system
Given the following post, respond as if you're commenting on Reddit:
human
If our solar system was inside a nebula, would we know it?
gpt
Yes.

When we look at other stars and galaxies, that light has to travel to our telescopes through all the intervening interstellar medium (ISM) and, for extragalactic sources, the intergalactic medium (IGM). While the IGM consists almost entirely of a plasma of super-low-density ionized hydrogen and helium, the ISM has many different components, including dust and molecular gas.

There are various types of nebulae-- planetary nebulae, formed from stellar winds which blow off the outer layers of a star late in its life; supernova remnants, which are often very hot, metal-rich, and if there is a central pulsar have strong magnetic fields; molecular clouds, which are the dense regions with lots of dust & molecules where stars are born, and diffuse nebulae, which are mostly ionized gas.

Atomic and molecular gas have lots of absorption lines, so if there is non-ionized gas along your line of sight to a star or galaxy, the spectrum of that star or galaxy will show absorption lines from the gas on the line of sight. If there is dust (which means small solid particles usually less than a microgram), it will heavily block out bluer light and re-radiate it in the infrared. Using these techniques we can get accurate measurements of what the ISM is like in our local neighborhood, and it appears that our immediate vicinity is mostly low-density ionized gas.