Links: Europa Life, Moon Geology, Citizen Activism

Some readings I perused over the past couple of weeks.

1) Our picture of habitability on Europa, a top contender for hosting life, is changing. Jupiter's moon Europa has long been a contender for hosting life. But lately some scientists have expressed their doubts. Europa has an ocean beneath a 20 km icy crust. Geologists now think that the sea floor is not active. They simulated conditions which could generate shallow earthquakes leading to fault movement and exhumation of fresh rock. Reaction of sea water and freshly exposed rocks is necessary for chemical reactions that sustain life. Results suggest an inert sea floor. Another study implied no magmatism on Europa. Rising magma brings with it heat and chemicals. But, could these be transient conditions that we have caught? Maybe there is a cyclicity to Europa's energy flow. Some interesting thoughts in this article.

2) China's Moon atlas is the most detailed ever made. The Chinese Academy of Sciences has released a stunning 1:250,000 scale geologic map of the moon. A decade of research has revealed 17 rock types ( I used to think only basalt!), 81 basins, and 12,000 odd craters! Compiled from orbiting satellites and then sharpened using data from the two lander missions.

3) How Punekars fought for their hill, Vetal Tekdi, to save its ecology. My city Pune has a proud tradition of citizen activism. For the past few years citizens have vigorously protested a road planned along a forested hill slope. This hill has been a life saver for thousands of citizens as a recreation spot. It hosts rich biodiversity and is an important groundwater recharge zone. The Pune Municipal Corporation is insisting on building this road, despite their own reports admitting an adverse environmental impact, and pointing to at best a short term marginal improvement in traffic flow. The fight to save the hill goes back a couple of decades. Shobha Surin has done a good job summarizing this long battle in Question of Cities.   

Links: Fire Use, Deep Water, Europa Geology

Sharing some interesting readings:

1) The Discovery of Fire by Humans. Jungle Book's primate king Louie was certainly aware of the transformative power of fire. As J.A.J Gowlett writes in a very informative review, many animals engage in fire foraging, opportunistically increasing their access to resources made available by natural fires. Early hominins too would have interacted with natural fires. The archeological record informs us that human engagement with and ultimately our control over fire was a long and convoluted process with evidence for early fire use going back to 1.5 million years ago. And would you believe it if I told you that the earliest preserved human fingerprint may be 80,000 years old and documents fire use? It was imprinted on a lump of pitch which is made by prolonged heating of tree bark. Pitch was used as a fixative in hafting. Fasinating stuff.  

2) The Deep Cycle of Water: Every schoolkid is taught about the hydrologic cycle wherein water moves between the atmosphere and shallow surface reservoirs. But water is present much deeper inside the earth, in fact it is present thousands of kilometers deep. It occurs not as free flowing H2O, but is incorporated inside the atomic structure of minerals as OH anions. It can escape this prison when minerals dehydrate during metamorphic reactions. The released water then rises and is expelled at the surface via volcanoes. In an alternate pathway, carried by sinking pieces of tectonic plates, water can reach even deeper in the earth, affecting the properties of the lower mantle and even the core. A short summary in Nature Geoscience on the state of our knowledge about this topic. 

3)  Plate Tectonics on Europa. The earth's outer silicate shell is broken up into tectonic plates which move around and jostle driving geologic activity and transforming the surface through geologic time. Scientists are looking to Jupiter's moon Europa and finding that its icy shell shows features indicative of intermittent plate motions, although the driving mechanisms will be different.  In Phys.Org, by Morgan Rehnburg. 

Books: Volcanoes, Mammals, Himalayas

 New arrivals on my book shelf.

Fire and Ice: Volcanoes of the Solar System. Earth has them. So does the Moon and Mars. While eruptions on these three is molten silicate magma, there is plenty of variety in the rest of the Solar System. Io has sulphur rich emissions which drape the surface with a coating of  sulphur. Pluto has eruptions of nitrogen, methane, and ammonia that solidifies to form icy rock. Tidal forces unleased by Saturn on its moon Enceladus ruptures the moon's surface and triggers eruptions of fluids that fall back as snow and also contribute to the formation of Saturn's rings. Volcanologist Natalie Starkey delves into our current understanding of volcanoes of the Solar System and what we can learn from them about planetary evolution. Fascinating topic!

