21 Oct 2007
Many of us have spent some time - OK, maybe too much time - playing with a computer program called Google Earth, available for free from Google for both Mac and Windows platforms. It is a detailed map of earth - that's it - but it is absurdly addictive for those of us who like to explore. Zooming down to just about anywhere on the planet, down to street level using satellite photos, is a virtual explorer's dream.
Well, as if it could get any better, it just recently did. Attached to the latest version of Google Earth is Google Sky, which attempts to do the same things for the heavens as Google Earth does for the planet.
Only now we're not globetrotters, skipping over the continents to see cities and mountains and monuments. Here we zip around the starry skies and explore the natural wonders there.
Opening up Google Sky will give you what seems like just a random array of white dots against a backdrop of constellations. Don't let the elementary school appearance fool you. What you are looking at is rich in big-person information.
Zooming into any area will reveal wall-to-wall stars of all colors and brightnesses. Here you will see the stars in their true colors: reds, whites, yellows, and blues.
Click on any highlighted named object and out pops a window of information about it, including type of object, description, and distance. And since Google is in charge here, there are links galore to online articles and images and blogs on the object you picked.
And, just as in Google Earth, you can add a variety of layers over the viewing area to enrich the exploring experience. This includes a layer for new backyard astronomers, a Hubble Showcase, one for the Moon and the planets, a User's Guide to Galaxies, and one called The Life of a Star.
And the background star field is no fake computer generated field, oh no.
During the 80's and 90's astronomers needed a highly detailed visual record of the sky, one reason of which was to help direct the celebrated Hubble Space Telescope though the celestial sphere. For the Northern Hemisphere, our own Palomar Observatory was used for this sky survey.
Specifically, it was the 48-inch Samuel Oschin Telescope - a stone's throw away from the great Hale Telescope - that was the workhorse behind this endeavor. The millions of star images provided in that project paint the visual backdrop of Google Sky's northern star field.
Try a ride for yourself. First, obviously, make sure you have downloaded the latest version from earth.google.com. Then open it up and fly to Orion and see the rich, star forming area in the Nebula. Veer on over to the constellation Virgo and zoom in closer and closer until you see a lot of fuzzy, but organized clouds. Each of those are galaxies in the Virgo Cluster, millions of light years away, each with its own billions of stars.
"The Life of a Star" layer will take you through the skies to see real images of stars in their various stages, from nursery to supernova remnant.
Or just be an adventurer and discover the beauty of the heavens in an arbitrary way in your own sweet time.
Is Google Sky perfect? No, the program is still in its infancy. Not all stars and galaxies are identified. There are artifacts from the original images that haven't been cleaned up and may be confusing for the novice. And for some reason a placemark for the Japanese Imperial Palace showed up in the constellation Vulpecula, and one for the Reichstag is right there in Ursa Major. I kid you not.
But over all, and considering the price, Google Sky is great fun. It is full of information and brings out the voyager in us all. And if past Google offerings are any indication of where this is going, Google Sky will just get better and better. Have fun!
And until next time, clear skies - real and virtual.
08 Oct 2007
There is so much attention in astronomy given to the evening skies that we often forget to mention that there is a morning sky, as well. To all those who wake at or before the crack of dawn to brave the traffic or open the store, to those who might be getting off work and making their way home in the wee hours, this column is for you.
One of the first objects our early bird readers may have noticed in the last month is a bright - very bright - "star" rising before the sun. That is Venus, our Morning Star. But wasn't it Venus that was the Evening Star just months ago, setting behind the sun in the east? What's it doing over here now, leading the sun?
It was doing what it does best and what it has been doing for countless eons, dancing around the Sun in its orbit. And since summer it has moved by us, in front of the sun, over to the other side. Thus, it now seems to lead our star through our skies rather than follow it. And the best time to see it as it leads that celestial race is in the morning before sunrise when the sky has not yet been blotted out by its starry partner.
Since our sister planet is still moving farther and farther over to the "right" side of its orbit we can observe over the next month how it rises earlier and earlier each morning before the sun. This won't go on forever of course. Venus will have to swing around back behind the sun to the other side to eventually again become our Evening Star. But don't hold your breath. She is booked as Morning Star into the next year, and won't be making an encore appearance as Evening Star until next summer.
One of the most obvious, if also very slow, processes occurring over the next couple months for our early rising readers is the sun's migration south for the winter.
It's been going on for a while, but since the sun is rising later and later every morning it is more convenient for morning commuters to notice.
Of course both the sun's delayed rising and its slow trip south are due to the tilt of our planet. We are tilting more and more away from our fiery gas giant. We are approaching North American winter. And as we do, the sun rises more and more southerly each day. And its rise is more and more parallel with the horizon, not the near straight up shot it is during summer. And it travels lower through the sky each day. Result: Less sun, less warmth, more dramatic shadows, more in-your-face sunshine.
Now migration of the sun is not restricted to the Morning Folk. Those who observe the setting of the sun will notice a similar effect in the west. The sun will set earlier, farther south and at a sharper angle. All making a homeward bound commute considerably less pleasant for them, as well.
Until next time, clear skies!