Archive for the ‘Petra’s Blog’ Category

One Year on Mars for Curiosity

Posted by Zoe on 5th August 2013 in Exogeology, Main Page, Petra's Blog

One year ago, the Curiosity rover landed on Mars.

Curiosity, also known as the Mars Science Laboratory (MSL), descended to the surface of Mars at 10:32 p.m. PDT on August 5, 2012 using the science fiction-sounding “sky crane” to land precisely, and thankfully, successfully.

Since that day, Curiosity has had an exciting year. In no particular order, here are a few of the rover’s major events, efforts, and discoveries:

  • Landing safely, of course.
  • Sending home her first pictures. There’s nothing like seeing an alien vista for the first time. We had seen this area of Mars from above, but when Curiosity snapped her first few photos and sent them back to Earth, we were at ground level, close up. We saw Gale crater in a way we never had before.
  • Curiosity's first image taken from the surface of Mars. (Image credit: NASA)

  • Finding rounded rocks in a riverbed. Apart from all the alliteration, this discovery is notable because it pertains to water in Mars’ past. These rocks tumbled around as they were pushed downstream by the current. They knocked into each other and became smaller and smoother and more worn down the farther they went. This happens here on Earth, which you might have noticed, and it’s why river rocks and smooth and rounded.

Rounded river rocks on Mars (left) and Earth (right). Image credit NASA/JPL-Caltech/MSSS and PSI

  • An anomaly with one of her computers’ memory and a switch to the second computer.
  • Starting to use her fancy science tools. Curiosity really is a Mars Science Laboratory. She has several cameras for navigation and taking pictures of the scenery which give you an idea of what the various sights like rock outcroppings, sand, river rocks, and everything else look like. She has a drill for taking samples. She has a scoop for…taking samples. Those last two, along with some other instruments, are on Curiosity’s robotic arm. She has spectrometers to identify materials using the light spectrum. She has a laser. With all these awesome tools and more, it’s pretty exciting that Curiosity has been using these tools throughout the past year.

Holes from Curiosity's drill (large hole) and laser ChemCam (small holes) in a rock called Cumberland. Image credit NASA/JPL-Caltech/MSSS

  • Trying to discover whether Mars has ever had a habitable environment. This one isn’t over, it’s ongoing. In fact, it’s one of Curiosity’s primary goals. An event relating to this goal is the time Curiosity found a rock sample that shows Mars may once have been habitable for microbes. There was also the time when she found evidence of water in a place called Yellowknife Bay.  Or course, I can’t wait to see what other evidence Curiosity might find.

But, Curiosity’s not done yet. The rover is on her way Mount Sharp. She’s finally driving, and even though it’s hard to leave behind the rocks nearer to the landing site, Mount Sharp promises to be even more intriguing. Why are we looking forward to investigating Mount Sharp? Well, it’s made up of layers. The layers in Mount Sharp might show us more about what Mars’ climate was like long ago and all the changes it has been through. How cool is that?

If you ask me, everything Curiosity has done in her first one year on Mars has been very cool.

-Petra Stone

Congratulations, Curiosity!

Posted by Zoe on 6th August 2012 in Exogeology, Main Page, Petra's Blog

Tonight, Curiosity reached its destination: Gale Crater, Mars.

Curiosity's first image taken from the surface of Mars. Woo-hoo! (Image credit: NASA)

Curiosity, also known as the Mars Science Laboratory (MSL), traveled for about 352 million miles (567 million km) from a cleanroom at JPL on Earth to a place called Mount Sharp in Gale Crater on Mars. It’s hard to imagine traveling so far.

Curiosity's cleanroom, way back in 2010.

Mount Sharp, the area on Mars Curiosity will explore. (Image credit: NASA)

Tonight, August 5, Curiosity’s team worked through the “Seven Minutes of Terror” while everyone else, including myself, just hoped and wished for the best.

Can you even imagine how hard it would be to land a rover? Can you imagine just how nervous you’d be that all the work put into Curiosity would either have the chance to succeed amazingly or just fail terribly? I can’t, but that’s what Curiosity’s team must have felt.

Landing Curiosity had several stages. (Image credit: NASA)

Finally, can you imagine the relief and excitement as Curiosity landed safely on solid ground? I can, but not even half as much as Curiosity’s team, I’m sure.

I’m so, so glad Curiosity made the landing safely. Congratulations, Curiosity! You ROCK!

Transit of Venus

Posted by Petra on 4th June 2012 in Main Page, Petra's Blog

Image credit: NASA

Tomorrow, you’ll have a once-in-a-lifetime opportunity to actually see a planet cross over a star. Venus transits our sun for the last time in over a century at 22:09 UTC, June 5th, so find a way to watch.

