Earth and Moon How Earth and the Moon Compare

Earth and the Moon in Space The earth and moon are part of the sun’s planetary system. The sun’s gravity causes the Earth-moon system to revolve (travel in a closed space). Orbit = the path Earth takes as it revolves. Earth’s orbit is an ellipse.Orbit Earth rotates (spins on its axis) around the sun in days. Axis = imaginary line that passes through Earth’s center and its North and South Poles. Night and day is determined by Earth’s rotation.

Earth and the Moon in Space Earth’s gravity causes the moon to revolve around the Earth in an ellipse orbit. The moon rotates on its axis in 27.3 days. The same side of the moon always faces this earth because it takes 27.3 days to orbit the earth and 27.3 days to rotate once on its axis. The moon reflects sunlight. Different shapes (phases) of the moon occur because the as it orbits the earth, it has a different position in the sky.(phases)

Solar and Lunar Eclipses Shadows occur in space Eclipse = a shadow that occurs when one object passes through the shadow of another Solar eclipse happens when Earth passes through a new moon’s shadow –Moon is completely covered by the sun –Sky darkens and only the outline of the sun shows –Partial eclipses occur when the earth passes through part of the moon’s shadow Lunar eclipse happens when a full moon passes through Earth’s shadow –Earth passes between the sun and the moon –The moon looks like a dim red circle There are seven eclipses in a year because the shadows don’t always line up –Two lunar eclipses –Five solar eclipses

The Moon’s Surface Moon began as hot, molten rock that cooled into a rocky crust There are 3 landforms on the moon –Craters –Highlands –Dark, flat areas There are large craters (as big as 54 miles across) and small craters (smaller than your fingernail) The dark flat areas were thought to be seas (maria) but are hardened lava As molten rock overflowed in some craters it cooled and formed basalt rock

Comparing Earth’s and the Moon’s Features Same… –Both Earth and the moon are rocky and dense –Both Earth and the moon are made up of the same materials (calcium, aluminum, oxygen, silicon, iron) –Craters are found on both the moon and the Earth Different –The moon has no atmosphere –The moon has no liquid water –The moon cannot be eroded by wind and water –The moon’s surface weather’s VERY slowly (millions of years).6