Our Juno spacecraft has just released some exciting new science from its first close flyby of Jupiter!
In case you don’t know, the Juno spacecraft entered orbit around the gas giant on July 4, 2016…about a year ago. Since then, it has been collecting data and images from this unique vantage point.
Juno is in a polar orbit around Jupiter, which means that the majority of each orbit is spent well away from the gas giant. But once every 53 days its trajectory approaches Jupiter from above its north pole, where it begins a close two-hour transit flying north to south with its eight science instruments collecting data and its JunoCam camera snapping pictures.
Space Fact: The download of six megabytes of data collected during the two-hour transit can take one-and-a-half days!
Juno and her cloud-piercing science instruments are helping us get a better understanding of the processes happening on Jupiter. These new results portray the planet as a complex, gigantic, turbulent world that we still need to study and unravel its mysteries.
So what did this first science flyby tell us? Let’s break it down…
1. Tumultuous Cyclones
Juno’s imager, JunoCam, has showed us that both of Jupiter’s poles are covered in tumultuous cyclones and anticyclone storms, densely clustered and rubbing together. Some of these storms as large as Earth!
These storms are still puzzling. We’re still not exactly sure how they formed or how they interact with each other. Future close flybys will help us better understand these mysterious cyclones.
Seen above, waves of clouds (at 37.8 degrees latitude) dominate this three-dimensional Jovian cloudscape. JunoCam obtained this enhanced-color picture on May 19, 2017, at 5:50 UTC from an altitude of 5,500 miles (8,900 kilometers). Details as small as 4 miles (6 kilometers) across can be identified in this image.
An even closer view of the same image shows small bright high clouds that are about 16 miles (25 kilometers) across and in some areas appear to form “squall lines” (a narrow band of high winds and storms associated with a cold front). On Jupiter, clouds this high are almost certainly comprised of water and/or ammonia ice.
2. Jupiter’s Atmosphere
Juno’s Microwave Radiometer is an instrument that samples the thermal microwave radiation from Jupiter’s atmosphere from the tops of the ammonia clouds to deep within its atmosphere.
Data from this instrument suggest that the ammonia is quite variable and continues to increase as far down as we can see with MWR, which is a few hundred kilometers. In the cut-out image below, orange signifies high ammonia abundance and blue signifies low ammonia abundance. Jupiter appears to have a band around its equator high in ammonia abundance, with a column shown in orange.
Why does this ammonia matter? Well, ammonia is a good tracer of other relatively rare gases and fluids in the atmosphere…like water. Understanding the relative abundances of these materials helps us have a better idea of how and when Jupiter formed in the early solar system.
This instrument has also given us more information about Jupiter’s iconic belts and zones. Data suggest that the belt near Jupiter’s equator penetrates all the way down, while the belts and zones at other latitudes seem to evolve to other structures.
3. Stronger-Than-Expected Magnetic Field
Prior to Juno, it was known that Jupiter had the most intense magnetic field in the solar system…but measurements from Juno’s magnetometer investigation (MAG) indicate that the gas giant’s magnetic field is even stronger than models expected, and more irregular in shape.
At 7.766 Gauss, it is about 10 times stronger than the strongest magnetic field found on Earth! What is Gauss? Magnetic field strengths are measured in units called Gauss or Teslas. A magnetic field with a strength of 10,000 Gauss also has a strength of 1 Tesla.
Juno is giving us a unique view of the magnetic field close to Jupiter that we’ve never had before. For example, data from the spacecraft (displayed in the graphic above) suggests that the planet’s magnetic field is “lumpy”, meaning its stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action (where the motion of electrically conducting fluid creates a self-sustaining magnetic field) closer to the surface, above the layer of metallic hydrogen. Juno’s orbital track is illustrated with the black curve.
4. Sounds of Jupiter
Juno also observed plasma wave signals from Jupiter’s ionosphere. This movie shows results from Juno’s radio wave detector that were recorded while it passed close to Jupiter. Waves in the plasma (the charged gas) in the upper atmosphere of Jupiter have different frequencies that depend on the types of ions present, and their densities.