Why is this so special?

If you have any astronomer friends, they’ve probably been blabbering on for months about orbital periods this, first contact that. Why won’t we shut up? Because this is literally once in a lifetime, and it’s kinda cool.

Venus, the next planet inward, will cross directly over the visible disc of the sun. It will appear as a tiny black dot, about one arcminute, covering a minuscule fraction of the disk. This isn’t a lot, but it’s enough to see with the naked eye—not the recommended way to view it, of course.

Venus’ orbit is slightly skewed compared to Earth’s, so Earth, Venus, and the sun only line up this way every 121.5 or 105.5 years. After this much time, Venus gets in the way of the sun twice, each time eight years apart. The last transit was eight years ago. The next, after tomorrow’s, will be in the year 2117.

Transits of Venus were historically used to calculate solar parallax. This eventually led to the astronomical unit, the distance from here to the sun, giving us a way to measure the solar system. Today, scientists’ observations of the transit will help in studying exoplanets.

Do you have a way to live 105.5+ more years or own a time machine? If so, I take back what I said about this being once-in-a-lifetime. Maybe it’s not so special. Even still, what’s the harm in watching?

How can I watch?

If you have vision and plan to keep it, then just going outside and staring at the sun isn’t the method for you. Consider these options instead:

  • Try making a pinhole projector.
  • Use eclipse glasses. These can be bought online or possibly at your local science museum gift shop. Don’t count on the museum shop though—they might have sold out with all the solar viewing going on lately.
  • If you have a telescope, use a filter on the front end (not the eyepiece) to protect your eyes and your telescope. Having a bit of magnification will help turn Venus from a tiny speck to a slightly less tiny speck.
  • Do you or a friend weld? No? Huh. Well, for those who do, wear #14 welder’s goggles to safely view the transit.
  • Do you have access to a device such as a computer, phone, or tablet which can connect to the internet? If not, can you please explain to me why somebody printed my website? If you do have access, check out NASA’s webcast from Mauna Kea, Hawaii.

Have fun, view safely, and keep me in the loop about that time machine!

Curiosity Launches Today

Posted by Petra on 26th November 2011 in Main Page, Petra's Blog

Hello, Petra Stone here with news about the Mars Science Laboratory, better known as Curiosity or the MSL. Today, this new rover finally launches on its journey to Mars.

Image from NASA

It’s been over eight years now since the last Mars rover launch, Opportunity’s in 2003. Now, Curiosity will set off on a mission to determine if life could have ever arisen on Mars, characterize the climate of Mars, characterize the geology of Mars, and prepare for human exploration. Those are the four main goals, but this newest and largest rover has eight more specific scientific objectives. There’s a lot in store for the MSL!

JPL cleanroom where Curiosity was built. Image credit Zoe Bentley.

Curiosity’s equipment ROCKS! It’s taking a drill, several cameras for steering and gathering data, a robotic arm, and even a tool called SAM with a laser in it which vaporizes rocks. No, I’m not kidding. The MSL is also powered by plutonium. This means dust buildups won’t keep Curiosity from getting the energy to explore. Even the way it lands is pretty cool. I can’t wait until Curiosity reaches Gale Crater in August next year.

Curiosity is scheduled to launch today at 10:02 EST from Cape Canaveral on board an Atlas V rocket. I can’t wait for this ROCKIN’ rover to get on its way!

Check out these webpages to learn more about Curiosity:
The Mars Science Laboratory’s website
NASA’s MSL Mission Page
Watch Curiosity Launch Live!

Mars Rover Landing Site

Posted by Petra on 29th July 2011 in Exogeology, Petra's Blog

The newest Mars rover, Curiosity (also known as the Mars Science Laboratory) has a landing site picked out: Gale crater, measuring about 150 kilometers across (93 miles) and at least 3.5 billion years old. The crater was chosen out of a hundred locations on Mars, which were gradually narrowed down, and the final choice was announced on July 22. Imagine how hard it would be to choose just one place out of one hundred to explore!

So, what is Gale crater like? There is a mountain made of layers of debris in the middle of the crater, probably made of sediment from the bottom of a lakebed or dust and volcanic ash blown by the wind. Erosion in the crater gives the rover access to the different layers. When Curiosity gets there, we’ll find out a whole lot more.

Are you curious to know when Curiosity will get to Mars? It’s currently scheduled to launch this November or December and land on the red planet in August of next year.

I can’t wait to see what Curiosity finds. You know how excited I get about exploring Mars. The Mars Science Laboratory ROCKS!

Here’s more information on Gale and Curiosity.

