Earth Moon and Sun Earth Properties of Earth

Earth, Moon, and Sun

Earth

Properties of Earth n Earth is a sphere - As early as 350 BC astronomers thought the Earth could be round - They saw shadows during eclipses and ships on the horizon

Properties of Earth - Sailors were often also astronomers - The study of the moon, stars and other objects in space is astronomy

Properties of Earth - They saw that the stars changed heights in the sky depending on how far north or south they sailed

Properties of Earth - The Earth is not a perfect sphere - It bulges at the equator and flattens at the poles - This is because of gravity and rotation

Properties of Earth n The Earth is rotating - Earth rotates around an imaginary line called an axis

Properties of Earth - This is what causes night and day - One complete rotation takes 24 hours

Properties of Earth n The Earth is revolving - While the Earth is turning on its axis it is also orbiting the sun

Properties of Earth - This orbit is called revolution - The earth takes 365 ¼ days to revolve around the sun

Properties of Earth n The Earth has a magnetic field - Because of rotation of Earth and convection within Earth a magnetic field is generated

Properties of Earth - This creates a magnetic north and south - This magnetic field protects us from harmful solar radiation by trapping particles from the sun

Properties of Earth - When particles from the sun interact with Earth’s magnetic field, a glowing display called an aurora can be seen in the sky This was left out of the packet – you will have to write it in on your own in the top left margin!

Properties of Earth - Magnetic north is found at an 11. 5 o angle to the rotational axis

Properties of Earth - The magnetic field also produces lines of alternating charge in rock at mid-ocean ridges

Seasons on Earth n Orbiting the sun - Earth’s revolution around the sun places the planet at different distances from the sun at different times during the year

Seasons on Earth - It is farthest from the sun around July 4 and closest to the sun around January 3

Seasons on Earth - This is caused by Earth’s elliptical orbit - An ellipse is an oval shape

Seasons on Earth n A tilted axis - Earth’s rotational axis is tilted 23. 5 o - This causes the seasons

Seasons on Earth - Daylight hours are longer for the hemisphere that is titled toward the sun (summer) and shorter if tilted away (winter)

Seasons on Earth - The hemisphere tilted toward the sun also receives more solar radiation