain the formation of a more ordered universe from a more ordered condensed structure that exploded and evolved to what the universe is right now?
There are entropic models of where gravity (and spacetime itself) comes from, they are kind of new and I don't know how well fleshed-out they are. But you are right that the expansion of the universe is crucial-- creating all that extra space is what provides the potential for more states, so that's what allows the ordered structures to form even when the universe at large is obeying the cosmological principle. The key point is, there is no rule that says the number of possible states cannot increase, the rule simply says that the universe will find ways to access the new possibilities for more states as they appear. If you don't notice that is happening, you might think order is increasing when in fact the universe becomes more disordered as it accesses this larger number of possible states.Where did the gravity come from and what is it's effect in the maintenance of a more ordered universe?
The Big Bang theory is the prevailing scientific explanation for the beginning of the universe. It states that the universe began as a singularity, a point of infinite density and temperature, approximately 13.8 billion years ago. This singularity then expanded rapidly, creating space, time, and all matter in the universe.
Scientists use various methods and tools to study the beginning of time, including observations of the cosmic microwave background radiation, which is leftover heat from the Big Bang, and experiments with particle accelerators to recreate conditions similar to the early universe. They also use mathematical models and theories, such as general relativity and quantum mechanics, to understand the fundamental laws of the universe.
Since we cannot observe the exact moment of the Big Bang, it is impossible to know for certain what happened at the beginning of time. However, through scientific research and theories, we can gain a better understanding of the early universe and make predictions about its evolution.
Dark matter and dark energy are two mysterious components that make up the majority of the universe. While we do not fully understand their nature, scientists believe that they played a significant role in the beginning of time by influencing the expansion of the universe and the formation of galaxies and other structures.
While the Big Bang theory is the most widely accepted explanation for the beginning of the universe, there are other theories that propose alternative ideas. Some of these include the steady-state theory, which suggests that the universe has always existed and is continuously expanding and forming new matter, and the oscillating universe theory, which proposes that the universe goes through cycles of expansion and contraction.