Earth and Mars / NASA

Mars has been a prominent figure in the lens of human awareness, imagination, and sense of adventure for centuries. It’s a fiery spark in the night, a celestial laser-pointer dot drawing our cat-like curiosity into space. But could our neighboring planet’s value to us exceed our wildest imaginings?

Is it a source of rich resources that could fuel voyages to even farther-out destinations? Is it a key to answering the age old question, “Are we alone”? Could it even be our best insurance policy for the survival of our species? Food for thought.

Scarcely a century since fiction writers began imagining a trip to Mars and only 50 years after we sent the first robotic probe, we have sent dozens of spacecraft, a handful of landers and still have the wheels of two rovers turning in those rusty soils.

The rovers Opportunity and Curiosity are drilling into rocks and scooping up dirt to look for signs of past water and life-friendly environments and have found such evidence in abundance in the composition of mineral deposits and structures of rock formations. Orbital spacecraft like the Mars Reconnaissance Orbiter may even have detected the action of sporadic liquid outbursts in present times. That Mars once had a warmer, wetter, probably much Earthier environment in the past is a speculation supported by mounting evidence.

Sending humans to Mars has been an on-again/off-again shuffle over the years. Back in the Apollo era when our country was spending a lavish 4% of the federal budget to put humans on the moon, there was optimism that this wind in the sails of the spirit of exploration would propel us not only to the moon’s surface, but carry astronauts to Mars, and ultimately beyond.

But the winds of public opinion and federal spending shifted and Apollo was cancelled, and as the story goes we haven’t been back there since.

In the George W. Bush era, the “Moon, Mars and Beyond” initiative challenged us to return to an outward path in the solar system by returning to the moon to establish a permanent base, and turn our sights again to Mars as the next destination of human exploration.

Recently, NASA Administrator Charles Bolden rephrased the M-M-B mission plan to better align the steps toward Mars with budgetary realities and to balance human space programs with more cost-effective robotic missions.  The more measured pace in the plan Bolden outlined would place humans on Mars sometime in the 2030s, and include an intermediary program to capture, move into lunar orbit, and explore an asteroid–largely for proving that we are ready for the considerably longer mission to Mars.

Critics of NASA’s plan, some in Congress, want NASA to pursue a more direct route and quicker pace to the surface of Mars—and while Bolden has signaled openness to input and “tweaking” of the plan, he states the shorter 10-year horizon some are pushing for is not financially “in the cards.”

Mars is in many ways a logical next step for humans in space. We can return to the moon, to study it further, to exploit its resources, and to further practice our set of skills for existing remotely beyond the Earth. The moon is an “easy” step outward since it is so close.

But Mars is the next step upward.

As a subject of scientific interest, Mars could prove to be the site where we find evidence that life on Earth is not unique in the universe –a defining moment in history if there ever will be one.

As a subject of human interest, Mars may be where we take the first stab at ensuring our survival as a species in the cosmos.

Some see Mars as a principle factor in the equation of the long-term survival of the human race. They posit that as long as we, as a species, live dependently on the Earth, a single planet, we are vulnerable to extinction by events of global devastation like a major asteroid impact, mega-volcanic cataclysm, or fatal self-inflicted mayhem like nuclear holocaust or runaway environmental collapse. With an established self-sufficient presence on Mars, should the Earth experience devastation then humans living on Mars could carry on the torch of humanity.

I hope to see the day when the first humans set foot on Mars—though I think a report of finding evidence for life there would be the more exciting news. Personally, I’m rooting for both within my lifetime.

Super CME of July 22 2012. The sun, hidden behind the black disk, is located at the white circle. (STEREO/NASA)

On July 22, 2012, a solar Coronal Mass Ejection (CME) of possibly the greatest recorded strength in history blasted by Earth’s orbit at a speed of 3000 kilometers per second, four times faster than a typical CME. Had it impacted Earth’s protective magnetic field, we could have experienced major disruptions in communication, brilliant aurora displays at tropical latitudes, damage to orbital satellites and possibly even major power blackouts.

Fortunately, the shot only crossed our bow and flew harmlessly into space.

July 2012 may sound like ancient history, but we can take this story as a reminder that today the sun is still riding the same high of solar activity that fueled this super-storm, and that it serves us well to keep our eye on that big orb in the sky.

The eruption was detected and tracked by NASA’s twin STEREO spacecraft and the European Space Agency’s SOHO satellite. By observing the high-speed mega-bubble of ionized gas from three different vantage points, STEREO and SOHO scientists were able to very accurately triangulate its speed and direction and also formulate an explanation for why this CME was so much faster than ordinary.

It appears that the path of this super-CME was cleared out by another CME that preceded it only 10 to 15 minutes earlier. This had the effect of clearing the plasma and straightening the magnetic field of the normal ubiquitous solar wind, allowing the second CME to travel more freely—maybe similar to how a bicyclist following in the wake of a truck encounters less wind resistance and can move faster than normal.

Solar flares and CMEs usually pass unnoticed by those not using high-tech telescopes and sensors on space-based observatories. Even when a CME impacts the Earth, its effects are mostly invisible in our daily experience. But occasionally we get a reminder that the sun is not merely a quietly glowing ball that warmly imparts the energy that sustains life on Earth.

