Mercury lesson 2

Roman god of Thievery, commerce, and travel. 

• 1st planet from the sun. 
• Ancient astronomers believed Mercury to be two different bodies but now it is known to be one body.
• It is a rocky planet. Temperatures range from 90 K to 700 K. 
• 1974, Mariner 10 took pictures of Mercury. Better pictures were taken in 2008. 
• Mercury so far seems to be completely bear.
• It's magnetic field is about 1/100th of earths. It is strong enough to deflect the solar wind and create a small magnetosphere around the small planet. 
• ^^^^ It is thought that it was a result of the fossil remnant when the core solidified. 
• Its interior must be dominated by a large, heavy, iron-rich core with a radius of around 1800 Kilometers. 
• A less-dense lunar-like mantle is above the core, to a depth of around 500-600 kilometers. Only around 40% of Mercury's volume (60% of its mass) is from inside its iron core.
• In the mid 19th century- Giovanni Schiaparelli used telescope to see it's surface features. He then concluded one side is always facing the sun. This is because the gravitational force that is on Mercury by the Sun had changed the planet’s rotation rate till the strongest pull on the magnetic field in the core was always pointed directly at the Sun!
• 1965- Discovered this was false. They sent radio signals towards Mercury and waited for the echoes to return. 
• The pulses were weaker than the original beam. The size of the radio signal dish allowed it to be possible for them to be able to find them and then study it to determine Mercury’s rotation rate.
• Mercury's rotation period is not 88 days. It is 59 days, 1/3 of the planet’s orbital period. 
• Mercury rotates three times when it has completed two orbits around the Sun.