Juno and Jupiter

Conversations in Science Juno and Jupiter
(First Aired as part of Jessie's POV on KLRNRadio, Wednesday, August 31, 2016)

There are many things about Jupiter that holds a great fascination to astronomers and other scientist. Even 400 years ago, Galileo was captivated by the giant gas planet, mapping its four largest moons, even though he didn't know Jupiter was a gas giant back then.

A model of the Juno spacecraft is seen at a news briefing, held before Juno enters orbit around Jupiter, on Thursday, June 30, 2016 at the Jet Propulsion Laboratory (JPL) in Pasadena, CA. The Juno mission launched August 5, 2011 and will arrive at Jupiter July 4, 2016 to orbit the planet for 20 months and collect data on the planetary core, map the magnetic field, and measure the amount of water and ammonia in the atmosphere. Photo Credit: (NASA/Aubrey Gemignani)

So why are we so interested in Jupiter? Well, Jupiter could quite possibly hold answers about the beginnings of our solar system. The planet is believed to be one of the first planets formed, with evidence that the cloud atmosphere has a similar composition to that found in the Sun. But we know little else with any certainty about the planet's composition and interior structure. Is there any water in Jupiter's cloud formations? Does Jupiter have a solid core? And what about the strong magnetic fields that surround the planet?

Let's face it, we have many questions about Jupiter and the other outer planets. What is in the core of the planets? Why is there such diversity in the moons around these planets? Why is there a vast difference between the outer planets and the inner planets?

All our years of ground-based observations of Jupiter had led to assumptions that proved to be wrong by the Galileo mission during 1995 through 2003. But now we have more questions than we have answers, leading to the current Juno mission, launch on August 5, 2011 and insertion into Jupiter's orbit on July 4, 2016.

Juno has now successfully executed the first of its 36 orbital flybys. It passed about 2,600 miles (4,200 kilometers) above Jupiter. This flyby was the closest that Juno will get to Jupiter during its prime mission.

Let's give that distance a little perspective. If you were to drive from New York City to Los Angeles, you will travel along 2,792 miles of road (4,493 km). The International Space Station orbits the Earth at a height of 250 miles above the sea level (400 km). And the moon is 239,000 miles (384,400 km) away.

Are you ready for the next crazy number? Juno was traveling at a speed of 130,000 mph (208,000 kph) during its flyby maneuver.

Again, for a little perspective... The cruising speed of a Boeing 747 is 550 – 600 mph (885 – 965 kph). The fastest plane (an X-15) clocked in at Mach 6.72, or 4,520 mph (7,274 kph). The International Space Station has a ground speed of 17,150 mph (27,600 kph).

At that crazy speed, and that close distance, it took Juno only 67 minutes to travel from pole to pole, collecting as much data as it could. (And for those who have an interest in image processing... That is a mountain of data to go through.)

Rick Nybakken, Juno project manager at NASA's Jet Propulsion Laboratory in Pasadena, California, said in a press conference, "Early post-flyby telemetry indicates that everything worked as planned and Juno is firing on all cylinders." With all the science instruments now on, and all systems go, it's not surprising that it will be a few days yet before scientist can start to comprehend what Juno is telling us about Jupiter, but I for one look to hearing about those preliminary results.

The images coming from Juno-Cam alone are enough to keep the imagination going... for a while at least.