Category: Astronomy

Lab assisgnment

https://cunysps.hosted.panopto.com/Panopto/Pages/Viewer.aspx?id=d590505e-e9ac-431d-92fe-ae6e0162ccd4

https://stellarium-web.org/

Instructions

This lab has three objectives. The first is to observe the period of revolution of the planets. The second is to measure the distance to each planet from the point of view of the Sun. The third and final objective is to use Kepler’s 3rd law and prove or disprove the existence of a constant resultant.

AST 101: Introductory astronomy: THE SOLAR SYSTEM LABORATORY ASSIGNMENT #2

Kepler and the Laws of Motion of the Planets

ALL WRITING IN RED MUST BE FOLLOWED BY YOU, THE STUDENT, IN YOUR OWN LAB REPORT)

Hypothesis

Keplers assertion that all planets and celestial objects observed to move, do so in elliptical orbits.

Question Asked: How can we empirically prove Keplers 3rd Law?

Introduction

Johannes Kepler was mathematical wizard who worked with Tycho Brahe. Using Tychos detailed observations of the celestial objects, Kepler was able to come up with empirical solutions to how the planets move and discovered that their motion was elliptical. A fact, which rescued the Copernican Heliocentric model from its many inaccuracies.

Summarized as the three laws:

INSERT THE THREE LAWS HERE AND A SUMMERY EXPLAINING THEIR MEANING. USE ILLUSTRATIONS IN ADDITION TO YOUR WRITTEN EXPLANATION, MAKING SURE TO REFERENCE YOUR IMAGE BOTH AS A FOOTNOTE AND IN YOUR RESOURCES SECTION AT THE END OF THE LAB

Objectives

This lab has three objectives. The first is to observe the period of revolution of the planets. The second is to measure the distance to each planet from the point of view of the Sun. The third and final objective is to use Keplers 3rd law, and prove or disprove the existence of a constant resultant.

Procedure

USING THE STEP BY STEP GUIDE IN APPENDIX A, WRITE UP A PROCEDURE EXPLAINING HOW YOU CONDUCTED THIS LAB. USE THE SAME FORMAT AND STYLE AS WAS PRESENTED TO YOU IN LAB #1.

AS PART OF YOUR PROCEDURE YOU WILL FILL OUT THE FOLLOWING TWO TABLES:

TABLE 1

Planet

Start Date(MM/DD/YR)

End Date(MM/DD/YR)

Orbital Period , p(days)

Orbital Period , P (years) p/365.25

Mercury

Venus

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

TABLE 2

Planet

Orbital Radius (a) (AU)

Orbital Period (P) (years) from table 1

a3 (AU3)

P2 (years2)

P2/ a3

Mercury

Venus

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

Discussion

IN THE DISCUSSION SECTION (FOR THIS LAB), YOU WILL WRITE A DISCUSSION OF YOUR EXPERIENCE, AND YOUR TAKE ON THE FOLLOWING QUESTION Discuss the importance of this lab assignment. How well did the your calculations fit with Keplers laws?

Conclusion

IN THIS SECTION YOU WILL ANSWER THE HYPOTHESIS, AND PRESENT A CONCLUDING STATEMENT ABOUT KEPLERS LAWS AND THEIR ROLE IN HELPING US UNDERSTAND THE NATURE OF CELESTIAL MECHANICS

References

INSERT YOUR OWN HERE

Chaisson, Eric and McMillan, Steve

Astronomy Today Volume I : The Solar System, 8th Edition, 2013

APPENDIX A STEP BY STEP INSTRUCTIONS

Instructions:

• Begin by launching Stellarium
• Set the default location by opening the Location window (You can find the Location icon at the left-hand side of the screen, or by pressing the F6 key). Enter New York City, in the search bar, and then click on New York City, United States of America.
• Make sure to check the box titled use current location as default and then close this window.
• We will be journeying to a viewpoint outside of the Earth. To do this we must make sure to turn off the atmosphere (A key), fog (F key) and ground (G key).

