Infrared images of Jupiter obtained by a ground-based telescope displaying changes in the stripes of Jupiter's clouds between 2001 and 2011 (dashed blue lines). (Credit: Arrate Antuñano/NASA/IRTF/NSFCam/SpeX)
While Jupiter’s Great Red Spot is one of the most well-known spectacles in the solar system, Jupiter’s clouds and stripes that are responsible for the planet’s weather patterns are highly regarded, as well. Though not nearly as visible in an amateur astronomy telescope, Jupiter’s multicolored, rotating, and swirling cloud stripes are a sight to behold for any astronomy fan when seen in up-close images. And, what makes these stripes unique is they have been observed to change color from time to time, but the question of what causes this color change to occur has remained elusive.
This next week will mark a scientifically valuable achievement for NASA’s Juno mission, as the pioneering spacecraft is slated to fly within 358 kilometers (222 miles) of Jupiter’s icy moon Europa on September 29 at 5:36 a.m. EDT (2:36 a.m. PDT) as part of its extended mission to explore the Jupiter system. A flyby this close to Europa’s surface will allow Juno to acquire some of the highest-resolution images ever taken of the icy moon. For context, the last mission to explore Europa in depth was NASA’s Galileo spacecraft, which got within 351 kilometers (218 miles) of the surface on January 3, 2000.
An amazingly active Io, Jupiter's "pizza moon" shows multiple volcanoes and hot spots in this photo taken with Juno's infrared camera. Credit: NASA / JPL-Caltech / SwRI / ASI / INAF /JIRAM / Roman Tkachenko
Thanks to a mission extension, NASA’s Juno probe continues to orbit Jupiter, being only the second spacecraft in history to do so. Since it arrived around the gas giant on July 5th, 2016, Juno has managed to gather a great deal of information on Jupiter’s atmosphere, magnetic and gravity environment, and its interior structure.
In that time, the probe has also managed to capture some breathtaking images of Jupiter as well. But on December 21st, during the probe’s sixteenth orbit of the gas giant, the Juno probe changed things up when four of its cameras captured images of the Jovian moon Io, showcasing its polar regions and spotting what appeared to be a volcanic eruption.
Jupiter's north polar region is coming into view as NASA's Juno spacecraft approaches the giant planet. This view of Jupiter was taken on August 27, when Juno was 437,000 miles (703,000 kilometers) away. Credits: NASA/JPL-Caltech/SwRI/MSSS
Jupiter’s north polar region is coming into view as NASA’s Juno spacecraft approaches the giant planet. This view of Jupiter was taken on August 27, when Juno was 437,000 miles (703,000 kilometers) away. Credits: NASA/JPL-Caltech/SwRI/MSSS
Saturdays’ close encounter with Jupiter soaring over its north pole was the first of 36 planned orbital flyby’s by Juno during the scheduled 20 month long prime mission.
“Soarin’ over #Jupiter. My 1st up-close look of the gas-giant world was a success!” the probe tweeted today post-flyby.
NASA released Juno’s first up-close image taken by the JunoCam visible light camera just hours later – as seen above.
Juno was speeding at some 130,000 mph (208,000 kilometers per hour) during the time of Saturday’s closest approach at 9:44 a.m. EDT (6:44 a.m. PDT 13:44 UTC) over the north polar region.
It passed merely 2,600 miles (4,200 kilometers) above the turbulent clouds of the biggest planet in our solar system during its initial 53.5 day polar elliptical capture orbit.
And apparently everything proceeded as the science and engineering team leading the mission to the gas giant had planned.
“Early post-flyby telemetry indicates that everything worked as planned and Juno is firing on all cylinders,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, in a statement.