Energy generated by nuclear fusion in the sun’s core constantly flows outward through the sun’s layers and into space, most benignly as sunlight. But some of that energy generates powerful magnetic fields that build up in locations on the sun’s surface and atmosphere. Just as when a rubber band breaks when twisted too tightly, the wound-up magnetic fields can reach a breaking point and snap.

When that happens, we see solar flares that superheat the sun’s atmosphere to millions of degrees and send out intense bursts of high-energy X-rays, and CMEs that belch out billions of tons of hydrogen plasma at typical speeds of a million miles an hour.

Solar magnetic activity rises and falls over an 11-year period: one solar cycle. At periods of minimal activity the sun is relatively quiet and the telltale markers of magnetic concentrations that we call sunspots are rarely seen for months at a time.

We are presently near the peak of activity of a cycle at “solar maximum.” The present cycle, number 24, has been less intense than cycles in recent history, with fewer and smaller sunspots and less flare and CME activity. But the epic CME in July 2012 shows us that even a lesser solar maximum can pack a punch on occasion.

In fact, it was during another similarly lethargic solar maximum in the 19th Century, that of solar cycle 10, when a major CME did impact the Earth and gave us our first insights into the connection between activity on the sun and its effects on Earth. Named the Carrington Event for the British amateur astronomer, Richard Carrington, who observed and recorded its effects in 1859, it was powerful enough to make its presence known even at a time before the existence of high-tech space telescopes and high energy electromagnetic detectors.

Carrington and another observer, Richard Hodgson, independently observed a brilliant solar flare that triggered a high-velocity CME. Eighteen hours later the CME arrived at Earth, firing up the auroras. They are normally only visible at extreme Arctic and Antarctic latitudes, but during this event became visible over much of the Earth — as far into the tropics as Tahiti and Cuba. The disturbance to Earth’s magnetic field induced electrical currents that caused telegraph lines to spark and even set fire to some telegraph offices.

Should a super-CME like the Carrington Event or the solar storm of July 2012 strike the Earth today, the results would likely be far more damaging than a few telegraph offices going up in smoke.

Today we live in a world far more vulnerable to solar activity; our electronic, wireless, and computerized technologies are sensitive to electrical surges and electromagnetic blasts. We rely on orbital satellites for communication and surveillance, satellites that are at the front lines of any onslaught by a solar storm. Some have estimated the damage that would be caused by a direct impact might total a couple of trillion dollars, 20 times the amount caused by Hurricane Katrina.

The good news? We observe the sun and its activity constantly with spacecraft like STEREO that can track CMEs and predict impacts with Earth. So at least we’d have a few hours’ warning.

Artist concept of exoplanet Kepler 10c (David Aguilar/Harvard-Smithsonian Center for Astrophysics)

How big can an Earth-like planet be? Astronomers thought they had a pretty good handle on this question but have just been given a fresh example for how nature never ceases to outpace our imaginations and show us something unexpected.

That example is Kepler 10c, an extrasolar planet astronomers didn’t think could exist: a heavyweight “Earth” two-and-a-half times larger and 17 times more massive than our own welterweight home world.

Kepler 10c was originally spotted in the data from NASA’s Kepler spacecraft, the most productive extrasolar planet hunter to date. Its diameter was measured to be 2.3 times that of Earth’s, but at the time its mass was unknown. Common wisdom in the planetary formation community was confounded when later observations with the HARPS-North instrument at the Telescopio Nazionale Galileo on the Canary Islands’ La Palma discovered that Kepler 10c weighs in at 17 times the Earth’s mass.

Before this discovery, planets with diameters between 1.7 and 3.9 that of Earth were classified as “gas dwarfs“: planets expected to have a heavy rocky core surrounded by an accumulated thick atmospheric envelope, more like a mini-Neptune than a maxi-Earth. But Kepler 10c’s calculated density pegs it as a rocky world like Earth: mostly solid, perhaps with a thin coating of atmosphere.

It was believed that such a massive solid planetary body would have developed a very thick sheath of gases during its formation, gravitationally snowballing to become a Neptune or even Jupiter-sized gas giant.

Beyond the commotion of the upset of conventional planetary formation theory, this heavyweight Earth opens up a lot of possibilities to the imagination. Science fiction stories have mused about the idea of high-gravity planets where its characters strain under their own weight just to move around.

A quick high school physics calculation shows that the surface gravity of Kepler 10c would be about 3.2 times what we’re used to. Imagine the exercise you would get just walking around: myself, I would be lugging around almost 700 pounds!

Kepler 10c also has over five times the real estate of Earth, even when counting Earth’s solid surface and oceans–a lot more room for people to spread out in. Land might be a lot cheaper.

But there’s a hitch to anyone thinking of opening a gym or flipping real estate: Kepler 10c is very close to its star, making a complete orbit in only 45 days. This means it is a hot, giant heavyweight world: almost 1400 degrees Farenheit! (Might be a good place to open a health spa.)