The function allowing us to view the solar system from above is called Solar System Observer.

• Use the search function (CTRL-F or F3) and enter Solar System Observer. Press Enter.
• To actually have the view point of any solar system object that youve selected enter CTRL-G (think GO).
• You should now be looking from a point high, high above the solar system. You can use the mouse to locate the Sun, or, once again use the CTRL-F or F3 to find the Sun and center it on the screen.
• We will adjust some the of the settings, so that we can view the planets in their orbits.
• Press F4 to call up the sky and viewing options screen.
• Go to the in the Sky tab
• Disable Dynamic eye adaptation and stars (uncheck the boxes)
• Go to the SSO Tab and make sure that the show orbits box is checked and the only orbits of the major planets box is the only one checked.
• Make sure that the Show planetary nomenclature is also checked.
• Change the tab to Markings and make sure to uncheck the Celestial Sphere box.
• When done, you can close this options window.
• Turn on the orbital lines, try pressing the letter O (which will look red), and begin zooming in and out to see the orbits of the planets (You can use your mouse wheel or the page up/down keys on your keyboard).
• As you zoom in and out, you can also start playing with time! Press the L key to move time forward, do this several times until you see the planets moving.

Tips:

• If you find that you are going too fast, press the K key to stop all motion and return you to normal time.
• You can always press the number 8 to return you to the present day.
• To go backwards in time, press the J key.
• What can you observe of the planets motion?

What is the relationship between the distance from the Sun and the speed at which the planets seem to move? OPTIONAL TO ANSWER

• Of the three laws, which law best describes this relationship? How? OPTIONAL TO ANSWER
• In the next part, we will be observing each planets orbital period (P) and Semi-major axis (a) and using this information, we will be proving that the ratio in Keplers 3rd Law is indeed 1.
• Image 1- Mercurys orbit

Image 1- Mercurys orbit

• We will start the exercise by zooming in on the planet Mercurys orbit. Make sure it fills the screen, but you are still able to see the entire orbit itself.
• Place a finger, or a piece of paper with tape to mark the position of Mercury on your screen. Note the start date on the table below.
• Press the L key to move time forward. No more than 7 presses should do it.
• When Mercury returns to its original starting point not the end date in the table below.
• Enter the amount of days it took for Mercury to complete one orbit. Convert this number into the equivalent amount of Earth years by dividing your finding by 365.25 days.
• Repeat this measurement for each of the planets in order. (We will not be measuring Pluto!)
• TABLE 1 FILL THIS OUT IN THE PROCEDURE SECTION

Planet

Start Date(MM/DD/YR)

End Date(MM/DD/YR)

Orbital Period , p(days)

Orbital Period , P (years) p/365.25

Mercury

Venus

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

• To find the distances that the planets are from the Sun, we must first go to the Sun!
• Use the CTRL-F or F3 keys to find the Sun. Then travel to the Sun by pressing CTRL-G
• Now, all you have to do is search each planets name in turn (again CTRL-F or F3) and obtain their distance information in au from the informational chart on the upper left hand of your screen.
• Fill in the information in the table below, and perform the necessary math indicated in each row. (round to the nearest hundredth -> two decimal points, ex: 8.9341=8.93)

Planet

Orbital Radius (a) (AU)

Orbital Period (P) (years) from table 1

a3 (AU3)

P2 (years2)

P2/ a3

Mercury

Venus

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

• TABLE 2 FILL THIS OUT IN THE PROCEDURE SECTION

View images for instructions and rubric. Use websites , , or to find article

Slides link use it for sources:

Winter Solstice on December 21: daylight lasts about 9 hours and 32 minutes. Afterward, the length of daylight is increasing.

Spring Equinox on March 20: daylight and night are equal length. Afterward, the length of daylight is increasing.

