Mars Rover (NASA)

If you’re like me, you’ve been following NASA’s desperate attempt to free Spirit, and the ongoing roving of the rugged little Opportunity. These two rovers, with Captain Jack like habits of not dying, are in part the creation of Steven Squyres. Next week, on Wednesday night, Squyres will be giving a talk here at SIUE. Come give him a listen?

Here are the details:

Steven Squyres
“Roving Mars: Spirit, Opportunity and the Exploration of the Red Planet”
Wednesday, February 17, 7:30 p.m.
Meridian Ballroom, Morris University Center
Sponsored by the Shaw Memorial Fund

Steve Squyres is the man responsible for taking us to the Red Planet and igniting a new firestorm of interest in space exploration. “Spirit and Opportunity” have always been prominent in the life of Squyres, best known as the face and voice of NASA’s spectacular mission to Mars using two high-tech robotic rovers. Spearheading a team of 3,000 and a budget of $800 million, the acclaimed scientist and principal investigator of NASA’s Mars Exploration Program will detail how he turned what seemed like an improbable dream into a reality. With a compelling voice and never before seen photos he will discuss the risks taken, the mistakes made and how the project’s goals were ultimately achieved.

Mars Rover (credit: NASA)

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1) Carrizozo Lava Flow (image: Google): Looking at Mars, we keep finding beautify lava flows that stream across the surface and end in sprawling lobes. Pouring over images of the Earth, we find the exact same thing (image left of Carrizozo Lava flow in New Mexico). To try and understand the Mars lava flow, a group of geophysicists set off to Carrizozo to see what they could see.

The talk presented by James Zimbelman started with the written notification, “This presentation has been approved for public release by White Sands Missile Range for unlimited distribution. The White Sands Missile Range Operations Security review was completed on February 25, 2008.” The Carrizozo Lava flow intersects White Sands Missile Range, and that added an interesting twist to trying to do field work. This poor determined researcher and his colleagues, I’m guessing, had to jump through more bureaucratic hops to get their Earth-based data then their Martian data – permission was required to explore the lave on the base, and then further permission was required to publish the research on the lava on the base. Perseverance paid off, however. This is neat piece of work.

In exploring the distal lobe of this 5000 year old lava flow, they found the 75 km long lobe was emplaced on an underlying slope of just 0.2-0.4 degrees. Various researchers have guessed the flow rate was somewhere between 5 to 800 cubic meters per second (a HUGE variation), which leads to an emplacement duration of between 2 months and 2-3 years. It always amazing me how slowly volcanoes can ooze their contents across the land. If you look at modern day Mt Saint Helene’s data you can watch the mountain steadily grow a new bulge over years and years! Not all volcanic processes are fast and explosive.

In the case of the Carrizozo lava flow, it appears that lava tubes slowly oozed their contents in a manner that created a triple terraced structure. Looked at from the side, the lava flow has three stair steps that can be explained via a three different mechanisms. It is possible (but not probably) that the lave just came out in a way that caused this three-layer wedding cake structure. More likely, however, the material either came out with a thin runny emerging first and creating the broad base and then the next two terraces were emplaced on top of the runny layer (after it had solidified), or it came out with a tall central lobe coming out first, and subsequent layers running along the sides creating each of the steps.

Topographically, the lava has many different structures (and plants – the photos he showed allowed the lava to in part be identified by where the most green stuff was located. I don’t think this will be true on Mars, but it is cool nonetheless to see it happen on Earth.) At the end of the lava flow, the material separates into different lobes (Zoom and pan at will in Google Map).

View Larger Map

If you look hard enough, you can see this as three different lobes that are bridged by “break out” lava, just like three streams of flowing water might be bridged by side channels. The break outs are very chaotic (called pahoehoe and pronounced ahoyhoy). There are also pits in the lava that have been partially infilled by other lava. Over all though, the terraces are fairly level in elevation on larger scales. These scientists hiked the whole width of the distal feature (I now know why everyone is skinny!) and mapped the features. Across each lobe, elevations typically varied by a couple meters or less on ~kilometer scales.

Taking this study and applying it to Mars, they find that small shield volcanoes, such as Pavonis Mons, has very similar features: “a low shield at the distal end with broad flat plateaus, lobate margins and topographics lows.” It appears that the Martian feature, like the Earth feature, was emplaced via lava tubes. It is guessed that were one to walk across the Martian feature, they’d find themselves on structure nearly identical (as nearly idebtical as any two geologic features can be) to the New Mexico Lava flow – just minus the plants.

In this talk on mars historic river systems, Ted Maxwell presented a visually stunning story rich with labeled MOC images. This is a bloggers dream come true – I can actually find what he said! Scientists out there reading – If you use archive data with filenames, please include the names on the overhead! Now, all that said, I’m suddenly realizing Malin changed their interface since the last time I used it, and I can’t find images by ID. Eek! Clearly I need to talk to Emily…

Anyway, back to science.

Basic story: Once upon a time on Mars, during a far distant epoch no one gave a date to, it rained on Mars. Like on Earth, this rain washed across the land, filling drainage ditches that merged into streams, that merged into bigger bodies, sometimes even filling basins (also called craters – it all depends on what you use them for). In some cases, these basins even overflowed, creating new stream and gully systems. One example is Durius Vallis.  Overflows were also found in Terra Cimmeria. The scientists studying these systems used the area of the region covered in gully networks and to determine what it took to fill the basins/craters. They found that in some cases the area that fed a basin was 15 times larger than the surface area of the basin! The basin above (image credit: NASA/JPL/University of Arizona) is Eberswalde Crater and is an example.

Calculating the exact volume of these basins/craters turned lakes in the modern era is difficult. They are often overlaid with lava/dust/other stuff that modifies their floor and changes the altitude change between rim and floor. Nonetheless, they sink in some cases, like the Eberswalde delta at -1400m, geological formations seen today may record the paleolake levels. In this case, the lake area is 400 square kilometers, and the contributing area feeding it is 4800 square kilometers!

