New stars keep forming in the universe thanks to all the nebulae. Now, we need Hydrogen to form stars and there would a time when all the hydrogen will get exhausted, and no more star formation will ...
There's plenty of data about the density of nebulae, and obviously they're pretty thin. This is space, after all, and these things are really, really big. But I'm wondering about the practical ...
How many of the luminous dots that we see naked are galaxies and not stars from our galaxy? I immagine that the majority of the luminous points that we see naked eye during the night, are actually ...
Why do some nebulae look like the billowing clouds? Wouldn't that require something like a viscosity in empty space?