The most violent celestial body in the solar system, sulfur dioxide spews out in large quantities, poisoning the atmosphere

On Earth, volcanoes are formed as tectonic plates continue to move. In the weakest part of the earth's crust, there will be hot magma spewing out, bringing huge disaster to the earth's life.

Volcanoes are indeed scary, but we should also be grateful that we live on Earth, not Io. As the most volcanically active planet in the solar system, every day on Io is spent in fear.

More than 400 active volcanoes are dotted on the 3,642-kilometer-diameter moon. Unlike Earth's volcanoes, which arise from plate movement, Io's volcanoes come from tidal forces. While under the gravitational pull of Jupiter, it also bears the gravitational pull of the other three giant satellites, which causes the material inside to keep churning and rubbing. While maintaining high temperature, it also has a lot of energy. In the end, some of them are volcanic form to release energy.

While spewing magma, Io's volcanoes also spew large amounts of sulfur dioxide. They are ejected in gaseous form, but freeze into a solid state in the low temperature of the night and coat the moon's surface. Therefore, we see Io, always showing a sallow yellow like a sick person.

So here comes the question: How much of the sulfur dioxide in the atmosphere of Io comes from the volcano and how much of the solid sulfur dioxide from the surface returns to the atmosphere after being sublimated by heat? For this question, scientists have not had an accurate answer.

Introducing the question, astronomer Imke de Pater of the University of California, Berkeley, said: "It is still unknown which process drives the changes in Io's atmosphere. Is it volcanic activity or when Io is bathed in sunlight from the sun? What about the gas that sublimates the ice on the surface?"

Although hundreds of volcanoes take turns releasing gases such as sulfur dioxide, the atmosphere on Io's surface is still very thin, with a pressure of only one billionth of Earth's. A large part of the reason is Jupiter. Studies have shown that a large amount of gas on Io escapes under the action of Jupiter, and 1 ton of gas can escape almost every second, forming a ring structure between Io and Jupiter, which is called Io Plasma circulation.

The remaining gas, while not much, can still give us a lot of information. Through the study of these gases, scientists can speculate on the possible internal structural geological processes of Io, and even help us understand similar processes on exoplanets. In addition, there are other celestial bodies in the universe that are also subjected to the tug-of-war of gravity like Io, but they do not produce the same effect. The reason for this also requires us to have a thorough understanding of the mechanism of Io's atmosphere. Can.

To crack these mysteries, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to observe Io in radio waves, using it to enter and exit Jupiter's shadow, or Jupiter's shadow. Weiyi's Evening and Dawn) process to analyze their long-cherished questions.

They first found that after Io entered the night, the temperature dropped below the freezing point of sulfur dioxide, causing it to condense and seal on the surface.

When Io returns to daylight, the frozen sulfur dioxide sublimates into the atmosphere. To their surprise, the process took only 10 minutes, much faster than expected. And this magical phenomenon is an important tool for studying the impact of Io's volcano on the atmosphere.

Astronomer Statia Luszcz-Cook of Columbia University said: "When Io enters Jupiter's shadow, out of direct sunlight, the temperature is too low for sulfur dioxide, and it condenses on Io. During this period, we can only see sulfur dioxide from volcanoes." With all the sulfur dioxide in the air condensed, the reappearance of this substance in Io's atmosphere during this period must have come from volcanic eruptions. This is an excellent opportunity to study the contribution of volcanoes to Io's sulfur dioxide.

With the powerful observational capabilities of ALMA, the research team clearly distinguished the sulfur dioxide and sulfur monoxide plumes on Io for the first time. They proved that sulfur dioxide released by volcanoes does play an important role in Io's atmosphere. Based on these images, they speculate that about 30%-50% of the sulfur dioxide in Io's atmosphere comes from volcanoes. Granted, that's not the vast majority, but for volcanoes, the numbers are pretty staggering.

At the same time, in areas without sulfur dioxide and sulfur monoxide, the researchers also found another substance, that is, potassium chloride in volcanic eruptions. This suggests that the magma systems beneath Io are not completely connected, otherwise they should be ejecting similar material. This suggests to us that Io's surface is more complex than we thought.

As a next step, the research team is preparing to measure the temperature of Io's surface, which will be of great help in further narrowing the proportion of sulfur dioxide emitted by the volcano. It's not an easy job, especially with temperature measurements on Io's lower elevations, but the research team thinks they can still do it.

De Pater said: "To detect the temperature of Io, we need to have a higher resolution, which requires us to observe the satellite for a longer time. We can only be in the sun when Io is in the sun. Observation when it is in the shadow, because it is not in the shadow for a long time. During such observation, Io will have an orbital angle of 10°. We need to use software to make an unobstructed image, which we This has been done before in radio images of Jupiter with ALMA and the Very Large Telescope."

As the most volcanically active body in the solar system, the internal structure of Io has always been one of the most curious questions for scientists. This is a supplement to what we know about the internal structure of the Earth. Only by understanding the structure of various rocky planets can we say that we really understand all the internal mechanisms of the Earth. For some problems that cannot be solved on Earth, we can only turn to other celestial bodies in the solar system, or even more distant exoplanets. Perhaps in the most distant places, there are the most recent secrets.