Jupiter: The new frontier
Dressed in a scarf patterned with stars, pants covered with planets and hair adorned with pencils and plastic stars, guest lecturer and astronomical historian Shelley Bonus took over the John Drescher Planetarium on Friday night. To a crowd of nearly 30 attendees, she spoke about what we know about our solar system’s largest and possibly oldest planet Jupiter and its moons.
In an hour-long presentation consisting of a variety of videos and images captured by professional and amateur astronomers, she discussed the activity on the surfaces of the moons, Jupiter’s famous red spot and the temporary impact scars left by comets and asteroids that have been easily observed in the upper atmosphere.
“It was the first planet that we witnessed being hit by a comet,” said Bonus. After its discovery by Carolyn and Eugene M. Shoemaker and David Levy in 1993, the Shoemaker-Levy 9 comet collided with Jupiter in 1994.
“Telescopes all around the world captured this comet breaking up and impacting Jupiter,” Bonus said.
She also highlighted NASA’s proposed orbiter mission to the moon Europa, which is thought to contain briny oceans capable of supporting life.
“It’s going to be a very exciting mission,” said Bonus. “Europa is icy and the ice is cracking and we see venting coming from the cracks.”
While this mission is scheduled for some time in the 2020’s, a mission to Jupiter has been underway for the last five years and is reaching its climax this summer.
In Roman mythology, god of war Jupiter veiled himself in clouds to conceal his mischief. It took his wife, the goddess Juno, to look beneath his facade and discover what he was hiding. Similarly, as part of their New Frontiers Program, NASA has sent a spacecraft, aptly named Juno, to uncover the mysteries underneath the cloud cover of Jupiter.
“There’s a lot we don’t know about Jupiter,” said Steven Levin, Project Scientist of the Juno Mission team working at the Jet Propulsion Laboratory in Pasadena.
“We look at it, we see these belts and zones, stripes in its atmosphere that are jet streams moving at hundreds of miles an hour. We see the bright red spot which is a storm twice the size of the whole earth. And we see the planet rotating every 10 hours — 300 times the mass of the Earth and rotating more than twice as fast. But we don’t see beneath those clouds in the upper atmosphere.”
Launched on August 5, 2011 from Cape Canaveral, Florida, Juno is scheduled to reach Jupiter on July 4 and begin its orbit. The entire spacecraft is about the size of a professional basketball court, with each of the three solar panels the size of a shipping container. In January, it broke the record for farthest traveled solar powered object.
Scott Bolton, the mission’s Principal Investigator, told JPL’s news media, “We are achieving these records and venturing so far out for a reason — to better understand the biggest world in our solar system and thereby better understand where we came from.”
Jupiter is thought to be the first planet to form. It is more than twice the mass of all of the other planets, comets and asteroids in our solar system combined. Therefore its gravity will affect everything else that formed after and it is less likely to have altered as much as the other, smaller planets when hit by comets and asteroids. Discovering its origins will help us to understand our own.
While Jupiter consists of mostly hydrogen and helium, the oxygen content, and therefore water content, is unknown. Scientists also believe that the pressure inside Jupiter is around two million times the pressure here on Earth, creating an ocean of liquid-metallic-hydrogen that produces the planet’s large magnetic field and bright auroras.
“So we’re sending a spacecraft to try to understand what the interior is made out of, how big is that core, how much water is there, how did the planets form – because the water… and the core tells you a lot about how it formed,” said Levin. “We’re using the magnetic field to figure out how planetary dynamos work — how do you make that giant magnetic field out of an ocean of swirling metal.”
The spacecraft is equipped with several scientific instruments intended to help scientists answer these questions as well as one instrument with another purpose entirely.
“There’s a camera on Juno called JunoCam. It was put there, really not for science, it was really put there for education and outreach,” said Levin.
On their website, www.missionjuno.swri.edu/junocam, amateur and professional astronomers alike are encouraged to upload their photos of Jupiter and participate in discussions on which sites NASA should take images of.
Bonus, an amateur astronomer herself, can attest to the attraction to the fifth planet from the sun. “The colors are amazing,” she said. “On a good night you can see these belts and zones and their colors.”
She ended the talk with a video of an insightful 9 year old boy named Evan talking about ants walking on a patio. “The human race is sort of like that,” he said. “After they discovered what’s up there, they know they’re only a little part of the huge galaxy.”