-Petra Stone

MESSENGER Orbits Mercury

Posted by Petra on 18th March 2011 in Exogeology, Petra's Blog

MESSENGER was inserted into orbit around Mercury yesterday, March 17th. Launched on August 13th, 2004, MESSENGER has been in interplanetary flight for over six and a half years! I bet that after this long waiting, the MESSENGER team is thrilled to finally be in orbit. As for me, I think visiting Mercury ROCKS!

MESSENGER is a NASA Mercury orbiter. It’s name is an acronym for MErcury Surface, Space ENvironment, GEochemistry, and Ranging. One of its goals is to learn about the topography of Mercury’s surface, and another is to find out the composition of its atmosphere.

On its way to Mercury, MESSENGER has had one Earth flyby, two Venus flybys, and three Mercury flybys. In one of these Mercury flybys, volcanism on the surface and water in the exosphere were discovered. Also on the way to Mercury, MESSENGER took this ROCKIN’ “family portrait” of our Solar System:

There’s a lot about Mercury we’ve found because of MESSENGER. For example, could you imagine seeing a whole side of a planet which you’ve never seen before? MESSENGER gave us just that in this picture:

The instruments on board will be turned on and checked on the 23rd of March, and on the 4th of April the mission’s primary science phase begins. I look forward to seeing what new discoveries are made about our amazing innermost planet!

Exogeology ROCKS!

-Petra Stone

Life As We Don’t Know It

Posted by Petra on 3rd December 2010 in Exogeology, Petra's Blog

What if someone found a creature that wasn’t like any other, a creature which wasn’t made of the same chemicals as anything else on Earth? Wouldn’t it ROCK to find something so different? That’s exactly what geomicrobiologist Felisa Wolfe-Simon discovered in California’s Mono Lake.

Extremophiles are organisms which can survive in extreme environments, such as intense heat or lack of light. An extremophile bacteria was found recently in California’s salty, alkaline Mono Lake. This extremophile, known as GFAJ-1, can survive high amounts of normally poisonous arsenic.

By weight, the human body contains 65% oxygen, 18.5% carbon, 9.5% hydrogen, 3.3% nitrogen, 1% phosphorus, 0.3% sulfur, and small amounts of several other elements. Even though there is so much oxygen in the human body, most of that is in the form of water, so we say that humans are carbon based. Most life on Earth has a similar composition. While GFAJ-1 is tolerant of arsenic, it’s not exactly an arsenic based life form. However, it does replace one of the basic ingredients for life. This unusual microbe is not only tolerant of arsenic, but is able to incorporate it into its cells.

Yesterday, NASA held a press conference explaining this surprising extremophile. Among the presenters was astrobiologist Pan Conrad, interviewee in Exogeology ROCKS! Episode 3.

Science fiction and real science have often considered replacing important elements with chemically similar ones, but until now, there haven’t been any real life examples. When given no phosphorus and a lot of arsenic, GFAJ-1 replaces the phosphorus in its body with arsenic and continues to grow. None of the bacteria have yet entirely gotten rid of the phosphorus originally in them, but I personally think that replacing most of it is exciting enough.

This discovery changes what we know about life. There are so many possible places a life form can survive on Earth alone. Maybe life on other worlds is more common than previously thought. I sure hope so.

Super Harvest Moon

Posted by Petra on 22nd September 2010 in Petra's Blog

Tonight I made a point of looking at the sky, the moon in particular. Why? Because tonight is the night of a “super harvest moon“.

A harvest moon is the full moon closest to the fall equinox. The equinox is a day when the day and night are exactly the same length, and the first day of fall (the same thing happens in the spring). The harvest moon usually happens at least a few days before or after the equinox, but this year’s is special.

Today, there is a full moon. Today is also the equinox. It’s not often the two occur on the exact same day.

I didn’t have the best view of the super harvest moon because it was cloudy where I am. I did see the moon peeking out from behind the clouds though, which was in my opinion beautiful. I also saw a small ring around the moon. It looked a bit like a rainbow. I was amazed at how bright it was outside even with the clouds.

Iceland Volcano Erupts!

Posted by Petra on 15th April 2010 in Petra's Blog

Wow! An eruption; that ROCKS! Only, it doesn’t at all. All flights to and from Iceland were postponed, including mine. It turns out I’ll have to wait a few more days before going home. The Icelandic volcano Fimmvorduhals near Eyjafjallajoekull glacier erupted just recently on March 21. It was a small, relatively harmless eruption. There was ash,  flights were canceled, and there were evacuations, but there wasn’t much damage done considering what could have happened. Yesterday it erupted again–and I was there. Well, not there precisely, but in Iceland, so I was affected by the eruption (just a canceled flight).

