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Radio JOVEJupiter is a source of powerful radio bursts that can produce exotic sounds on ham radio receivers. NASA scientists are helping students tune in to the giant planet as part of an innovative educational program called Radio JOVE. |
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"We've come up with a radio-telescope kit that most high school science classes can put together," explains Thieman. "The kits include all of the parts required to construct a 20 MHz receiver, along with transmission cables and wire for the antennas. The antennas are dual half-wave dipoles, each about 20 feet long and mounted 20 feet apart. The kit doesn't include the PVC structures we recommend for mounting the wires, but those are inexpensive and easy to get at a local hardware store. You can also use wood for mounting." You might imagine that a radio telescope capable of detecting a planet hundreds of millions of kilometers away would be expensive, but these kits sell at cost for just $115.
Radio JOVE participants can build their own radio telescopes, make observations, and help scientists monitor activity in Jupiter's enormous magnetosphere. It's the whole scientific process in one project, says Thieman. For students who can't build their own radio telescope, there will be an online observatory where kids can monitor Jupiter on the World Wide Web. For more information about how
to join, visit the Radio
JOVE home page at the NASA Goddard Space Flight Center. Where does the radio laser mechanism get so much power? It's
a circuitous story that starts on Jupiter's volcanic moon Io.
[Editor's note: this description is simplified for clarity. Unlike a DC circuit that you might construct using batteries and wires for a science fair project, plasma physicists believe that current in the Io-Jupiter system is carried by a type of magnetic plasma wave called Alfven waves. The details are the subject of ongoing research.] This awesome current is the power source for plasma waves that give rise to the laser-like radio emissions. The radio signals travel away from Jupiter's magnetic poles in cone-shaped beams that rotate with the giant planet every 9 hours and 55 minutes. In this respect Jupiter is like a slow-turning pulsar. When the beams sweep past our planet, listeners can pick up Jovian radio bursts in the shortwave bands between 15 and 40 MHz.
Above: This frame from a
computer animation shows the cone-shaped radio emission beam
near Jupiter's north magnetic pole. (Not shown is another conical
beam near the south magnetic pole.) The radio beams are hollow
cones, meaning that Earth-bound observers can pick up signals
only when the thin edge of the cone sweeps past our planet. The
loop labeled IFT is the "Io Flux Tube," a bundle of
magnetic field lines that pass through Io and connect to Jupiter's
polar auroral zone. The powerful electrical current that powers
the radio laser flows along magnetic field lines in and near
the IFT. For a better view of Jupiter and its rotating emission
beams, please view these AVI animations courtesy of Prof.
Kazumasa Imai of the Kochi National College of Technology
in Japan: #1 (3.2
MB), #2 (3.7 MB),
#3 (3.7 MB), #4 (6.9 MB). When it comes to sound effects, woodpeckers and ocean waves
can't hold a candle to Jupiter. Jupiter
Easy Listening Center
A Radio JOVE Tailgate Party One of the first Radio JOVE student teams, at the Lexington
Traditional Magnet School in Lexington, Kentucky, made a successful
observation of Jupiter late last year. On the night of October
22, 1999, students, teachers and parents set up an observing
station in Mt. Sterling, Kentucky, on a farm far from any electrical
interference. They arrived early enough to enjoy a festive cook-out
before the late night observations began. It was the first-ever
Radio JOVE tailgate party!
"At first, when I heard about the Radio JOVE project, I thought it would be interesting to listen to storms on Jupiter," wrote Nazrana Karim, a student at the Lexington Traditional Magnet School. "We had to meet after school two days a week to construct the radio telescope. It wasn't that hard, but we put a lot of effort into it and we built a great antenna. "We put the antenna up twice for the media and once for the real thing. [The big day] was awesome. We had a party and then, at 2:00 AM, we went out to [our teacher] Mr. Salmons' farm to listen to Jupiter. "I can't exactly describe the sound. It was like a hurricane - only there were outbursts and explosions. I had a great time and I realize that an opportunity like this [might] only come along once in a lifetime." "We recommend that Radio JOVE participants build
the kit and make their own observations," says Jim Thieman.
"But we realize that some schools won't be able to do that,
so a second way of participating is to get data
online from the University
of Florida Radio Observatory. (UFRO)." "By the fall of 2000 we'll have live streaming audio
sounds as well as total power measurements for 7 spectral channels
from 18 to 32 MHz, which is the optimum range for observing Jupiter
from ground based stations," says Francisco Reyes, the director
of the UFRO. Like Jupiter, the Sun is a powerful source of shortwave radio
bursts. Solar radio activity is especially high now with the
solar maximum expected to begin sometime in the year 2000.
Stay tuned to Science@NASA for more information and updates
about Radio JOVE and and radio emissions from Jupiter. |
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May
22, 2000 -- As the planet Jupiter passes behind the Sun this
month, it's temporarily lost from view to astronomers. "Out-of-sight"
doesn't necessarily mean "out-of-mind," though, when
it comes to the biggest planet in the solar system. Even now,
scientists from NASA's Goddard Space Flight Center and the University
of Florida are busily working on 
Bonus Track: Like Jupiter, the Sun is a powerful source of radio
bursts at shortwave frequencies. To hear an example of an 18
MHz solar burst, download 
Right:
Students from the Sonoma Valley High School in Sonoma, CA, pose
next to their completed Radio JOVE radio-telescope kit,
consisting of a 20.1 MHz receiver and dual phased dipoles. Students
in Kentucky used classroom-built equipment like this to record
Jovian radio bursts on October 22, 1999.
The
UFRO, located in a central Florida pine forest near the mouth
of the Suwannee river, hosts an array of unusual-looking antennas
designed to capture signals from Jupiter and the Sun at shortwave
frequencies. Led by University of Florida Professors Alex Smith
and Thomas Carr, scientists and graduate students have been collecting
radio data from Jupiter at the UFRO since the mid-1950's. It's
North America's premier facility for low frequency planetary
radio astronomy, and now it's about to go online.
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