Summer Solstice on June 21: daylight lasts about 14 hours and 47 minutes hours. Afterward, the length of daylight is decreasing.

Fall Equinox on September 22: daylight and night are equal length. Afterward, the length of daylight is decreasing.

For the first two questions below, please enter your data into the one of attached table formats. Remember to put the table (or the same format in text) into your discussion post. Copy and paste it & check to ensure your data is there before submitting!

1. The Farmer’s Almanac was an annual publication begun 1792 when George Washington was president; it includes Sun and Moon information to help with planting and harvesting crops. Open the website

a. Enter your zip code in the San Francisco Bay Area. For today’s date, write down the times of sunrise and sunset and the length of day into the table.

b. Now, using the same zip code, change the date to one week from today. Enter these times of sunrise and sunset and length of day into the table.

2. Now we will try a different website that allows you to look up the times for other countries:

a. Choose one city from the Southern Hemisphere list to enter for today’s date:

Buenos Aires, Argentina

Sydney, Australia

Cape Town, South Africa

Enter the city you chose and the times of sunrise and sunset into the table.

b. Now look up the data for Ny-Alesund today. Enter the times of sunrise and sunset into the table. Now look over the other rise and set times for the month for 3d.

c. Look up the data for Macap, Brazil today. Enter the times of sunrise and sunset into the table. Now look over the other rise and set times for the month for 3e.

3. These are short answer questions that can be completed in just a couple sentences; more are welcome but I promise no essays are required. Please put each answer on its own line with 3a, 3b, etc, thanks!

a. Comparing the length of day for today and next week that you found for the San Francisco Bay Area, what season must it be? How can you tell? (I know you know what season it is without looking at these numbers. I am asking how you can tell by looking at the numbers based on the season science you have learned this week. You will want to explain how you know based on the table numbers.)

b. Looking at the lengths of daylight, are we moving towards a solstice or towards an equinox? Specifically referring to the table data, how can you tell? What page of the Content Slides (not the video) supports your answer?

c. Compare the rise and set times for the city you chose in Question 2 with those from San Francisco in Question 1. Based on your knowledge of seasons in the two hemispheres of Earth, what season is it in the city you chose? Is this what you expected or are you surprised? Explain based on what you learned about seasons this week. What page of the Content Slides (not the video) supports your answer?

d. Is it possible to determine Ny-lesund’s season/location from the rise and set times you looked at? Specifically referring to the data you viewed, why or why not? What page of the Content Slides (not the video) supports your answer?

e. Is it possible to determine Macap, Brazils season/location from the rise and set times you looked at? Specifically referring to the data you viewed, why or why not? What page of the Content Slides (not the video) supports your answer?

4. Now we will use a free planetarium app (image below) to look at some constellations:

These are some detailed instructions but they will help you learn this fun planetarium app! When you open the app, go to Settings in the upper lefthand corner. Turn off Milky Way and DSS; turn on Ecliptic. Click on the three bars at the upper left of the larger area to remove the Settings area so the larger area is all you see. At the bottom left, enter San Francisco, CA as your location. By default, you are looking North as denoted by the N. Use your cursor to carefully rotate the land in the app until you are looking South (S). Go to the lower middle icons and turn on the Constellations icon. Now go to the lower right-hand corner and set the date to today’s date and the time to midnight 00:00).

a. List the Zodiacal constellations you can see at this date and time in order from left to right.

b. Change your location to New York, NY. For the same date and time and direction in New York, list the Zodiacal constellations you can see in the same order.

c. Change your location to Macapa, Brazil. For the same time and direction, list the Zodiacal constellations you can see.

d. Was anything about b or c different or unusual compared to your experience in San Francisco? Why or why not?

5. Answer in at least two full, thoughtful sentences in your own words. Did anything you learned this week about the seasons surprise you? If so, let us know what surprised you and why. If not, when and how did you learn about the cause of the seasons based on Earth’s rotation and revolution