While no one piped up and offered a specific year range when liquid water appeared, they did work to bin the time frame using craters. They found that Small impact craters in the a Noachian crater floor in MOC R1001508 is etched but relatively well preserved. At the same time a southern crater shown in MOC E040005 is deeply etched with light-toned fractured material exposed by the etching. These are seen as possible basin deposits from wetter days.

It appears certain that these are ancient features. It is cool to image rain sweeping through the now dry frozen land scape. Can you imagine Meteor Crater in Arizona filling up with water and overflowing in rivers and streams that flood the surrounds? That’s what happened on Mars! And sometimes, the paleolakes – the craters filled with water, were interconnected as one basin flowed into another, as water flowed.

What a different world it was then!

Now, on to the lunar magnetism.

Below is a detailed map of the magnetic field strength across the surface of the moon (credit: Lunar Prospector). The origins of the field, and the details of this field are extremely confusing, To try and make sense of this, I’m going to integrate content from across many of the morning presentations.

The overall structure of this magnetic field is fairly noisy, although the structures in the magnetic field do correlate roughly with topographic features. Here are the same maps showing topography (credit: Clementine)

There is rough correlation between the magnetic strong points matching the far-side basin and the lowest magnetic field corresponding with the lunar mare. Looked at in detail, there is also correlation between central up-wellings in craters and magnetic field strength.

What is missing from our understanding is the source of this magnetism. At one point in its past the moon was geologically active with lava flows. It is possible the moon once had a magnetic dynamo inside like the one the Earth has. While this dynamo could have died as the Moon cooled, the magnetic field that dynamo could have created may have become frozen in the magnetic rocks formed during that period of high magnetism. As the rocks cooled, the atoms in the liquid material would have aligned along the magnetic field and they would have stayed aligned as the rock cooled, and then hung out on the moon for a few billion years. Heating material, exposing it to a magnetic field, and then cooling it in the magnetic field is one way magnetic can be made commercially.

At the same time, it’s possible such a dynamo never existed, and the magnetism came from hitting the moon with large impactors. This is the equivalent of magnetizing a nail by hitting it with a hammer. The shock can knock the atoms into alignment if it is hard enough.

It is possible that both methods of creating magnetic fields takes place (and if there was a dynamo, it is most probable that the modern magnetic observations reflect both the dynamo and the impacts.

The best way to try and understand if there was a lunar dynamo is to look for patterns in the magnetic properties of individuals rocks as a function of when they formed. A rudimentary study of rocks that have published data shows that between 3.0 and 3.6 billion years ago sampled rocks have much higher magnetic field. When a detailed study is done to figure out if these are primary magnetic fields, there are problems with all the samples. Problems include measurements not being reproducible, the magnetic fields changing between measurements, and single samples having materials with different field directions/strengths. In careful analysis using many methods, not one rock could be found to have clear cut, consistent across methods, measurements. This could have to do with reheating (heat erases magnetic fields), or the magnetic fields just not coming from an ancient lunar magnetic field (called a paleomagentic field).

While some scientists are struggling to prove paleofields in old rocks, others are finding there are some rocks with planer magnetite (magnetic material) that have huge magnetic values. Magnetic anomalies in these rocks are over quartze grains next to ferromagnetic materials. This raises the question, can this type of rock play a role in the magnetic central uplifts in craters (magnetized central peaks). The answer seems to be yes, and the central magnetized peaks in to craters seem to best be explained either as material shocked into a magnetized state during impact, or that became magnetized after melting during impact, and aligned into a magnetized state.

Many talks, many questions, and no clear answers. Magnetic fields are in physics, astronomy, and geophysics one of the hardest things to understand. For now all we can really say is the Moon has fossil magnetic fields, and some of them (but maybe not all of them) were induced during impacts.

I just finished listening to one of the most fast paced, data flying talks I’ve seen so far. In 15 minutes, dozens of PowerPoint slides flew furiously as J.C. Andrews-Hanna presented tantalizing new results that indicate that Mars may have been hit by a 2230km diameter impactor early in its history (for perspective, Mars’ diameter is ~6800km – what hit it was ~1/3 its current size!).

Here are the details. Anyone who has looked at a topographical map of mars (above right) has probably noticed that the planet has a split topography with one pole being significantly lower elevation than the other. Along with the lower elevation, the crust in these regions is also much thinner. This is referred to has the Mars dichotomy. People trying to understand this weirdness, not seen on such large scales anywhere else in the solar system, have struggled because the boundary of this giant basin are cut into by the Tharsis Bulge – a giant lava flow punctuated with three volcanoes. In order to fully understand this problem, it is necessary to see beneath the lava. Luckily, this can be done with gravity mapping. By comparing the topographic maps with gravity maps, it is possible to build to build theoretical models of lava and crust geometries that reproduce the mass-densities required to recreate the gravity seen in gravity maps and confined to the observed geometries in the top maps. Through these models, this team finds that the basin boundary is continuous beneath the Tharsis bulge, and smoothly spans adjoining features.

When looked at globally, these newly traced boundary allows them to see that the basin is a beautiful elliptical shape super-imposed on a (formerly) spherical planet.

Prior to this dataset, two different and competing models existed to explain this thin crust – thick crust dichotomy. One model was based on internal (called endogenic) theories and impact theories (in fact, the prior speaker had the misfortune of presenting one of these endogenic models). Internal dynamics, such as large upwelling of materials, can alternatively thicken crust if the act in one set of ways, or thin crust if the act in another set of ways. No matter how they work, however, they don’t generally create elliptical shaped effects on the surface. This makes the new data very hard to explain with endogenic theories – they aren’t completely knocked off the table, they just require a lot more add-ons (ones that don’t currently exist) to fit the data.

Impact models, however, can easily (if you have a big enough supercomputer) reproduce an elliptical basin. Infact, several large basins on various objects in the solar system have elliptical basins that look very very similar to the thin crust – thick crust boundary when Tharsis bulge is corrected for.

More tantalizing evidence that this is an impact event exist in Arabia Terra. This regions northern and southern boundaries are parallel and match the expected spacing for an impact the size of this basin. These boundaries could be the double ridge of a of a partial ring boundary, where the rest of the boundary has been erased through cratering, much of it during the age of heavy bombardment. These ring sections also match the structures found with smaller craters when they are properly scaled.

