ORBITAL PATTERNS OF JUPITER’S MOONSDoug Jenkins and Tammy Schmidt, The Evergreen State College, Olympia, WA 98505

ABSTRACT

Jupiter possesses a dynamic satellite system whose mythology dates from the Roman dynasty. In 1610, Galileo’s discovery of moons orbiting Jupiter destroyed the widely accepted geocentric model of the universe. Like Galileo, we also observed moons orbiting Jupiter with the use of binoculars and a telescope from two locations. Empowered with this knowledge, we calculated the mass of Jupiter and its monthly angular movement, which allowed us to determine when Jupiter will return to the same celestial location as it was in May 2004.. We perceived the motion of the moons to be orbiting the polar regions. Like many fundamentals in science, perceptions are deceiving.

http://www.solarviews.com/ss.html

REFERENCES

Freedman, R.A., and W.J. Kaufmann III. 2002. Jupiter: Lord of the Planets and The Galilean Satellites of Jupiter. pp. 283-321 In Universe, 6th ed., W.H. Freeman and Company, New York.

Washburn, M., 1983. Distant Encounters: The exploration of Jupiter and Saturn, Harcourt Brace Jovanovich, San Diego.

Ancient Roman Gods and Goddesses. 14 May 2004 http://www.crystalinks.com/romegods.html

Hebe and Ganymede. 14 May 2004 http://www.online-mythology.com/hebe_ganymede/

Io and Callisto. 14 May 2004 http://www.online-mythology.com/io_callisto/

Jupiter. 11 May 2004 http://www.solarviews.com/eng/jupiter.htm

Jupiter’s Moons. 14 May 2004 http://rds.yahoo.com/S=6038183:D1/CS=6038183/SS=47365422/*http://www.enchantedlearning.com/subjects/astronomy/planets/jupiter/moons.shtml

ACKNOWLEDGEMENTS

Doug would like to thank his wife for her understanding during his all-night stellar observations. We would like to thank E.J. Zita for her constructive comments and direction. We would like to thank the Cal staff for their technological assistance.

 

SUMMARY

•From Earth’s perspective and due to Jupiter’s angular movement of 1o per month, the planet will return to its current location in 30 years.

•Using Kepler’s 3rd law and Newton’s 2nd, the mass of Jupiter is 1.8 x 1027 kg.

•The orbital movements of the moons appeared to deviate from Jupiter’s equatorial plane. The optical illusion was created because of Earth’s axial tilt.

•Ganymede, Europa and Io share predictable orbital patterns in a 1:2:4 ratio.

•Our null hypothesis is not rejected for the four-moon Jovian system because our study period was too short to get adequate data on Callisto’s orbit.

METHODS

Observations were conducted on clear nights at two areas from 26 April to 20 May 2004. Observer 1, located at 47o N, 123o W (Olympia, WA), used 8 x 42 binoculars to record relative positions of the moons to Jupiter. Observer 2, located at 47o N, 122o 36’ W (Steilacoom, WA), used a 910 mm Dobsonian telescope with a 10 mm objective. Observers coordinated their viewing times to coincide with each other as well as to track the directional movements of the moons. Each observer drew sketches of the moons’ positions. The observers compared sketches and calculated the orbital period for each moon. The mass of Jupiter was determined using Newton’s 2nd law and Kepler’s 3rd law.

HYPOTHESIS

The purpose of this project is to track the orbital movement and period of each moon by conducting observations over a one-month period. We will compare these observed data with actual data collected from scientific resources in order to predict the location of each moon on successive nights. We will calculate the mass of Jupiter based on the period of its moons. We will calculate the exact celestial return of Jupiter based on its movement throughout the month. We will also build a scale model of the Jovian system for presentation. Our null hypothesis states that Jupiter’s moons have no relative orbital pattern.

Mass of Jupiter determined from the orbital periods of its moons (Newton’s 2nd law and Kepler’s 3rd law).

Alignment of Io, Europa, and Ganymede every 7 days. Predictable orbital periods of Io, Europa and Ganymede. Jupiter’s angular movement of 1o/month = 30 yr return.

http://www.solarviews.com/ss.html http://www.solarviews.com/ss.html http://www.solarviews.com/ss.html http://www.solarviews.com/ss.html