Mercury

The Planet Mercury is the closest planet to our sun. It is the smallest planet in the solar system. It has NO Moons.

The Mariner spacecraft was first to photograph Mercury in 1975. it only mapped 40%–45% of the planet's surface. The Messenger Spacecraft launched in 2004 to photograph it in more detail.

In Roman mythology; Mercury is the God of commerce, travel and thievery. The planet probably received this name because it moves so quickly across the sky.

It orbits the Sun once every 88 days. (Pretty quick year!) How big? Diameter: 3,032 miles at its equator, which is about two-fifths of Earth's diameter. It orbits the Sun once every 88 days. (Pretty quick year!)

To make one orbit (revolution) in 88 days, Mercury has to travel at 30 miles per second!

36 million miles from the Sun. Rotates slowly… it takes 58.6 days to rotate once. This means there are less than 2 days in a Mercurian year! 5.5% the mass of the Earth

Has a very elliptical (oval-shaped) orbit. At perihelion (closest to Sun) it is about 28.5 million miles away. At aphelion (furthest from Sun) it is 43.5 million miles away.

Mercury is not easily seen from the Earth. because it is so close to the Sun!

The only planet more dense is Earth. The only planet that ROTATES slower is Venus. An object that weighs 100 pounds on the Earth would weigh only about 38 pounds on Mercury! (Less mass = less gravity)

Like Earth’s interior, it has a layered structure. Mantle, liquid outer core, and a solid inner core beneath the crust. How do we know? Mostly guess work! We observe surface features, size, infer density and use scientific theories that we test here on Earth to predict what it must be like.

The core generates a magnetic field only about 1% as strong as that of Earth's. The radiation would kill us quickly. WEAK!

Surface similar to that of our Moon. Mercury Moon The craters are made by rock impacts, and are never removed. no atmosphere! no rain, no wind, no erosion! Why no atmosphere? Not enough gravity to “hold on” to one.

Caloris Basin is largest crater at 800 miles in diameter. Such a hard impact, resulted in “weird terrain” on the other side of the planet because of the seismic waves.

Some craters on Mercury contain ice! The floors of the craters are permanently shielded from sunlight, so the temperature never gets high enough to melt the ice. Not what you’d expect on the closest planet to the Sun!

Extreme temperature variations: As high as 840°F in sunlight As low as -275°F in darkness Why? No atmosphere to “smooth out” temp