Earth in the UniverseEarth in the Universe

Or . . .where the heck did we Or . . .where the heck did we come from?come from?

Origin and age of the UniverseOrigin and age of the Universe

The majority of The majority of scientists think that scientists think that the universe is the universe is extremely vast and extremely vast and about 14 billion about 14 billion years old.years old.

They’re right, I was They’re right, I was there.there.

In the BeginningIn the BeginningThe Big Bang TheoryThe Big Bang Theory

The Big Bang theory states that about 14 The Big Bang theory states that about 14 billion years ago all matter and energy started billion years ago all matter and energy started out concentrated in a small area and started out concentrated in a small area and started expanding after a massive explosion.expanding after a massive explosion.

After approximately a billion years, matter After approximately a billion years, matter began to organize, forming stars and early began to organize, forming stars and early galaxies and the universe kept expanding. galaxies and the universe kept expanding.

Evidence of Big BangEvidence of Big Bang

Cosmic background radiationCosmic background radiation (microwaves) from Big Bang mixed with (microwaves) from Big Bang mixed with energy given off by stars in all parts of the energy given off by stars in all parts of the universe has been detected.universe has been detected.

Celestial objects are moving away from Celestial objects are moving away from Earth meaning that the universe is Earth meaning that the universe is expanding. This is proven by a expanding. This is proven by a red shiftred shift in in the electromagnetic spectrum due to the the electromagnetic spectrum due to the Doppler Effect.Doppler Effect.

Red ShiftRed Shift Every element in a star emits energy in specific Every element in a star emits energy in specific

electromagnetic wavelengths. electromagnetic wavelengths. By measuring these, scientists see a shift in the By measuring these, scientists see a shift in the

colored lines toward the red or blue end of the colored lines toward the red or blue end of the spectrum. This is due to the Doppler Effect.spectrum. This is due to the Doppler Effect.

Short Waves Long Waves

The Doppler EffectThe Doppler Effect

Waves are Waves are compressed to the compressed to the front and extended front and extended to the rear of a to the rear of a moving object.moving object.

When something When something is moving closer to is moving closer to Earth there is a Earth there is a blue shift and blue shift and moving farther moving farther away a red shift.away a red shift.

Structure of the UniverseStructure of the Universe

The basic structural unit of the universe is the The basic structural unit of the universe is the galaxy. galaxy.

A galaxy is a collection of billions of stars and A galaxy is a collection of billions of stars and various amounts of gas and dust held together various amounts of gas and dust held together by gravity. by gravity.

The average galaxy has over 100 billion stars The average galaxy has over 100 billion stars and there are over 100 billion galaxies.and there are over 100 billion galaxies.

Our solar system is part of the Milky Way Our solar system is part of the Milky Way Galaxy.Galaxy.

The Milky WayThe Milky Way The Milky Way is a spiral shaped galaxy.The Milky Way is a spiral shaped galaxy. Our solar system is positioned between two spiral arms Our solar system is positioned between two spiral arms

about two-thirds of the distance out from the galactic about two-thirds of the distance out from the galactic center.center.

Milky Way – top view Milky Way – top view and side view.and side view.

StarsStars

A star is a large ball A star is a large ball of gas held together of gas held together by gravity, that by gravity, that produces tremendous produces tremendous amounts of energy amounts of energy and shines.and shines.

Our sun is Earth’s Our sun is Earth’s closest star.closest star.

Energy ProductionEnergy Production

Nuclear fusionNuclear fusion is the process is the process of fusing together (or of fusing together (or combining) two nuclear combining) two nuclear particles, such as two particles, such as two protons, or a neutron and a protons, or a neutron and a Uranium nucleus. Uranium nucleus.

It occurs inside It occurs inside starsstars, and is , and is the main way in which stars the main way in which stars convert matter energy into convert matter energy into electromagnetic energy. electromagnetic energy.

Star ClassificationStar Classification Stars are classified Stars are classified

and grouped by and grouped by surface temperature surface temperature compared to compared to luminosity.luminosity.

About 90% of About 90% of studied stars appear studied stars appear in the in the main sequence.main sequence.

Our Sun is an Our Sun is an average star in the average star in the middle of the main middle of the main sequence.sequence.

SUN

Birth of the Solar SystemBirth of the Solar System

The solar system formed about 5 billion The solar system formed about 5 billion years ago from a rotating disk of years ago from a rotating disk of interstellar dust.interstellar dust.

Scientists hypothesize that the cloud Scientists hypothesize that the cloud began to slowly condense and spin due to began to slowly condense and spin due to gravitational attraction between particles.gravitational attraction between particles.

As the cloud spun faster it collapsed into a As the cloud spun faster it collapsed into a disk shape with a dense center.disk shape with a dense center.

Geocentric ModelGeocentric Model The The Geocentric ModelGeocentric Model of of

our Solar System, is a our Solar System, is a description of the description of the cosmos where where Earth is at the orbital is at the orbital center of all celestial center of all celestial bodies. This model served bodies. This model served as the predominant as the predominant cosmological system in cosmological system in many ancient civilizations many ancient civilizations such as ancient Greece. such as ancient Greece.

Heliocentric ModelHeliocentric ModelHeliocentrismHeliocentrism is the is the

astronomical model in astronomical model in which the Earth and which the Earth and planets revolve around planets revolve around a relatively stationary a relatively stationary Sun at the center of Sun at the center of the Solar System. the Solar System.

