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----------------- - 1729 - Walk with Venus on a Starry Night?
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- A late walk under a starry sky. I like to observe the setting stars. Like Venus setting on the western horizon last night. It gives you a sense of the Earth’s rotation. Of course the best way to see the Earth’s rotation is to put a camera on the sky and take an all night time exposure.
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- The rotation is obvious with the axis pointing to the North Star, Polaris. The Earth is rotating 1,038 miles per hour, standing at the equator traveling east.
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- If you were on Venus you could walk west and keep the same stars overhead, because the rotation is so slow, 243 days. Walking west on the equator on Venus at 4 miles per hour would do the trick. Of course, you would have to walk for 243 days to complete one “day”
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- The other problem is you could not walk on the equator because it is too hot, 864F. And, it is not just the equator the whole planet is that hot.
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- And, you could not see the stars anyway because the light does not penetrate the 60 mile thick atmosphere. The atmosphere is so thick the pressure is 90 time greater than on Earth.
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- And, you could not breathe because the air is 96% carbon dioxide and 3% nitrogen. Earth is 77% nitrogen and 21% oxygen, thanks to the plants and the vegetable gardens.
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- January 2015 the spacecraft “ Venus Express” is burning up as it descends into the atmosphere. It started “aeorbraking” in the upper atmosphere using its polar cell panels in June 2014. Its communications and fuel ran out in November. The 2,800 pound spacecraft has been orbiting and collecting data on Venus for the last 8 years .
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- The Venus Express was launched November 9, 2005 at a cost of $110 million. It arrived Venus April 11, 2006 after a 250 million mile journey.
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- Venus has an iron core like Earth but has no magnetic field because it rotates so slowly.
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- The atmosphere is so thick light can not penetrate so the spacecraft must use ultraviolet and infrared wavelengths to study the surface. It also used a plasma analyzer, a magnetometer, and a radar sounder.
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- The Magellan spacecraft orbited Venus 1990 to 1994 and used radar to map 98% of its surface.
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- Venus Express mapped the surface temperature using infrared. Because Venus is too hot to have rain there is very little erosion to its surface. And, there is almost o wind due to its slow rotation.
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- The Venus surface is 750 million years old and pretty much undisturbed There are not many craters, like on Mercury, because most meteors burn up in the thick atmosphere and never reach the surface.
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- Venus is 81.5% the mass of Earth. Its diameter is 94.9% that of Earth’s. Its density is about the same 5,240 kilograms/meter^3 versus Earth’s 5,510 kilograms/meter^3. Its atmosphere contains clouds of sulfuric acid, sulfur dioxide and water.
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- (1) There are several other Reviews available upon request:
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- #1706 The atmospheric pressure would crush a submarine, equivalent to being 3,000 feet under the ocean.
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- #1480 Venus crossed the Sun June5,2012 and the observation was used to calculate the distance to Venus , 27.6 million miles.
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- #1368 The reflectivity of Venus is 75% compared to Earth’s 29%.
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- #1176
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- #945 Venus greenhouse effect
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- #817 Some 20 probes / spacecraft have visited Venus from 1962 to 2013.
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- # 587 Venus is tilted 177 degrees, just 3 degrees from the perpendicular
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- (2) Mass of Earth 5.9742*10^24 kilograms. 4.87*10^24 kilograms, 81% Earth’s
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- Radius Earth = 3,962 Times 2*pi the circumference = 24,900 miles
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- Radius Venus = 3,760 miles Times 2*pi the circumference = 23,625 miles
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- Speed of equator, Earth in 24 hours = 1,038 miles per hour
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- Speed of equator in 243 days, Venus = 4 miles per hour
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--- 707-536-3272 ---------------------- Friday, January 23, 2015 ---
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