EarthSky’s Deborah Byrd created this 1-minute video abstract for you, on Io‘s volcanoes.
- Jupiter’s rocky moon Io is probably the most volcanically lively world within the solar system. It has tons of of volcanoes, some with erupting lava fountains dozens of miles (kilometers) excessive.
- Io’s volcanoes have been lively for billions of years, a brand new research says, ever since Io first shaped.
- How do they know? The researchers studied the ratio of various mild and heavy sulfur isotopes in Io’s skinny environment. The outcomes recommend the volcanoes’ age, and in addition present clues about how a lot sulfur Io has misplaced since its formation.
Jupiter’s moon Io is known for the tons of of volcanoes dotting its floor. It’s probably the most volcanically lively world in our solar system. However how lengthy has Io had its lively volcanoes? Researchers on the California Institute of Know-how (Caltech), New York College and NASA’s Goddard Area Flight Heart said on April 18, 2024, that Io’s volcanoes have been erupting for billions of years, since simply after the little moon 1st shaped, together with our sun, Jupiter, Earth and the remainder of our solar system.
The conclusions are primarily based on new evaluation of sulfur in Io’s skinny environment. That is smart, as a result of sulfur performs a key function on Io’s floor and in its environment. A few of Io’s volcanoes spew sulfur and sulfur dioxide in nice plumes extending miles (kilometers) above Io’s floor. In depth plains of sulfur lie in a frosty coating on most of Io’s floor.
For those who might stand on Io and not using a spacesuit (not actually doable since Io is bathed in excessive radiation from Jupiter), you’d discover it smells like rotten eggs, on account of its sulfur. Now that sulfur has offered clues to the historical past of Io’s lively volcanoes.
The researchers revealed their peer-reviewed findings in two new papers on April 18, one in Science and the other in JGR Planets.
New evaluation of sulfur isotopes from Io’s volcanoes
So, Io’s volcanoes emit rather a lot of sulfur. And Io’s environment is 90% sulfur dioxide. The analysis crew performed an evaluation of isotopes of Io’s atmospheric sulfur. This offered clues as to how lengthy Io has been in orbital Laplace resonance with two different moons: Europa and Ganymede.
In different phrases, Io completes 4 orbits of Jupiter for each two orbits of Europa and one orbit of Ganymede. Because of this, the moons all pull on one another gravitationally. This causes their orbits to be elliptical relatively than round. And in flip, Jupiter’s robust gravity then heats the interiors of the moons. This is the reason Europa and Ganymede have subsurface oceans and Io has magma and volcanism.
By analyzing the isotopes, scientists might inform how lengthy Io has been in orbital resonance and, due to this fact, volcanically lively. To do that, they used the Atacama Giant Millimeter/submillimeter Array (ALMA) telescope in Chile.
The sulfur atoms on Io have numerous isotopes. That’s, they’ve various numbers of neutrons. Sulfur-32 and sulfur-34 each have 16 protons, however the first has 16 neutrons, whereas the second has 18. The extra neutrons an atom has, the heavier it’s. On Io, the heaviest sulfur atoms are on the backside of the environment, whereas the lightest are close to the highest.
Ever-changing floor and environment
Although Io total is billions of years outdated, similar to all the opposite our bodies within the solar system, its floor is just about 1,000,000 years outdated. It’s because its floor is at all times being replenished by new materials from its quite a few volcanoes.
Io’s environment is at all times altering, too. Collisions with charged particles in Jupiter’s magnetic discipline strip away the already-thin environment into space. This occurs at a charge of 1 ton per second. Due to this fact, the lighter sulfur isotope on the prime of the environment, sulfur-32, will get depleted quicker. By calculating how a lot sulfur-32 is lacking, the researchers can decide how lengthy Io has been volcanically lively.
This animation is an artist’s idea of Loki Patera, a lava lake on Io, made by utilizing information from the JunoCam imager onboard NASA’s Juno spacecraft. With a number of islands in its inside, Loki is a despair full of magma and rimmed with molten lava. Video through NASA/ JPL-Caltech/ SwRI/ MSSS/ YouTube.
Sulfur ratios
The researchers appeared on the ratio of sulfur-32 to sulfur-34 in Io’s environment. Within the early solar system, the ratio was about 23 atoms of sulfur-32 for each one atom of sulfur-34. That ratio is identical at this time for any physique that has remained unchanged because it first shaped. However that’s not the case with Io. By far, most of its authentic sulfur – 92 to 99% – has been misplaced. Although a lot of the unique sulfur – the lighter isotope sulfur-32 particularly – has been misplaced, this additionally exhibits Io will need to have been volcanically lively since quickly after its formation.
And that, in flip, exhibits Io has been in a Laplace orbital resonance with Europa and Ganymede for simply as lengthy.
Historical past of Io’s volcanoes
Whereas the brand new findings present Io has at all times been volcanically lively, there are nonetheless numerous doable particular situations for the historical past of the moon. This consists of the chance that Io was as soon as much more volcanically lively early on than it’s now. As Ery Hughes, previously from Caltech and co-author of the primary paper in Science, explained:
As a result of numerous the sunshine sulfur is lacking, the environment we measure at this time is comparatively ‘heavy’ when it comes to sulfur. Key to reaching such heavy sulfur in Io’s environment is the method of burying the heavy sulfur again into Io’s inside, in order that it may be launched by volcanoes time and again. Our modeling exhibits that sulfur will get trapped within the crust of Io by reactions between the sulfur-rich frosts, that are deposited from the environment and the magma itself, permitting it to be finally buried into Io’s inside.
On April 18, 2024, NASA additionally launched new video animations of a lava lake and steeple-like mountain on Io. Test them out!
Backside line: A brand new research reveals Io’s volcanoes have been erupting for billions of years, ever for the reason that small moon of Jupiter first shaped.
Source: Isotopic evidence of long-lived volcanism on Io
Source: Using Io’s Sulfur Isotope Cycle to Understand the History of Tidal Heating
Read more: Jupiter’s moon Io as you’ve never seen it
Read more: Jupiter’s moon Io: Global magma ocean, or hot metal core?