Don’t ask me how to pronounce the name of the glacier; I have no idea, even though I’ve been hearing it on all the television and radio channels (I’m not a linguist). The volcano is just as difficult to pronounce. Somehow I manage to get the locals to understand me when I’m pronouncing local cities and words. It helps to know that “j” is pronounced like “y”…

I wish I’d been nearer to the volcano, but on the other hand, I was far enough to be out of harm’s way. Even still, I would have loved to see it erupt (from the sky)! Not only was there lava, but this time there was flooding due to the fact that the volcano was under a glacier! The March eruption wasn’t directly under the glacier, so there wasn’t any flooding. But yesterday’s eruption was in the main crater, which was underneath the icecap. I should figure out what would happen if a volcano erupted under the north Martian ice cap…

There might even be another eruption. There’s another volcano, Katla, which is more destructive and has an easier name. It could affect a larger area than Fimmvorduhals, even causing global damage! Fimmvorduhals, which was the one that erupted yesterday, had ash that spread all the way to the UK and stopped flights to and from there. A colleague of mine in Ireland told me that her flights were canceled due to ash there (the ash can cause a lot of damage to airplane motors)! Wow, ash can go a long ways! The lava itself seems to be less of a problem than the ash and flooding. I hope I get to see something from above when I fly home.

I guess I’ll have a bit more time to look around as a tourist before I go, and time to do more research, too, of course. Isn’t it awesome that geology can be so exciting? It’s not all just looking at rocks. Exogeology is pretty exciting, too. I mean, Io has more volcanic activity than any other body in the Solar System. And ice on Mars is being studied for traces of water ice, which is part of what I’m doing right now! Exogeology most certainly ROCKS!

To find out more about the recent Iceland eruption, read these articles:

The last link has a great photo; it really shows the scale of the eruption.

About Me

Posted by Petra on 11th April 2010 in Petra's Blog

If you’ve been reading this blog, you’ll already know me a bit. But I want to give you a better idea of what I’m like. For starters, I’m Petra Stone, an exogeologist. I love geology and astronomy, but I also love writing and traveling. The following are some questions that I’m often asked by people:

What are you currently working on?

  • I’m currently in Iceland working and studying glacial formations. This is research for the Mars mission I’m working on which is going to Mars’ north pole.

What is your favorite planet?

  • My favorite planet is Mars, because I think the geology is fascinating.

What is your favorite color?

  • Purple, of course! That’s why the planet on this website is purple! :)

What is the best project you have worked on?

  • My favorite projects to work on have included: identifying Martian rocks, using relative dating on alien formations, and traveling to far-off locations around Earth. I’ve never been off of Earth, but I’m sure it would an amazing experience. I’ve worked with several astronauts here at NASA who have been off-world and they’ve told me some fantastic stories.

What things do you like to do (what are your hobbies)?

  • Other than my job, some of my hobbies are reading, jewelry making (I bead memory wire bracelets usually), rock collecting (I have a huge collection with geodes, and jasper, and malachite, oh my!), stargazing and learning the myths behind the constellations, and of course, writing this blog! I like finding unique arts and crafts projects too, that can be really fun. I also love hiking. I love getting a great view of the area, and it gives me a chance to look at the rocks. :)
  • Another interest of mine is photography. I can never get my regular camera to take great objects like the moon, but it’s fun to get photographs of other things. I’ve taken photos of places I’ve been, things I’ve seen, and whatever I want to keep a record of or I just think looks cool. It can come in handy to be a fairly good photographer when you’re classifying rock samples (I use several special cameras for my job), but what really ROCKS is when I have the opportunity to take photographs through a telescope. Telescopes at observatories have great cameras for visible and non-visible light! I could never get photographs like those with my own camera. To see some samples of these, be sure to check out the NASA image gallery!

What is your favorite movie and/or television show?

  • I like science fiction movies and TV shows best, but I also like mystery shows. I like non-fiction TV shows too, but I often find long documentaries too long–I prefer shows to have a fictional storyline if they’re going to be really long.  The exception to this is The Elegant Universe. If you’ve ever been interested in physics, that show will get you even more interested! Seeing that for the first time really piqued my interest in string theory and m-theory.
  • My favorite TV shows are The Universe, Doctor Who, and, of course, Star Trek (all series, but Voyager is my favorite).

What are your favorite books?

  • Books I like are usually fantasy, not science fiction. I really enjoyed the Harry Potter series, the Percy Jackson series, the Magyk series,  and similar types of novels. I also really enjoy reading non-fiction science, especially if it has to do with time travel! I read magazines, technical periodicals, as well as the latest papers that my colleagues publish.

