so if we were in a nebula?

[Manok101]

I have often wondered, if the solar system moved through a nebula of some kind, would we here on earth notice?

[lukebl]

Maybe we are already in one, but that it's so diffuse we can't see it? Perhaps subtle changes in the density contributes to variation in solar radiation and thus climate change.

[661-pete]

There are some who say, we are in a nebula already - M42 - or, to be more exact, the outer reaches of M42 of which Barnards Loop is a faint manifestation. The claim is that M42 actually extends thousands of light years out into space, far enough to envelop our Solar System. Of course it's not all very bright...

Things would be a lot different, it's said, if the Tarantula nebula NGC2070 in the LMC, or NGC604 in M33, were at the same distance from us as the heart of M42. They would shine bright enough to cast shadows and literally light up our night sky. Perhaps that's a better image of what 'living in a nebula' would be like...

[cantab]

I've wondered about this too. Nebulae look reasonably bright to us, but from inside, would that light just be too diffuse to really perceive much?

[lukebl]

.... Perhaps subtle changes in the density contributes to variation in solar radiation and thus climate change.

I would add that I've long believed that the biggest, and I mean BIGGEST, influence on climate change is variability in the solar radiation, and nothing that we humble humans do or don't do will influence climate change (which is undoubtedly happening, as it always has done throughout the earth's history) in any noticeable way. Not denying that we're wrecking the planet in other ways, though. But that's for another discussion.

....ducks and dives for cover.

[assasincz]

I reckon this is the issue - if we really are located within a nebula, it would be fairly difficult to notice visually.

If I am not mistaken, the density of nebular clouds often does not exceed more than dozens of atoms (hydrogen, helium or trace elements) per square meter. Simply said, it would be similar to standing in a thin mist - you notice it in the distance, but in immediate vicinity, there is hardly any evidence of it.

That said, however, when observing M13 globular in Hercules recently, I found myself carried away by thoughts on what would the night sky look like, should you be standing on a planet, orbiting a star within the centre of the globular cluster. I would look amazing, wouldn't it?

On a similar note, I recently wondered about how lonely and desperatly desolate would the cosmos seem from a planet, if it were catapulted by gravitational forces out from some galaxy, far away from any galactic cluster; sailing for billions of years through empty space, with absolutely nothing to be seen for millions and millions of lightyears away, not even any substantial amount of matter. Utter, freezing darkness, I reckon. You wouldn't even see the planet's surface, in fact. Frustrating, isn't it?

[Shibby]

I'm sure I read somewhere that the Solar System is near the centre of some sort of void in the gases of the Milky Way. I can't find this anywhere now, but I'll keep looking...

Edit: Here we go. We are within the "Local Bubble" http://en.wikipedia.org/wiki/Local_Bubble

[jimmyjamjoejoe]

Scientists Now Know: We're From Sagittarius Dwarf Galaxy!

Seems we're just passing through anyway

As for the nebula, who knows. It depends on our position within it and the density i guess, but i doubt it would affect the solar system too much due to the heliosphere. Would probably make the sky some pretty colours if it were dense enough though

[DavidOfBanff]

I reckon it's fortunate we're where we ar in so many ways.

For instance if the sky were much brighter, or emptier, the planets would not be so obviously odd in their movements, so Kepler and all those old genii would never have come up with the laws of motion, subsequently refined by Einstein, leading to all sorts of modern technology. Including this laptop probably.