Astro Bob A look at celestial happenings in the Northland and beyond Bob King View my profile Click here to view previous posts or additional resources

Billion year odyssey

Two photos of the space station as it crossed the Belt of Orion last night about 6:45 p.m. Lars Waldner took the photo at left, I shot the other. We're only about five miles apart but notice the difference in their paths.

Orion's Belt was faintly visible last night when the International Space Station (ISS) passed by. These two photos were taken from the neighboring townships of Lakewood and Rice Lake. Even that small difference in distance was enough to noticeably alter the track of the ISS for each of us. Lars' photo shows a direct "hit" with the middle belt star Alnilam. He shoots, he scores!

Here are times for viewing the space station throughout the coming week weather permitting. If you live outside the Duluth region, just click HERE and type in your zip code for times for your city. In all the passes listed below, the ISS will first appear in the western sky and move eastward across the northern sky. On the 10th-12th, if you have an open view to the northeast, you can use binoculars to watch the sun set on the station (it turns deep red) before it fades away in Earth's shadow.

* Tonight beginning at 7:07 p.m. A high, brilliant pass. It will cross the Bowl of the Big Dipper before fading out in the northeast.

* Monday March 8 at 7:32 p.m.

* Tuesday March 9 at 6:22 p.m. (another bright one) and again at 7:57 p.m. when it will first appear due north moving to the east.

* Wednesday March 10 at 6:47 p.m.

* Thursday March 11 at 7:12 p.m.

* Friday March 12 at 7:37 p.m.

* Saturday March 13 at 6:26 p.m.

This diagram shows all the stars within 12.5 light years of the sun. Sirius and Alpha Centauri are circled. Credit: Richard Powell

Everything is so far away in space. How do we grasp the meaning of stellar distances and time? Take the light year, a popular yardstick use to measure distances to other stars and galaxies. This is the distance that light, traveling at 186,000 miles per second, travels in one year. On the scale of the Milky Way galaxy one light year isn't very much yet it tallies up to 6 trillion miles. The nearest star beyond the sun is the Alpha Centauri system at 4.4 light years or about 26 trillion miles away. 26 trillion ... hmmm ... sounds about as meaningful as the deficit.

We can easily convert light years into time. Since light from Alpha Centauri takes 4.4 years to reach our eyes, the starlight we see tonight is 4.4 years old and left the star in late 2005. A more familiar star is the red supergiant Betelgeuse in Orion at a distance of  640 light years. When it winks at you tonight, those light rays started their journey around the year 1370 during the era of the Black Death or bubonic plague that wreaked havoc across Europe and the Middle East for decades. On the brighter side, the light from the Seven Sisters cluster tonight left just about the time Galileo pointed his first telescope at the heavens.

The core of the Corona Borealis Galaxy Cluster. The galaxies are the fuzzy, yellowish ovals. Credit: Jim Misti

Tucked into a corner of the distinctive constellation Corona Borealis the Northern Crown is a distant galaxy cluster cluster called Abell 2065, the Corona Borealis Galaxy Cluster. This dense cluster contains over 400 galaxies and depending on the source, is 1.1 to 1.5 billion light years away. On a recent night I was able to see only a half dozen of its many members, and they were all extremely faint. While I enjoyed the satisfaction of observing something so remote I needed a more tangible way to appreciate how ancient the light was that touched my retinas. That's when rocks came to the rescue.

In the Duluth and Lake Superior area, the crust of the Earth rifted or split some 1.1 billion years ago. Multiple flows of lava poured out from below and piled one atop the other until more they were more than 10 miles thick. The splitting eventually came to a halt and left a basin that was filled much later by glacial melt waters, some of which survives to this day as Lake Superior. Streams and rivers tumbling toward the lake cut through the ancient lavas exposing many of its layers in great cliffs and canyonlike walls.

An exposure of volcanic rock -- most likely rhyolite -- along Amity Creek is cracked into multiple layers from erosion. The rock poured out from fissures in our planet's crust over a billion years ago. Photos: Bob King

Last week I walked a frozen creek that passed several spectacular exposures of this once molten rock. Reaching out my hand to touch the cracked and crumbling layers, it struck me that this rock was laid down at nearly the same time that light from the Corona galaxies wended its way up the telescope tube to my eye. Man, that's old. I stood there for a while and let it all sink in. Galactic light had found its match in rocks that were literally in my own backyard. I may have been standing still but my thoughts were traveling faster than light through deep time.

Although we may never be able to truly appreciate the distances and time intervals the universe tosses our way, once in a while we're allowed a glimmer of the reality.

A very nice exposure of fractured volcanic rock. This wide view gives you a good idea of a typical river scene along Lake Superior's north shore.

Posted by: rking@duluthnews.com on 3/7/2010 at 9:56 AM | Comments (0) | Permalink | Edit

Tags: daily updates, space station, light year, alpha centauri, corona borealis, galaxy cluster, amity creek, astro bob, life, iss, betelgeuse, lava