We've been lucky enough to see flybys of all planets and many other objects in the solar system, providing us unique close-up views. But on the most giant planet, the north pole remained an enigma until just earlier this month. NASA's Juno spacecraft imaged the area, providing us a hint of flybys yet to come.
RELATED: Jupiter's Wild North Pole Photographed
What have we learned about other poles in our neighborhood? Read below for a few examples.
We've visited Jupiter again and again over the past few decades, but one area of the giant planet has always remained a mystery. Earlier this month, the Juno spacecraft imaged the planet's north pole for the first time. It's just a first glance, but scientists are already seeing some new things, such as few signs of storms or bands as in other areas of the planet. "This image is hardly recognizable as Jupiter," principal investigator Scott Bolton, from the Southwest Research Institute in San Antonio,
said in a statement
. Another notable finding: no hexagon was visible on the giant planet, similar to what has been discovered on Saturn.
Image: Jupiter's north pole. Credit: NASA/JPL-Caltech/SwRI/MSSS
The Cassini spacecraft, which is is finishing operations at Saturn next year, has been watching the north pole of the planet closely since the sun illuminated the region in late 2012. This 2013 image shows just how complex the hexagonal-shaped storm system at Saturn's north pole is. They have seen a lot of small haze particles and few big haze particles inside the storm, which is the opposite of what is seen outside of the hexagon. The weather feature itself is unique in the solar system and is huge: 20,000 miles (30,000 kilometers) across with 200 mph (322 km/hr) winds. "The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable," said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology,
in a 2013 statement
. "A hurricane on Earth typically lasts a week, but this has been here for decades -- and who knows -- maybe centuries."
Image: The hexagon on Saturn's north pole. Credit: NASA/JPL-Caltech/SSI/Hampton University
Because so many spacecraft have visited Mars, we are lucky to have lots of pictures of its poles. There even was a spacecraft that landed close to the north pole in 2008, called Phoenix. Scientists are interested in how the ice at the poles (both water ice and carbon dioxide ice) affect weather throughout the year, since these poles wax and wane with the seasons. There is also interest in finding out what the ice is made of and if it could be hospitable to life. This simulated 2016 image is based on data from NASA's Mars Reconnaissance Orbiter and is believed to show information from the last Martian ice age. "Where the edge of the ice cap has retreated, sheets of sand are emerging that accumulated during earlier ice-free climatic cycles," NASA
said in a statement
. "Winds blowing off the ice have pushed loose sand into dunes, then driven them down-canyon in a westward direction."
Image: A simulated 3-D perspective view of Chasma Boreale on the north polar cap of Mars. Credit: NASA/JPL/Arizona State University, R. Luk
Mercury's north pole has been examined both from space and from Earth. The NASA MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging) spacecraft orbited the planet between 2011 and 2015, and in recent years several radar telescopes have also taken a look at the north pole. Why all the interest? In one word: ice. It's only in recent years that ice has been confirmed on Mercury's surface, mainly in permanently shadowed craters. This is an extraordinary find given that the planet is so close to the sun. Scientists are trying to track the history of water in our solar system to figure out how it got to Earth, as well as other planets. One theory is that it arrived at our planet via comets, although Rosetta's studies of Comet 67P/Churyumov–Gerasimenko revealed that the comet has a different type of hydrogen in its water than we do here on Earth.
Image: An orbital mosaic of Mercury's north pole based on data from the MESSENGER spacecraft. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
5) The moon
This 2011 image of the moon's north pole is based on data from NASA's Lunar Reconnaissance Orbiter. Like Mercury, scientists have been looking at the moon's north pole closely to determine permanently shadowed regions in which ice could lie. Depending on how abundant the ice is, it could serve as a valuable resource for future human colonies exploring our closest large celestial neighbor. The ice finding came somewhat as a surprise to scientists, since all evidence from the Apollo missions showed a dry surface. It was only during missions in the 1990s and 2000s that more information about the moon's composition came to light.
Image: The moon's north pole, based on imagery from NASA's Lunar Reconnaissance Orbiter. Credit: NASA/GSFC/Arizona State University
Saturn's soupy moon Titan is a world of bogs and hydrocarbon rain. In 2015, scientists revealed a huge cloud of frozen compounds above the moon's south pole. What's more extraordinary is Titan's polar clouds form differently than on Earth (through water evaporating from the surface, hitting cooler temperatures high in the atmosphere, and condensing). "Circulation in the atmosphere transports gases from the pole in the warm hemisphere to the pole in the cold hemisphere,"
NASA wrote at the time
. "At the cold pole, the warm air sinks, almost like water draining out of a bathtub, in a process known as subsidence."
Image: A south polar vortex on Titan imaged by the Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science Institute
Enceladus is a moon known for having more than 100 geysers of water that regularly spray into space, likely from an ocean below its icy crust. It's unclear if that ocean hosts life, but the Cassini spacecraft has performed several flybys and the data could be used for future landers or orbiters. This image montage shows how bright the north pole is, due to all the material deposited from ice and vapor at the south pole.
Image: The north pole of Enceladus in a montage of images from NASA's Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science Institute