If there was a match for the most interesting moon in our solar system, Callisto would be a counterpart. Jupiter's second -largest moon has larger craters of impact on its surface than any other planetary body in the solar system and has tons of ice on its surface.
For decades. Researchers theorizing that rest under Callisto's surface is a liquid salted ocean that covers the whole moon. After carefully considering data from 30 years ago, researchers now have strong evidence that such an ocean really exists.
A team led by Corey Co Cochran from the NASA planetary interiors and geophysics department did not start looking for an ocean of Calisto. According to Cochran, the team worked on Different projectincluding Scan the moon of Neptune Triton To see if there is an underground ocean.
This presented a challenge because of Triton's intense ionosphere, which is the last layer of the atmosphere before the space begins. Since Callisto also has an intense ionosphere, the team decided to test its methods of 30-year measurements made by NASA's Galileo mission. That mission began in 1989 and scanned Jupiter and its moons between 1995 and 2003.
“Our conclusions were made possible by analyzing the measurements that were acquired by the flying of Calisto, which was usually neglected in the community, due to the presence of increased” noise “attributed to the plasma of the environment,” Cnet told CNET in E -Mountain.
“We were able to use pre -developed plasma simulations to remove this blurred plasma noise source from measurement, so that the ocean signal can be analyzed independently,” Cochran said.
In short, Galileo's readings were initially difficult to interpret because of Calisto's strong ionosphere. After Cochran and his team cleaned the readings, they were able to take into account the data, and strongly suggested that there was an ocean under the rocky exterior of the moon.
The ionosphere looks like an ocean
It takes so long to prove the existence of an underground ocean of Calisto because the strong ionosphere imitates the readings they would receive if there is such an ocean.
“Basic physical law of nature (Faraday's Magnetic Induction Law indicates that if you move a magnet relative to any conductive material, such as copper wire, you will create electric current within that wire that is synchronized with the movement of the magnet,” Kochran explained. “That current will then create a secondary magnetic field (due to the movement of electrons in the wire) called an induced magnetic field, which shows the properties of the conducting material.”
Cochran said this also works with planetary bodies. The moon or planets with sufficient internal heat can have a liquid salted ocean below the surface. These oceans are electrically conductive thanks to salt in the water. Thus, scientists can use magnetometers to measure an induced magnetic field that “retains the properties of the ocean,” Cochran said. In other words, the oceans can be found based on the magnetic fields they create.
Since the moon like Callisto on Jupiter and Triton on Neptune have very strong ionospheres, readings with magnetometer become so noisy that researchers have trouble realizing whether what they see is an ocean or just a random noise from the extra energy in the ionosphere. That is why researchers have been stuck on the potential underground ocean of Calisto for decades.
The next steps
Science will not have to wait another 30 years to find proof. Sailing NASA's Clipper's mission to NASA Last year they are due to reach Jupiter and his moons in 2030, while the European Space Agency Mission juice should arrive in 2031. Both missions will almost certainly provide more data on Calisto research.
Regarding the information they collect, Cochran told us that no different data is necessarily. Instead, these are more data.
“Proving the existence of Calisto's ocean from new measurements simply comes down to the fact that there are more measurements available to analyze,” Cochran said. “For every flying that occurs for each of these missions, only a very small picture at the time of the magnetic field surroundings is captured by the magnetometer.”
Cochran said that data from Clipper and Juice missions from Europe would help “fill the holes” from the Galileo mission, we hope that it allows researchers to finally prove whether there is an ocean of Calisto. Additional data will also help researchers assess how the thick ocean layer of Calisto is, as well as the thickness of the icy lining that lies on top of it.
Can I have a life on Calisto?
NASA and the European Space Agency would not send missions to Jupiter without good reasons to do so. And one is this: Europe's hidden waters are advantages For extraterrestrial life.
“It is possible that the ocean of Europe can support life because we know that it hosts key ingredients to support it, those that are water, basic chemical elements and energy (eg a source of heat from within) over a time span long enough to develop life,” Kochran said. “Europe's Clipper is actually a living mission (not to confuse life) that will provide the data needed to better help us answer this question. By that time, it is difficult to comment on whether it is likely. “
But there is a growing case for Calisto's life. There are A surprising amount of oxygenAnd no one can understand where most of them came from. Pair it with the increased probability of an underground ocean, and although it is still far from safe work, it is enough proof to justify to look at the moon Jupiter when the missions arrive in 2030 and 2031.