How do cosmologists and astronomers know that stars are hydrogen molecules fusing into helium? Have they literally detected the nuclear fusion within stars taking place, or is this simply a theory? Thanks.
so it's just a theory? good to know.
QUOTE (graciassenor+May 12 2008, 10:53 PM)
How do cosmologists and astronomers know that stars are hydrogen molecules fusing into helium? Have they literally detected the nuclear fusion within stars taking place, or is this simply a theory? Thanks.
OK, I'll risk it....
It is a theory (not "just" a theory, I hate that usage of the term, implying that the poster does not know the difference between a theory and a hypothesis), a theory supported by an astounding amount of observation, and predictive of more astounding amounts of observations...
By the way, hydrogen fusion is a mechanism fueling main-sequence stars only, in later stages of the star's life heavier elements will be fused, up to and including iron, which eventually results in a supernova in stars massive enough, again, in conformance with theoretical predictions.
OK, I'll risk it....
It is a theory (not "just" a theory, I hate that usage of the term, implying that the poster does not know the difference between a theory and a hypothesis), a theory supported by an astounding amount of observation, and predictive of more astounding amounts of observations...
By the way, hydrogen fusion is a mechanism fueling main-sequence stars only, in later stages of the star's life heavier elements will be fused, up to and including iron, which eventually results in a supernova in stars massive enough, again, in conformance with theoretical predictions.
QUOTE
graciassenor Posted on May 13 2008, 08:53 AM How do cosmologists and astronomers know that stars are hydrogen molecules fusing into helium? Have they literally detected the nuclear fusion within stars taking place, or is this simply a theory? Thanks.
short answer: the first step of the proton-proton chain reaction produces neutrinos. neutrinos have been detected coming from the sun.
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