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---------------------- 2735 - VENUS - explain its strange rotation ?
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- What causes Venus’ atmosphere to have a “super-rotation“. On Venus, the winds can move up to 60 times faster than the planet itself, and though the planet takes 243 days to rotate, the atmosphere only takes four days to circle the planet. That works out great for airplane routes.
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- This particular Review discusses the strange rotation of the Venus” atmosphere. There are several more Reviews that are about other interesting aspects of our sister planet. Here is one and the others are listed at the end of this Review.
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- 2246 - Venus our sister planet. What is it really like there? What are the “gravity waves” spotted in its upper atmosphere? Could Venus ever have had conditions that could support life? Could this tell us about the likelihood of finding life on similar bodies like these exoplanets? What is the history and the math used to study the planet next door?
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- Think about the very first paragraph for a minute. The winds are moving 60 time faster than the planet underneath them? How is that possible?
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- For comparison, Earth’s atmosphere moves much slower at between 10% to 20% the speed of the planet. That is why its takes less time to fly to New York and longer for the return flight back to San Francisco.
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- Scientists have known since the 1960s that Venus is a super-rotator, but haven’t been able to figure out why.
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- In 2016, researchers found a large stationary gravity wave structure in Venus’ atmosphere. The bow-shaped structure stretched for 6,200 miles across Venus’ cloud tops. It remained stationary relative to the surface of the planet, while the atmosphere maintained its super-rotation.
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- In 2018, scientists proposed what role the massive wave played in the planet’s super-rotation. The gravity wave on Venus is so huge because the atmosphere only moves in one direction, while on Earth, for example, more variable winds don’t create such massive wave structures. This huge wave tugged on the planet, altering its rotation rate, but that does not explain Venus’ super-rotation.
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- There is more going on in Venus’ atmosphere, and that the super-rotation is related to not only atmospheric tidal waves, but to other features as well. There are two contributing factors to Venus’ super-rotation.
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- At the equator, solar heating creates atmospheric tidal waves on the day side. On the night side, cooling creates the same waves.
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- At the poles, something else is happening. Atmospheric turbulence and other kinds of waves are having a more pronounced effect.
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- Spacecraft carrying five different cameras: three infrared, one ultraviolet, and one visible light, are imaging the atmosphere. The ultraviolet and infrared images from the spacecraft develop a precise method of tracking clouds. The cloud tracking led to accurate measurement of wind velocities. From there estimates were made on what contribution the atmospheric waves and the turbulence made to Venus’ super-rotation.
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- The first thing was temperature variations. There were atmospheric temperature variations between altitudes that couldn’t be explained, unless there was atmospheric circulation across latitudes. Since such circulation should alter the wind distribution and weaken the super-rotation peak, it also implies there is another mechanism which reinforces and maintains the wind distribution.”
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- What was these other mechanisms? After more analysis of the data, and more modeling, the scientists came up with something else: the “thermal tide“. A thermal tide is a variation in atmospheric pressure due to the diurnal differential heating of the atmosphere by the sun. This thermal tide is responsible for the wind at low latitudes.
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- These thermal tides play a role in acceleration at mid and high-latitudes, while having a small deceleration effect at low latitudes.
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- The proposed system maintains this super-rotation of Venus' atmosphere. The thermal tide towards the equatorial top enforces the westward super-rotation.
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- The atmosphere is controlled by a dual circulation system: the vertical circulation that slowly transports heat towards the poles and the super-rotation that rapidly transports heat towards the planet's nightside.
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- Circulation along meridians slowly moves heat towards Venus’ poles, while super-rotation moves heat from the day-side to the night-side.
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- Venus has a very long solar day. It took scientists a several Venus years to figure all this out.
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----------------------- Other Reviews available about the planet Venus:
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- 1925 - Venus our sister planet . . What is it really like there? What are the “gravity waves” recently spotted in its upper atmosphere? What is the history and the math used to study the planet next door?
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- 1873 - Venus and Mercury. Space probes to the inner planets have brought us new knowledge of the Solar System formation. Like expected new knowledge has brought new mysteries to solve.
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- 1778 - Venus must have some resurfacing hiding many old crater scars. Mars and Venus, our Sister Planets. Mars has become a cold, dry desert with an ultra-thin atmosphere. Venus has turned itself inside-out with intense heat and an ultra-thick atmosphere. Earth is in the middle.
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- 1729 - Walk with Venus on a Starry night .
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- 1368 - - Venus is our nearest planet. Next to the Moon it is the brightest object in the night sky. Its reflective clouds make it the brightest in reflecting sunlight. A property called “albedo” , or, reflectivity. The Reflectivity of Earth is 29%. The reflectivity of the Moon is 12%. The reflectivity of Venus is 75%.
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- 945 - Venus greenhouse effect.
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- 817 - Venus mysteries. Venus is our next door neighbor in the Solar System. It is about the same size as Earth, 82% in mass but 95% in diameter, 7,521 miles versus Earth’s 7,926 mile diameter. Venus is closer to the Sun at 72% of the Earth-Sun distance. You would think that Venus would have many more similarities with Earth, but the truth is it could not be much different. Venus is the brightest, hottest, deadliest, second closet planet to the Sun.
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- 587 - Venus is tilted just 3 degrees from perpendicular. It takes 163 days to reach our sister planet, the second rock from the Sun, and it should arrive in April, 2006. Venus is the third brightest object in the Sky following the Sun and the Moon. It is also called the evening star and the morning star. It is our sister planet because it is so close, formed at the same time and about the same size. Venus diameter is 7,521 miles, Earth is 7,926 miles, a difference barely the distance from San Francisco to Los Angeles. Venus is 5 *10^24 kilograms and Earth is 6*10^24 Kilograms, 81.5% the mass of the Earth . But Venus is different:
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- 1480 - Learn how to calculate the Venus transit of the Sun. It happened in 2012. The transit took 67 hours on June 12. The next transit is in 2117. These transit measurements were first made in 1761, then again in 1769 making a calculation for the Earth - Sun distance to be 93,726,000 miles. Today our precise measurement is 92,955,000 miles.
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- May 9, 2020 2735
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--------------------- Sunday, May 10, 2020 -------------------------
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