Carpe Cosmos

The universe waits for no one. Celestial events and phenomena are occurring all the time, some with more frequency than others. Astronomical objects are coming in and out of view— monthly, seasonally, cyclically.

None of these occur on your schedule or my schedule. They occur on their own schedule, on a cosmic schedule. It is up to us to make ourselves available to witness them, to be at the right place at the right time, so to speak.

You don’t necessarily need a pile of high-priced equipment to seize the cosmic moment. In fact, some of these spectacles are best viewed with the naked eye. A selection of my favorites are listed below. Pencil a few into your datebook, won’t you?

1) Total Lunar Eclipses. Lunar eclipses occur only at Full Moon. When the Sun, Earth, and Moon are aligned such that the Sun casts Earth’s shadow on the Full Moon, we experience a lunar eclipse. A lunar eclipse may be partial or total, depending upon the alignment of the three bodies. When all three line up so that the Moon is entirely within Earth’s shadow, it's called a total lunar eclipse, and the Moon turns red. Really! It’s a phenomenon that’s even visible in the city, and you won’t soon forget the eerie sight.

The next total lunar eclipse will occur on December 21, 2010. Totality begins at 12:40 a.m. Mountain Time (adjust for your time zone) and ends at 1:53 a.m. Mountain Time. It will be visible throughout North America.

You can practice with a partial lunar eclipse on June 26, 2010. This one’s pretty well placed for the continental U.S., with the exception of the East Coast. You’ll need to get up in the wee hours on the 26th and watch the Moon setting, just prior to sunrise. This is when you’ll see a portion of the Moon in shadow— at greatest eclipse, about 50 percent.

2) Meteor Showers. Comets leave behind clouds of debris when their orbits take them near the Sun. Subsequently, when Earth, on its orbit around the Sun, plows through one of these debris clouds, we experience a meteor shower.

The Perseids (PURR-see-yidds) are a reliable shower active from mid-July through the end of August. This year, they peak on the morning of August 12, 2010. The peak date, as well as a day before and a day after, are all good times to plan to view them. You’ll need to watch for them between midnight and dawn. This year should be optimum viewing, as the waxing crescent Moon will set before midnight and therefore won’t wash out the sky.

You won’t see many “shooting stars” in the city, so find yourself a dark site away from urban light pollution. A meteor shower is Mother Nature’s fireworks show. Don’t miss out.

3) Planetary Alignments. Because the planets all travel at different speeds around the Sun, they periodically catch up to one another. From our vantage point on Earth, the naked-eye planets can sometimes appear to be close to one another in the sky, as they pass. In addition, they may happen to be nicely placed near a crescent Moon, since the Moon is always changing position in our sky over the course of a month.

These picturesque groupings are called alignments, and the combination of bright objects makes an easy observing target even for city dwellers. Here are some nice upcoming alignments to watch for:

Looking west after sunset on July 31
Star maps created with Your Sky

On July 31, about a half hour after sunset, look west for a trio of bunched-up planets: Venus (the brightest), Mars (reddish-colored), and Saturn (golden-colored). Mercury is there too, but hanging low over the western horizon, so it will be a challenge.

Looking west after sunset on August 13

On August 13, about a half hour after sunset, look west for the aforementioned trio with the crescent Moon now joining them.

4) Milky Way. You might call this one the “main event,” as the Milky Way is our home galaxy. How wicked cool is it that we can look up at the night sky any time of the year and see an edge-on view of the spiral arms of our platter-shaped galaxy? Well, that is, if we get away from city lights. Unfortunately, 20 percent of the world’s population can’t see the Milky Way from where they live, due to light pollution.

Naked eye, we see what looks like a long filmy cloud stretching across the sky, but we know it’s composed of billions of distant stars. Yes, billions! If you haven’t experienced it, get yourself out to the country immediately if not sooner, and look up. You won’t be sorry.

Giving Thanks

These are a few of my favorite things.


