1. Mercury Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Mercury, The Innermost Planet Mercury is one of the least explored planets in the Solar System –Makes it hard to observe because it NEVER gets more than 28º from the Sun’s glare. –Mariner 10 (1974) provided most of the information we have flew by the planet (at 10,000 Km) and sent pictures back to Earth. Mapped the whole planet –NASA’s MESSENGER mission returned to Mercury in 2011 for a more in-depth study.

3. Mercury, The Innermost Planet Planet of Extremes –On the dayside, surface temperatures is about 800.6 degrees F (427 C) –On the darkside, temperatures drop as low as -297 degrees F (-183 C) THIS IS THE MOST EXTREME TEMPERATURE RANGE between night & day OF ALL PLANETS. –Mostly due to NO atmosphere This causes the planet to shrink and swell.

4. Mercury, The Innermost Planet Planet “sort of” has an atmosphere BUT not really: –thin helium,(also sodium, oxygen, potassium & hydrogen)

5. Mercury, The Innermost Planet Atmosphere is blown away by the Solar Wind of the Sun. This is because of: –Low gravity of mercury. –And…

6. Mercury, The Innermost Planet The sodium and oxygen particles the blistering solar wind kicks up are the primary components of Mercury's wispy atmosphere, or "exosphere,“

7. Mercury, The Innermost Planet Through interacting with the solar wind, they become charged in a mechanism that's similar to the one that generates the Aurora Borealis on Earth.

8. Mercury, The Innermost Planet Planet of Extremes –Very eccentric orbit, coming as close as.29 AU and as far as 0.41 AU (.387 AU) 1 AU = 93,000,000 miles –(from sun to earth) Very elliptical orbit 36,000,000 miles (35,991,000 miles) –Tilt of 28 degrees –Incline plane of 7 degrees

9. Mercury, The Innermost Planet Planet of Extremes –Rotation period –58 days/15 min/28 sec (59 days) –spin on axis or day & night –Mercury rotates once every 58.647 days, which is exactly 2/3 of its orbital period of 87.970 days, so it turns on its axis exactly 1 1/2 times during one of its years,

10. Mercury, The Innermost Planet Planet of Extremes –Revolution period is 87.97 days (88 days) Rotation is one and a half times for each orbit around the sun. This means there are 3 days in every 2 years on Mercury This is the 3:2 Synchronous orbit –Caused by: »Close to the Sun »Very eccentric orbit »High Density »Tidal Torque (pull from Sun) –Means the same side faces SUNWARD at perihelion This makes it the MOST elliptical orbit of ANY major planet

11. 3:2 Orbital Resonance Mercury is tidally locked to the Sun –Similar to the way the Moon is tidally locked with the Earth –After one orbit around the Sun (88 days), the planet has rotated on its axis 1.5 times –It then takes two orbits for Mercury to rotate three times!

12. 3:2 Orbital Resonance Mercury is tidally locked to the Sun –Similar to the way the Moon is tidally locked with the Earth –After one orbit around the Sun (88 days), the planet has rotated on its axis 1.5 times –It then takes two orbits for Mercury to rotate three times!

13. 3:2 Orbital Resonance Mercury is tidally locked to the Sun –This is called a 3:2 orbital resonance –Sunrise and sunset are very strange on this planet! The Sun actually undergoes retrograde motion through Mercury’s sky!

14. Most likely resembles the Moon Surface is covered with craters and lava flows Fewer of the craters overlap Craters are similar to the Moon’s, with rays and crater walls Lower crater rims due to Mercury’s higher gravity

15. Caloris Basin Early in Mercury’s history, a huge impact occurred on the surface

16. Caloris Basin Formed an impact site known as the CALORIS BASIN

17. Caloris Basin CALORIS BASIN It is a Large Basin that almost split planet in two. Planet hit with a 60 mile wide iron Meteor. Leaving the LARGEST CRATER IN THE S.S.

18. Caloris Basin CALORIS BASIN 300Km (812.5miles) across and about 1 mile high

19. Caloris Basin The impact was so great that shock waves traveled through the planet and shook up the terrain on the opposite side!

20. Caloris Basin This created on the other side (opposite) where shock wave converged is known as WEIRD TERRAIN It formed about Kilometer or 2 per SECOND… Also there are Cliffs similar to earth (Valley) called: Scarps

21. Scarps Running across Mercury’s surface are scarps, kilometer-tall cliffs that are the result of the shrinking of the planet as it cooled Scarps are similar to wrinkles in an apple’s skin that form as it dries The presence of these cliffs suggests that the core of Mercury is large and metallic – something that would shrink significantly as it cools

22. The Interior of Mercury Mercury’s density is unusually high, 5.4 kg/liter Indicates a very large iron core covered by a thin silicate mantle

23. The Interior of Mercury Sounds of the Planet https://www.youtube.com/watch?v =894Aejo-R0U

24. The Interior of Mercury Mercury may have a molten iron core, despite its size This core may be the cause of the weak magnetic field (similar in shape to the Earth’s, but much weaker)

25. Why is Mercury so dense? It is possible that Mercury once had a thicker mantle, but a collision removed most of the material, leaving only the core and a little lighter mantle material behind

26. Unit 38 Mercury Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.