Some celestial objects stand alone. Others pull us in with their complexities. Want to study astronomy without looking all over the night sky? Try the Summer Triangle. It is well up in the East throughout the next few months, moving slowly overhead as June and July give way. It is a science course unto itself.
The Milky Way serves as a mottled background to the three constellations—Lyra, Cygnus and Aquila—whose alpha stars—Vega, Deneb and Altair, respectively—provide the contours for our attention. Those three stars come in as the 5th, 12th and 19th brightest in the sky. Each has a story to tell.
Vega is just a kid. It formed about 450 million years ago. In contrast, Earth is approximately 4.5 billion years old. Scientists have had their eyes on Vega for many years, studying what may be a planetary system developing around it. Such a discovery could provide insight into how our fellow planets and asteroids came to be when the Sun was much younger.
While we await new data from that work, Vega serves as a way to locate its neighbor, the famous Ring Nebula. It is a fantastic sight at high magnification. Discovered in 1779 by Charles Messier, it is the remnant of a star that has shed its hydrogen, shrinking into an incredibly hot White Dwarf. Its radiation illuminates the immense gas cloud surrounding it.
Deneb is both the apex of the Northern Cross and the tail of the Swan. Depending on perspective, you can either follow the cross down to its base or head along the swan’s neck until you reach Albireo, a double star that is an unforgettable telescopic sight. Deneb is unimaginably large, estimated to be about 200 times the size of the Sun.
The third vertex of the Summer Triangle is Altair, an absolute speedster. Despite its size, comparable to the Sun, it takes just ten hours for it to rotate, causing it to distort and significantly flatten. Given Earth’s one-day rotation, we’re moving at about 1000 mph along the equator. Altair’s rapid spin equates to 650,000 mph. Talk about having the wind in your face!
Meanwhile, nearly midway between Vega and Altair is a group of stars, an asterism, called the Coat Hanger. Nothing binds the members of this sight, they just happen—from our vantage point—to look just like those things in our closets.
So, in this one section of the sky we have constellations, asterisms, a nebula, and three incredible stars, enough to keep astronomers endlessly busy. Most importantly, collectively, they tell us about ourselves, about how stars sometimes line up, how they live and die and how different, and sometimes quite alike, they are. They take us on a ride of discovery into the past and into the future.
The Summer Triangle has it all. You can admire it as a single entity, or break it down into its parts, intermingling and illuminating an array of wonders that have captivated stargazers for many centuries. It reminds me of the Grand Canyon in that it challenges you to understand so much of what is so hard to understand. It is a place, with just a glance, where I can let go, where I can stand in awe of the gift of such magnificence while, effortlessly, feel the mundane rapidly drift away.
Harold Meckler can be contacted at glusk@proton.me