So, Kepler 10c is definitely a horse of a different color. To date, 1,794 exoplanets have been confirmed to exist, most of which fall into the larger “ice giant” (like Uranus and Neptune) or “gas giant” (Jupiter, Saturn) categories. With more recent discoveries of smaller planets that fall into categories like gas dwarf, super-Earth, Earth and sub-Earth sized, we may find that the possible characteristics of planets is even more diverse than what Kepler 10c has pushed us to imagine.

Right now the scientific puzzle astronomers have to solve is how Kepler 10c developed into what it is today: new heavyweight record-breaking rocky planet champion of all time — for now….

Artist’s conception of the OCO-2 satellite in orbit. Scientists hope it will yield the most precise picture yet of Earth’s carbon cycle. (NASA-JPL)

It took five years, two launch vehicles and more than a half-billion dollars, but NASA scientists have at last attained their goal of putting a satellite in orbit that will help track carbon dioxide in the atmosphere, oceans and forests.

On the first attempt five years ago, the first Orbiting Carbon Observatory never made it into orbit. A piece of the nose cone designed to protect the satellite during launch never separated. Burdened with the extra weight, the satellite crashed into the ocean somewhere near Antarctica.

Tuesday morning, NASA tried another launch from Vandenberg Air Force Base on California’s Central Coast. This one, dubbed OCO-2, is riding a different launch vehicle and has a few tricks that the original OCO lacked. But with less than a minute to go, the scheduled 2:56 a.m. launch was scrubbed by a disruption in the water supply to the launch pad. NASA and contractor United Launch Alliance made another attempt on Wednesday morning that was successful. “Initial telemetry shows the spacecraft is in excellent condition,” NASA said in a post-launch release. They had only a 30-second launch window each day, in order to place the satellite exactly where it needs to be in orbit.

The service tower at Vandenberg Air Force Base rolls back from the Delta II rocket that will carry the Orbiting Carbon Observatory into space. (Craig Miller/KQED)

Like the original, OCO-2 is designed to circle the Earth from pole to pole, mapping CO2 behavior on a grid similar to the globe’s lines of longitude. CO2 molecules absorb light according to their own unique pattern, so onboard instruments will break down reflected sunlight into spectral colors to measure atmospheric carbon with unprecedented precision.

Beyond that, the $465 million satellite is designed to track the way CO2 is absorbed by earthbound carbon sinks such as plant life and how it’s released by man-made and natural sources. Scientists say this will yield an accurate mosaic of the planet’s “breathing,” which will allow better forecasts of the buildup of greenhouse gases that contribute to global warming and climate disruption.

“The science is absolutely important,” said Mike Freilich, from a spot overlooking the launch pad on Monday. Freilich heads the Earth Science Division at NASA. “Understanding the naturally distributed sources and sinks of carbon — what the processes are in the ocean, what the processes are on land, is critical for us to be able to understand how the Earth will be able to evolve going in to the future with the 36 gigatons of carbon per year that we put in.” Then he added, “I think it’s a testament to the percieved importance of this mission that we got a second chance.”

OCO-2 will even be able to detect the tiny amount of heat and light emitted by plants during photosynthesis, which mission scientists say is another useful measure of carbon dioxide uptake. It could lead to much improved forecasts for crop yields, they say.

It’s amazing what you can see from 438 miles up.

Opportunity’s record breaking milestone marker: Lunokhod 2 Crater. (NASA/JPL)

One of NASA’s most senior and still-operational spacecraft reached a milestone: the rover Opportunity completed its first 25 miles traveling across the surface of Mars!

On Earth twenty-five mile trips are humdrum half-hour hops to your Aunt’s house. But for a semi-autonomous, remotely controlled robot exploring a planet millions of miles away, it’s simply awesome.

In its 10-year trek, Opportunity made a good living crater crawling, trading up with each new hole in the ground it explored. In fact, Opportunity was a craterteer from the moment it landed and rolled into a small pit called Eagle Crater in 2004 –which caused NASA engineers and scientists to hold their collective breath for fear that it might not be able to get out of the hole.

But get out it did and Opportunity began its drive across Meridiani Planum, the vast plain it had come to investigate for geologic signs of past water on Mars. Along the way Opportunity traded up to Endurance Crater, a 426-foot impact feature that would be its first intentional crater crawl, and later Victoria Crater, a half-mile impact basin with exposed rock strata along its edge that were prime targets for seeking sedimentary layers that might have been water-laid.

Opportunity found ample signs of ancient, extinct waters: gray hematite “blueberry” spherules it found along the way, intricate patterns in sedimentary features it scrutinized with its microscope, and other dry but suggestive clues.

After spending almost two years exploring around and below the rim of Victoria Crater, mission directors decided to risk a much longer drive of discovery toward a much larger crater, the 14-mile wide Endeavour. They were not certain that the aging rover would survive the journey, but the potential payoff was considered worth the risk — plus it was the only way for the rover to trade up to a crater larger than Victoria. It was also during this long march to the horizon that Opportunity’s Mars-roving buddy around the planet in Gusev Crater, Spirit, ceased functioning, leaving Opportunity the sole functioning robot on the planet.