Do you enjoy writing?

  • I absolutely love writing! I spend most of my time writing papers about geology and exogeology (since those are the topics I know best and they are what I spend most of my time researching), but every once in a while I’ll take an interest in other topics and feel like I just have to share my findings with the world!
  • I occasionally even write haiku! Here are two examples:

Twinkling balls of light
So many lightyears away
Estrellas lindas

Rocky Mars landscape
Red mesa towers above
Like Arizona

As you can see, there’s a lot more going in my life than just my job. However, exogeology just happens to be what I like most, and a lot of the things I like are somehow related (ultimately everything seems to be related if you think about it enough). That’s just what I like!  It’s why I became an exogeologist.

Sometimes Being Stuck is a GOOD Thing!

Posted by Petra on 10th April 2010 in Petra's Blog

The Mars Exploration Rover Spirit, as  you may or may not have heard, is STUCK. Rover operators have tried all sorts of maneuvers to get Spirit out of the sand, but nothing has worked. I’m amazed at how persistent the rover team is on trying to free the rover. They’ve tried going backwards, and using the robotic arm to move the sand around Spirit. Still no good. Two of the wheels aren’t working now either. I can’t believe Spirit is in such a bad position. Of course this means it can’t go anywhere or see anything new, but…

Even if the rover doesn’t get out it can still be useful in such a way that it was never intended to be! The rover team has become very inventive in what they’ve thought to do with Spirit. Mars wobbles, or “precesses“, as it rotates on its axis. A stationary probe (like the stuck Spirit) would be very useful in measuring how Mars spins. The rover team has thought of a plan of how to measure this.  This is how looking past your problems and working with what you have, rather than what you wished you had, can be a really important skill!

Why exactly would we care about Mars’ wobble? Because how a planet precesses is slightly different depending on whether it has a solid or molten core. Earth has a molten core, but if its core were solid then our own planet’s wobble would be different. Wouldn’t that be weird? Not to mention Earth wouldn’t have a magnetic field. Exogeologists (myself included) want to know what Mars’ core is like, so measuring precession would give very good information on the interior structure of Mars. I’d find out so much more about the planets if I knew this. It would help a lot in understanding the way they all work.

There’s only one problem. Martian winter is coming soon! This means decreased sunlight for the solar powered rover. I’m not an expert on robotics, but I do know that if Spirit runs out of power (its “spirit”), it’ll go into hibernation and use the little sunlight it receives for solely charging its battery. When it’s in hibernation, a rover can’t communicate with Earth. That could be a big problem, I think, for the team of rover operators and for myself. I get lots of good data from that rover! What’s more, the rover has survived three winters before this by tilting its solar panels northward in order to get the best angle to the sun. But doing this isn’t possible in Spirit‘s current predicament. I sure hope this can be fixed before the season changes!

I hope you thought this was as interesting as I did, and I’d like to officially wish the Spirit rover team good luck!

I’m Petra Stone, and Exogeology ROCKS!

My Travels

Posted by Petra on 9th April 2010 in Petra's Blog

I love to travel! I’ve been to many different countries, and nearly every U.S. state. I love going to different places and seeing the world! Some of my favorite vacations were combined with fieldwork, often unintentionally. An example of this is when I went to White Sands, New Mexico. I went there to study the dunes, and I went sledding on the sand. Alamogordo, the closest town to where White Sands is located, is a town devoted to astronomy! This is where the New Mexico Museum of Space History is located (and I highly recommend it for all ages). I also went to the solar observatory nearby in Sunspot, NM. You can’t tell from their websites just how different the observatories I’ve been to are, but they really are distinct!

Here are photographs I took of the gypsum dunes at White Sands:

Another one of my favorite trips was to the Arkansas Crater of Diamonds. It’s pretty much what it sounds like: a crater with diamonds in Arkansas. The Crater of Diamonds is the only place in the world open to the public to find diamonds. It’s not an impact crater, it’s a diatreme. That’s  volcanic crater formed by an explosion from a buildup of gas. The explosion helped to bring diamonds to the surface. I identified the rocks in the crater as lamproite, and I found some beautiful butterscotch colored jasper. I also found some quartz fragments, and volcanic tuff. I expect the moon looks a bit similar to the crater, with the gray volcanic rocks and tuff. I didn’t find any diamonds, unfortunately. The area around the crater was a very pretty and humid forest environment though, so only the crater itself is at all like something found somewhere other than Earth.