Mapping out these ions in the jovian system helps us understand how the upper atmosphere works including the aurora. Beyond the visual representation of the data, the data have been made into sounds where the frequencies and playback speed have been shifted to be audible to human ears.
5. Jovian “Southern Lights”
The complexity and richness of Jupiter’s “southern lights” (also known as auroras) are on display in this animation of false-color maps from our Juno spacecraft. Auroras result when energetic electrons from the magnetosphere crash into the molecular hydrogen in the Jovian upper atmosphere. The data for this animation were obtained by Juno’s Ultraviolet Spectrograph.
During Juno’s next flyby on July 11, the spacecraft will fly directly over one of the most iconic features in the entire solar system – one that every school kid knows – Jupiter’s Great Red Spot! If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno.
A ‘Ring of Fire’ solar eclipse is a rare phenomenon that occurs when the moon’s orbit is at its apogee: the part of its orbit farthest away from the Earth. Because the moon is so far away, it seems smaller than normal to the human eye. The result is that the moon doesn't entirely block out our view of the sun, but leaves an “annulus,” or ring of sunlight glowing around it. Hence the term “annular” eclipse rather than a “total” eclipse.
Here’s the orbital period of our solar system’s 8 major planets (how long it takes each to travel around the sun). Their size is to scale and their speed is accurate relative to Earth’s. The repetition of each GIF is proportional to their orbital period. Mercury takes less than 3 months to zoom around Sol, Neptune takes nearly 165 years.
Yes, I’m still in orrery mode - a little one set in a pocket watch case. The planets are solid metal - gold, silver and copper tones. It was made to be a desk ornament but could be very carefully used as a fob or pendant. It doesn’t move - no orbit or rotation - just an assemblage piece made to look like it might move.
This graphic, released by NASA and JPL shows the orbits of all 1,400 known potential impactors above 140 metres across (enough to do some serious damage) that might someday collide with Earth. None are a threat during the next century, but the chaotic nature of orbits means that they need to be monitored in order to refine our understanding of the risk they pose and in case their orbit gets modified by passing near a gravity well. The largest circle is Jupiter, next in Mars, and the thick white circle our Blue Marble.
New radar technique locates lost Indian Lunar orbiter, NASA probe.
Using previously untested radar techniques, NASA has successfully located two Lunar-orbiting spacecraft, one of which has not been tracked since 2009.
Scientists from the Jet Propulsion Laboratory in California beamed high energy microwaves at the Moon from the Goldstone Deep Space Communications complex in California. The waves bounced off the Moon and were picked up by the Green Bank Telescope in West Virginia. By using the return signal to estimate velocity and distance, JPL scientists were able to locate NASA’s Lunar Reconnaissance Orbiter – which is still operating and is currently tracked by the agency.
However, the team also located India’s derelict Chandrayaan-1orbiter whose mission ended in 2009. Due to regions of the lunar surface with a stronger gravitational pull than others – known as mascons – the spacecraft’s orbit could have been radically altered or it could have even crashed into the moon.
Since the spacecraft was known to be in a Lunar polar orbit, the team directed the microwave beam just above the Lunar north pole and hoped the spacecraft would intercept it. The returned beam picked had a radar signature in accordance to what a small spacecraft wold be expected to make. Furthermore, during the four hours the Chandrayaan-1 test took place, the spacecraft crossed the beam twice in the amount of time it was predicted to make a single orbit and return to the same point. Due to the varying strength of the Moon’s gravity over regions of different composition – known as mascons – the spacecraft’s location had to be shifted by nearly 180 degrees.
Scientists were not certain if the tests, which occurred in July 2016, would be successful. Although interplanetary radar has been used to track asteroids millions of miles away using the same technique to locate a small satellite around the moon was untried. The technology demonstrated could be useful in planning future lunar missions. The Indian Space Research Organization has no intention to reactivate the Chandrayaan-1 spacecraft, whose mission ended in 2009.
Chandrayaan-1 was India’s first Lunar mission, launching in October 2008.