4 ms·
It's pretty easy to forget that the sun is a ball of gas. It not very dense (roughly 1/4 the density of the earth). So it's extremely unlikely that a specific h
by bognition 5y ago
It's pretty easy to forget that the sun is a ball of gas. It not very dense (roughly 1/4 the density of the earth). So it's extremely unlikely that a specific hydrogen atom will undergo fusion during the lifetime of the sun. However the sun is also ENORMOUS. So in the aggregate there is a lot of fusion going on and a lot of energy is being produces. However its not super dense.
From wikipedia: https://en.wikipedia.org/wiki/Sun#cite_ref-power_production_density_84-0 https://en.wikipedia.org/wiki/Sun#cite_ref-power_production_...
The large power output of the Sun is mainly due to the huge size [...] Theoretical models of the Sun's interior indicate a maximum power density, or energy production, of approximately 276.5 watts per cubic metre at the center of the core,[77] which is about the same power density inside a compost pile
- CRConrad 5y agoSo it's low in terms of "amount of energy in relation to amount of hydrogen in the star"? But wouldn't much of the un-fused hydrogen be eligible to fuse at some later time, if for instance convection streams pull it down into the deeper (=higher-pressure) zones of the star? So it seems to me the relevant measurement ought to be the ratio of energy per hydrogen atoms fused, not hydrogen atoms total. (Certainly in a reactor, where presumably all or most of them should be.)
- ZeroGravitas 5y agoA song about the sun being a ball of gas, for those that find it hard to remember: The Sun Is A Mass Of Incandescent Gas https://g.co/kgs/g8rKyh https://g.co/kgs/g8rKyh A follow up song, correcting the incorrect physics of the first one: Why Does the Sun Really Shine? https://g.co/kgs/2QKBdw https://g.co/kgs/2QKBdw
- mannykannot 5y agoInside the sun's core, where the fusion occurs, the density is considerably higher - 150 g/cm3 vs. 5.5 g/cm3 (average) or 13 g/cm3 (inner core) for the earth.