Redshift What is Redshift?Astronomers can learn about the motion of objects by looking at the way their color changes over time, or is different from the expected.
Create a Hubble Tuning Fork diagram Galaxies are huge collections of stars, gas and dust held together by gravity. Our Galaxy, the Milky Way, is known as a spiral galaxy as it has spiral arms that wind their way around the center of the galaxy (or bulge). The first galaxies were identiļ¬ed as far back as the 17th Century by Charles Messier. Messier compiled a list of 110 star clusters and spiral nebulae which he discovered while searching the sky for comets. It wasn't until the early 20th century however that these nebulae were in fact spiral galaxies.