Dance of the Planets
Watching the naked-eye planets (Mercury, Venus, Mars, Jupiter, Saturn) rhythmically huddle and disperse is like watching an intricate dance. These planetary alignments are the result of our earthbound view of the naked-eye planets moving in their respective orbits around the Sun. Some are traveling faster than Earth; some are traveling slower. The resulting variety of configurations gives us a sense of the “clockwork of the universe” and reminds us that everything is in motion.

Solar system diagram created with Solar System Live

Be sure to look southwest after sunset on Monday, December 1, when Venus, Jupiter, and the crescent Moon will bunch up in the twilit sky. Venus will be the brighter of the two star-like objects you see, and Jupiter the fainter. The waxing (growing) crescent Moon will be about 15 percent illuminated.

While you're enjoying the alignment, look for earthshine on the Moon. Earthshine is sunlight reflecting off the surface of the Earth and illuminating the dark part of the Moon. Even though the bright crescent is the only part of the Moon’s face being directly illuminated by the Sun, if you look carefully, you’ll see that the rest of the Moon’s face is glowing faintly with reflected glory: earthshine.

Shooting Stars
Wishing on a “falling star” is one of the guilty pleasures of the stargazer. Even after you know that falling stars, aka "shooting stars," are meteors, you can still appreciate this charming holdover from early folkloric traditions.

A meteor is the streak of light we see in the sky when a bit of dust or space debris hits Earth’s atmosphere at high velocity. A meteor shower occurs when Earth encounters a stream of debris left behind by a comet’s close approach to the Sun. Sporadics are meteors not associated with a particular shower.

Meteor showers occur reliably around the same time every year, as Earth returns to the point in its orbit where the debris field lies. Whenever you like, you can find out what meteor showers are currently active by visiting this website and scrolling down to the Meteor Shower Calendar.

Meteor storm - 1889 engraving by Adolf Vollmy

If you’re lucky, you might someday see a meteor storm, a very intense meteor shower with a high frequency of meteors. One of my top ten stargazing experiences ever was viewing the 2001 Leonid meteor storm. The meteors came so fast and furious, it was a bit like watching a fireworks show. I was with a large group of fellow amateur astronomers at a dark-sky site, and the oohs and aahs from the crowd as particularly fine meteors blazed across the sky just added to the ambiance of the event. We all knew we were seeing something rather spectacular.

Cosmic Dust Bunnies
Interplanetary space is not empty. Our solar system contains a vast number of minute particles, some left over from the time of planet formation and some ejected from passing comets or asteroid collisions. Light from our Sun illuminates the myriad particles lying in the solar system plane, and sometimes we see the reflected sunlight as a luminous pillar of light called the zodiacal light.

The zodiacal light (zoh-DYE-uh-kull) is a large, roughly triangular or cone-shaped glow in the night sky, extending upwards from either the eastern or western horizon. The base of the triangle or cone— the widest part of the glow— is at the horizon. The zodiacal light is typically seen in the spring above the western horizon after sunset and in autumn above the eastern horizon before sunrise.

If you're fortunate enough to view the zodiacal light when transparency (atmospheric clarity) is good and the sky is inky black, you may notice the light pillar has a yellowish cast. Our Sun is, after all, a yellow star, so it shines with a golden light.

Cone-shaped glow of zodiacal light above sunset glow
Image source: ESO

The zodiacal light is subtle and can be quite challenging for the beginner to spot. A dark site away from urban and suburban night lighting is critical for success, as is avoidance of a moonlit night.

Believe me, this phenomena is worth a little extra effort. It’s quite a rush when you spot it, especially when you then start thinking about what you’re looking at— vintage dust from when the solar system formed. The goofy image that always pops into my head is the Sun as a clean freak with a big flashlight, showing us what lurks under the furniture.


The Way
My personal pet name for our home galaxy, the Milky Way, is simply “the Way,” because it represents for me a way of being and a way of seeing. I learned an important lesson a number of years ago on a camping and observing trip in southern Arizona. I had spent the better part of a night looking through the eyepiece of my telescope, hunting various galaxies, globular clusters, and nebulas on an observing list and methodically ticking off those “faint fuzzies” as I found them. Straightening up from the eyepiece to stretch my back, I faced south and audibly gasped. The woods south of the clearing where I and my partner were observing were on fire!

To be continued…