How would look like a real nebula from inside ?

General physics and astronomy discussions not directly related to Celestia
Avatar
Topic author
Cham M
Posts: 4324
Joined: 14.01.2004
Age: 59
With us: 20 years 5 months
Location: Montreal

How would look like a real nebula from inside ?

Post #1by Cham » 04.03.2005, 19:52

I'm wondering how a real typical nebula would look like at VERY close range, or from the inside. How luminous should it be for the human eye ? How contrasted and colorfull should it be ? Astronomers out there, any idea ? T00fri ? Selden ? Evil Dr. Ganymede ?
"Well! I've often seen a cat without a grin", thought Alice; "but a grin without a cat! It's the most curious thing I ever saw in all my life!"

Avatar
selden
Developer
Posts: 10190
Joined: 04.09.2002
With us: 21 years 10 months
Location: NY, USA

Post #2by selden » 04.03.2005, 20:30

Sadly, the brightness of a nebula is the same no matter how close you are to it. Although the total light increases as you get closer, it's spread out over a larger area on the sky. The two effects exactly cancel one another :(
Selden

Avatar
Topic author
Cham M
Posts: 4324
Joined: 14.01.2004
Age: 59
With us: 20 years 5 months
Location: Montreal

Post #3by Cham » 04.03.2005, 21:05

So all those "artisitc" images we can find on the various NASA web sites, about exoplanets with nebulae as backround, are all BS ? Sad.
"Well! I've often seen a cat without a grin", thought Alice; "but a grin without a cat! It's the most curious thing I ever saw in all my life!"

Evil Dr Ganymede
Posts: 1386
Joined: 06.06.2003
With us: 21 years 1 month

Post #4by Evil Dr Ganymede » 04.03.2005, 21:30

selden wrote:Sadly, the brightness of a nebula is the same no matter how close you are to it. Although the total light increases as you get closer, it's spread out over a larger area on the sky. The two effects exactly cancel one another :(


How about if stars are illuminating it though? Wouldn't you get nebulosity visible aroun those regions?

Avatar
selden
Developer
Posts: 10190
Joined: 04.09.2002
With us: 21 years 10 months
Location: NY, USA

Post #5by selden » 05.03.2005, 00:30

Cham,

Think of such pictures as long exposures. Or "artists' impressions."

EDG,

The brightness (number of photons per second) per unit area will be unchanged. Remember that the reason stars don't burn (tiny) holes in our retinas like the sun does is that their images are blurred out over a much larger area than they "should be" because of diffraction and poor focusing.

Added slightly later:
With good seeing conditions, some nebulosities should be barely visible, just like the zodical light in our solar system can just barely be seen. It's a dust cloud with similar density.
Selden


Return to “Physics and Astronomy”