Why is star formation slowing?

“FAST and DESI reshape our view of cosmic evolution. Credit: National Astronomical Observatories of China and Shanghai Astronomical Observatory of CAS” (ScitechDaily, The Universe Has Plenty of Fuel. So Why Is It Making Fewer Stars?)

Why is star formation slowing? All the time? The entropy in the universe grows. This causes the situation. The atomic hydrogen starts to move faster. The size of the universe expands. That causes its temperature to drop. When the universe expands, the distance between objects grows. That means more space between hydrogen atoms. Radiation has a stronger effect on those atoms. 

Because. There is no resistance to that movement. 

Star formation requires a mass center. That gravitational center collects gas atoms around it. The gravitational center starts to pile gas faster and faster. And then, after billions of years, the star ignites. Its fusion starts. Another way to make this effect is to create an electron or proton beam. That travels through an interplanetary or interstellar nebula. That forms a so-called cold quantum point in that nebula. And that starts to pile matter into that point. 

When difference. Between temperatures in the universe decreases. Those cold points will not collect matter like they did in the past. If. The temperature in the interplanetary or interstellar nebula. It. Is only. A couple of degrees higher than the energy minimum. If that cold point starts to pile the matter in one point.

The temperature. Or energy level at that point must be so much lower. That. It causes the particle flow and impact at that point. This forms a gravity center that pulls the nebula into that point. 

Lower-energy points act like low-pressure points. They collect matter around them. 

The particle or radiation beam. Bakes the low-pressure points in the electromagnetic field. When the universe expands, matter becomes thinner. This means that particle beams travel through the nebula. Its effect is weaker. Than. It is in dense nebulae. When. The density of matter decreases. That means. The interaction between particles turns weaker. 

When the universe expands, interplanetary or interstellar nebulae turn larger. But they lose their density.  Nebulae's internal gravitational effect becomes weaker. 

“About 4.5 billion years ago, the Universe was forming stars at roughly 2.5 times the rate seen today. During the same period, however, the density of neutral atomic hydrogen was only about 1.4 times greater than its current level.” (ScitechDaily, The Universe Has Plenty of Fuel. So Why Is It Making Fewer Stars?)

There are two densities. The homogeneous hydrogen nebula cannot form stars. There is a possibility. That, in some cases. Internal gravity pulls the entire nebula together. And that can form a black hole. Star formation happens around the gravitational center. 

Global density and local density. Star formation happens in nebulas. And nebulas are local density. When reseachers wonder why star formation decreased 2,5 times. But. The universe's density decreased only 1,4 times. They should keep focus on local density. 

If. Interplanetary or interstellar nebulae turn thin. That decreases their internal gravity effect. And that slows star formation. Another thing is. In. Thin nebulae. Stars turn smaller. Their radiation pressure breaks the nebula. When.  The nebula’s internal gravitation is weak. The. Star can destroy the entire nebula. 

If. We compare that to the young universe. In the young universe, the energy minimum was higher. That made energy travel more slowly away from galaxies. Today, the energy minimum is lower. And energy travels faster away from galaxies. And that forms whirls and increases entropy. Energy that travels away from a galaxy. Causes the situation. That galaxy is colder. And the energy flow. That source is in the center of the galaxy. Pushes those hydrogen atoms away from each other. This means that the interplanetary nebulae were denser in the young universe. 

https://scitechdaily.com/the-universe-has-plenty-of-fuel-so-why-is-it-making-fewer-stars/