With over 400 active volcanos, Jupiter's moon Io has been called the most volcanically active celestial bodies in our solar system. The moon has been an object of fascination with scientists and new images captured from an array of telescopes have given new insight into the spectacular moon. While only slightly larger than our moon, Io (which was named after a mortal woman who is transformed into a cow during a fight between Zeus and Hera in Greek mythology) is pitted with hundreds of volcanoes, some of which are so powerful that their eruptions can be seen using large telescopes on Earth.
The new images are brought to us by ALMA, or the Atacama Large Millimeter/submillimeter Array of telescopes in Chile, and they give us amazing images of Io's signature color palette of yellow, white, orange and red. These colors come from the sulfurous gases spewing from the moon's many volcanoes that freeze when they meet the cold temperatures of the icy surface. Io's surface is about negative 230 degrees Fahrenheit, which negates the heat coming from the volcanoes. Io's atmosphere is so faint that it's about a billion times thinner than Earth's.
The clarity of the ALMA images revealed distinct plumes of sulfur dioxide and sulfur monoxide coming from the volcanoes, contributing between 30% to 50% of the moon's atmosphere. In addition, researchers found potassium chloride gas, a common component of magma, emerging from the volcanoes, which suggests that the magma reservoirs differ between volcanoes.
This most famous image captured shows Jupiter's moon Io in a combination of radio and optical light, with a separate image of Jupiter behind it. Data from ALMA show for the first time plumes of sulfur dioxide (in yellow) that rise up from its volcanoes.
"However, it is not known which process drives the dynamics in Io's atmosphere," said study author Imke de Pater, a professor of astronomy, Earth and planetary science at the University of California, Berkeley, in a statement. "Is it volcanic activity, or gas that has sublimated (transitioned from solid to gaseous state) from the icy surface when Io is in sunlight?"
"When Io passes into Jupiter's shadow, and is out of direct sunlight, it is too cold for sulfur dioxide gas, and it condenses onto Io's surface. During that time we can only see volcanically-sourced sulfur dioxide. We can therefore see exactly how much of the atmosphere is impacted by volcanic activity," said Statia Luszcz-Cook, study coauthor and observational astrophysicist at Columbia University, in a statement.
Io is caught between Jupiter's massive gravity and the tug of orbits from the planet's other moons like Europa and Ganymede, which contributes to the activity on Io. Some of its volcanoes are massive, like Loki Patera, which is 124 miles across.
"As soon as Io gets into sunlight, the temperature increases, and you get all this (sulfur dioxide) ice subliming into gas, and you reform the atmosphere in about 10 minutes' time, faster than what models had predicted," de Pater said.
"By studying Io's atmosphere and volcanic activity we learn more about not only the volcanoes themselves, but also the tidal heating process and Io's interior," Luszcz-Cook said.