Keplers Law and Barycenters

Keplers Law and Barycenters

by Mr. Bienkowski

How do Kepler’s laws describe Earth’s orbit?

Beginnings

​Johannes Kepler, working with data painstakingly collected by Tycho Brahe (from 1576-1601) without the aid of a telescope, developed three laws which described the motion of the planets across the sky. 

Kepler’s First Law

Law of Orbits: All planets move in elliptical orbits, with the sun at 1 focus.

An ellipse is an oval shape centered on 2 points instead of 1 point.

The orbital period of a planet is how long it takes for it to travel a complete orbit around the Sun… a year!

Kepler’s Second Law

Law of Areas: A line that connects a planet to the Sun sweeps out equal (=) areas in equal (=) times.

Earth sweeps out a longer path when it is closer to the Sun.

Earth moves fastest when it is closest to the Sun

​

Kepler’s Third Law

Law of Periods: The square of the orbital period of any planet is proportional to the cube of the semi major axis of its orbit. 

P² = a³ If you know the distance of a planet to the Sun, you would be able to figure out its… orbital period. Basically… The closer a planet is to the Sun, the shorter its orbital period is. (planet closer to Sun takes less time to orbit.)

​One more thing....

​Barycenter

​•A planet, such as Earth, actually orbits…

–a point between it and the Sun called the center of mass

–This center of mass is called the barycenter.

​

​A Barycenter is ...

​• the point between 2 objects where they balance each other.

​•It is the center mass where two or more celestial bodies orbit each other.

​

​•The Sun, although the center of the solar system, is not stationary, it moves as other planet’s gravity “tug” on it.  But it never strays too far from the solar system’s barycenter.

Multiple Choice

Planets orbit the Sun in a shape called a(n)

• circle
• ellipse
• focus
• perihelion

Multiple Choice

Where is the planet moving faster

• Position A to B
• Position B to C
• Position H to I
• Position I to J

Multiple Choice

A planet moves __________ when it is farthest from the sun.

• faster
• slower

Multiple Choice

The farther away a planet is from the sun, the _______ it takes it to orbit the sun once. 

• longer
• shorter

Multiple Choice

What does Kepler's 1st Law state?

• all planets move in elliptical shaped orbits around the sun

• all ellipses have one foci

• the area that a planet revolves around the sun is equal

• the speed that a planet revolves around the sun changes

Multiple Choice

Kepler's 2nd Law deals with 

• the shape of the planets' orbits
• the speed/area the planet travels 
• the length of time it takes the planet to orbit the sun

Multiple Choice

The center of mass of an object

• Angle of Insolation
• Barycenter
• Equinox

Multiple Choice

Which of the following is SMALLEST

• Solar System

• Galaxy

• Universe

Multiple Choice

What unit is used to measure distances in space?

• Light year

• Kilometer

• Miles

• Solar unit

Multiple Choice

What causes the seasons to change?

• The earth rotates on its axis
  
• The earth revolves around the sun
  
• The earth's axis is tilted
  
• Wind patterns on earth

Multiple Choice

The splitting of an atom into smaller parts.

• Astronomical Unit

• Nuclear Fusion

• Foci

• Nuclear Fission

Multiple Choice

The combining of several small nuclei into one large nucleus with the subsequent release of huge amounts of energy.

• Astronomical Unit

• Nuclear Fusion

• Foci

• Nuclear Fission

Multiple Choice

Is the center of mass of two or more bodies that orbit one another and is the point about which the bodies orbit.

• Nutation

• Precession

• Barycenter

• Nuclear Fission

Multiple Choice

The Earth's orbital motion around the sun. Takes 365 days.

• Nutation

• Rotation

• Barycenter

• Revolution

Multiple Choice

A tide just after the new or full moon when there is the greatest difference between high and low water.

• Neap

• Rotation

• Spring

• Revolution

Multiple Choice

_______are daily changes in ocean water.

• Waters

• Tides

• Colors

• Earths

Multiple Choice

The tidal force exerted by the ______ is stronger that the tidal force exerted by the _______.

• earth, ocean

• sun, moon

• moon, stars

• moon, sun

Multiple Choice

What season is when the north pole is tilted toward the sun?

• summer
• winter
• fall
• spring

Multiple Choice

Earth revolves around the sun

• Precession
• Rotation
• Revolution

Multiple Choice

When Earth orbits around the sun, it slows down when it is close to the sun. It speeds up its orbit when it is further from the sun. This is because the sun's gravity is stronger when you are closer to it.

• Kepler's 1st law
• Kepler's 2nd law
• Kepler's 3rd law
• Nutation

Multiple Choice

Which of the following is LARGEST

• Solar System

• Star

• Planet

• Moon

Multiple Choice

What is the sequence of the following three terms in order from Largest to Smallest- 

• galaxy, universe, solar system
• universe, galaxy, solar system
• solar system, galaxy, universe

Multiple Choice

Which type of motion causes night / day? 

• Rotation
• Revolution
• Kepler's 1st Law
• Nutation

Multiple Choice

Which term describes when the Earth spins on its axis.

• Rotation
• Revolution
• Kepler's Laws
• Precession

Multiple Choice

The energy from the sun is created by a process called:

• nuclear fission
• nuclear fusion
• nuclear reaction
• nuclear core

Multiple Choice

A tide just after a new or full moon when there is the greatest difference between high and low water. 

• Neap Tides
• Spring Tides