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.