Five plus one

Would you like a free treat, something to salve the post-holiday credit card bill blues? I know I would. After my December spending spree I can’t even afford to pay attention. Here is something I can heed, though: Our solar system is putting on a grand display right now. For the first time in over a decade, all five “visible” (easily seen with the naked eye) planets are showing themselves at the same time.

This has been a news item in a lot of papers. Overall, in our age of NASA, the Hubble telescope, and so on, astronomy news is a popular part of current events. Many such stories, however, are on the scientific side of things, and, though they often have cool photos taken with impressive instruments, they usually don’t present readily viewable treats for the casual stargazer.

The five-planet event, by contrast, is perfect for casual stargazing. This certainly applies to anyone in Saipan who wants to take a look. This viewing window will be open for about three more weeks.

No telescopes or binoculars are needed. A cup of coffee might come in handy, though, since this is a just-before-dawn gig. A computer comes in handy too, since EarthSky.org features a “guide to the five visible planets.” The guide’s graphics can point anyone in the right direction so they know where to look.

But here’s a quick-and-dirty: About an hour before sunrise, Mercury rises above the horizon near the point where the sun is about to rise. From Mercury, the other planets are strung across the sky in a line that extends to the west.

The sequence of the line is like this, moving from east to west: Mercury, Venus (which will be very bright), Saturn, Mars, Spica (a star), Jupiter (very bright, but not as bright as Venus). The moon can be in the mix as well along that general line, but its exact location depends on which day you catch it.

We can, meanwhile, enjoy the concept right now without having to get into the navigational details.

There are really six visible planets if we include Earth, so I guess we’ll call this gig five-plus-one.

Since we’re taking inventory here, we’ll note that the two most distant planets, Uranus and Neptune, aren’t on the stage for this. Uranus is said to be naked-eye visible under very good conditions, but that’s not easily visible on the order of the five “visible” ones. And Pluto, which is even more distant than those two outliers, has been demoted from planet status since my school days.

Me, I’m an old-school kind of guy, and our solar system, including Earth, is, indeed, really old. We’re talking about 4.5 billion years old. You and I are rooted in truly ancient stuff.

I consider myself fortunate to live in an era when we can have some perspective about the scale of this gig. This perspective started coming into focus only about 100 years ago.

It’s tempting to think that Earth-bound stuff comes and goes, while all the stars endure as a constant backdrop, but things are more interesting than that.

In contrast to our solar system’s long history, many of the bright stars we see are only a fraction of our sun’s age. Many of those same stars will burn out long before our sun hits the skids. Indeed, the “live fast, die young” philosophy applies to cosmic stars every much as movie stars. The bigger and brighter a star is, the faster it burns out; some are mere cosmic eye-blinks.

The scale here is very wide. Our sun, for example, is about half way through a 10 billion year life span. By contrast, a really massive star might only live to be about 3 million years old, which means our sun will have a lifespan that’s about 3,333 times longer than the massive star.

By contrast, there are some smaller stars that might live for 10 trillion years, so, taking this into account, the scale of star lifespans is so wide we can’t really get our heads around it.

The small stars are, in fact, getting a lot of attention these days. By some accounts, most stars in our cosmic neighborhood are dwarf stars, of which there are several types.

One type that gets a lot of attention now is the “brown dwarf,” which was a mere theoretical notion when I was in college. These were thought to be sort of junior stars that didn’t make it into full-blown star status. More recently, though, they’ve been tallying more and more actual discoveries. Since these objects are so low-powered they are hard to detect, but instruments are getting better all the time. There may be as many as 100 billion brown dwarfs in our galaxy alone. And, yes, they have detected planets orbiting brown dwarfs, so things get even more interesting.

Faced with all this cosmic weirdness, our solar system seems like a cozy and snug home.

Cost of last Christmas? $1,839.77, plus interest. A cup of coffee in the pre-dawn hours? $1.50. Getting a five-plus-one view of our solar system? Priceless.