This dual view of Jupiter was taken on August 23, when NASA’s Juno spacecraft was 2.8 million miles (4.4 million kilometers) from the gas giant planet on the inbound leg of its initial 53.5-day capture orbit. Credit: NASA/JPL-Caltech/SwRI/MSSS
Indeed Saturday’s encounter will count as the closest of the entire prime mission. It also marks the first time that the entire suite of nine state-of-the-art science instruments had been turned on to gather the totally unique observations of Jupiter’s interior and exterior environment.
“We are getting some intriguing early data returns as we speak,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio, in a statement.
“This is our first opportunity to really take a close-up look at the king of our solar system and begin to figure out how he works.”
Additional up-close high resolution imagery of the Jovian atmosphere, swirling cloud tops and north and south poles snapped by JunoCam will be released in the coming weeks, perhaps as soon as next week.
“We are in an orbit nobody has ever been in before, and these images give us a whole new perspective on this gas-giant world,” said Bolton.
“It will take days for all the science data collected during the flyby to be downlinked and even more to begin to comprehend what Juno and Jupiter are trying to tell us.”
The prime mission is scheduled to end in February of 2018 with a suicide plunge into the Jovian atmosphere to prevent any possible contamination with Jupiter’s potentially habitable moons such as Europa and Ganymede.
“No other spacecraft has ever orbited Jupiter this closely, or over the poles in this fashion,” said Steve Levin, Juno project scientist from NASA’s Jet Propulsion Laboratory in Pasadena, California. “This is our first opportunity and there are bound to be surprises. We need to take our time to make sure our conclusions are correct.”
The team did release an approach image taken by JunoCam on Aug. 23 when the spacecraft was 2.8 million miles (4.4 million kilometers) from the gas giant planet on the inbound leg of its initial 53.5-day capture orbit.
One additional long period orbit is planned. The main engine will fire again in October to reduce the orbit to the 14 day science orbit.
Animation of Juno 14-day orbits starting in late 2016. Credits: NASA/JPL-Caltech
The solar powered probe will collect unparalleled new data that will unveil the hidden inner secrets of Jupiter’s origin and evolution as it peers “beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere.”
The Juno spacecraft was built by prime contractor Lockheed Martin in Denver.
Illustration of NASA’s Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA’s Jet Propulsion Laboratory. Credit: NASA/Lockheed Martin
The last NASA spacecraft to orbit Jupiter was Galileo in 1995. It explored the Jovian system until 2003.
In the final weeks of the approach before Jupiter Orbit Insertion (JOI), JunoCam captured dramatic views of Jupiter and all four of the Galilean Moons moons — Io, Europa, Ganymede and Callisto.
At the post JOI briefing at JPL on July 5, these were combined into a spectacular JunoCam time-lapse movie released by Bolton and NASA.
Watch and be mesmerized -“for humanity, our first real glimpse of celestial harmonic motion” says Bolton.
Video caption: NASA’s Juno spacecraft captured a unique time-lapse movie of the Galilean satellites in motion about Jupiter. The movie begins on June 12th with Juno 10 million miles from Jupiter, and ends on June 29th, 3 million miles distant. The innermost moon is volcanic Io; next in line is the ice-crusted ocean world Europa, followed by massive Ganymede, and finally, heavily cratered Callisto. Galileo observed these moons to change position with respect to Jupiter over the course of a few nights. From this observation he realized that the moons were orbiting mighty Jupiter, a truth that forever changed humanity’s understanding of our place in the cosmos. Earth was not the center of the Universe. For the first time in history, we look upon these moons as they orbit Jupiter and share in Galileo’s revelation. This is the motion of nature’s harmony. Credits: NASA/JPL-Caltech/MSSS
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
United Launch Alliance Atlas V liftoff with NASA’s Juno to Jupiter orbiter on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer/kenkremer.com
The Moon occults Jupiter on July 15th, 2012. Image credit and copyright: Ziad el Zaatari.
So, are you catching sight of the waxing crescent Moon returning this week to the early PM sky? The start of lunation 1157 gives folks observing Ramadan here in Morocco a reason to celebrate, as it marks the end of dawn-to-dusk fasting. Follow that Moon, as it’s about to meet up with the king of the planets this weekend.