Three years after leaving Victoria, in 2011, Opportunity arrived at the rim of Endeavour where it has been exploring ever since. In its time at Endeavour, the rover has found even more clues pointing to the younger Mars’ wetness, including additional detections of hematite, as well as a vein of material containing calcium, sulfur and water that most closely resembles gypsum. The presence of gypsum may indicate past water of more neutral pH, which could indicate an environment that was suitable to nurture life—life as we know it, at least.

Opportunity has been joined by the larger, next-generation rover Curiosity, the nuclear-powered traveling laboratory currently exploring the lower layered slopes of Mount Sharp in Gale Crater. And though Curiosity has traveled little more than five miles to date, if it shows even half the pluckiness of its elder Opportunity, we should expect to see another off-world roving record broken sometime in the next few years.

Craters, if you haven’t guessed, are preferred targets for remote explorations of Mars, and for good reason: impact craters expose Mars’ past to our scientific curiosity. The walls of craters are literally stacks of sedimentary geologic history, sheared through and unearthed by the force of the impacts that create them. In the case of Gale Crater, the depression also served as a collection basin for sediment that layered up over hundreds of millions of years and was subsequently exposed by erosion.

One day, maybe not far off, distance records like those of Lunokhod 2 and Opportunity and perhaps Curiosity will be dashed the rocks by more sophisticated robotic explorers and even human-driven vehicles. But today the prize and pride belong to Opportunity.

Artist concept of NASA’s MAVEN spacecraft. (NASA)

On September 21, NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft will go boldly where no one has gone before: to the very top of the Martian atmosphere!

One might ask, with all of the amazing imagery and mind-opening discoveries made by the fleets of orbiters, landers and rovers that have explored Mars’ surface, why is anyone interested in the rarified gases at the highest layers of Mars’ already rarified atmosphere? The answer, as it turns out, is a tale of two planets: Mars and Earth.

When we first started to explore Mars with robotic spacecraft in 1965 and compared it to our home planet, we were struck more by the differences between the two than the similarities. Our home world is wet, vibrant and greenly alive, while rusty-red Mars was found to be dry, desolate and lifeless — more like our Moon with a thin wisp of atmosphere.

Over a campaign of exploration spanning decades, we have gathered a great deal of observational data that has told a much more nuanced story of Mars: a wet, active and far more Earth-like Mars than imagined even in a lot of science fiction. The reason we failed to see the similarities at first is that it required looking across a gulf of time, and it takes time, and data, to reconstruct an accurate picture of the past.

Mars, we now know with fair certainty, once had a thicker, warmer atmosphere and a water cycle with precipitation, river systems, and wide shallow, likely salty seas. Whether life ever emerged on Mars is still a question, but the environment we are sensing a couple billion years in the past feels temperate and inviting.

So what happened? Why is Mars today a cold, dry desert world with an atmosphere a hundredth as thick as Earth’s? Where did its warming, protective atmosphere disappear to — and could the same thing happen to other planets, even Earth?

That’s where MAVEN comes in. MAVEN’s scientific instruments are designed to characterize the nature of not only the upper Martian atmosphere and ionosphere, but its interaction with the solar wind: the stream of electrically charged particles that blows constantly from the sun and across all of the planets of the solar system.

If MAVEN determines that the solar wind has indeed eroded Mars’ atmosphere into space, does that mean the same thing will happen to Earth?

This may be where one of those stark differences between Mars and Earth becomes important: a global magnetic field. Earth has one: a global dipolar magnetosphere generated by currents deep inside our planet and emanating outward into the space surround it. The solar wind’s particles are ions — electrically charged hydrogen nuclei for the most part. When an electrically charged particle moves through a magnetic field, its path is deflected. That’s how an old-style television set (pre-flat screen CRT, or cathode ray tube, technology) deflects a beam of electrons to paint a luminous picture on the phosphorescent screen.

Earth’s atmosphere is completely enclosed within the larger volume of space occupied by the magnetosphere, so it is shielded from the mayhem the solar wind probably inflicts on the bare, unprotected ionosphere of Mars. So erosion of the Earth’s atmosphere is not presently a big concern, though it would be if we ever lost that protection.

Mars, however, does not have an active global magnetic field today, and may not have had one for a long time now. Past orbiter missions have detected patches of localized magnetic fields emanating from the Martian crust, which may be the “fossil” remnants of a global field that sheltered Mars in its warm and wet youth, but their influences are weak, scattered, and do not extend to the higher regions of Mars’ atmosphere.

Understanding exactly what is taking place where the solar wind collides with Mars’ atmosphere will give us better insight into its loss over time, and how the surface environment has evolved in response to that loss. In turn, we may be getting a glimpse of what could happen to the Earth in the hopefully very distant future.

Amazing what studying a few sparse molecules can tell you.

Rock strata exposed along the margins of the valleys in the “Pahrump Hills” region on Mars. (Curiosity/NASA)

Over two years since landing on the gravely floor of Gale Crater on Mars, NASA’s Mars Science Laboratory rover, Curiosity, has reached the base of its primary mission goal, Mount Sharp: a 3-mile-high mound of sediment that preserves a geologic record of Mars going back billions of years.

