What is a interstellar cloud made of?

Answer 1

Since interstellar clouds are most often overdensities in the interstellar medium, they have overwhelmingly similar chemical compositions - most of them (about 90%) being hydrogen, although this may be molecular, or ionized (plasma), with most of the remainder being helium. Heavier elements and compounds have been discovered spectroscopically in interstellar clouds, including more recently some unexpected light organic molecules.

Answer 2

Most interstellar clouds are made up of various gasses. The most common ones seen spectroscopically in these clouds are Hydrogen, Helium, Methane, Cyanide, Ammonia and Nitrogen. The clouds also are made up of interstellar dust - in fact, we often would not be aware the clouds were there at all if we didn't see the light of the nearby star(s) reflecting off of that dust.

Answer 3

Interstellar clouds are composed mostly of gas, particularly hydrogen and helium, with small amounts of heavier elements like carbon, oxygen, and nitrogen. These clouds also contain dust particles made up of silicates, carbon compounds, and ice grains. The gas and dust in interstellar clouds provide the raw materials for forming stars and planetary systems.