The dynamics required in this type of a collision are quite scary. According to work being done by Marinova et al (Nature, in revision), models with a 45 degree impact angle and a 2230km diameter impactor match the observations. There is precedence for this type of event however – both Earth and Mercury seem to have been hit by objects that were similarly large fractions of the planets mass.

It really looks like the north – south hemisphere dichotomy in crustal thickness is the result of an ancient impact, and the boundary is an isostatic, ellipticalboundary “separating two provinces of distinctly different curstal thickness, clearly preserved to the present day.” While endogenic models are killed off, it is much harder to require this was created by endogenic effects.

So, I think it is safe to say, in the early days of the solar system, Mars got womped in a really cool way.

At the end of the talk someone asked (huge paraphrase): Why isn’t their a resultant moon? Look at the Earth-Moon system as an example. Why didn’t the same thing happen at Mars?
Andrews-Hanna: Formation of Moon not inevitable. Mercury may also have had the same [type of impact event] happen, and in fact and in models a moon isn’t produced. Moon lack of a moon being inevitable as a problem for people originally trying to model production of the moon. This isn’t a problem.

That last 20 minutes did give me a chance to hear one of the best exchanges I’ve heard so far:
Alan Stern: MSL can launch in 2011 if we miss the launch window [due to everything being behind schedule]. Infact, we can even launch in 2010 and hang out in a gravity assist Earth orbit that gets us to Mars the same time as the 2011 launch. That doesn’t get us to Mars any faster, but it gets MSL out of California.
Audiance: HUGE laughter (reason: As long as the mission craft is in California being worked on, there are HUGE cost over runs and there is a large jeopardy of the mission being canceled)

There was also some one question from the audience worth reporting that I caught. Paraphrased a lot, the question was, “What about launch vehicles?”
Alan Stern: We used to have cheap launch on Delta 2s. We’re running out of them. Today they are expensive because the military isn’t using them anymore, and NASA bares the brunt of maintaining launch pads. This makes the Delta 2s almost as expensive as the Delta 4s – which are too big for most purposes, so you’re wasting money. There is a tiger team of (impressive list of folks) to work on figuring this out. Solutions include ideas like co-manifesting and lower cost options, including the commercial Taurus 2, and lower cost future purchase of Delta 2s. Unfortunately, it will be higher cost because 1 company runs the launch industry. … we are looking forward to Falcon and Taurus, but they still need to be proven. We can’t identify yet what we will be buying in the future. We will have RFPs before the end of the year to buy rockets to get us out through 2015.
I’m most annoyed that I didn’t catch the whole thing, but I did arrange with Stern, who was running to catch an airplane, to get an interview with him later. I’ve actually had a problem trying to get interviews. NASA folks are mic-phobic and I’ve heard over and over that people can’t talk on things and I need to contact some other person higher up the food chain. This is annoying when I just want to interview people about what they just publically presented. Alan Stern is one of the names people keep giving me – He is someone who *can* talk on the record.

One of the reasons I missed Stern’s talk was the desire to get lunch. One problem with this and all meetings is the 24 hr content feed. Official meetings are running basically from 8:30am to 7pm or later (both Tuesday and Thursday official activities run until 9pm). There are no breaks for food. If you want to eat, you have to miss something. Oh well.

While seeking fluid and internet to post this I encountered my best overheard exchange of the day: “So What are you up to?” “Mars stuff. A little bit of MRO. And I’m looking at getting into the Moon more.” I’m not sure why this struck me as so funny, but it did.

The thing that really has to be brought home is how organics really can exist in briny solutions (really saly water).  In the laboratory, MgSO4, NaCl, MgCl2, CaCl2 Fe2(SO4)3 and other organics have happily formed. Temperature really is the limit to life as we know it.

This team looked at the temperature fluctuations at 6 Martian Lander sites: Viking 1 & 2, Mars Pathfinder, Opportunity, Spirit, and the upcoming Phoenix landing site.

They found that diurnal (day to night) temperature fluctuations on Mars are huge. At the most extreme site, the Mars Pathfinder site, temperature go from almost 270K during the day to just under 190K at night (26F to -117F!). The temperature is only above the magical 253K for about 2.5 hours at the surface. Fluctuations are less as you go below the surface, but things also don’t get above 253 as easily, and even a few centimeters below the surface the never hit the critical temperature.

This means life needs to exist at the surface or just below the surface, and any microbial processes that take place must act quickly while the microbe is warm, and then the system has to shut down.

Looking at all sites, from North to South, they find Phoenix’s site is just too cold, while Opportunity and Spirit consistently get to prime temperatures every day of the year. The Opportunity site is most ideal – 253K is reached at soil depths of  1-1.5 cm every day and the triple point of water occasionally reached. At that site, the habitability zone extends down about 2cm (for life as we know it).

While there is concern that Mars extremely thin atmosphere causes liquids to evaporate, salty liquids offer a solution – in addition to being liquid at lower temperatures, they also evaporate so slowly they don’t go away during the day before the refreeze at night. This means it is possible to imagine microbes at site’s like Oppurtunity’s (and perhaps something crawled off Oppurtunity), existing protected from high UV just a centimenter or so below the surface in salty brine.

Sadly, Opportunity doesn’t have the labs necessary to look for this tantalizing possibility. ExoMars, however, will be able to look.

This well-worded PowerPoint was on vertical geochemical profiling across a 3.33 billion year microbial mat from Barberton (translation: the looked at the fossil remains of a microbes that had grown in layers, one atop another). This particular fossil discussed is one of the oldest high quality fossils (and in fact the speaker started by saying pointedly into the mic – I think in a ribbing manner – to an early speaker that when he said there are no good fossil microbial mats from early Earth, he was wrong – just plan wrong (she actually used much stronger language, delivered with a British accent, that made everyone laugh).) I wish I could have heard everything she said clearly. Here is what I did grock: There are some really well persevered early microbial fossils that are very similar to modern biolaminared sediments (sediments that are filled with different layers of often different colored microbes) on tidal flats. These microbes form layers that are sometimes only microns thick! In the fossils, we see the same fine layers. The fossils are preserved by fine silicates (the stuff that makes sand and glass). When alive, these microbes “fed” in layers, with microbes on the top using the Sun to grow, and nutrients then passing (via death and excretion) from layer to lower layer.

