Earth

Physical Properties

• Surface Gravity: 9.80 m/s^2
• Escape Speed: 11.2 11.2 km/s
• Sidereal rotation period: 0.9973 solar day
• Axial tilt: 23.45 degrees
• Magnetic axis tilt relative to rotation axis: 11.5 degrees
• Mean Surface temperature: 290 K
• Number of moons: 1

Physical Properties (cont)

• Orbital Semimajor Axis: 1.00 AU (149.6 million km)
• Orbital Eccentricity: 0.017
• Perihelion: 0.98 AU (147.1 million km)
• Aphelion: 1.02 AU (152.1 million km)
• Mean Orbital Speed: 29.79 km/s
• Sidereal orbital period: 1.000038 tropical years
• Orbital Inclination the Ecliptical: 0.1 degrees
• Mass: 5.976 * 10^24 kg
• Equatorial Radius: 6378 km
• Mean Density: 5520 kg/m^3

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Orbital Properties

• Earth spins on a line called the axis which runs from the North Pole to the South Pole, while also orbiting the sun.
• The tilt of Earth's axis results in the planet receiving varying amounts of sunlight throughout the year, causing a change in season.
• It takes Earth 24 hours to complete a rotation on its axis(solar day), and roughly 365.256 days to complete an orbit around the sun(sidereal year).
• Earth orbits around the sun in an ellipse

Fun Facts

• Earth is mostly iron, oxygen, and silicon
• It is the only planet not named after a God
• Earth's water was initially trapped within the planet
• It has relatively few visible impact craters
• It's not perfectly round due to its equatorial bulge
• Standing on the equator you would be spinning around Earth's center at 1000 miles per hour. At the poles you would be standing still
• Humans have only explored 5% of the ocean
• Some scientists believe that at one point, the Earth may have had two moons
• It's been called the "Goldilocks Planet"
• 620 million years ago, the Earth day was 21.9 hours long

The Atmosphere

The Atmosphere (cont.)

• Earth reradiates heat absorbed from the sun, partially trapped solar rays (Greenhouse Effect)
• Primary atmosphere (H, He, Methane, Ammonia, H2O), Secondary atmosphere (expelled by volcanic gases), Mostly N atmosphere appeared

• atmospheric density decreases with increasing altitude
• convection (rising of warm air replaced w/ cool air) occurs in the troposphere contributes to convection cells/atmospheric heating
• ionosphere is highly ionized by the Sun's high energy of its radiation spectrum; ionization degree increases w/ altitude
• ozone layer: metween mesosphere/stratosphere, incoming solar uv rays absorbed, damaged by chlorofluorocarbons

Earth's Composition

Earth's Surface

Composition cont.

• 30% of the Earth's surface is made up of landmasses & 70% of it is made up of water
• The outer layer formed a hard, rocky crust as lava cooled about 4.5 billion years ago
• This crust is made up tectonic plates which are constant motion due to convention currents on the mantle; these cause earthquakes & mountain ranges when they collide
• These plates are floating on the lower mantle
• They move an inch per year (continental drift)

• The crust is composed of 47% oxygen; 27% silicon; 8% aluminum; 5% iron; 4% calcium; 2% magnesium, potassium and sodium
• The mantle is roughly 1,800 miles deep and is composed mostly of silicate rocks rich in magnesium and iron.
• The inner core is made of iron and has a radius of about 760 miles. The outer core is composed of a nickel-iron alloy and is about 1,355 miles thick.

• Earth is a rocky planet
• Earth's outermost layer is the crust. It is divided into huge tectonic plates that move frequently, causing earthquakes or the formation of deep trenches when they collide.
• The mantle is the middle layer composed of silicate rocks which rise when heated and sink when cool.
• The Earth's core is made up of two parts: the solid inner core and the liquid outer core

Earth's Moon

• The Earth has one moon
• It goes through phases from the new moon to the full moon in about 27.3 days (sidereal month)
• The moon is 4.53 billion years
• It is about 1/4 the size of the Earth but bigger than Mars
• Evidence suggests that it formed when a big collision tore a chunk of Earth (large impact theory)
• It is made up of mostly iron & causes tides as its gravity pulls on the Earth

Internal Structure

• Earths internal structure is divided into three parts which are the Crust, Mantle, and core.
• The outermost layer is the crust. The crust is the thinnest layer of the Earth ranging from 3-30 miles thin.
• - The crust has two main divisions which are the oceanic crust and the continental crust.
• - The oceanic crust is thinner (3-4 miles) and is composed of basalt. The continental crust is 20-30 miles and is composed primarily of granite.
• The next layer of Earths interior is the mantle. It is composed of rocks that are rich in iron and magnesium. It has an average thickness of 1,793 miles.

Earth's Magnetosphere

Internal Structure ...

• Earths magnetosphere is formed through the interaction of solar winds and Its magnetic field.

• The Bow shock is formed when the pressure from solar winds compresses the impact side of Earths magnetic field.

•The magnetosheath is between the bow shock and magnetopause and it is an area of high particle energy flux. This is an area where solar winds collect and form pressure.

• At the magnetopause, the pressures from solar wind and the planetary magnetic field are balanced.

• The magnetotail extends far beyond Earth with two main lobes called the Northern and Southern tail lobes. (3,900,000 mi) These tails are the source of polar auroras.

• - The mantle makes up about 84% of Earth's volume.
• - The Upper mantle is made up of rocks brittle enough to break and collide causing the formation of Earths features. The 7/8 major tectonic plates are found between the lower crust and upper mantle of the Earth.
• - Earths plates are moved by convection that is caused by the heat of the core.
• The innermost layer of the earth is the core. •The core has a radius of 2,000 miles and is mainly made up of iron and nickel alloy.
• The core is divided into a liquid outer core and a solid inner core. Although the inner core has a higher temperature, the pressure from all of the surrounding rock forces the atoms tightly together which prevents the liquid state.
• The core is the source of Earths internal heat as it contains radioactive materials that release heat as they break down. (Potassium 40, Uranium 238, Thorium 232)

Earth

Kassandra Perez, Noelani Powers, Juan Rivera, Sabrina Wahid