VENUS IS A BURNING-DESERT WORLD
Planet	Water	Greenhouse	Lightning	Spacecraft	Express	Transit	Resources

Venus is nearly a twin to Earth in size. However, it has atmospheric pressure on the surface 90 times that of Earth. The temperature on the surface of Venus may be as high as 900 degrees Fahrenheit.

Scientists already had a runaway-greenhouse explanation in which water existed on Venus, but only as vapor. In a greenhouse effect, Sun heat is trapped by gases in a planet's dense atmosphere.

VENUS

The wet-greenhouse and the runaway-greenhouse theories have a greenhouse effect in common.

In the runaway-greenhouse explanation, Venus was said to be so hot that its water existed only as vapor and had no chance to condense to liquid on the surface. Water vapor rose into the atmosphere, where radiation from the Sun cracked it into separate oxygen and hydrogen atoms. The hydrogen escaped into space and water couldn't form.

But the Ames researchers, looking at different climates on Venus, Earth and Mars, didn't like the runaway-greenhouse explanation. That old theory forgot that the Sun was 25 to 30 percent cooler 4.5 billion years ago. It also did not account for the water loss.

Is Earth A Greenhouse? The wet-greenhouse theory might be a model for Earth. Scientists are concerned that burning fossil fuels puts too much carbon dioxide into Earth's air, causing the atmosphere to trap heat from the Sun. That could raise air temperatures gradually, increasing sea levels as polar ice melts.

However, Earth is farther from the Sun and has a different atmosphere which is expected to prevent the climate catastrophe that turned Venus into a desert.

NASA scientists have bounced radar waves off cloud-shrouded Venus and detected colossal highly-reflective blobs and rings that may be lava flows or volcano crater rims rich in fool's gold.

The radar survey by researchers from NASA's Jet Propulsion Laboratory (JPL), Pasadena, California, turned up more evidence that volcanoes have erupted on Venus within the last few million years, maybe even within recent centuries.

Learn more:

Venus
• Venus Planet Profile  NASA JPL
• Venus Described  SEDS Nine Planets
• Exploring Venus  STO
• Exploring Venus index  STO
• Planet Venus  STO
• Venus Water  STO
• Venus Greenhouse  STO
• Venus Lightning  STO

Venus Transit
• Venus Transit 2004  STO
• Guide to Viewing the Transit  Science @ NASA
• Guide to Viewing the Transit  Science @ NASA
• 2004 Venus Transit Resource Guide  NASA Sun-Earth Connection
• Movies and diagrams of the transit  Astronomy magazine
• Venus Transits of 2004 and 2012  NASA Goddard
• Guide to the Transit of Venus  Sky & Telescope magazine

Captain James Cook
• James Cook and the Transit of Venus  Science @ NASA
• James Cook and the Transit of Venus  Blue Latitudes
• James Cook Journals  National Library of Australia
• History of Cook's Endeavour  HM Bark Endeavour Foundation
• James Cook Transit Timing Measurements  Royal Society of London
• South Seas Voyaging  National Library of Australia
• James Cook Drawings of 1769 Venus Transit  Armagh Observatory
• Capt. Cook's Voyages  Linda Hall Library History of Science

Exploring Venus and the Solar System
• Venus Spacecraft  STO
• The Pioneers  STO
• The Voyagers  STO
• Exploring the Solar System  STO

How to watch the Sun safely
• Safe Sunwatching  Science @ NASA
• List of solar filter suppliers  Sky & Telescope magazine
• Solar Filter Safety  Sky & Telescope magazine
• Close-Up of a Star  Sky & Telescope magazine
• A Beginner's Guide to Solar Observing  Sky & Telescope magazine

Read more about the Solar System . . .
Star:	The Sun
Inner Planets:	Mercury	Venus	Earth	Mars
Outer Planets:	Jupiter	Saturn	Uranus	Neptune	Pluto
Other Bodies:	Moons	Asteroids	Comets
Beyond:	Pioneers	Voyagers