Finding fossils of such large age indicates that life pretty much popped up as soon as it possibly could have on the early Earth. This raises the question – how? While the origin of life was not discussed, several presenters looked at the origins of organic materials.

In a presentation by Jennifer Blank, the “Modeling of Comet-Earth Collisions to Assess Survivability of Organic Materials During Imact” was addressed. Her team did simulations of a1 km sphere of pure water impacting the Earth and a variety of angles. They studied the peak temperature of the material during impact, how the water behaves, and estimated final temperature ejected material that made it to (and stayed on) Earth.

Their simulations used the Lawrence Livermore Labs GEODYN Hydrocode. They found that for a 11.2km/s of a impact, pretty much nothing stayed a temperatures that would allow life (this is a head on collision, and really, those are bad). At more oblique angles, such as 30 degrees between ground and impact and 15 degrees the ejecta are cooler with a higher area of material distribution.

She did some neat things with her simulation. One movie she showed traced just the location of liquid water in the impacting comet. You could see it space and  you can do things like “turn on” liquid water, showing only where materials at certain temperatures are distributed. The material is heated via both shock heating deceleration (largely frictional) heating. Based on conservation of Mass, Momentum and Energy, the model can sort out the amount of mass surviving at different temperatures. They found that with the lowest impact angles (15 degrees), 79% of the mass didn’t get lost (generally splashed back up at vaporized), and of this 25% of the material condensed, 55% was at temperatures <870K, and 44% <373K. This last fraction is most important. That 44% at <373K could carry organics – and life – on a comet successfully to the Earth’s surface. This surviving material is highly dispersed, often over 1000s of km.

Continuing the theme of impacts, the next talk looked at HCN class organic molecules from impacts. Presented by K. Hurosawa, new research found that oblique impacts (those with small angles between the ground and impact), produce fine grained impact fragments that actively interact with an ambient atmosphere due to aerodynamic ablation – this means there is a downrange moving vapor cloud from the impact that is filled with N2, CN C2 and C-rich organics layers in fragments. These layered grains can undergo surface organic material formation. To estimate the yield of HCN during impact, the team needed to look at CO2 densities, pressures, and other properties in vapor clouds. In large vapors, C, H, and N diffusion works more slowly, and high impact velocities are have a negative impact or organic molecule formation. In general, HCN is more stable at lower temperatures. The question is, during impacts can HCNs form? This team used lasers to simulate the energies of impact using laser ablation. The laser targeted sintered graphite targets in a gas mixture rich in N, C, H, and I think there was also O listed (slides are flying fast and furious). They found a HCN column density of 10 mol/m^2 spread over 10^2 km^2 for a Carbonaceous Chontrite impactor 300 m in diameter that is an oblique impactor. A large dispersion of fragments is required for efficient HCN production and this is possible with shallow impact angles. This process may cause a significant concentration of HCN on the Early Earth.

Bottom-line of the morning: Life has been around a long time and both comets and asteroids can deliver and/or create organics to the Earth’s surface.

From there it went to the story of the lunar poles. Presented by P. Lucey. A lot of focus is going into trying to understand the Moon’s poles as we gear up for new (and more lasting) manned missions to the Moon. The most often stated reason in the media for going to the poles is the possible water frozen in the crater areas that are in constant shadow. The truth is, I learned today, that there is also a lot of really cool science that can come out of this, and it is simply easier for humans and machines to function in the constant environment of the pole.

At the equator of the moon, a given plot of land or crater floor will go through a month long day to night to day cycle, with temperatures fluctuating 100s of degrees. These large temperature swings are not good things. At the poles, which are only inclined 1.5 degrees relative to the sun (compared to Earth’s 23 degree tip that leads to our seasons). This small inclination means that temperatures are pretty constant. In the areas that are in constant shadow, things maintain a temperature of 25K, which while extremely cold is at least constant. At the same time, by just sticking something straight up out of a crater, you can put it in constant sunlight. In this way, we could keep our equipment cool in the dark and feed it energy from solar panels placed in perpetual day light.

In thus very cold, very constant environment, it is possible to study gases in a variety of way – yes I said study gases on the moon. Sources of volatiles (a fancy word for gases that like to escape when warm but can be frozen) include comets, asteroids that formed with in the icy boundary (wet asteroids), and even interplanetary dust particles. These volatiles can help us understand the things as varied as Giant Molecular Clouds (like Bok Globules) and space weathering (the process of the space environment altering the chemistry of soils via many mechanisms, including solar wind bombardment, cosmic rays, and others). The Molecular Clouds are perhaps one of the more fascinating applications there has been some talk in the literature (the references given were Talbot & Newman 1977 and Pavlov et al. 2005) that the Earth regularly passes through molecular clouds and this changes the ability of light to make it from the Sun to the Earth, casting us in an interplanetary fog. This has been termed the “Snowball Earth,” and has been linked as a possible (but much debated) cause of past extinctions. It is possible evidence of these interactions is trapped on the moon. More likely, we’ll fund hydrogen trapped in silicates and different organics that formed in the extremely cold “space weather” of the shadows of the polar crater walls. There is a lot to learn, and right now all we can really do is speculate at what might be there waiting. An actual robotic or manned mission will be needed to make measurements.

From the poles, the topic changed to Craters. Put simply, the older the surface, the more craters it has, and the younger the surface the less craters it has. By counting craters you can to get the relative ages of different regions (radiocarbon dating is required to get years attached to our understanding of A is older than B). (silly note: the person next to me looked at me like a crazy person for needing to write down how crater aging works). Here are the steps: 1) Map homogeneneous areas (in terms of composition as determined from Clementine data), 2) Determine the number of primary craters as a function of size (how many big, how many medium, how many small, etc), 3) determine cumulative crater frequency for craters >= 1km (that means you make a plot and fit a line), 4) fit local distribution to lunar standard distribution (do you have more or less than average, and by how much). This provides relative age. Bonus step: Use coorelation between radiometric ages of returned lunar samples (Apollo moon rocks) and crater numbers to derive age for areas containing Apollo missions. This gets you a model age for different areas.

