In astronomy, the interstellar medium (or ISM) is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field.
I’ve recently fallen in love with time lapse videos of the sky, and posted a few lovely ones. We’re setting the bar even higher now, with this brilliant work from photographer Terje Sorgjerd. What happens here is truly magical: a Saharan windstorm invades the sky and throws it into chaos, while the Milky Way is [...]