The Birth of the SunThe Birth of the Sun

As the concentration of As the concentration of gas continued to gas continued to collapse, temperature collapse, temperature and pressure at its center and pressure at its center increased.increased.

The temperature and The temperature and pressure became so pressure became so great that nuclear fusion great that nuclear fusion reactions began.reactions began.

This was the birth of our This was the birth of our Sun. Sun.

The Formation of the PlanetsThe Formation of the Planets

The materials in the disk surrounding the young The materials in the disk surrounding the young sun became the solar system’s planets and sun became the solar system’s planets and other objects.other objects.

Temperatures within the disk varied and as a Temperatures within the disk varied and as a result different elements and compounds result different elements and compounds condensed in different areas of the disk.condensed in different areas of the disk.

Heavier elements condensed in the hotter region Heavier elements condensed in the hotter region closer to the sun and lighter elements closer to the sun and lighter elements condensed farther out.condensed farther out.

Celestial bodies smaller Celestial bodies smaller than planets called than planets called planetesimals at first planetesimals at first formed.formed.

Through collisions and Through collisions and mergers the planets began mergers the planets began to form.to form.

The densest material sank The densest material sank to the center of the forming to the center of the forming planets. And the lighter planets. And the lighter elements formed layers elements formed layers closer to the surface.closer to the surface.

For example, For example, dense elements dense elements such as iron and such as iron and nickel make up nickel make up Earth’s core and Earth’s core and less dense less dense elements such as elements such as silicon and oxygen silicon and oxygen make up Earth’s make up Earth’s crust.crust.

The Terrestrial Planets

The inner planets closest to the sun are all rocky and dense.

All of the terrestrial planets are close in size to Earth.

In order for the sun they are: Mercury, Venus, Earth and Mars.

Asteroid BeltAsteroid Belt

The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets.

Jovian or Gas PlanetsJovian or Gas Planets

The Jovian Planets are far from the Sun and The Jovian Planets are far from the Sun and largely gaseous.largely gaseous.

They have relatively large diameters, low They have relatively large diameters, low densities and no solid surfaces.densities and no solid surfaces.

These planets have many moons and rings. These planets have many moons and rings. In order from the Sun they are: Jupiter, Saturn, In order from the Sun they are: Jupiter, Saturn,

Uranus and Neptune.Uranus and Neptune.

PlutoPluto• Little is known about Pluto due to its great distance from us.

•There is debate about whether it is actually a planet or a large asteroid.

•Currently, Pluto is not classified as a planet.

Our Solar SystemOur Solar System

How to Remember the PlanetsHow to Remember the Planets

MMy y VVery ery EExcellent xcellent MMother other JJust ust SServed erved UUs s NNachos.achos.

Mercury, Venus, Earth, Mars, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, NeptuneJupiter, Saturn, Uranus, Neptune

Motions of the PlanetsMotions of the Planets

Planet rotation – spinning on an imaginary Planet rotation – spinning on an imaginary axis.axis.

Period of rotation – the amount of time it Period of rotation – the amount of time it takes for a planet to make one rotation. takes for a planet to make one rotation. This determines the length of a planet’s This determines the length of a planet’s day.day.

Ex. Earth’s period of rotation is 23hrs, Ex. Earth’s period of rotation is 23hrs, 56min, 4 sec. Neptune is 16hrs.56min, 4 sec. Neptune is 16hrs.

Period of revolution – movement around the sun Period of revolution – movement around the sun in a path called an orbit. Ex. Earth’s is 365.26 in a path called an orbit. Ex. Earth’s is 365.26 days, Pluto’s is 247.7 years. days, Pluto’s is 247.7 years.

A planet’s period of revolution increases the A planet’s period of revolution increases the farther away it is from the sun.farther away it is from the sun.

Earth’s orbit and other planets is in a shape Earth’s orbit and other planets is in a shape called an ellipse. called an ellipse.

The degree of flattening of an ellipse is called The degree of flattening of an ellipse is called eccentricity.eccentricity.

Revolution EccentricityRevolution Eccentricity• How far it is from a perfect circle.• A perfect circle is 0, a straight line is 1.

How Eccentricity is CalculatedHow Eccentricity is Calculated

distance between focilength of major axis

Eccentricity =

Major Axis

Foci

The sun is always one of the focal points.The sun is always one of the focal points. The elliptical shape of planetary orbits causes The elliptical shape of planetary orbits causes

the planets to vary in distance from the sun the planets to vary in distance from the sun during a revolution.during a revolution.

AphelionAphelion is farthest away and is farthest away and PerihelionPerihelion is is closest.closest.

Gravity and Orbital VelocityGravity and Orbital Velocity

Gravity – the attractive force that exists Gravity – the attractive force that exists between any two objects in the universe.between any two objects in the universe.

Larger objects with more mass exert a Larger objects with more mass exert a greater gravitational force. Objects closer greater gravitational force. Objects closer together also exert a greater gravitational together also exert a greater gravitational force.force.

When a planet is closest to the sun its When a planet is closest to the sun its orbital velocity increases. Farther away it orbital velocity increases. Farther away it decreases.decreases.

Closest to the Sun a planet has the fastest orbital velocity due to the gravitational pull of the Sun.

Fastest hereSlowest here