“It is an exciting time and a huge milestone since we have finally arrived at the base of Mt. Sharp … the destination of the Curiosity rover,” says Dr. Paul Mahaffy, Principle Investigator of the Sample Analysis at Mars (SAM) team at NASA’s Goddard Space Flight Center. “There is plenty of evidence in our new site, named the Pahrump Hills, of flowing water, and the outcrops to be explored at this location is in a geological formation called the Murray Formation.”

Why did it take Curiosity almost two years to reach the mountain it was sent to investigate? A person could have walked the distance from the landing site to its present location in an hour.

Part of the reason, especially during the last year, was for the health and safety of the robot. Some of the terrain it has driven over was rougher than expected and sharp rocks have caused excessive wear and tear on four of its six wheels. Navigating through this challenging terrain required some care, and decisions were made to approach the mountain by a different route than originally planned.

“The route of NASA’s Mars Curiosity rover up the slopes of Mount Sharp on Mars is indicated in yellow in this false-color image. The rover’s current position is marked with a star.” Credit: NASA/JPL-Caltech/Univ. of Arizona

“Although Mt. Sharp had been the original destination of the mission,” says Dr. Mahaffy, “the Curiosity rover had been diverted from a direct path … by the compelling evidence early in the mission of an ancient lakebed in the opposite direction…. Exploration of the minerals and stratigraphy of this lakebed had realized significant mission objectives of identifying a habitable environment with all the ingredients necessary for life present billions of year ago in an ancient lake.”

The attractive region, dubbed Yellowknife Bay, kept NASA scientists busy and Curiosity close to its landing spot for nearly a year. And though Curiosity’s primary destination was Mount Sharp, its mission is to assess the suitability of Mars’ environment in the past for supporting microbial life, so the detour through Yellowknife Bay was time well spent.

I know about the “ooh, shiny” compulsion. On many an on-foot exploration of my favorite place, Death Valley, I have experienced the same thing—and since Death Valley has been used as a surrogate for Mars in science fiction and in engineering tests of Mars-bound robots, Curiosity and I are simpatico. So many canyon climbs and ridge crawls and playa strolls that I made were the result of seeing something across the landscape that looked interesting and wanting to check it out.

So now the “real” adventure begins on the slopes of Mount Sharp. How far will Curiosity climb, and what will it tell us about how Mars’ environment has changed over billions of years? I can’t wait to find out.

Keep those wheels rolling, Curiosity!

Mammoth Rocks, Sonoma County (Andrew Alden)

Every year, around the opposite side of the calendar from Earth Day, is a loosely organized event called Earth Science Week. (It also has a Facebook page.) Earth Science Week is October 12-18 this year, and the special theme for 2014 is “Earth’s Connected Systems.” Think of it as a series of treasure hunts with a mass demonstration in the middle.

Sunday the 12th launches Earth Science Week with International EarthCache Day. EarthCaches are a science-oriented kind of geocache—you visit a precise location, using a GPS instrument, and follow a set of instructions to learn about what geological feature you’re seeing there. Unlike ordinary geocaches, you don’t retrieve a hidden box and trade for one of the trinkets inside. But you can earn a special EarthCache souvenir that day.

Monday is Earth Science Literacy Day. Task forces of geologists have been debating the concept of “Earth science literacy” for the last few years, deciding what are the most important things we want you to know. The Earth Science Week website suggests that you start with nine “big ideas.” This page is pitched at teachers, but you can be your own teacher any time.

Honeycomb weathering at Pebble Beach, San Mateo County

Tuesday is No Child Left Inside Day. Teachers are finding it more and more of a hassle to take their classes outdoors, despite the well-known benefits of simply getting outside and walking around. Why not skip the permission slips and do it yourself, with or without a child of your own. Teachers of all kinds, even informal ones like most of us, can use a page of ideas and guidelines from the Earth Science Week organizers.

National Fossil Day is Wednesday, October 15. This is mainly celebrated by the National Park Service, and events are scheduled across the country. If you happen to be in Washington DC, the Smithsonian Institution is sponsoring a set of activities. But my friends on Twitter will surely be showing off their fossils that day too.

Thursday coincides with the Great California ShakeOut. Participating is very simple to do—at 10:16 that morning over 10 million people across the state will conduct a massive “drop, cover, and hold on” drill. This is something that we need to work into our culture—consider it a part of your identity as a Californian, and it only takes a minute. If you have more time, there are plenty more steps you can take on the ShakeOut site. My favorite easy-to-remember tip is “text first, talk second” after a major earthquake to save the load on the mobile phone network.

Thursday is also tagged as Geoscience for Everyone Day. Earth science Week’s sponsor, the American Geosciences Institute, pitches this as a day for people to explore careers in the geosciences, especially those from under-represented groups. I’ve written more about that for KQED.

Serpentinite in the Oakland Hills, Alameda County

Friday is Geologic Map Day, celebrating one of my favorite things in geology, the colorful maps that show the different types of bedrock in a region. Geologic maps aren’t just beautiful and interesting—they’re useful for planning anything that digs up the ground, for finding minerals and avoiding hazards, and for a deeper understanding of the countryside around us. The California Geological Survey has a bunch of free maps online on its Information page.

