“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.” – Carl Sagan, Cosmos.
In the warm summer night of the north hemisphere, under the cover of thousands of stars that twinkle restless from sunset to dawn, you can look up to the sky to discover a new world (or maybe a million of them). In a not-so-little place between Sagittarius and Scorpio the Milky Way can be found. That cloudy strip of sky is the combination of many of the stars that make our galaxy, the neighborhood we live in. In that place, many different celestial objects can be seen: a few of them with the bare eyes, many more with the aid of technology. Telescopes, binoculars… even a camera, with its ability to capture, accumulate, and condense light into a thin layer of paper or semiconductor plastic can show many more objects that share our sky that we could imagine. Galaxies, nebulae, star clusters, luminescent gas clouds… all of them, millions of kilometers away from us, shining in the sky with the light that they used to be. Some of those objects threw their light in our direction much before we were even born, and the light has traveled for years until one night, that few photons that managed to finish their journey, collided with our eyes or camera showing us a little part of the mystery of the universe.
In today’s picture, we can see that strip of sky I talked about. Sadly, the reflected light of near towns and cities is enough to avoid capturing the Milky Way (the orange glow in the bottom are the lights of a city 13 km. away from the camera position, with a few hills in between). But that doesn’t mean that many brilliant objects can’t be seen. In the image below some interesting points are marked:
1- Sagittarius, the archer. Located near the Milky Way, is one of the most interesting places to start looking for exotic objects in the sky. This constellation is located in the ecliptic, which means that the sun crosses it along the year. In the ancient times (it’s not true anymore), if you were born while the Sun was in this constellation, you were given this sign in your horoscope, unless…
2- …the Sun was around here, in which case you were given the Scorpio sign. In this constellation is located Antares, a star so bright and red that it was considered the rival of Mars (Mars, in Greek mythology, was named Ares, so Antares comes from anti-Ares).
3- M22, an elliptical globular star cluster (in the sky, stars that we see close together can be very far apart between them, and is only our perspective what make them appear close. In a cluster, they really are physically close). It is one of the brightest clusters that can be seen with the naked eye. It is 12 thousands million years old and has at least 70,000 stars, although we can only see a few of them with our eyes. It is known to have a planetary nebula, which means that, perhaps, tiny little green humanoids could be walking there right now… or not.
4- M21, an open cluster of stars. It is only 1.4 million years old and has “only” 57 stars.
5- M7, an open cluster of stars known as the Ptolemy Cluster. It is 200 million years old and has 80 stars. Its composition is similar to the one in our Sun.
6- M6, the Butterfly Cluster. Seen with enough zoom resembles a butterfly. Although close to M7 in the sky they are really 800 light-years apart. This makes them independent clusters. But the stars that form both clusters are related, as all of them come from the same cloud of gas. This makes them gravitationally bound together and both travel in the same direction along the universe.
So… If you have a camera, and you have enough time, why not going out one night to see how our neighbors are? Just forget behind our brilliant moon and our shiny cities and adventure into the darkness of the countryside. Walk a few kilometers away and look up. Any camera can capture enough dim objects to amaze you for hours. A tripod is a must, and good company is also recommended. Just point upwards, increase your ISO over 800 and acquire light for a few seconds. And enjoy, of course.
Could you imagine a better way to spend a summer night?