There are some wonderful books in the libraries and book stores showing fantastic pictures of the natural beauty of our parks, splendors around the world and entrancing pictures taken by the Hubble Space Telescope. But there are wonders right above our heads that we often fail to see, the beautiful and delicate tapestry of the clouds! It’s true on some days, there are no clouds to be seen or the sky is covered with dull flat clouds that wouldn’t inspire us. But every few days, some truly wondrous cloud sculpture can be seen looking upward. Our eyes are just right for viewing the cloud with our wide angle coverage. Also our eyes can discern a great range of detail and shading, giving us a super high definition look upwards, better than the highest resolution digital camera available in our stores. (Only the digital cameras on large observatory telescopes with hundreds of millions of pixels can surpass the human eye.)
What causes clouds to form? As moist warm air rises, it cools and water vapor condenses out on tiny dust particles to form tiny water droplets, too small to fall. (The upward motion of the air pushes upward against the small water droplets with a force that is greater than the weight of the water droplet.) These rising currents of warm air are called thermals. Why does warm air rise? Warm air is less dense than cooler air so it is buoyed upward by the surrounding cooler air. (This is how a hot air balloon works; the heated air inside is less dense than the surrounding air, which pushes the balloon upward.)
At the top of some clouds where the sun shines, the water droplets evaporate while at the bottom of the cloud, new droplets form, causing the cloud to reform. So most clouds are in a process of renewal, just as our bodies where cells wear out and new cells being formed by cell division.
There are three main types of clouds, primarily based on their altitude or height. The highest clouds are the Cirrus clouds, from 20,000 to 45,000 feet (roughly 4 to 9 miles up), made up of ice crystals (water droplets freeze). These are most delicate clouds, very wispy and resembling the spread out tail of a horse. As the sun or moon shines through Cirrus clouds, the crystals can form a ring around the moon or sundogs, detached bits of a rainbow on either side of the sun. Then there are the jolly white Cumulus clouds, resembling lumps of cotton or stacks of mashed potatoes, floating a few miles up and made up of tiny water droplets. Here one can imagine the head of a dog, the profile of a human face, the rump of an elephant, etc. The last and least interesting cloud type is the Stratus or layered clouds, often dark and gloomy. Some cloud types may visit the middle or Alto heights (up to 4 miles up) then become more concentrated (as for cirrus) or more thinned out (as for the cumulus).
What I really enjoy about the clouds are several types of clouds in the same direction where a near cloud (a thin cumulus cloud) passes by a well stacked bank of cumulus with a break of blue sky just beyond. Then there are the clouds with a silver lining, as the sunlight illuminates the edge of the cloud.
There is no other planet in our system that has such beautiful clouds. For Mercury is nearly airless, Venus is sheathed with dense sulfurous clouds that never allow direct sunlight to reach her surface and Mars has mostly dust clouds. The giant planets have multiple layers of clouds that completely shield their liquid surfaces (where their air has become liquid due to high pressure). The best extraterrestrial clouds in our solar system would be Saturn’s large moon Titan, where the clouds are made of methane and ethane, raining down hydrocarbons down on this moon’s cold surface (-280 F).
Enjoy the light of the Harvest Moon through most evenings this week. On Thursday, the planets Mercury and Saturn appear very close together in the 6:30 a.m. Eastern dawn. Above this planet pair is the brilliant planet Venus.
Our free public October program at the Frostburg State Planetarium is “Bare Eye Astronomy,” showing each October Sunday at 4 p.m. and 7 p.m. This is an ideal program for anyone to better understand and appreciate the night sights seen with your eyes alone. The Planetarium is in Tawes 302, nearby the Compton Science Center, the FSU Clock Tower and the Performing Arts Center. You may park anywhere except the slots reserved for the handicapped (if you don’t have a placard). Visit the FSU Web site at www.frostburg. edu to print out a map showing the main buildings and parking areas if you are not familiar with the FSU campus. We don’t admit late comers; seating is limited.
Dr. Bob Doyle invites reader’s comments or questions, phone (301) 687-7799 and leave a message or email rdoyle@frostburg.edu.
Bob Doyle - Astronomy
Check out the majesty of the clouds
- Bob Doyle - Astronomy
-
-
Here’s your chance to meet the bears
This afternoon our weekly Sunday programs will resume at 4 p.m. in the Compton Science Center, Room 224. Compton is the large building across the Tawes Hall, set for demolition.
-
Scientists are uncovering Earth’s distant past
Powerful telescopes can look far away (also far back in time) to learn about the early universe; earth scientists using radioactive dating and isotopic analysis can investigate the first few billion years of our Earth’s history.
-
Teachers must show what is important
As well as teaching college, I do sessions in the elementary schools and frequent public presentations; I feel I have a good sense of what makes an impression on my listeners.
-
Students can become self-directed learners
The last of seven principles featured in the book “How Learning Works” is influencing students to become self-directed learners. This applies primarily to what students do out of class, involving homework, studying for tests, doing papers and assignments.
-
Here’s how students organize knowledge
The 2010 book, “How Learning Works” by five researchers in the Pittsburgh area has a wealth of insights as to how teachers can influence students to be more effective learners.
-
Here are the best sky sights through June
Thanks to the predictive power of astronomy, here are the best bare eye or binocular sights in the first half of 2012.
-
Tawes Hall was site of many good memories
In a few weeks, the interior of Frostburg State’s Tawes Hall will start to be gutted; in a month or so, the outside walls will begin to be knocked down.
-
Students need motivation to learn
Most teachers from elementary to college often wonder, “How can I get some of my students motivated? Then they could learn a great deal more in class, from their readings and from their assignments.”
-
Prior knowledge can affect your learning
This column will review the first of the seven principles from “How Learning Works,” one of the most significant books in education in recent years. This principle is “How Does Students’ Prior Knowledge Affect Their Learning?”
-
Seasons and solstices mark the year’s passage
Many think that in winter, we are farthest from the sun. There is also a widespread belief that in summer we are closest to the sun. In truth, both beliefs are wrong. The Earth-Sun distance varies by 3.4 per cent through the year while the solar insolation (watts/square meter) at midday on a flat surface varies by 80 per cent.
- More Bob Doyle - Astronomy Headlines
-
Here’s your chance to meet the bears
