Bellwork

1. What is the force that pulls the planets towards the sun?

2. What is the force that wants the planets to keep in a forward motion in a straight line?

3. How many planets do we have now?

4. Give another name for the inner planets. Give another name for the outer planets.

In your Table of Contents…

• Add Mercury and Venus Notes

Mercury• Closest to the sun• No moons• Extremely hot

temperatures on one side and extremely cold temperatures on the other.

• Now the smallest planet in our solar system

Mercury• Physically, Mercury is similar in

appearance to our moon as it is heavily cratered.

• Mercury has a rocky body like the Earth, but its atmosphere is very thin or weak.

• Mercury has been visited by only one spacecraft, Mariner 10.

First fly-by was on March 29, 1974. Many photos were taken and Mariner 10’s infrared radiometer was able to take measurements of the gases in Mercury’s atmosphere.

3 Mercurys = 1 Earth

Mercury’s Orbit: The first orbital path from the sun.

Mercury

• Distance from sun• Period of rotation• Period of revolution• Diameter• Surface temperature• Surface gravity

3.2 light-minutes58 days, 16 hours88 days4,879 km-173 to 427°C38% of Earth’s

VENUS

• Second planet from the sun

•Rotates in the opposite direction than earth (Venus=retrograde)

•Venus has no moons

•Is the hottest planet

Earth’s Twin?

• In many ways, Venus is like Earth’s twin.

• They have about the same size, mass, and density.

• BUT…Venus rotates in a different direction so… the sun rises in the west and sets in the east. (Retrograde rotation)

http://www.cosmos4kids.com/extras/dtop_solsyst/venus_580.jpg

Venus• Has the most dense atmosphere than any of the

terrestrial planets• Mainly consists of carbon dioxide but also some

deadly acids• The carbon dioxide traps thermal energy

causing a greenhouse effect-causing the temperature to be so high

• Average temperature 464*C • Venus has the hottest surface of any other

planet in the solar system!

Venus is’ Orbit

Second orbital path

VENUS

• Distance from the sun• Period of rotation• Period of revolution• Diameter• Density• Surface Temperature• Surface gravity

• 6.0 light-minutes• 243 days (retrograde)• 224 days, 17 hours• 12,104 km• 5.24 g/cm3• 464* C• 91% of Earth’s

• Venus is the brightest object in the sky after the Sun and the Moon, and sometimes looks like a bright star in the morning or evening sky. We can't see the surface of the planet because it has a very thick atmosphere filled with clouds that strongly reflect sunlight.

• Nonetheless, space missions sent to Venus have managed to land on and photograph the surface while the Magellan spacecraft mapped the surface of the planet from above.

• These maps reveal a surface covered with craters, over 1600 major volcanoes, mountains, large highland terrains, and vast lava plains.

MagellanMay 4, 1989

VenusVenus

http://www.sciencechannel.com/video-topics/space-videos/mercury.htm

(space school)

Add a fact about Mercury and Venus to your Planetary Placement.