The reason ages of different areas on the moon vary is volcanism. The moon had active volcanism for roughly 3 billion years. There is a clear evolutionary motion of where things formed. This indicates that heat producing elements (things inside the moon radioactively decaying) allowed volcanism to exist until recently (which to a geologist means until 1 to 2 billion years ago). This volcanism peaked 3.5 billion years ago in the model ages presented.

The craters can also be used to address basalt thickness (basalt is what they are calling the stuff the volcanos spewed – I really really need to read a geology book). The measure the thickness by matching theoretical crater ditributions to determine what is not seen. For instance, are the tiny craters missing in an areas that has a lot of larger craters? Based on what is erased, they can determin the depth of erasing material – the Basalt that flowed from fissures to fill in the craters. They estimate the Basalt is generally 30-60 m deep.

While the Basalt was formed over several billion years, and it is observed to come in both titanium rich and titanium poor types, maps created by Lucey et al 2000 correlated with the presented crater counts didn’t show that the composition of the Basalt changed with time. Titanium rich and poor basalts erupted at same times and across the whole formation period. The region studied was limited to a region of the nearside Mare Basalts, and LROC data will allow this study to expand and address more regions on the moon. Since the moon doesn’t suffer wind, rain, and platetechtonics, it is possible to imagine one day having a map of “This region formed when…” for the lunar surface.

The Mare Basalt is something I have to admit I haven’t thought a lot about before today. It is the dark stuff that makes up the rabbit or the old man in the moon, and it exists mostly on the near side of the moon (the side we get to see). I knew it was a type of lava flow, but I hadn’t understood all the things people study about it. In addition to studying the history of Basalt formation via cratering, work is also being done using Moon Meteors (chunks of moon that got knocked off in an impact and landed on Earth), to study the age of the moon and what formed when.

The Moon formed after the Earth, and is actually a blasted off chunk from a giant impact event (we think). This rather traumatic experience occurred 4.5 billion years ago. Over the years we have found more than 50 lunar meteors on our planet and ~10 (approximately means some are being argued over) are what are called Crystalline Basalts (the remaining are Feldsphathic and Basaltic). Translation – about 10 are cool lava rocks that we can date and the others are less useful rocks for this purpose, but are still cool. Of those 10, the youngest is NWA 773, which is 2.8 billion years old, and the oldest is Kalahori 009, which is 4.35 Billion years old. (There is also a possibly younger rock in the Apollo samples, that may be 2.4 years old).

The oldest rock, Kalahori 009, was found in Botswana in 1999 and is very large, weighing in at 13.5 kg! It contains phosphates that can be used for aging and both its mineralogy and oxygen isotopes indicate that its lunar (certain oxygen isotope ratios are particular to the Earth-Moon part of the solar system, and certain mineral ratios are typical for the moon and not the Earth.) By studying this rock and a lot of chemical processes that went into forming this rock, including the radioactive decay of Uranium into Lead and the Argon-Argon crystallization, they were able to identify its age and thermal history through multiple techniques. This allowed them to discover that the lunar highlands formed in two stages, including volcanic modification in a second stage of lunar crust formation.

How this volcanism worked is actually a fascinating mathematical story. L. Wilson gave a captivating to a geek presentation that in pure algebra, with variables identified with the occasional word, went through and demonstrated that the eruptions that deposited the Basalt were turbulent with a flow velocity of 2.5 m/s and an effusion rate of ~1×10^6 m^3/s. (for the uber geek: a fit to a laminar flow model gave a flow of 65m/s and a Reynolds number of 1.6×10^6!!!). The flow was most likely limited by the volume of material in a reservoir, with a 300 km flow taking a day and half to 4 days, depending on slope of fissure. He even estimated the size of the fissures based on observed dikes and flows. He estimates the volume of a dike to be not less than 10.8km^3 to 54km^3 depending on if it is long and skinny or, well, more rotund in shape. Dancing through the numbers, he showed how the densities of the magma, the crust and the lunar lithosphere all balance to point to specific flow rates and geometries, indicating that global compression of the lunar ground caused late stage volcanism to be extremely finely balanced between material lerupting through the lunar surface or instead tunneling through the subsurface forming intrusions. He suspects much more basalt exists in these underground intrusions than in the volume of lava we see.

On that wonderfully mathematical note, my brain was fully sated.

Nonetheless, I tried to cram one more talk into my mind and my notes on my laptop.

The very first talk on the new NASA GRAIL mission was the last talk I saw in the morning. This mission is designed to determine the internal structure of the moon using gravity modeling. While this is part of SELENE’s mission, the GRAIL mission will do it with higher precision – this is the most over designed mission ever. They are utilizing existing technologies that were designed for Earth studying (and other) projects, and it just happens that these technologies allow them to do the moral equivalent of measuring the distance between Houston and Florida with Vernier Calipers. Check out the mission page here.

I’m afraid that if I consume any more content at this moment I’ll have the mental equivalent of what happened to that guy on Monty Python who consumed just one last wafer thin mint. Therefore (warning: I may not post this until the end of the day), I’m going to go get lunch.

As you may have read at the time, there were several reports of toxic fumes associated with this impact, and some fear that it was actually a missile or falling piece of space debris. All these reports and fears appear to be nothing more than over-active imaginations at work. This was a rock. More accurately this was a Rocky Asteroid called a Chondrite (sub type H). This is good news, but a bit troubling. This type of asteroid turned meteor turned meteorite isn’t supposed to be able to make landfall when small. It was thought (using what are called Pancake Models) that these objects burn up in the atmosphere and spread into a cloud of small, unlikely to survive to the ground, pieces.

Clearly, the models were missing something.

This Carancas crater is/was (it’s quickly eroding) about 14 meters in diameter and the ejecta from the impact spread over 300 meters, with one chunk going through the roof of a shed a couple hundred meters from the impact site. While many of the meteor bits were taken by locals, tourists, etc before the scientists got there (you can actually buy some here), the total mass of the meteor bits and dust still at the site when the scientists got there was surprisingly large. It is estimated that the impacting “object” (I’ll explain below) was roughly 1m in size and 1780 kg.

