plus any exotic species of particles that may have existed,Īll packed into a tiny volume with enormous kinetic energies.whatever’s responsible for dark matter,.all the matter particles of the Standard Model,.It’s incredibly hot and dense, with some 10⁹⁰ particles, antiparticles, and quanta of radiation all possessing enormous energies billions of times what even the Large Hadron Collider at CERN can achieve.
When we think about the Universe in the earliest stages of the hot Big Bang, we’re imagining all the matter and radiation that we have today - currently spread out across a sphere some ~92 billion light-years in diameter - packed into a volume about the size of a soccer ball.
Our entire observable Universe was approximately the size of a soccer ball some 13.8 billion years ago, but has expanded to be ~46 billion light-years in radius today. Our Universe, from the hot Big Bang until the present day, underwent a huge amount of growth and evolution, and continues to do so. Moreover, “organized” isn’t quite a sound way to think about it, even though we use “disorder” as an offhand way to describe entropy. The Universe not only wasn’t maximally organized, but had quite a large entropy even in the earliest stages of the hot Big Bang. Does it mean at the moment of big bang the entropy was minimal (zero?), the universe was maximally organized?” “According to the second thermodynamic law the total entropy is always growing. But what if we go all the way back to the earliest times of all: to the very first moments of the Big Bang? If entropy has always increased, does that mean that the Big Bang’s entropy was zero? That’s what Vratislav Houdek wants to know, asking: If you look at the Universe today and compare it to the Universe at any earlier point in time, you’ll find that the entropy has always risen and continues to rise, with no exceptions, throughout all of our cosmic history. This is true not only of a closed system within our Universe, but of the entire Universe itself. One of the most inviolable laws in the Universe is the second law of thermodynamics: that in any physical system, where nothing is exchanged with the outside environment, entropy always increases. FEILD (STSCI)) Entropy always increases, but that doesn’t mean it was zero to start with. In fact, the entropy was finite and quite large, with the entropy density being even higher than it is today.
Entropy has always increased from any moment to the next, but that doesn’t mean that the Big Bang began with zero entropy. Looking back a variety of distances corresponds to a variety of times since the Big Bang.