Let’s continue our survey of Messier objects. Check some basic info if you’re joining late here. This one’s a beauty:
The original reason for numbering cloudy objects in deep space was to eliminate them from consideration as comets. Once the 17th and 18th century astronomers had their list, whatever wasn’t on them would be the short-term comets in our own solar system.
The so-called Lagoon Nebula is numbered eight by Charles Messier. Over five thousand light years away, about one-sixth of the distance from the Earth to the galactic center. That puts it in the constellation of the archer, Sagittarius.
Astronomers speak of nebulas as clouds. They are literally that. But clouds like the ones we see in the home skies of Earth? A lot more than water vapor. Right (Credits: A. Caulet (ST-ECF, ESA) and NASA) is a central portion of the Lagoon. What are those colors? Filtered by the Hubble Telescope, hydrogen shows as green, oxygen as blue, and sulfur, a little bit of red.
Amazing, eh, that we can discern the chemical elements of the universe from impossibly far away. We also know M8 is a nursey for new stars. In some tens of thousands of years, this cloud will look a bit more like M7 or the other open clusters we’ve seen so far in this series.