Here are a couple of photographs from when I went rock collecting there:

I went to Sunset Crater Volcano National Monument just recently. I needed to see a volcano in order to compare and contrast with Io and Martian volcanoes like Olympus Mons. Most of my work is with Mars, but I’ve been doing research for some probes like Cassini and New Horizons, too. Some of the things I found showed me that Sunset Crater is not like Olympus Mons, since Sunset Crater is a cinder cone and Olympus Mons is a shield volcano. I climbed to the top of Lenox Crater, a cinder cone right next to Sunset Crater (which you’re not allowed to climb). It was a bit tricky, especially since rocks kept getting in my shoes. It seemed a bit strange to me that there are volcanoes in Arizona, but I figured out the answer. It’s a hot spot! There are no tectonic boundaries in AZ, but mantle plumes can happen anywhere. That’s something I study with other planets, too: I find something which seems strange and I figure out what caused it. It’s like a mystery! Exogeology ROCKS!

Here are a couple of photographs I took at Sunset Crater:

I just plain like traveling, and pretty much anywhere I go I can find something that ROCKS! I take little trips around the state, like to Sunset Crater, all the time. I enjoy visiting (and using) observatories, seeing geologic formations, and going to places that are completely non-exogeology related. Be sure to look at the Telescopes and Observatories page written by Zoë to see some of the telescopes I’ve used. I want to see all the most varied and interesting places I can! But I always go back to Arizona. I love it here. Besides, what better place could there be for doing what I love? Geology and astronomy both seem to lead me all over the globe, but the best place is back home in Arizona. It works out well for me!

Geography and Astrology

Posted by Petra on 8th April 2010 in Petra's Blog

Whenever I try to tell anyone what my job title is, nobody understands! I got so frustrated when I went to a geology conference and everybody kept asking me what my sign was! That’s not what I do! I’m pretty sure I’m a Virgo, but I have no idea what that means! The same thing happens when I meet astronomers. They keep assuming that I know stuff like the capital of Nebraska. I am not an astrologer and not a geographer, I’m an astronomer who is also a geologist.

Sometimes people just slip up even when they do know the difference. I had a pretty funny conversation with my grandparents when I tried to explain my job. Here’s pretty much how it went:

Grandpa: “I heard you’re an astronaut now, Petra. That sounds exciting.”

Me: “No, Grandpa. I’m not an astronaut at all, I’m an exogeologist.”

Grandma: “You’re an ex-geologist? I thought you just started this job, whatever it is. What are you doing now?”

Me: “Ex-o. Ex-o-geology is the geology of other planets.”

Grandpa: “Oh, geography!”

Grandma: “Have you made many maps dear?”

Me: “No, not geography. And mapmaking is called cartography.”

Grandpa: “Cartography? I’ve always wanted to draw cartoons. Can you draw Pluto?”

Me: “Grandpa, I’m not a cartoon artist. How’d we even get on that subject? I study things like volcanoes and craters. Geology. And I haven’t tried to draw Pluto. But there’s this spacecraft that’s headed to…oh, that Pluto.”

Grandma: “Oh, geometry, with the shapes!”

Me: “That’s mathematics, Grandma. I’m an exogeologist. That’s a combination of geology and astronomy. I look at space rocks.

Grandma: “Like the astronauts got from the moon?”

Me: “Yes! Exactly!”

Grandpa: “That sounds fun.”

Me: “Yes, it ROCKS!”

Grandma: “So when will you be going to the moon?”

I hope this helps you to tell the differences between exogeology and completely different jobs. My grandparents finally understood after that long conversation, and I can usually get people to at least say it right. People who just haven’t heard of exogeology, or even geology or astronomy, are just part of the job. I can’t blame them really, although it is annoying. For now, I’m Petra Stone signing off. Exogeology ROCKS!

Thinking About Martian Sunrises

Posted by Petra on 7th April 2010 in Petra's Blog

Yellow in the clouds
Pink and purple everywhere
Blue and bright orange sky

Cholla sunrise

I stayed up late last night working on a project that’s due really soon, and I stayed up so late that I saw the sunrise before I went to bed. It was beautiful! The sky got slowly lighter, and in the East the sky just above the horizon was peach and red. The sky above that turned slowly bluer.

I couldn’t help thinking of what the sunrise on Mars would be like. The Martian sky is red because of all the dust (with iron) in the air, but it can refract light in a similar way to Earth’s atmosphere. So, if I were on Mars right then, the colors would be reversed. The sky would be turning a brighter shade of red, with the sky in the horizon looking a bit blue or green. It would be amazing! Someday Martian colonists will get to see those sunsets and sunrises. I’m not sure I could get used to that though. I love my Arizona sunrises and sunsets!

