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Published on 02/02/1998 All articles from this issue

Astronomer takes Morning Forum on tour of solar system

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By Marjorie Kellogg-Van Rheeden

Special to the Town Crier

In a lecture sprinkled with stardust and humor, Andrew Fraknoi, chairman of the Astronomy Department at Foothill College, led the Los Altos Morning Forum Jan. 20 on an armchair tour of space

"Exploration of planets that revolve around our sun teaches us how we evolved," Fraknoi said. "The janitorial services were not up to snuff when the solar system was formed, so there are still asteroids, comets, meteorites, and cosmic dust flying around the planets. All are part of our cosmic home."

Over billions of years, the impact of space debris has caused craters on the Moon.

"Footprints left when man first walked there will be preserved for billions more years," Fraknoi said.

Venus is veiled by a thick layer of clouds consisting of sulfuric acid and carbon dioxide. "We think there hasn't been a clear day there in three billion years," he said.

Sunlight filters through but there is no vent for escape, so the heat is trapped. Surface temperatures have built to 900 degrees Fahrenheit.

"Wear a space suit, take a fan," Fraknoi said. "If you were to land there unprotected, you would be asphyxiated, french fried, or crushed. A Russian spacecraft was able to land on Venus and send back images for about 25 minutes before becoming french fried."

Radar beams that penetrated the clouds found Venus' surface full of volcanic activity. As lava seeps up, it forms plateaus 15 to 20 miles across.

The spacecraft Viking visited Mars.

"It looked like an inviting desert scene, but if you stepped out unprotected your first breath would be your last," Fraknoi said. "There is no water, the very thin air is 95 percent carbon dioxide, and (air) pressure is low enough to make your blood boil.

"But billions of years ago evidence shows that Mars had rivers, floods, tributaries, a thick atmosphere, more pressure, and lots of water, much like Earth. Inhospitable for life today, ancient Mars may have been a place where life tried to begin in our solar system. Eventually spacecraft will dig beneath the surface in search of preserved fossil evidence."

Mt. Olympus is the largest of many volcanoes on Mars, Fraknoi said, three times the height of Mt. Everest."

The giant planet Jupiter, where 11 Earths could fit side by side at equator, is mostly made of gas and liquid and has four planet-sized moons.

"You could not land on Jupiter. You would sink in," Fraknoi said "Spinning on its axis, Jupiter only takes 10 hours to make a complete turn. A storm has been seen raging unabated since the first telescope was invented."

Saturn is also mostly gas and liquid, he said. It's a favorite because of its rings, which appear solid but are made of chunks of ice ranging in size from that of a grain of sand to a large truck.

Uranus is interesting to scientists because it orbits on its side, Fraknoi said. "Something big hit it early on. It fell over, indicating that the early solar system may have been a very violent place."

Pluto, the only planet that doesn't orbit on a plane, has not been visited, he said. Small, rocky and icy, Pluto travels among the giant outer planets, going in and out of the orbit of Neptune.

"For the first time in human history we have discovered very dim and hard to detect planets among the big, bright, easy to see stars. Outside our system, we now know there are planets that exist other than the nine we have seen," Fraknoi said.