Saturday winds up the week with International Archaeology Day, sponsored by the Archaeological Insitute of America. There are many events scattered around the country and the calendar, but I suggest that your nearest natural history museum would welcome visitors, that day or any other one.

Earth’s connected systems reach into the atmosphere and space as well as into the ground and the deep past. That’s why the space agency NASA is getting involved, too, with a set of events aimed at students and teachers. Perhaps you’d like to learn about clouds with a team of NASA atmospheric scientists; that’s happening Friday morning.

To me the converging objects of the universe perpetually flow,

All are written to me, and I must get what the writing means.

Walt Whitman

The connections of the Earth’s systems mean that everything geologists study can be brought to bear on global problems, often in unexpected ways. The central problem of climate change, and how we can cope with it, has connections throughout Earth science. Keep that in mind as you learn more about geology, the central science, next week.

Maps of carbon and oxygen coronas of Mars’ extended atmosphere. (MAVEN/NASA)

NASA’s latest mission to Mars, MAVEN (Mars Atmospheric and Volatile Evolution), entered Martian orbit less than a month ago on September 21. It’s already begun to reward us with revealing insights into the disappearance of Mars’ atmosphere.

Until now, robotic missions have been concerned with Mars’ surface conditions: composition of rocks and soil, mineral deposits, topography, sedimentary layering, and surface weather and climate, not to mention keeping an eye out for signs of life, past or present.

The intensive investigation of Mars’ surface over the decades not only introduced us to a cold, dry desert planet, but also revealed that it wasn’t always so. Long ago in Mars’ past, the evidence tells us, the climate was much more Earth-like: a thicker, warmer atmosphere, lakes and seas of liquid water, precipitation and runoff. And, most tantalizing of all, conditions suitable for sustaining some form of life.

Today Mars’ atmospheric pressure at ground level is over a 100 times thinner than Earth’s, unable to hold much heat and too thin to support surface water in liquid form. There is a lot of water on Mars, we have found, but it’s all locked up as subsurface and polar ice.

A planet’s climate is largely determined by its atmosphere, so scientists have sent MAVEN to explore why Mars has lost so much of its gaseous cocoon.

Early returns from MAVEN’s Imaging Ultraviolet Spectrograph have shown us the “coronas,” or thin, highly extended envelopes of gases stretching into space from Mars. The instrument allows scientists to map the coronas of specific gases, like oxygen, carbon and hydrogen, the byproducts of the breakdown of water and carbon dioxide molecules.

The process scientists believe is responsible for the slow leak of Mars’ air, and what MAVEN has been sent to investigate, is the interaction of the high-energy particles of the solar wind with molecules at the top of Mars’ atmosphere. Solar wind particles—mostly protons–would impart their energy to atmospheric molecules, essentially giving them the boost needed to escape Mars’ gravity.

On September 26, a coronal mass ejection (CME) — a powerful blast of high energy particles — erupted from the sun into space, and NASA scientists predicted that it would impact Mars on September 29. MAVEN successfully measured the CME’s arrival at Mars on the predicted day.

Comet Siding Spring at Mars. (NASA)

Once MAVEN enters the full science investigation phase of its mission, sometime in early to mid-November, it will also be able to observe in detail how such blasts of high energy solar particles actually interact with Mars’ atmosphere and verify the suspected mechanism of Mars’ atmospheric demise.

In other Martian news, on Sunday, October 19, the comet C/2013 A1 “Siding Spring” will pass within 85,000 miles of Mars—one third the distance between Earth and the moon—and there is a chance that particles in the comet’s tail will sweep over Mars. This not only poses some risk of impact by high-speed dust particles with orbiting spacecraft, including MAVEN, it also gives those spacecraft the chance to observe the interaction of a comet tail with a planet’s atmosphere.

“Desert selfie” in the driest place on the planet: the Atacama Desert in northern Chile.

If you want to go to Mars but can’t quite afford the hundreds of billions of dollars for a ticket, there is another solution: consider instead a trip to the Atacama Desert in Chile. This place is not a typical holiday destination, but for those of us who want that out-of-this-world experience, this is as Martian as it gets. The wettest part of the desert receives a mere 15mm of rain a year, and even that is a monsoon compared with the 2mm of rain that falls once per decade in the hyper-arid core of the Yungay region.

When flying into the region last month on a small connecting jet from Santiago to Antofagasta, the closest town to the desert where I’d collect samples for my research, I stared out of the window at the Atacama below — noticing the geomorphological similarities between the driest desert on Earth and many of the satellite and rover photos I have analyzed from Mars.

And during the first day of my field campaign with scientists from NASA Ames Research Center and NASA Goddard Space Flight Center, our team drove approximately 600km through the Atacama; not a single insect collided with our truck’s windshield. In this desolate and extraordinarily dry environment, it is hard to imagine that Mars is still 1000 times drier than the driest part of the Atacama.

