EARTH in Space

with average distance of 92,955,820 miles (149,597,890 km) from the sun,

is the third planet and one of the

most unique planets in the solar system.

It formed around 4.5-4.6 billion years

ago and is the only planet known to

sustain life.

presence of water over 70.8% of

the planet allow life to thrive.

Earth is also the fifth largest planet

in the entire solar system.

EARTH

Earth has an estimated mass of 5.9736 × 10 24 kg.

Its volume is also the largest of these planets at 108.321 × 10 10km.

Earth is the densest of the terrestrial planets as it is made up of a crust, mantle and core.

•Earth's Size

Earth’s Rotation and Revolution

As the earth revolves around the sun, Earth’s axis remains tilted at 23.5°

The north end of the axis points toward the north star (Polaris)

Earth rotates 360° from west to east (counter clockwise looking down from the north pole) in 24 hours, at an angular rate of l5° per hour (360°/24 hours = 15°/hour)

•Earth’s Rotation

•Tilt of the axis always stays the same

• • 1851, Foucault’s pendulum will appear to change in a predictable way.

• • Why is this evidence? There is no force acting on the pendulum to make its plane of oscillation rotate or go around its own axis

• • It would continue to swing in the original path if Earth did not rotate.

•1. Evidence of Earth’s Rotation

• • Coriolis Effect – the tendency of objects moving over the earth (air, water, planes, projectiles) to be deflected (curve away) from a straight line path. The French scientist, Gaspard Coriolis, first explained the deflection of objects moving over the surface due to Earth’s rotation

• • The deflection is to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

• • This deflection occurs because Earth’s surface is rotating with respect to the objects.

•2. Evidence for Rotation

Earth’s Revolution

• Earth revolves around the sun in a slightly eccentric elliptical orbit or path once a year• It takes Earth 365.25 days to revolve 360° in its orbit around the sun. It moves approximately 1° per day. (360°/365.26 days = 1° per day)• Aphelion – the point on the Earth’s orbit is farthest from the sun.(Early in July)• Perihelion – the point of the Earth’s orbit is nearest the sun.(January)

• • Seasonal Constellations: Because of the Sun’s annual motion, some constellations are visible at night only during certain seasons.

• • Constellations are visible when the dark side of Earth (away from sun) faces toward the constellation.

•Evidence of Earth’s Revolution around the Sun

•The 12 constellations the sun appears to travel through during the year

• • Because of Earth’s revolution about the sun, near stars seem to shift their position against the farther stars (closer star – greater the shift)

• • If you observe the same star while earth is at 2 different points during its orbit around the sun, the star’s position relative to the more distant background stars will appear to change.

Evidence of Revolution: Parallax Shift

•Parallax Shift

SUMMER

• • The sun is nearer the center of the sky; rays fall directly to the ground and the radiation is more intense and more concentrated.

• • The hottest time of the year.

• • This begins about June 22 in the northern hemisphere

and December 22 in the southern hemisphere.

WINTER

• • The sun is lower; nearer the horizon.

• • Heating is less intense and the nights are longer than the day.

• • Longer night of the year occurs in December 22 in the north and June 22 in the south.

•The Earth’s Seasons

SPRING OR VERNAL EQUINOX

• • All parts of the earth receive the same amount of sunlight.

• • Daytime is equal to night time

• • In the Northern Hemisphere, it begins on the 21st day of March.

AUTUMN OR FALL EQUINOX

• • Direct rays of the sun strike the equator.

• • 12 hours of days and nights throughout the world.

• • In the Northern Hemisphere, it starts on the 23rd day of September.

The Earth’s Precession

It is conical movement of the Earth’s axis around a line joining the poles.

It lasts for a period of 25,780 years

It is like the conical motion of a spinning top but opposite in direction to that of the rotation of the earth.

This is the reason why our polar star keeps on changing. During the building of the pyramids-Thuban is the polar star and many years from now, it will be the star Vega.

LOCATION and TIME

All places were located their distances from two lines.

•Latitude - The north-south location of any place on the earth.

•Longitude – The east-west position of a place.

•

• Location

Parallels of Latitude-Changes in location in a north or south

direction are described by just such a system of lines parallel with the equator.

•

•North Latitude• - includes all the parallels that can be

drawn between the equator and the north pole.

South Latitude• - includes those parallels between the

equator and the south pole.

Meridian- Imaginary Lines

Prime Meridian- Longitude line

• Longitude

•Sundial• Time measured with a sundial is called “Apparent solar time”.

• (Perihelion) Nearest the sun• - 91,300,000 miles from the sun.

• (Aphelion) Farthest point• - 94,500,000 miles.

• Average Distance• - 92,900,000 miles.

•Time by the Sun

Thank you for listening

God Bless