venus and mercury
DESCRIPTION
Venus and Mercury. The Inner Planets. Venus. Only a bit smaller than Earth Nearest planet (26 million miles) Shows phases as it orbits the Sun Most circular orbit Atmosphere mostly Carbon Dioxide 90 times as dense as Earth Runaway Greenhouse Effect Surface Temperature 450 C (850 F). - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/1.jpg)
Venus and Mercury
![Page 2: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/2.jpg)
The Inner Planets
![Page 3: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/3.jpg)
Venus• Only a bit smaller than Earth
• Nearest planet (26 million miles)
• Shows phases as it orbits the Sun
• Most circular orbit
• Atmosphere mostly Carbon Dioxide– 90 times as dense as Earth– Runaway Greenhouse Effect– Surface Temperature 450 C (850 F)
![Page 4: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/4.jpg)
Venus’ Odd Rotation• Venus Rotates in 243 days relative to the stars• Longer than its year (225 days)• Solar Day = 117 days• You can jog as fast as Venus rotates• Opposite to all other planets’ rotation
(retrograde)• Why?
– Mega-Impact?– Tidal Effects?– Possible tidal lock on Earth?
![Page 5: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/5.jpg)
Venus from Pioneer Venus Orbiter
![Page 6: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/6.jpg)
Polar View of Venus
![Page 7: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/7.jpg)
Topography of Venus
![Page 8: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/8.jpg)
Earth Elevations
![Page 9: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/9.jpg)
Radar Map of Venus
![Page 10: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/10.jpg)
Radar Map of Venus
![Page 11: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/11.jpg)
Surface of Venus
![Page 12: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/12.jpg)
Venus has
Craters
![Page 13: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/13.jpg)
Venus is Volcanic
![Page 14: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/14.jpg)
“Pancake” Volcanoes
![Page 16: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/16.jpg)
Coronas
![Page 17: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/17.jpg)
How Coronas Form?
![Page 18: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/18.jpg)
Venus Differs from Earth in One Important Way:
• Venus has no Plate Tectonics
• Earth’s internal heat causes hot material to rise within Earth and plates to move
• Venus’ crust is too rigid
• Heat builds up and escapes in planet-wide volcanic activity
• Last event about 600 million years ago
![Page 19: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/19.jpg)
Why Venus Has No Plate Tectonics
• It’s Hot! We’d expect hot rocks to be less rigid, not more!
• But it’s also dry! Dry rocks are ten times stronger at high temperatures than wet rocks.
• Earth is wet. That affects not just the outside, but the inside as well.
![Page 20: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/20.jpg)
Did Venus Once Have Oceans?
• Resurfacing means no visible trace of early history
• Deuterium: Ghost of a Vanished Ocean?– Deuterium is hydrogen with one neutron– Twice as heavy as normal hydrogen– Less likely to escape– D/H on Venus 100x that of Earth
• Photodissociation + Stripping– Venus lacks magnetic field
![Page 21: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/21.jpg)
Venus and the Da Vinci Code• 13 Venus years = 13 x 224.7 = 2921.1 days
• 8 Earth Years = 8 x 365.25 = 2922 days
• 5 Synodic periods of Earth and Venus = 5 x 583.9 = 2919.5 days
• 1/5 of a circle = 72 degrees
• In 583.9 days, Earth moves 360 + 215.5 degrees (almost 360 + 3 x 72)
• In 583.9 days, Venus moves 720 + 215.5 degrees
![Page 22: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/22.jpg)
Venus and Earth
• 13 Venus years = 13 x 224.7 = 2921.1 days
• 8 Earth Years = 8 x 365.25 = 2922 days
• 5 Synodic periods of Earth and Venus = 5 x 583.9 = 2919.5 days
• 12 Venus rotations = 2916 days
• Venus shows nearly the same face to Earth every 584 days.
![Page 23: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/23.jpg)
Venus and Earth
![Page 24: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/24.jpg)
Mercury• Closest planet to Sun
• Very elliptical orbit (e = .205)
• Only 3000 miles (5000 km) in diameter
• Rotation locked to Sun: 3 rotations in 2 orbits (58 days)
• Moon-like on the outside (craters)
• Earth-like on the inside (dense core, magnetic field)
![Page 25: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/25.jpg)
Mercury’s Rotation
![Page 26: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/26.jpg)
Mercury’s Interior
• Density = 5.43 (Earth = 5.5)
• Much smaller than Earth, less pressure inside
• Core about 2/3 of Mercury’s diameter (Earth = ½)
• Mega-Impact may have blown away silicate outer part
![Page 27: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/27.jpg)
Mercury from Mariner
10, 1973
![Page 28: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/28.jpg)
Mercury has Craters
• Not as dense as on Moon
• Most of Mercury covered with lava plains (intercrater plains)
![Page 29: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/29.jpg)
Mercury has a huge
impact basin, the
Caloris Basin
![Page 30: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/30.jpg)
Because of Mercury’s locked rotation, it has two
“hot poles”
![Page 31: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/31.jpg)
And Mercury has the last thing you’d expect to find: ice caps
![Page 32: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/32.jpg)
Mercury’s ice seems to be hiding in polar craters
![Page 33: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/33.jpg)
We’re B-a-a-ck
![Page 34: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/34.jpg)
![Page 35: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/35.jpg)
“Spider” Crater
![Page 36: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/36.jpg)
Caloris Basin
![Page 37: Venus and Mercury](https://reader035.vdocuments.us/reader035/viewer/2022062315/568151fd550346895dc03673/html5/thumbnails/37.jpg)
Volcano on Mercury