NASA spacecraft beams back tantalizing images of volcanic world Io

There's a moon teeming with lava-spewing volcanoes in our solar system, and a NASA spacecraft is getting closer to this intense world.

The pioneering Juno spacecraft, which arrived at Jupiter in 2016 and is now swooping by the planet's intriguing moons, recently snapped images of the Jovian moon Io from some 32,044 miles (51,570 kilometers) away. The March 1 images are Juno's "best images so far of Io's colorful surface," Jason Perry, a professional imaging processor who uploaded new photos to NASA's Juno website, noted online. The images allow planetary scientists and the public to spot surface features and volcanoes on Io — the most volcanically active world in our solar system.

In 2023, the views of Io will get increasingly clearer and more intriguing. Juno will swoop progressively nearer to Io as it loops around Jupiter and approaches the dynamic moon's orbit. By year's end, the spacecraft will pass just some 930 miles, or 1,500 kilometers, from Io. (For reference, the moon is some 240,000 miles from Earth.)

"We're marching closer and closer," Scott Bolton, the Juno mission's principal investigator, told Mashable.

"It's a real tortured moon," Bolton, who works at the Southwest Research Institute, a research organization that often partners with NASA, added. "It's just this beautiful place."

Io is tortured because it's stuck in a relentless "tug-of-war" between the massive Jupiter and two of Jupiter's other big moons, Ganymede and Europa — a world that might harbor a sizable ocean. This powerful push and pull creates profound heat inside a world that's a little larger than our moon. All this heat seeks to reach the surface, resulting in molten lava and extreme volcanism. It's extremely unlikely a world swimming in lava could host conditions for even the hardiest of life to evolve. But other moons in our solar system could potentially contain suitable conditions for life to evolve in their subsurface, like the Saturnian moons Enceladus and Mimas (and, of course, Europa).

These latest Io images were taken during Juno's 49th trip around Jupiter.

Scientists like Bolton use these images to, among other things, identify new volcanoes. The darker spots are often places where eruptions have occurred, and other recent NASA imagery shows that this volcanism is incessant. A looming question is whether a global magma ocean oozes inside Io, or if there are just giant pockets of molten rock.

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When the Juno spacecraft gets nearer to Io, it's not directly approaching the moon, but veering by the moon's orbit, as shown in the graphic below. During each orbit, Juno will snap pictures at the closest approach before it once again whips around the gas giant Jupiter. By the end of December 2023, Juno's orbit (PJ 58) will bring it within some 930 miles of Io. It's a much-anticipated event.

Repeatedly zipping around Jupiter is no simple task for a robotic spacecraft. Radiation levels around the planet are high, owing to the energized particles trapped by Jupiter's huge magnetic field. That's why the spacecraft's vital electronics are housed inside a hardy "radiation vault." Now entering its eighth year of operations, let's hope the robot continues to hold up as it explores Jupiter's fascinating moons, hundreds of millions of miles from Earth.

"It's an armored tank," said Bolton. "And the shields are holding."