FirstLight Astronomy Club

33°29.6'N / 117°06.8'W / 1190 ft.

The Swan

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It is a joint venture of ours here to understand the skies above - from the creation of the universe to the end of time, from giant galaxies to tiny meteors and everything in between. And part of our attempt to understand it all is to become more familiar with our night sky. So this time we are going to take a quick look at a constellation - an easy one to find - called Cygnus. Ready?

Above your heads in the evening is a relatively simple collection of stars that looks like a giant cross. It will appear at this time of the night as a nearly upside-down cross if you’re facing north looking up. That would be Cygnus, the swan. Most constellations look nothing like what or whom they are supposed to represent. This one almost does.

You can picture a flying swan's body, head to tail, as the length of the cross, and the outspread wings as the perpendicular part of the cross. It would look, in all its glory, as if a giant swan were flying south. 

Within our swan constellation is an asterism, the Northern Cross. An asterism is a set of stars that actually looks like something. For example, there are the Great Square of Pegasus, the  "W" of Cassiopeia, and, of course, the Big Dipper inside Ursa Major, the Great Bear. The Northern Cross asterism is nearly the whole of Cygnus itself.

There are a couple of things to look for in Cygnus, only one of which needs a small telescope. 

At the foot of the cross is Albireo. If you can see this "star" through a telescope you'll be pleasantly surprised. It is not a single star after all, but a pair of stars about 400 light years away.

The beauty of this pair is the obvious color difference of the two, one being blue, the other reddish. Most people think all stars are white. Not so. Albireo's mixed couple show a marked color difference between cooler red stars and the much, much hotter blue stars. 

Along the length of the swan's body you can see the faint Milky Way. Sadly, it is only now on moonless nights away from the city lights that one can see the Great White Way painted through the Great Swan.

At the head of the cross is the bright, giant star, Deneb. How big is Deneb? Recent data show it to be about 100 times bigger than our sun, pouring out about 60,000 times more energy. It's a killer.

And Deneb is also a part of another asterism, The Summer Triangle, which includes nearby Vega and Altair, a little to the south. 

It doesn’t take too much effort to get to know the night skies. As the skies get darker earlier approaching winter, take some time to get to know them. They can become great friends.

The Indescribable Vastness of the Universe - Part 2

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Last time here we looked at the utterly incomprehensible enormity of the universe. This week we take a look at some of the philosophical views that spring from that vastness.

One view takes a slightly depressing slant on it all. You might recall from last time the size comparison of the universe to the earth: If our planet represented the size of the entire visible universe, then planet Earth would be about the size of a single tiny, invisible atom. You would be ten thousand times smaller still.

That is small. Too small for some. How can we have any significance, how can life have any meaning, if we are nothing but a speck in the cosmos? The vastness of the universe genuinely sends some into a nihilistic funk. 

There are a couple logical problems with that conclusion. One is that size does not determine worth. A 6-foot-tall human is not more important than one only five feet high. A house is not worth more than a child because it is bigger than that child.

And the volume of the space one exists in does not determine one's worth. If I walk from my small classroom into the gigantic gym, my significance does not diminish suddenly because my "living space" just got way bigger. 

Still, that's not enough for some. So I'd ask you to try this on for size.

For you to be reading this right now, the universe has to be the size it is now. If it were bigger or smaller, the likelihood of our very existence decreases rapidly. Here's why.

We live in an expanding universe, one that has been growing rapidly since its birth more than 13 billion years ago. If our universe were smaller, assuming we are the same age, that means our expansion rate would have been slower. So what?

Well, a slower expanding universe is not a good thing. If we were to have expanded more slowly, the great bunches of stuff that our universe was made of then would have collapsed together under the influence of gravity, not having had enough time to spread out and away. 

There would not have been generations of stars to spew out the periodic table of elements. There would have been no formation of planets and all other consolation prizes like trees and rocks and you and me. We would have a lot of black holes and not a whole lot else.

And if we had expanded any faster to be bigger, most stars would never have had time to form in the first place, matter having spread out now too far too fast. No stars, no solar systems, no earth, no us.


This universe, it turns out, is not too big, not too small, but just right. 

When we see the vastness of space, some of us recede into the depression of perceived insignificance. But others see an enormous universe of grandeur and beauty and design. Study the universe and it seems almost tailor-made for a tiny planet peopled with human beings. That, dear reader, is significant. 
Temecula Valley High School / Temecula, CA · Some images © Gemini Observatory/AURA Contact Me