Transcript Jupiter and its moons

ORBITAL PATTERNS OF JUPITER’S MOONS
Doug Jenkins and Tammy Schmidt, The Evergreen State College, Olympia, WA 98505
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ABSTRACT
HYPOTHESIS
SUMMARY
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.
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.
•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.
Alignment of Io, Europa, and Ganymede every 7 days.
Predictable orbital periods of Io, Europa and Ganymede.
•Using Kepler’s 3rd law and Newton’s 2nd, the mass
of Jupiter is 1.8 x 1027 kg.
Jupiter’s angular movement of 1o/month = 30 yr return.
•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 fourmoon Jovian system because our study period was
too short to get adequate data on Callisto’s orbit.
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.
METHODS
REFERENCES
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.
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.
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Mass of Jupiter determined from the orbital periods of its moons (Newton’s 2nd law and Kepler’s 3rd law).
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.onlinemythology.com/hebe_ganymede/
Io and Callisto. 14 May 2004 http://www.onlinemythology.com/io_callisto/
Jupiter. 11 May 2004
http://www.solarviews.com/eng/jupiter.htm
Jupiter’s Moons. 14 May 2004
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