Astronomy

What do YOU know about the Universe? DO NOW/Warm-Up Answer Question: What do YOU know about the Universe? Discovery Education : A View of the Universe Write Questions in Do Now Section of Binder Follow along by answering the questions as you watch the video Title: Discovery Education : A View of the Universe What is another name we can use to call the universe? What can each point of light in the universe become? What is the yellow star in the spiral galaxy orbited (circled) by eight planets called? About how old is the universe? (http://player.discoveryeducation.com/views/hhView.cfm?guidAssetId=fafa34ff-5c7c-44f5-9422-e989f1967d1c&play=true&preview=true&skin=&small=true)

Day 1 Lesson Objective Today you will be able to: Explain the origin of the Earth’s motion based on the origin of the galaxy and its solar system. Recall Earth’s role in the hierarchy of organization within the universe and in the developmental continuum. (Universe is made of galaxies which are made of many stars. Some stars have planetary systems similar to our solar system. Earth is a satellite planet of one particular star.)

How our Universe Formed Theory of how the universe formed called the Big Bang Theory Big Bang Theory – the universe formed from a massive expansion approximately 14 bya The Universe is expanding and the visible edge is about 13.7 billion light years away

The universe began billions of years ago as a tiny dot that exploded into today’s huge system of stars and planets.

Cosmic background radiation Support for the Big bang Theory Red shifts Cosmic background radiation Radio signals coming from every direction in space. Believed to be created by the big bang explosion.

The Expanding Universe 1929 – Edwin Hubble found that the universe is expanding Estimated distances, relative brightness, Doppler red shifts

Dimmer galaxies had greater red shifts  farthest from Earth https://www.youtube.com/watch?v=y5tKC3nEx2I Hubble’s Law: the more distant the galaxies have greater red shifts, therefore they are moving away at faster speeds. Milky Way Galaxy…spiral shaped!

Hubble Law Lab Hubble’s Law : the more distant galaxies have greater red shifts, therefore they are moving away at faster speeds.

Hubble’s Law

Transitioning to Objective # 2 • Recall Earth’s role in the hierarchy of organization within the universe and in the developmental continuum. (Universe is made of galaxies which are made of many stars. Some stars have planetary systems similar to our solar system. Earth is a satellite planet of one particular star.)

Note: Our solar system is part of a bigger system called a galaxy Note: Our solar system is part of a bigger system called a galaxy. Our galaxy (Milky Way) is part of a bigger system called the universe Milky Way Galaxy…spiral shaped!

Galaxies and Stars Galaxies – billions of star groups more than 100 billion galaxies, each containing billions of stars Milky Way Galaxy…spiral shaped!

So, how did our Solar System form? The Nebular Theory – explains that solar system was formed from a rotating disk of dust and gas Formed ~4.6 bya

1.Solar System began as a giant ball of dust and gases (after the Big Bang) Cloud flattened as it spun around, forming an accretion disk. ►Sun formed in the middle from all the heat in the middle of the disk Cooling of the disk caused small shapes to form 4. These cool forms combined to make the 4 SOLID inner planets The lighter material combined farther away, forming the 4 GASEOUS outer planets

Do Now What is the big bang theory? What is some evidence to support the big bang theory? What is a red shift and what does that tell us about distance of objects in space? Explain in your own words what Hubble’s Law states. Hint: think about your lab from last class

Day # 2 Objective 3 &4 Today you will be able to: • Explain planetary orbits especially that of the Earth, using Kepler’s laws. • Explain relative motion of the Earth in the solar system, the solar system in the galaxy, and the galaxy in the universe—including the expanding nature of the universe; Orbital motion (Earth around the Sun- once/year, seasons depend upon an approximate 23.5 degree tilt); Rotation around our axis (day/night,)

Earth’s Role in the Solar System The universe is made of galaxies which are made of many stars. Some stars have planetary systems similar to our solar system. Earth is a satellite planet of one particular star (our sun).

