Moon

MOON...what do you know about moon? why the moon is vital for life?
let's explore about moon !
first... we should know the characteristics of moon.

The Moon is an astronomical body that orbits planet Earth, being Earth's only permanent natural satellite.

Distance to Earth: 384,400 km

Radius: 1,737 km

Gravity: 1.622 m/s²

Orbital period: 27 days

Polar radius: 1736.0 km (0.273 of Earth's)

Axial tilt: 1.5424° to ecliptic; 6.687° to orbit plane;

Miguel Claro recently sent Space.com this beautiful image of the moon and Earthshine taken from Almada, Portugal on Feb. 1, 2014. “I could see the night side of the moon very well illuminated by the Earth reflected light, like if it was full moon,” Claro wrote Space.com in an email. “This impressive phenomenon known as Earthshine, was described and drawn for the first time, by the great Leonardo Da Vinci about 500 years ago in his book Codex Leicester.”

Credit: Miguel Claro | www.miguelclaro.com

HOW BIG IS THE MOON? 

Earth's moon is the brightest object in our night sky. It appears quite large, but that is only because it is the closest celestial body. The moon is a bit more than one-fourth (27 percent) the size of Earth. Did you know that Earth's moon is the fifth largest moon in the solar system.

The moon's mean radius is 1,079.6 miles (1,737.5 kilometers). Double those figures to get its diameter: 2,159.2 miles (3,475 km). The moon's equatorial circumference is 6,783.5 miles (10,917 km).

The moon's surface area is about 14.6 million square miles (38 million square kilometers), which is less than the total surface area of the continent of Asia (17.2 million sq mi or 44.5 million sq km).

Mass, density and gravity

The moon's mass is 7.35 x 1022 kg, about 1.2 percent of Earth's mass. Put another way, Earth weighs 81 times more than the moon. The moon's density is 3.34 grams per cubic centimeter (3.34 g/cm3). That is about 60 percent of Earth's density. The moon is the second densest moon in the solar system; Saturn's moon Io is denser, with 3.53 g/cm3.

The moon's gravitational force is only about 17 percent of Earth's gravity. A 100-pound (45 kg) person would weigh only 17 pounds (7.6 kg) on the moon. A person who can jump up 10 feet on Earth would be able to jump almost 60 feet on the moon.