The chemical interaction between the gas and dust in interstellar space can be quite complex. Given the low temperature and pressure of space, one might think that chemical reactions are simple and rare, but as I’ve written about before, the surface of dust grains can act as a kind of catalytic converter that allows complex chemistry to occur.
Yes, there is a giant cloud of alcohol in outer space. It’s in a region known as W3(OH), only about 6500 light years away. Unfortunately it is methyl alcohol (commonly known as wood alcohol, though this stuff is not derived from wood), so it isn’t suitable for drinking. There is some ethyl alcohol (the drinkable kind) there as well, but it’s not nearly as common.
Between the vast expanse of stars in our galaxy there is diffuse gas, dust and plasma known as the interstellar medium. It has been known for quite some time through its effects on radio waves and other light sources. But making a detailed map of this medium has been difficult.
Earth gets bombarded from space all the time. With all the micrometeorites, not to mention the occasional meteor or comet, almost 50 tons of material falls to Earth every day. Since all this material from space reaches Earth, you might think that interstellar material falls to our planet all the time. But it turns out that isn’t the case. The vast majority of material comes from within our solar system. Even cometary material comes from the Oort cloud at best, and that’s still on the outer edge of our solar system. There is plenty of interstellar gas and dust beyond our solar system, but even when some of it heads our way it tends to be pushed away from the inner solar system by the solar wind. So we haven’t had any samples of interstellar dust to study.
When light passes through gas and dust in the interstellar medium, some of the light is absorbed. Since the gas and dust only absorb certain wavelengths or colors of light, by by looking at these absorption bands we can determine the type of material that makes up the interstellar media. Well, most of the time. It turns out there are a range of absorption bands that we haven’t been able to identify. They are known as diffuse interstellar bands.
Usually in astronomy we study objects by the amount of light they emit. Most regular matter gives of light in some form or another. Even the cold interstellar medium will emit some light at infrared or radio wavelengths. But one downside of this is that the light generally comes from the surface regions of an object. To study the interior of an object we generally have to use aspects of emitted light from the surface to determine properties of the interior. For bright objects like stars this works pretty well, but for dim objects like dark interstellar clouds this is more of a challenge.
Stars form within large clouds of gas and dust known as stellar nurseries. Of course, when a star forms, that leaves less gas and dust to form other stars. So you can do a bit of simple math concerning star formation. Take the rate at which new stars form in a galaxy (and their typical mass), compare that to the amount of gas and dust a galaxy has, and you can estimate the time over which stars can form.