The Search for the Unknown

Posted by Petra on 6th April 2010 in Petra's Blog

As I said before, part of being an exogeologist is getting to explore! From the bright Sun and its flares, to the outermost reaches of the Oort cloud, exogeologists get to see it all! The most exciting part is discovering new things about unexplored places.

Moons are some of the most diverse objects; some are like planets with volcanoes and atmospheres, and others are like asteroids with odd shapes and cratered surfaces. Titan has a thick and hazy atmosphere, which just makes me wonder, “What’s down there?”

Exogeologists like myself decided that Titan was a good place to explore. The Cassini-Huygens mission was and is set to explore and study Saturn and Titan. The Huygens lander detached from the Cassini spacecraft and landed on Titan. It found that there is water ice on Titan, the atmosphere is made of methane and nitrogen, and there even seems to be an underground ocean of liquid water! How cool! Literally, because Titan is so cold being so far from the Sun.

Speaking of being cold and far from the Sun, exogeology is also used for studying Kuiper Belt objects, or KBOs. The most famous KBO is Pluto, the famous dwarf planet. Just let me call it a dwarf planet for the purposes of this one blog, okay? :) Pluto and other dwarf planets are mostly made of rock and ice, like asteroids. We don’t have many good photographs of Kuiper Belt objects, so that’s one thing that I’d like to do in the future: take pictures of KBOs.

The most mysterious places to see are exoplanets, planets orbiting other stars! There are planets of all shapes and sizes out there, and exogeologists are finding more all the time! It rocks that there are other solar systems!

No matter where you look, you just might find something new and exciting! Exogeology ROCKS!

Exploring the Red Planet, Part Two, Mapping

Posted by Petra on 5th April 2010 in Petra's Blog

Photograph by NASA, found at

An important part of exogeology is exploring! Rovers on the surface and orbiters up above the surface both tell us a lot about the surface of Mars.

The Mariner spacecraft were the first to provide closeup photos of another planet. That’s really impressive. There were a lot of flybys and orbiters since then, and now NASA has an amazingly good photograph of how Mars looks from space.

The other part of mapping Mars is actually going down and looking at everything close up. Rovers and landers like Viking and the Mars Exploration rovers worked hard to do that. The Viking missions were the first successful Mars landers, and there’s a picture Viking 2 took in the photo gallery.

The Mars Exploration rovers, Spirit and Opportunity, have been exploring Mars for a lot longer than was expected, and I’m still receiving data! Someday there will even be astronauts going to Mars! Exogeology ROCKS!

Exogeology on Earth

Posted by Petra on 4th April 2010 in Petra's Blog

Yes, on Earth! Even though I mainly study other planets, Earth is a great place to see all sorts of geologic formations! Let me tell you about some great things to see on Earth that I’ve seen on the planets and moons.

Wait, craters on Earth? I thought there were only craters on the Moon! No, actually there can be craters on just about anything (as long as it has a solid surface; there aren’t craters on jovian planets). Earth has relatively few though, because smaller meteors burn up in our thick atmosphere. But some of the few meteor craters there are on Earth can be quite something to see! It’s almost like you’re on the moon! Barringer Crater in Arizona is the best example. Most craters on Earth are a bit less dramatic though, after being eroded for thousands of years. It gives you a great sense of what you’re dealing with to go and see a real crater.

Canyons are usually carved out by rivers, so why would they be in a list of exogeology related formations? After all, Earth is the only planet with such a large amount of water. Well, I’ve added them for a couple reasons. The first is that there are some formations that can best be described as canyons, even though they’re not made in the same way as the canyons we’re used to seeing. Take Mars’ Valles Marineris. It’s the largest canyon in the Solar System, but it’s a rift valley (a type of fault). On the other hand, there are channels on Mars that might have been made by the flow of water, like dried up riverbeds. I’ll talk about that more in a later post.

Ice fields are the only formation on this list I have yet to see. I’m actually going to be flying to Iceland for a few days to study glaciers. Because of this, posts over the next few days will be automated while I’m gone. Ice has been found all over: in comets and asteroids, on moons (Europa in particular), and on Mars. The gas giants are theorized to have icy cores. But not all this ice is actually frozen water. Europa might have water ice, but we don’t know for sure. Comets have water ice though. Water is so important on Earth that I think everything with water is exciting! Water is necessary for life, and that’s something I’d be thrilled to find. Could you imagine? I’m a huge science fiction fan, and that inspires me to think about big new scientific discoveries like life or undiscovered planets all the time. I’m getting off topic. Let’s get back to those awesome rocks!

