Jupiter’s moon Europa is believed to have a sea of water inside the crust made of ice, and the possibility of extraterrestrial life is pointed out. NASA has published a study that suggests that Europa’s surface could sparkle in the dark.
NASA is planning a detailed exploration of Europa, where life is expected, and plans to launch a probe called the Europa Clipper around 2023-2025. The research team at the Jet Propulsion Research Institute, which develops and operates unmanned probes, is studying the effects of radiation on the Europa surface.
Jupiter is known to emit massive amounts of radiation, and massive amounts of radiation are pouring into satellite Europa. In order to see how the organic matter under the ice reacts to irradiation, the research team conducted an experiment that reproduced the surface ice component of Europa and actually irradiated it.
According to past observations, it can be seen that the ice on the surface of Europa is made of chlorides commonly found on Earth, such as water, magnesium sulfate, and sodium chloride. The research team used the equipment to irradiate the ice that reproduced the Europa surface, and as a result, it was confirmed that the ice itself shined by irradiation before organic matter.
When radiation is irradiated on ice, the phenomenon of light emission occurs when electrons in a metastable state absorb light energy by irradiation and return to the ground state. This phenomenon itself has been known from before, and the same structure is used for dosimeters that measure radiation dose.
It is pointed out that the moon reflects the sun’s light shining in the dark night sky, but the Europa luminous structure is completely different from the moon, so it is shining from the side where the sun does not overreach. The research team explained that if Europa is not exposed to radiation, the shaded areas of the sun like our moon will be dark, but due to Jupiter radiation, Europa will shine even in the dark where sunlight does not reach.
The results were surprising to the research team. He explained that the very weak and sparkling sodium chloride saline solution changed the direction of the research. The light emitted by Europa ice appears green to the naked eye, but in some cases it appears blue and white because the color of the light that changes the composition of chloride contained in the ice also changes. The research team said they could not imagine seeing something like this. When they tried to create a new ice, the light looked different, and when checked with a spectrometer, the light spectrum of each ice star was different.
From these results, the research team revealed that there is a possibility to reveal the ice composition from the light spectrum using a spectrometer for Europa exploration. He added that these changes could give a clue as to whether Europa has the right conditions for life. Related information can be found here .