  

Beasts Before Us: The Untold Story of Mammal Evolution and Origins. Untold because most authors begin where the Dinosaurs end. The starting point is  usually at 66 million years ago, when a meteorite changed the world in an instant, reorganizing and vacating ecosystems into which mammalian lineages radiated. The story told by Elsa Panciroli goes way back, when Synapsids, the branch that led to mammals diverged from the common ancestor of mammals and reptiles. Repeat three times before going to sleep every night. Mammals did not evolve from Reptiles. These two groups shared a common ancestor in the Carboniferous about 300 million years ago. More and more fossils  are revealing that these early mammalian lineages were quite diverse, and not mere stunted underlings to the more popularly known Dinosaurs. For a lucid audio discussion of this book, listen to Elsa Panciroli on Paleocast Podcast- Beasts Before Us. 

 

 Himalaya: A Human History. My friend Emmanuel Theophilus is sure to like this one. I am thoroughly enjoying it. I didn't know much about ancient Tibet and Nepal, and what a rich history these two regions have! Ed Douglas tells these stories with panache and verve. And with a light touch. Lost empires,  ancient trade routes, master craftsman, art, architecture, spiritual masters, crafty power brokers, bloody military campaigns, missionaries, adventurers, botanists, colonialism, and recent geopolitics.  It really is an enthralling narrative of the epic history of this mighty mountainous region. I'll use the word 'remote' more carefully hence in my conversations about the Himalaya. This one is for you Theo!  

Mars Rover Scientist John Grotzinger Explains What It Is All About

Science Friday hosted Mars Rover Project Scientist John Grotzinger. He explained with clarity the instruments on board and what the mission is about:

From the transcript:

But from orbit, we could already tell that as we approached this mountain in the middle of Gale Crater that we informally refer to as Mount Sharp, that there's a succession of layers that are five kilometers thick, so that's a bit over three miles. And it's almost three times as deep as the Grand Canyon. And what we learned ever since the time of John Wesley Powell's pioneering trip down the Grand Canyon, staring up at the walls of the canyon and wondering what those layers preserved, I think we're doing the same thing.

We look up at this, and we can only imagine that this represents a tremendous swath through the geologic history of Mars, its early environmental evolution of what might be tens, hundreds, maybe even a billion years, hundreds of millions of years to a billion years. And that interval of time that we're sampling occurred somewhere between three and four billion years ago.

So we're for the first time really probing the next dimension of Mars exploration, which is the dimension of deep time.

Fascinating....Curiosity is not equipped to directly sense any signature of life like microbial respiration. It's all about doing as thorough a job of documenting the mineralogy and geochemistry of the rocks and piecing together a story of the geological evolution of the sampled terrain. In doing so, the hope is to identify habitable environments, a place that had or has water.

Back on earth, life in the Pasadena diner called Conrad's frequented by Mars mission scientists just got a lot busy. From the recent Nature News article :

Grotzinger was a regular at Conrad’s in 2004, before and after his working days on the rover Opportunity, which landed that year along with Spirit, its twin, comprising the Mars Exploration Rover mission. Because the rovers were positioned on opposite sides of Mars, one team would be having breakfast while the other would be eating dinner. “The waitresses were always confused,” he recalls. This time there is only one rover, but still no standard working day. Adapting to ‘Mars time’ requires starting each Earth day 40 minutes later than the last to match Martian daylight, inducing a state of perpetual jet lag.

Also, Mars Rover Curiosity is tweeting. You can follow the mission @MarsCuriosity. What a great way to engage the public in this mission and get them excited about science.

I am the 1,001,964th follower! Looking forward to at least two years of updates from the mobile geology lab on Mars...