Home Page

The complete history of the Universe -- from the Big Bang to 200 my into the future

Loading

History of the Universe eBook. 398 pages, 300 illustrations only $2.99

Previous pageNext page

Stars

Molecular Clouds

As the gas and dust of the disc of a galaxy is squashed by the spiral arms, the gas condenses onto stardust grains to form molecular clouds, so-called because they contain molecules, which we explain later in this story. These are so dense that light cannot pass through them. They are the dark areas we see when we look at the Milky Way. When seen through a telescope they often reflect the light of nearby stars.

Image of M16 molecular cloud by NASA, ESA, STScI, J. Hester and P. Scowen (Arizona State University)

In the Galaxy we can identify many of the molecules which life uses: methane, ammonia, water and formaldehyde have been identified. Amino acids, purines, and pyrimidines are possibly out there too, all forming on dust grains and eventually getting frozen into comets. This means that the raw materials of life are common in the Universe. Is life common too?

Previous pageNext page


History of the Universe eBook. 398 pages, 300 illustrations only $2.99

eBook only $2.99
398 pages, 300 images

"I find the science fabulous...an extremely useful teaching tool."
Professor David Christian

Become a Citizen of the Universe

and get your free badge!