I'm interested in what forces collectively act upon a body in space (obviously radially, so they usually cancel) due to pressures caused by emitted radiation (of any type, strength, "size"). Can you give me a good book to read or paint a better picture for my understanding. Or help me clarify this question further. I would include static electric as well as magnetic fields (is this "radiation"?).


All objects in space emit a spectrum of electromagnetic radiation which closely approximates a black body spectrum that depends on their temperature. In addition, space is filled with electromagnetic radiation (also approximating a black body spectrum) corresponding to a temperature of about 2.7 degrees K, which approaches a true blackbody spectrum to a few parts in 10,000. This means most bodies in space will be absorbing and re-emitting that background radiation and will be striving towards thermal equilibrium with it.

Very hot objects like stars will radiate a spectrum corresponding to temperatures of between a few thousand degrees K and tens of thousands of degrees K and because of their size, the amount of power they emit is very large. That radiation will significantly warm objects nearby.

Because objects in space are nearly always electrically neutral, electrostatic forces will tend to cancel out.

If an object is electrically conductive and is moving through the magnetic field of another nearby object, both current flow and a magnetic field will be induced in it, and that induced field will affect the movement of any charged particles nearby. Since stars usually have large magnetic fields and emit streams of energetic and charged particles, a planet nearby (like Earth) will feel those effects.

The details of all these processes are taught in astrophysics classes on the university level and fill whole volumes of books, which means that this forum is not really the right place to get tutored on this topic.

  • $\begingroup$ The CMB background is at 2.7K. Blackbody radiation is a conceptual ideal. Nothing emits blackbody radiation because nothing is in perfect thermal equilibrium and absorbing all light incident upon it. In particular almost nothing in space is anywhere near a thermal equilibrium with the cosmic background radiation. $\endgroup$ – Rob Jeffries Jul 26 at 4:45
  • $\begingroup$ will edit this now. $\endgroup$ – niels nielsen Jul 26 at 5:15
  • $\begingroup$ will also post a question myself about it. $\endgroup$ – niels nielsen Jul 26 at 5:22

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