The parent body was likely much larger. Using modeling, it is estimated that a roughly 2ton object hit the atmosphere at 75 degrees. As it passed through the atmosphere braking and breaking took place, with the object fragmenting in such a way that the pieces didn’t have the energy necessary to pass through the  bow shock (a special type of shockwave that comes off the nose of an object passing through a medium). With all the fragments trapped inside the bowshock they were effectively collimated and in many ways acted like a single object, hitting the ground in a stream. The impact contained roughly 62 million joules of kinetic energy, and flung the soil up into a really cool crater. Unfortunately, this object landed on the bank of what was a dry riverbed. As it dug into the earth, it hit the water table (only about 1.5 meters down, and within 15-30 minutes the crater floor was filled with water.

Over the months since the impact the sides of the crater have slumped, objects in the crater rim have slid down, and erosion has taken place. Soon this crater will look like just another watering hole for the local llamas – It will just be a local watering hole surrounded by fascinating dust and rocks. (Samples collected contained glassy particles and lapillus fragments.)

This impact raises some intriguing questions. Objects like this could have hit us often, but because the craters really aren’t all that dramatic, they may have eroded into oblivion before anyone figured out their significance.  Have we been getting casually drizzeled on by Chondrites on the scale of decades (or longer) and just not known it? The newly realized threat these rocky bodies pose to life on Earth needs to be assessed. While this object didn’t cause any significant economic or bodily harm (and in fact appears to be lining a few pockets with green), it could have.  This object did force one farmer to repair a roof, and it could conceivable have destroyed a building if it had hit a support structure (or just hit a weak building). Now, as we map the skies with LINEAR and the upcoming LSST telesocpes, we need to consider broadening our idea of dangerous, and look a bit harder for the rocks that just might decide to impact.

Craters. Double-ringed craters. Craters with lumps in the middle. Craters with smooth basins in the middle. Craters overlapping craters.

Mercury is, put simply, littered with craters.

The come in chains. They come in clusters. They come in different periods of time.

In the heavily cratered areas on Mercury, there are two different populations that came in two different periods of time. (We know this from looking at how they overlap.)

2600 craters were measured in just 4 of MESSENGER’s new images!

Caloris Basin – S. Murchie presenting

Thought to be the youngest basin on Mercury. There is a main rim and ejecta and lineated plains surrounding it.

Basin originally formed in dark materials similar to highlands. Volcanism filled it in, but smaller (more recent) cratering re-exposed the darker material and also exposed deeper redder material. These colors only appear in color stretched images, but the non-stretched images are still fabulous. Click below to see hi-res image. Basin is circled.

Remarkably – this planet I learned in school was metal rich and very dense has low (e.g. not yet detected) surface iron according to the lack of 1micron iron line detection. This region was one of the best hopes for finding it because it dredges up deep material. They looked for the line, and the line didn’t look back.

all images credited to: NASA/Johns Hopkins University Applied Physics Laboratory / Carnegie Institution of Washington

The atmosphere of this awards ceremony is very damp. I mean that quite literally. The announcements are not only being punctuated by our applause, but also by spectacular thunder. There is an amazing downpour going on outside, and my suit jacket is hanging on a chair drying out. In about 50 feet it got soaked through. It was amusing to see several of us adults with students and rental cars dropping our students off at the door and then making made dashes across the parking lot to get to the building. All I could tell Rebecca as we watched the downpour was “Welcome to Texas.” (The rain drops were actually bouncing.)

They are now listing all the amazing achievements of Dr. Robert Pepin, the Masursky prize winner. He is the author of several books and over 150 papers. He sits on many committees and leads many large projects. His work focuses on, well, astronomical dust. It doesn’t sound interesting to most, but dust is at the heart of star and planetary formation.

Through careful astronomical observations of dust in clouds, astronomers have been able to figure out the structure of interstellar dust. These grains have an silicate core surrounded by organic materials. These grainy structures come in many shapes. (One looks, in his words, like a Mandorbort turtle). These grainy structures are amorphous and are seeded by materials from stars. This is material like the stuff being actively pulled off of the star Mira.

From spectra and polarimetry astronomers have studied this dust at a distance – observing it in clouds like the Bok Globules. Planetary scientists like Pepin are able to study these grains more directly. He studies the grains that have been trapped within meteors and captured in aerogel as from comets.

The StarDust Aerogel dust-capture program provided astronomers their first chance to examine in a laboratory material from the solar system that is basically in its raw form. The aerogel

The dust they are finding appears to have formed in high temperature environoments – enevironments the comet could not have endured! – implying these chrystalline grains come somewhere else. The composition of the grains appears completely average for our solar system, implying they are native and not something that came from beyond our solar system. This is direct evidence that comets are filled with stellar silicate dusts that have mixed back into the galaxy.

Comets aren’t the only place we’re finding this type of dust. In asteroids (which we observe in laboratories after they’ve opted to become meteors), dust grains are also seen. These are considered some of the first forming (condensing) materials in the solar system. We judge their age by looking at isotope ratios (the ratio of atoms with 1 number of neutrons to atoms with a different number of neutrons – in this case the oxygen isotopes). What is amazing is the same types of grains are being found in comets and in inclusions in asteroids.

What’s funny is some jeweler somewhere made slices of a meteor into pendents and the pendents have inclusions (called condules) with dust grains in them. For just $45.95 you can order one of these pendents (from an unlisted site) and where something older than the Earth around your neck. The speaker is saying that Salvador Dali asked a scientist he knew to brings a selection of these condules  to his private railroad car so he could commune with the ancient energy in the condule. Oh my!

In addition to silicates and organics, they are also finding noble gases – gases that prefer not to bond with things – trapped in the grains.

By studying all these grains that are embedded in such different objects as comets and asteroids, it is possible to start to piece together a more detailed model of how our solar systems early solar nebula mixed particles. In the early nebula magnetic field lines tangling and untangling themselves in a process call magnetic reconnection may have sent huge amounts of energy fluxing through the solar system. This large energy surge could have lofted chunks of gas and dust out of the solar nebula. This flung material would then have gravitationally rained back into the solar system with material falling back into the disk at distances like that of Neptune or larger. This would effectively mix material through out the solar system, allowing forming asteroids and comets to both contain identical grains.