On July 9th, the 5-day old waxing crescent Moon will pass Jupiter. You can see ’em both Saturday night, high in the western sky at dusk. For a very few observers in the southern Indian Ocean and Antarctica, the Moon will actually occult (pass in front of) Jupiter, centered on 10:11 Universal Time (UT). The Moon will be 32% illuminated crescent during the pass, and Jupiter will present a disk 34” across, just over a month past quadrature on June 4th with a current elongation of 60 degrees east of the Sun. Jupiter just passed opposition for 2016 on March 8th, and is now headed towards solar conjunction on the far side of the Sun on September 26th.
The occultation footprint for the July 9th event. Image credit: Occult 4.2 software.
2016 Planetary Occultations
This is the first of four occultations of Jupiter by the Moon in 2016; the next occur over subsequent lunations on August 6th, September 2nd and 30th before the relative motions of the Moon and Jupiter carry them apart, not to meet again until October 31st, 2019. And though most observers will miss this weekend’s occultation, we’ll all get a good view of the pairing worldwide. Unfortunately, the view gets successively worse (though more central) for the next few lunations, as the occultations of Jupiter by the Moon occur close to the Sun.
Looking west on the evening of July 9th. Image credit: Stellarium.
Here’s another reason to celebrate and show off Jupiter at this weekend’s star party: NASA’s Juno spacecraft has just entered orbit around the gas giant world. This is only the second time a mission has orbited Jupiter (the first was Galileo) though lots have performed brief flybys, using the enormous pull of the planet for a gravitational boost en route to elsewhere. Juno is currently the only spacecraft in operation around Jove, and will conduct 36 looping science orbits around the planet before meeting its fiery end in February 2018.
A montage of daytime planets (and one Moon and one star). Image credit and copyright: Shahrin Ahmad (@shahgazer).
Yay, humans. Here’s another feat of visual athletics you can attempt this weekend: can you spy Jupiter near the waxing crescent Moon… in the daytime? It’s not that tough, if you know exactly where to look. Deep blue skies for maxim contrast are key, and don’t be afraid to cheat a bit and use binoculars or a wide-field DSLR shot to tease bashful Jupiter out of the daytime sky. Your best bet might be to start hunting for Jupiter 30 minutes prior to local sunset. Hey, if the Sun is still above the local horizon, it still counts! We’ve actually managed to nab Jupiter and Venus before sundown at public star parties on occasion, kicking things off a bit early.
Hunting for Jupiter in the daytime on July 9th. Image credit: Starry Night
Now for the ‘wow’ factor. The Moon is 3,474 kilometers across, and on average, 400,000 kilometers or 1.25 light seconds distant. Jupiter, at 140,000 kilometers across, is currently 5.9 Astronomical Units (AU) or 880 million kilometers away, 2,200 times more distant at 49 light minutes away. You could fit Jupiter and all of the other planets in the solar system – excluding Saturn’s rings — between the Earth and the Moon… not that you’d want such mayhem, of course. Hey; then, for the very first time in the history of human astronomy, Jupiter could occult our puny Moon…
Occultations are abruptly swift affairs in a glacially slow universe. The leading edge of the Moon moves about 30” a minute, taking 17 seconds to cover the disk of Jove. Follow Jupiter this summer, as it’ll pass just 4′ from Venus in the dusk sky on August 27th.
More to come on that soon. Here’s a final thought: has anyone ever tried to observe a radio occultation of Jupiter by the Moon? It’s certainly possible, as Jupiter is a prominent amateur radio source, crackling in the sky. And hey, the daytime sky thing wouldn’t be an issue…
We’d be thrilled to hear that, against all odds, someone on a remote windswept island or on a ship in the distant Indian Ocean actually managed to catch this weekend’s occultation!
