A while back I used the fictitious city of Trantor in Isaac Asimov’s Foundation Trilogy to describe the concept of no night. Trantor was not just a city, it was the entire planet, made into one obscene ball of light, with no night. Sure, you could darken your room, but the outside world was still awash in artificial light. Sure, you “go outside” on top of a mile high building to see the city, but you sure could not see the night.
Or we could be living on a planet within a globular cluster (if planets can even form there due to stellar gravitational dynamics). Now, that would be amazing! Amazingly bright all the time that is. Fortunately, Earth is in the outer third of our galaxy, the Milky Way. On the best and darkest nights around 4500 stars are visible, tops. We can see a smattering of bright stars, but most are not bright, bright enough to see but not brilliant like Sirius, Arcturus, Betelgeuse, etc.
If we were situated similarly within a globular cluster, we would be looking at a minimum of 10,000 stars at night, many would be very bright, and some way brighter than Venus. A few would be bright enough to be easily seen in daytime. Then, looking toward the cluster’s core at night, well, it would take our breath away. It would be a massive, glowing, fuzzy ball of stars. And the color! Most stars in a globular cluster are older than our Sun, many yellow and red giants. Throw in a sprinkling of young blue giants and the night sky would be a carnival! But no night to see, just bright lights.
That is the ultimate nightmare of night sky defenders…loss of the night.
The good news, Trantor is fictitious and of course we do not live on a planet in a globular cluster, whew! We on Earth are in a beautiful spot, with stunning night sky views, and the Milky Way around us. OK, I qualify this statement with – If you are in an area not spoiled by light pollution.
I have harped about light pollution down here but now we are threatened by light pollution from above too. Yes, from above. Researchers from the European Space Agency and Royal Astronomical Society are concerned about the number, size, and reflectivity of the latest batch of artificial satellites. There are several private and government projects worldwide that expect to launch as many as 100,000 new satellites in the next few years. Most are small, low orbit devices aimed at providing internet and communications availability everywhere.
The risk to astronomy? All the additional reflected light will negatively affect night sky darkness, no matter where you are!
What’s in the Sky?
May 12 & 13; dusk; west: On the 12th, a thin crescent Moon is just below Venus on the horizon. On the 13th, the Moon is higher, and closer to Mercury.