Tau Boo A’s flip might not be entirely identical to Sol’s back flipping behavior, however. While the Sun is observed to flip fully every 22 years, Tau Boo A’s flips may be faster paced. This particular star has a GIANT planet in a very close orbit. The planet is 6.5 Jupiter Masses in size and orbits just 0.046 AU from Tau Boo A. (Mercury’s orbit is 0.39 AU in size!) As this large star flies around every 3.3 days it carries the star’s surface with it. According to the press release, “It is possible that the giant planet that has already managed to speed up the surface of tau Bootis is also spinning up the magnetic engine of its host star.”

Here’s how that works. As far as we understand it, stellar magnetic fields are created in or near the boundary layer between the part of the star that transfers energy via radiative transfer (like heat transferring up a pot handle) and the part that transfers it via convection (like a lava lamp). In this boundary zone are ionized (charged) particles. As they rotate around the star like so many particles flowing through so many circular wires, their motion generates magnetic fields. Since the inside of the star doesn’t rotate like a solid, all these moving, magnet making charged particles can have a myriad of interactions that lead to all sorts of magnetic behavior (and misbehavior).

It is possible that the gravitational pull of the planet Tau Boo b (lower case is the planet), on Tau Boo A tugs that layer of the star, carrying it around faster and faster, and possibly accelerating the process that leads to the magnetic pole flip.

That said, magnetic fields are very very hard to understand. Lots of modeling needs to be done. And even if the models show that the planet should accelerate the field flip, the result won’t be fully trusted until we observationally see the flip happen a few more times. Astronomers will be watching to see what happens. They have some hope – if the planet had a 11ish year cycle between half flip (north goes to south), we would have had a less than 1 in 5 ish chance of seeing the flip in the past 2 years of looking. The fact that we saw it is just enough improbable that it hints (and I won’t saw more than hints) that the cycle is maybe shorter.

Maybe.

It’s just kind of cool to imagine a planet twisting up a star.

(And if you want to know how to name a star, check out Fraser’s site)

Image credit: Karen Teramura (UH IfA)

This particular discovery caught my attention for two reasons. First off, the data on this object spans ~14 years – that is a lot of data to put together. Second, this is a really close binary to have a planet! They found a planet (2.96 Jupiter masses or larger) orbiting 2.63 AU from a star that has a companion at 17.23 AU. This system is HD196885A and the announcement came in a paper with A.C.M. Correia as lead author.

Imagine the chaos involved in forming this little world. Its Sun, an F8 star, is a bit brighter (2.4 Solar Luminosities) and a bit larger (1.33 Solar Masses) than our own Sun. While this star was forming, it flared and crackled with high-energy outbursts. Meanwhile, its red dwarf companion collapses into its own violent beginning; red dwarfs also go through a terrible toddler phase of coronal mass ejections. Between these two angry youth, this planet settled into an orbit around the larger star, and pulled itself together to grow into a gasy giant. Now, 2 billion years into its evolution, the F star has settled down into a few billion years of peace and quiet. Eventually, the F star will bloat up into a red giant, go through a new round of shape shifting as it bloats and shrinks and bloats again. All the while, the planet will sit a possibly safe distance away, watching as its main source of heat and light falters and fails and eventually collapses almost completely into a white dwarf star. As the F star’s atmosphere floats away, it will form a planetary nebula that enshrodes this new found gas planet and its M-star guardian. As that white dwarf cools into ash, the dwarf planet will continue to glow, allowing the planet to experience a no onger heliocentric series of seasons, as it orbits toward and away from its secondary warmth.

What an odd fate this newly discovered planet has had and will see. What a weird place to find a planet. It really seems that alien worlds can be found in perhaps any stellar environment.

image credit: NASA/JPL-Caltech

And then…

And then she takes it all away.

A trio of new articles in the journal Science indicate Mars may be just another dry, lave covered world. (see HiRISE for information) In the first article, they take a new look at the gullies formed inside craters. Some of these gullies have appeared in recent years and it had been hoped that perhaps they had formed when underground water emerged for some unknown reason. New studies, however, indicate that these gullies may just be dirt tumbling down steep crater walls. The HiRISE team’s analysis notes there are light colored sediment deposits up hill from the gullies, and it would make perfect sense that some of the hill just broke away and tumbled down making a dirt dug gully. Dirt 1, Water 0.

(Their second story is emotionally neutral. They focus on the Martian North Pole, and in a study of 30-cm resolution images they found that their are signs of ice motion (called mass wasting), flow, and debris piling up. All these processes are things we see on Earth, and it is neat to see them on Mars as well.)

The third HiRISE paper brings us more sad news. Athabasca Valles had previously been believed to be the site of vast outflows of water, and had what many had believed were shore lines. Now, looking at these geological features in higher resolution, it looks like this area is just another lava flow. At some point in Mars past, some Martian Mt St Helens let loose and carved out part of the planet, leaving behind a beautiful sheen of lava and deceiving geology. No water. Just rock. (Lava 1, Water still 0)

And then…

And then she throws us a bone.

In yet a forth study, this time using Mars Odyssey, a series of caves were located in the side of the volcano Arsia Mons. The way these caves were found was really neat. During the day they appear as slightly cool spots on the surface, and at night they appear as slightly warm spots in thermal maps of the planet. Just like caves and Earth-berm houses here on Earth, the cave walls act like insulation a help maintain the temperature inside the caves at a fairly constant level. The scientists point at that these caves, in addition to providing thermal protection also provide a certain amount of radiation protection. If life could exist anywhere on the surface of Mars, those caves represent both a good place for us to put life (like astronauts) and look for life (like not-much-oxygen needing bacteria). There (of course) is a cavaet: The caves are at a high altitude and even by Martian standards the atmosphere is thin. (image credit: NASA/JPL-Caltech/ASU/USGS)

Oh fickle Mars, how you toy with our hopes. You offer us the promise of water and life everywhere, but no where. When will you reveal your secrets? Do we really need to explore your every beautiful crevice crater with our robotic fingers and we look to tickle out a bit of truth?