In the Atacama, I had to readjust my perception of time and dominance of normal erosion processes. In most terrestrial environments, water is responsible for carving the landscapes we see. But in Yungay, the soils and boulders have been etched for millions of years by wind, the rare miniscule rainfall and extraordinarily, earthquakes. Scientists estimate that the Atacama has experienced approximately 30,000 seconds of rock-shaping shaking over the last few million years. The result is some of the most Mars-like terrains you can find on Earth.

Boulders in the driest part of the Atacama are commonly marked by light-toned grooves worn into the surface by nearby boulders during earthquakes.

When I began my Ph.D. over two years ago, I could have only hoped that my thesis project would have taken me to the most Martian place on Earth, covered from head-to-toe in a sterile suit, dust mask and gloves for hours in order to collect uncontaminated sediments for analysis.

My research interests lie at the juncture point between geology and biology. I want to understand how exactly the chemical constituents that make up life get preserved in the rock record on Earth, especially in Mars-like environments. This will help to enable me to make a prediction about how and where we might be able to find molecular evidence of past life (if there ever was any) on Mars.

Clean sampling of biomarkers in the desert soil requires suits, gloves, masks, goggles, and sterile tools to make sure no contamination ends up in the sample.

The utility of Mars analog environments like the Atacama is paramount. These unique locations provide a test-bed of sorts to begin to understand in greater detail geological processes occurring hundreds of millions of miles away on another planet. This is why many scientists, including myself, travel to Mars analogs to study geological processes up-close and to take samples back to our labs to examine them with analytical instruments that would be extremely difficult and costly to send to the red planet.

An outcrop of lake bed deposits captured by Curiosity’s MastCam in August, 2014 (MSL/NASA)

On Monday, NASA announced some surprising results from its exploration of Gale Crater on Mars by the Mars Science Laboratory rover Curiosity. The crater was once the site of a vast lake—and not merely a fleeting puddle of moisture that came and went early in Mars’ history, but a lake that appears to have filled Gale Crater, dried up and filled it again, repeatedly over a much longer period than wet conditions were believed to have persisted.

Gale Crater and its central mound of sedimentary rock, Mount Sharp (MSL/NASA)

Not long after Curiosity began exploring the rubble-filled bottom-lands at the floor of Gale Crater, it began to find clues that liquid water was present there at some time in the distant past.

Most recently, Curiosity has investigated a 500-foot-high section of exposed sedimentary rock at the base of the mountain–called the Murray Formation–the rover’s first peak into the layered geologic history of the crater. The layers of sediment appear to have been laid down by alternating river, lake, and wind deposition, indicating a cycling between wet and dry conditions in at least the local climate that repeated many times over perhaps tens of millions of years.

If this interpretation of the geologic evidence is correct, during wet periods water entered the crater in rivers flowing down the crater walls, possibly supplied by thawing ice or snow accumulations in the surrounding higher ground. The inflow carried large amounts of silt and sand and deposited it on the crater floor.

Then, the climate changed and the lake waters dried up, leaving the lake bottom bare and dry and exposed to deposition of dust and sand by wind action, adding a layer on the water-deposited bed. Then, another wet period arrived, the lake filled again, and more water sediments were laid down. And so on, many times, over a long period.

The prospect that liquid water was present and stable on Mars’ surface over long periods of time also enhances the conversation about the possibility that life could have appeared there at some point. We have not found evidence of life on Mars so far–but how cool would it be to find a fossil in one of those layers of rock?

As Curiosity climbs up the slopes of Mount Sharp, it will encounter higher formations of sediment laid down at later times in Mars’ history, giving us a more comprehensive profile of the changing climate than those represented by the rocks at the rover’s current digs.

The ancient lake that once filled Gale Crater must have been a fantastic sight. If you’ve ever seen Crater Lake in Oregon and were impressed by its size—well, Crater Lake is only five miles wide. Gale Crater, as it is today, is 96 miles across!

Artist concept of New Horizons at the Pluto system. (NASA)

Only 84 years after its discovery in 1930 by Clyde Tombaugh, it is the eve of our first-ever close-up look at everyone’s favorite dwarf planet, Pluto. NASA’s New Horizons spacecraft will make a fly-by on July 14th, after a high-speed, nine-year voyage.

New Horizons was recently brought out of its cold-sleep “cruise” mode in preparation for the historic encounter on July 14. Picture the opening scene of the movie “Alien” as the crew is brought out of hibernation; it’s something like that, but smaller and without actors.

Even now, the best images of Pluto, captured with the Hubble Space Telescope, show little more than areas of light and dark coloration. Perhaps they’re similar to squinty telescopic views of the planet Mars in the 19th century, or the first blurry close-ups of Jupiter’s Galilean moons by the Pioneer spacecraft, which arguably offered more to the imagination than the eye.

In the coming months, as New Horizons gets closer to the Pluto system, NASA scientists will check out all of its instrumentation, to make sure it has suffered no ill effects from cold sleep. They’ll also start gathering data on Pluto, its large moon Charon, the smaller moons in the system and the environment of the space in Pluto’s region of the solar system–the frontier of the Kuiper Belt. In May, New Horizons will be close enough to Pluto to capture better images than what we have from the Hubble Space Telescope–and then, we’ll begin to see things, not just imagine.

