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[rstormview]

I would appreciate expert opinion, could a near infinite cloud of hydrogen reach a flashpoint from its own gravity?

[CraigD]

Welcome to hypography, rstormview. :) Please feel free to start a topic in the introductions forum to tell us something about yourself.

 

... could a near infinite cloud of hydrogen reach a flashpoint from its own gravity?

I think you’re asking if a cloud of hydrogen can collapse due to its own gravity until its center becomes hot and dense enough to begin fusing hydrogen into helium.

 

This is, of course, how stars are theorized to form, in a process usually called something like “protostellar cloud collapse”. Astronomers have very high confidence that mainstream star formation theories are correct, because they’re able to observe so many different stages of the process in different moments and places. Also, as computers have become larger, faster, and cheaper, it’s increasingly possible to accurately model the behavior of large gas clouds, making it possible to test and refine these theories.

 

The main question is not whether clouds collapse to form stars, but what triggers them to collapse. Models show that, unless disturbed by outside influences, such as colliding with gas from another cloud, such as when galaxies pass through one another, or gas ejected from powerful events like supernovae.

 

The answer to the question then, is I think that a protostellar cloud could collapse purely due to its own gravity, but that this would take much longer than if it was triggered by external “triggers”, so most cloud collapses are caused by these triggers. The rarity of “untriggered” collapses may have been much different in the very early universe, when the first (population III) stars formed. At present, I think this is an open theoretical question. As better computers, computer models, and telescopes (such as the James Webb Space Telescope in 2018) are made, I expect more certain answers.