One day we will send astronauts to you, and they will force you to reveal your secrets.

Maybe.

As well as getting their ideas, I thought I’d ask what you, my often silent non-student readers, think are useful ways to remember the planets and stars. So, in the comments, give me a sentence to remember you and the stars and planets by!

What do I use?
For planets (M V E M J S U N): My very evil mother just served us nothing.
For stars (O B A F G K M): Oh, be a frightening Godzilla. Kill Mothra!

What do you use?

Locally, COROT (vaguely rhymes with Inspector Perot), obtained first light today (image above, credit CNES 2006 – D. Ducros). This orbital observatory will dedicate it self to the search for rocky worlds around other stars. A product of the European Space Agency, COROT will study nearby stars with its 30cm telescope, looking for slight changes in brightness indicative of planetary transits. The images it takes will also be useful for asteroseismology, the study of how stars bump and wiggle in reaction to chemical and thermal processes deep beneath their surfaces. Pre-launch calculations predict that every 150 days (the time COROT will spend studying one area of the sky), COROT could discover 10-40 rocky planets and tens of gas giants. Since the first published discoveries of an extrasolar planet around a pulsar in 1992, and around a normal star in 1995, astronomers have only discovered 209 extrasolar worlds. With COROT, that number could double in as little as 1 year.

A little farther out, the STEREO spacecraft (left, credit: NASA/Johns Hopkins University Applied Physics Laboratory) are swinging past the moon on their way to their final orbital homes ahead of and behind the Earth. From these positions they will produce three dimensional images of the Sun in much the same way that your two eyes are able to give you a three-dimensional view of the world around you.

Out near Jupiter, the New Horizons (right, credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)) mission is zooming toward its first major science target. While zipping past our solar system’s largest gas giant, New Horizons will test its instruments. New Horizons images will be the first close ups on Jupiter since the Galileo spacecraft ended its life by plunging into Jupiter’s atmosphere on Sept 21, 2003 (I’m personally looking forward to seeing what New Horizons can learn about Red Spot Junior.)

Somewhere out past Mars, Stardust is waiting to learn if NASA will let it visit more comets. Launched in 1999, this little capsule that could imaged asteroid Annefrank in November 2002 , investigated comet Wild 2 in Jan 2004, and returned to Earth a sample of comet and interplanetary dust in January 2006.

Also on the go are Mars Express, Venus Express, Rosetta, SOHO, XMM-Newton, Integral, Hubble, Spitzer, Cassini, Voyager I, Voyager II, Spirit, Oppurtunity, and many many more space craft. In recent decades NASA and ESA have demonstrated over and over that while they have their moments of bad luck and stupidity (Mars Polar Lander, anyone?), they can very successfully get to objects all over the solar system and explore them in ways that both bring home good science and get the public interested in space.

At the same time, the private sector is getting in on the space gig as well. SpaceX is readying to test their Falcon 1. Virgin Galactic has a business plan and has partnered with Scaled Composited (the guys behind SpaceShipOne, GlobalFlyer and nospaces in names) to get everyday men and famous dudes into space starting sometime in the next couple years. Bigelow Aerospace has inflated modules on orbit and is aiming to start launching hotel pieces late this year. Along side these companies are roughly two dozen competitors, all aimed at making a buck off of space. Today, the sky isn’t a limit for companies seeking to get people and goods farther, faster and cheaper.

In my ideal fantasy universe, each agency and company is able to thrive doing what it does best. In the case of space, NASA and ESA and their international government run space agency brethren use tax dollars to explore with robots and probes, doing the science that serves to excite and inspire, but that doesn’t exactly do much to raise anyone’s financial bottom line. At the same time, the I dream of seeing some of the two dozen plus commercial space corporations becoming tomorrows PanAm and TWA or UPS and FedEx as they compete to get people and goods everywhere. In this perfect fantasy world, Mars gets explored by man, but it is paid for in the same commercial spirit that the Dutch and British East Indian Trade Companies paid to explore the Earth’s ocean’s.

But today’s space reality is far from my personal fantasy. Today, NASA’s space science budget is getting raped by the manned space program. With congress announcing that budgets will be flat in this first quarter of 2007, NASA Administrator Michael Griffin has said he will be compensating for a half-billion dollar funding hole by taking money from programs he believes are low priority to fund the International Space Station and Orion crew exploration vehicle programs. So far, money has been cut from weather and climate research budgets, and a lot of people are holding their breath as they wait to see what space exploration programs get put on hold and/or canceled.

So, here is my question for the people who figure out how NASA dollars should be calculated. When was the last time a press release from the International Space Station (ISS) took someone’s breath away the same way Cassini images so often do? When was the last time science results from the ISS made people think life the way the results of finding evidence on Mars so often do? What exactly has the ISS done for anyone lately? Our failure to be on time and on budget has got to be annoying our international collaborators. I’m not really sure what we’re learning, and I try to stay up to date on this stuff. I do think we need to replace the shuttle, but before we go building heavy-lift, Moon and Mars heading vehicles, shouldn’t we be asking, what do we need people doing in space? The Mars Rovers have demonstrated that we can reprogram robots to do new things from great distances. People are great construction workers. We can repair things really really well. Having the ability to go into orbit, grab a satellite and fix or update it is really useful. I can totally get behind that type of a project. But, we can’t take a person and put it in a parking orbit like we did with Stardust, and spend a few months trying to figure out what to do next.

But NASA is gearing up to make fewer StarDusts and to spend my tax dollars putting people on Mars. I don’t like this, so what can I do? Well, I can sign petitions, like the one put together by the Planetary Society, and I can write my congressional representatives. And I can ask you to think about what you feel NASA, ESA, or any other tax dollar spending space agency should be doing, and once informed, write to let the people spending your tax dollars know what you think they should be doing.

Space is the last great frontier, and while I don’t advocate filling it with garbage, I like to thinking that we are slowly decorating our corner of the universe with bits of science gleaning flying metal bits.