Most detailed picture of Pluto to date. (Hubble Space Telescope/NASA/ESA)

What will New Horizons tell us about distant Pluto? That’s the exciting part: we don’t know, yet. Scientists have some ideas of what to expect, but if the history of close-encounter exploration of other solar system objects is a guide, we could be in for some surprises. Before we saw them up close, we knew nothing of the active volcanoes on Io, the deep liquid water ocean on Europa, the surface lakes and seas of liquid methane on Titan or the water geysers of Enceladus. Every object we’ve sent spacecraft to, it seems, held surprises for us. Why would Pluto be any different?

Pluto is what astronomers call a dwarf planet, one of presently five solar system objects that were given this classification back in 2006, shortly after New Horizons was launched. Pluto is small, with about one-sixth the mass of Earth’s Moon, and probably made of a mixture of rock and ice. Traces of a very thin atmosphere have been detected, composed of nitrogen, methane and carbon monoxide. Pluto’s large moon Charon is fully half of Pluto’s diameter, making the pair more of a double object than a dwarf planet and its moon.

Beyond these physical characteristics, and the system’s orbital and rotational properties, we know very little—and doubtless a minuscule fraction of what we will know after the July encounter. There’s a whole new world just on the horizon.

This year promises a bumper crop of discoveries on dwarf planets. Not only does New Horizons reach Pluto in July, but another NASA spacecraft, Dawn, will arrive at and enter orbit around Ceres in the Main Asteroid Belt in March. Ceres was once classified as the largest asteroid, but lost that status at the same time Pluto was demoted from planethood. In fact, this is Ceres’ second reclassification, as it was originally designated as a planet, just like Pluto–though in Ceres’ case one can argue that the change in status is a promotion. But when it was discovered that Ceres was one of many objects orbiting the sun between Mars and Jupiter, the term “asteroid” was coined and Ceres was reassigned as the largest of this new class.

Following New Horizon’s fly-by of Pluto, the probe will coast on into the Kuiper Belt, with possible future encounters with other poorly understood Kuiper Belt Objects on the more distant horizon.

NASA’s SMAP satellite will capture microwave radiation from the Earth to measure soil moisture. (NASA)

Thursday morning a rocket was scheduled to lift off from Vandenberg Air Force Base on California’s Central Coast, tricked out with instruments that could provide better weather forecasts and more clues to where the drought is headed. (Update: NASA rescheduled Thursday’s launch for Saturday due to high winds and technical problems).

It’s not one of NASA’s catchier names, but the satellite known as SMAP, for “Soil Moisture Active Passive” is designed to provide — for the first time — highly precise maps of water stored in topsoil around the world. Scientists say that’s an important cog in the planet’s water cycle.

“Much like when you perspire, your sweat evaporates and cools your body,” offers Kent Kellogg, the mission’s project director at the Jet Propulsion Lab in Pasadena.

“As it evaporates it seeds the atmosphere with moisture, so that clouds can form, and then precipitation can occur.”

From more than 400 miles up, SMAP will measure differences in natural microwave radiation coming off the Earth. Kellogg likens it to a big pair of night vision goggles in the sky, but measuring radiation on a much lower frequency (so, no, it doesn’t mean NASA can watch you skulking around at night). Wetter soil is cooler and drier soil warmer. From that, scientists can derive water content accurate down to about 6 square miles. Kellogg says that could improve local flood forecasting and drought management.

“If you know how much water is in the soil, if you think of soil as a sponge and you know how full of water that soil or that sponge is, you can have a much better prediction of the likelihood for flooding to occur,” explains Kellogg.

Currently soil moisture is mapped using a relatively sparse network of individual ground-level probes. SMAP will constantly map soil conditions globally. Record high temperatures have stoked evaporation from soils, making California’s current drought even worse.

“SMAP will give us a much more accurate measurement of the rate of change of drought-prone areas,” says Kellogg. “Are they getting larger or getting smaller?”

They’ve been getting larger in California lately, given the historically dry January that’s just winding down, with little precipitation on the horizon. Of course, it’s hard to see clearly more than about ten days out with current weather models. NASA expects SMAP to help with that as well, possibly adding days to the range of reliable regional forecasts.

“Understanding soil moisture conditions in regional areas can give us a lot of insight into the likelihood for rain to form and for the regional temperatures,” says Kellogg.

But SMAP will have its limitations.

“We do not expect to use SMAP data at this point,” says Roger Bales, a climate scientist at the University of California, Merced, “in part because we do not expect it to provide relevant soil moisture information for the areas where we work.” Bales has spent years developing a ground-based network of sensors to measure soil and other hydrologic conditions in the Sierra Nevada, much of which is heavily forested.

“SMAP has some limitations on measurements of soil moisture when the soil is covered by canopy,” or snow in a wet year, Bales points out. “We also understand that SMAP will mainly measure moisture in a thin surface layer of soil, and our interest is more on the deeper soil profile.”

But with its 20 or so ground passes per day, Kellogg expects SMAP to provide useful data on more exposed ground, such as the millions of acres of irrigated land in California.

SMAP will be the fifth and final addition to a suite of recently launched earth science satellites that track attributes ranging from precipitation to the carbon cycle.