I have a plethora of questions regarding thermodynamics and all of them came to my mind while I was thinking about how the greenhouse effect actually works. (hence the title)
The sun emits radiation, which after 8 minutes hits the surfaces on planet earth. Here this radiation is reflected OR absorbed and turned into thermal energy.
Now from my understanding, thermal energy is kinetic energy on the particle level. For this form of energy to be transferred or absorbed, the particles would have to hit less energetic particles and thus energize them, which then would make them “warm” right?
Assuming that my explanation is mostly correct, why does space around us not heat up? By that logic, the particles in an imperfect vacuum would have to be highly energetic because of constant unshielded exposure to the light of millions of stars.
Would that also mean that sunlight consists of extremely fast particles that energize surfaces when they hit them? (If not, how does sunlight energize particles.
Why exactly does the thermal energy not just escape into space? Earth seems to be more energetic than space around us. Normally two asymmetric thermodynamic systems would balance out.
Sorry if I’m way off. I’m merely an ignorant student.
In: Physics
Much of the thermal energy does indeed still radiate out into space. However, photons that would otherwise be headed towards space may instead be absorbed by greenhouse molecules which then re-radiate the energy in a random direction. Sometimes this direction is space, but sometimes it’s back towards Earth.
Also, the systems don’t balance out the way you propose as even though space is very cold, there’s nearly no matter for conduction or convection to draw heat away from the planet. Thus heat loss is via radiation. But when you have something hindering the radiation of heat into space, the result is that the planet increases in temperature.
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