Mercury images- Similar to our Moon

0 Mercury images- Similar to our Moon

0 Venus & Mercury 2-8-07

0 I. Mercury A. 0.4 AU from sun

0 A.U.= Astronomical unit = 93,000,000 miles This is the distance of Earth from Sun so we compare all planets to our distance.

0 2. close to sun in sky a) morning or evening “star” ( not a star but looks like one. )

0 b) poor photos Earth’s atmosphere distorts image

0 Earth View

0 B. Rotation 1. once in 59 Earth days (siderial period) Siderial means with respect to stars.

0 C. Revolution 1. once in 88 Earth days Time to go once around the Sun.

0 D. Length of day (solar rotation) 1. 176 Earth days This is a strange effect. Look at the diagrams and I will explain it when I return.

0 2. One Mercury day = 2 Mercury years

0 3. Determine motion by RADAR Radio detection and ranging

0 E. Temperature 800 o F -280 o F

0 F. Albedo= 1. Light reflected Light received

0 2. Mirror albedo is 90% Black is 0% Mercury is 6%

0 3. Dark, like moon

0 G. Mass 1. 5.5% of Earth

0 H. Density 1. same as Earth 2. must have iron core

0 I. Spacecraft Observations 1. unmanned

0 2. Mariner 10 a) 3 flybys b) 1974

3. Messenger Mission Left Earth August 2004 Arrived at Mercury in 2011 Still There

0 4. Photographs a) craters flatter than moon

0 Why? greater gravity softer surface eroded

0 b) maria c) scarps cliffs hundreds of miles long

0 Scarps are wrinkles.... Cracks in the crust

0 scarp

0 4-22-13 scarp

0 d) Weird Terrain Grooved areas with smooth area in between

weirdterrain

Cause? 180o from large crater

Mercury images- Similar to our Moon