Three Ways in Which the Earth Moves 1.Rotates (Rotation) 2.Orbits 3.Revolves (Revolution)

Ways the Earth Moves Rotates = spins. The earth makes 1 full rotation every 24 hours. The axis of the Earth is tilted at an angle of 23.5 degrees. The axis always points towards the North Star

Ways the Earth Moves We have day and night because of the Earth’s rotation. Draw the picture below in your notes

Ways the Earth Moves The Earth also revolves around the sun in an elliptical orbit. The earth makes one full revolution around the sun every 365.25 days. 365 days = 1 year

Kepler’s Laws Provide Definition of Kepler’s Laws, Precession, Nutation and Barycenter. Draw a picture illustration Explain how you would act it out

How Earth’s Formation Affected Earth Earth orbits the Sun following Kepler’s 3 laws of planetary motion The path of each planet around the Sun is an ellipse Equal areas are covered in equal time The length of time it takes a planet to orbit the Sun is proportional to its distance from the Sun

Kepler (1571-1630) came up with these scientific laws and they are still used in Astronomy today! http://www.youtube.com/watch?v=pJlTuvHg6wY&feature=fvsr

1st Law: Law of Ellipses The path of the planets around the sun are elliptical in shape with the center of the sun being located at one focus The shape of the ellipse is determined by the location of the two focus points!

2nd Law: Law of Equal Areas This law states that an imaginary line from the sun to a planet sweeps out equal areas in equal time intervals

Kepler’s 2nd Law of Planetary Motion

Are they the SAME? The short wide glass is holding the SAME amount of water as the tall skinny glass!

Planet moves FASTER in orbit when CLOSE to the SUN, and SLOWER in orbit when FAR FROM the SUN WHY? GRAVITATIONAL PULL

Keppler’s 3rd Law

Kepler’s Three Laws of Planetary Motion (A Summary) Each planet takes an elliptical path around the sun Planets travel faster when they are close to the sun and slower when they are farther away from the sun The amount of time needed for a planet to revolve around the sun is proportional to the the planet’s distance from the sun B C A

Precession The direction this axis of a planet is pointing in will change, but the tilt will not change. This will change the stars near the pole but will not change the seasons (as long as the angle of the tilt, 23.5 in the case of Earth, stays the same)

Precession Animation http://www.youtube.com/watch?v=CUZOXczMfMo

Nutation Nutation happens when the axis of a planet starts to wobble (do the wobble!) The angle of the axis will change during nutation ½ degree one direction or the other Nutation happens over the course of 18 years Nutation is a direct result of the moon (or moons) of a planet

Barycenter A barycenter is the point between two objects where they balance each other (For example, the middle balancing point on a scale).

Barycenter Example For example, the moon does not orbit the exact center of the Earth, but a point on a line between the Earth and the Moon approximately 1,710 km below the surface of the Earth, where their respective masses balance. This is the point at which the Earth and Moon orbit as they travel around the Sun

Do Now Draw a picture of the Earth on it’s axis. At what degree is it tilted? Describe Kepler’s first law. What does the law of equal areas state? Draw a picture depicting his 1st and 2nd law. Describe Kepler’s third law.

Application and Critical Thinking Questions In degrees, what is the tilt of the Earth? Summarize and explain all 3 of Kepler’s laws of planetary motion into one or two sentences. How does precession affect the Earth’s rotation and revolution? Explain in your own words what nutation is . Based on the concept pf barycenter, explain the evolutional relationship between the sun and the earth.

Exploring Orbits: Eccentricity Lab Goal: To draw variously-sized elliptical orbits by changing the locations of the two foci points and then using that information to analyze the orbits of our solar system’s planets. Video Demonstration:https://www.youtube.com/watch?v=P-Gq75hQdfw

Demo/Group Work Activity What does eccentricity measure? Ms. Sterling observed the orbital path of Mars. From the data she collected, she found the focal point length to be 10 light years and the major axis length to be 22.5 light years. Find Mars’ eccentricity based on her observations. Planet X has an eccentricity of 0.0803 and Plant Y has an eccentricity of 0.8030. Using these measurements explain the paths of these planets around the sun.