Lots of interesting things in the news this week. We begin with Saturn’s 313-mile diameter moon Enceladus. Recent close flybys of the moon by the Cassini spacecraft have revealed more than 90 jets spraying water vapor, particles and organic compounds from its south polar regions. The source of these otherworldly geysers is believed to be a huge underground sea. Cracks in Enceladus’ crust of ice allow the warmer water to shoot out and crystallize in the cold vacuum of outer space.
Cassini has flown through the spray and used its ion and “tasted” the watery jets with its neutral ion spectrometer. Besides water and organic materials , the probe has found salt in the ice with the same salinity as that in Earth’s oceans. Add the fact that the temperature in the fissures is more than 200 degrees warmer than the average surface temperature of -330 Fahrenheit, and you begin to wonder if Enceladus might provide a hold for life.
Carolyn Porco, planetary scientist and leader of the Imaging Science team for Cassini, thinks so. “”The kind of ecologies Enceladus might harbor could be like those deep within our own planet. Abundant heat and liquid water are found in Earth’s subterranean volcanic rocks. Organisms in those rocks thrive on hydrogen (produced by reactions between liquid water and hot rocks) and available carbon dioxide and make methane, which gets recycled back into hydrogen. And it’s all done entirely in the absence of sunlight or anything produced by sunlight.”
You only have to look at deep sea explorer’s James Cameron’s record-breaking solo dive of 35,756 feet to the deeps of the Mariana Trench Monday to know that life thrives in extreme environments. Even in that utterly dark, crushing-pressure and near freezing environment, he saw inch-long shrimp-like arthropods swimming outside the window of his submarine. Protected from the bitter cold and dangerous radiation of space, tiny microbes inside Enceladus might be swimming about just as comfortably.
Enceladus gets its heat from Saturn. The ringed giant’s powerful gravitational pull on the moon makes it flex one way and then another during its 33-hour long orbit, warming the interior and melting ice to make water. Picture Enceladus as one of those liquid-filled hard candies. For all we know, it could be snowing bacteria on the moon as material from the jets freezes and settles back on the surface.
About a week ago I shared amateur astronomer Wayne Jaeschke’s photo of an oddball cloud high above the surface of Mars that looked like a bump along the planet’s edge.
While both water and dry ice clouds are common on Mars, this one seemed unusually high. Everything from a high-altitude dust storm to the plume of an unseen impact were suggested as the cause. Amateurs continued shooting the planet and the pros studied pictures taken by the Mars Reconnaissance Orbiter’s Mars Color Imager. Nothing has turned up yet in the spacecraft images, indicating the cloud was brief-lived. Scientists are still going over pictures taken by Mars Odyssey orbiter’s Thermal Emission Imaging System (THEMIS). Perhaps they’ll find something there.
According to Bruce Cantor, senior staff scientist at Malin Space Science Systems, the phenomenon is most likely a cloud or haze composed of water ice that forms during the early morning hours.
Tonight the moon’s a day past first quarter in the constellation Gemini the Twins. It’s high in the south at nightfall and beckons anyone with a small telescope to stop and see the craters.
First quarter to gibbous phase is the best and most convenient time to see the hundreds of craters that carve bowls of every size in the lunar landscape. The larger ones have spectacular mountain peaks in their centers formed from material that rebounded upward after the impact. While the planets take time and experience to discern their details, the moon lets it all hang out.