Sand dunes can be found wherever there is sand, wind, and a dry climate. I went to the White Sands National Monument recently, and it was beautiful! As soon as you drove into the park there were sand dunes as far as you could see. The field of dunes was comparable to some of the dunes on Mars. An even better comparison is Utah’s Coral Pink Sand Dunes State Park. The reddish sand makes it feel as if you’re really on Mars. Dusty parts of deserts are also good places to look for dust devils, a common sight on the red planet.

Yes, I know, I was supposed to tell you about formations and not minerals. But minerals are important too! You need to look at the big things and the little things. There are a whole bunch of rocks and minerals that occur on Earth and also in space. One of my favorites is hematite. That’s an iron based mineral common on Mars. It comes in a few different forms. One form of hematite is red and rocky, and another is silvery gray and metallic. Iron in rocks is what makes Mars red! Moon rocks are pretty cool too; a rock from a lunar mare is made of the same thing as lava rocks on Earth! That ROCKS! 😉

Volcanoes have been found on Mars, Venus, Mercury, and Io. And on Titan there are cryovolcanoes! There are active and inactive volcanoes all over Earth that are fascinating to see in person. I try to go to as many volcano sites as I can during field research.

Plate tectonics is the process that makes the continents move. They spread apart like at the mid Atlantic ridge, and move under each other (called subduction) in places like Japan and the Aleutian islands of Alaska. The Earth’s surface is changing! And what’s more, there used to be plate tectonics on ancient Mars, and there still are on Titan!

Strata is just another term for rock layers. There are strata everywhere! That’s because rock layers can form all sorts of ways, like an ocean depositing sand on a beach or volcanoes erupting new lava flows. Strata can show a lot about that geographical area’s past. One time I looked at the strata in the Grand Canyon to figure out what order things happened in. I could easily see that the layers on the bottom formed first, then were tilted, and then that surface was eroded flat. More layers formed, and finally the Colorado River eroded the rocks away to create the Grand Canyon! How cool is it that you can tell what was happening for millions of years just by looking at rocks? I say that ROCKS! I do the exact same sort of thing when I look at strata from anywhere.

Can you believe so many of the same things happen on Earth that happen on other planets? I think it’s amazing. Exogeology ROCKS!

A Day in the Life of an Exogeologist

Posted by Petra on 3rd April 2010 in Petra's Blog

Want to know just what an exogeologist does all day? Well, maybe I can show you just how cool this job is!

When I start working for the day, the first thing I do is see if I’ve received any new data. This could be from other exogeologists or from different spacecraft. I sometimes even get rock samples to analyze. If I do, I’ll take them to the lab. There I’ll test the sample to find out its composition.

There are lots of tests I can do. I can test minerals for streak, hardness, cleavage or fracture, and of course note the color and shape of the crystals. For example, let’s say I was given a mineral sample to identify. It has cube-shaped crystals, and is gold in color.  I rub it on a streak plate, and the streak is greenish black. I’ll scratch it with various tools and deduce that its Mohs hardness is 6. When I break it with a hammer, the place where it breaks is conchoidal (a distinctive curved shape). All these things put together tell me that my mineral is pyrite. If I were given a rock sample, there are a lot of various tests I could do to classify a rock, like cutting a thin slice and looking at it under a microscope.

  • Here’s a quick tip about classifying rocks: If it has bubbles, it’s got to be igneous. Those bubbles are called vesicles, and they’re made when gas bubbles are trapped inside a rock as it cools.

Some days I’ll go to an observatory to do research on a planet. I need to reserve the telescope ahead of time usually. When I used a telescope at the Kitt Peak observatory, I had to reserve the telescope years in advance! But it was worth it. I got some great photographs of Jupiter and a comet during my time at the telescope. I’ve used lots of different observatories, and it’s always been productive. Well, except for that one time when it rained… I had to cancel. I must have been really unlucky that time. But that’s the trouble with astronomy; sometimes you just have to wait for another clear night. At least every other time went well.

Other days I’ll get information from a spacecraft or lander! That’s my favorite part! Once, I got to help with the LCROSS mission and interpret data from the spectrometer. The goal was to find water, and we did! That ROCKS! Since Mars is my specialty, I’ve been receiving data from the Mars Odyssey orbiter, which maps the amount of chemical elements and their distribution. I loved working on that. Maybe I’ll get to interpret data from the upcoming Mars Science Laboratory (MSL). Part of the MSL’s mission will be to study the geology of Mars.

Exogeology ROCKS!

Exploring the Red Planet, Part One, Water

Posted by Petra on 2nd April 2010 in Petra's Blog

Photograph by NASA, found at

I’ve been getting  some data from my favorite planet–Mars!

Mars being researched right now by people looking for water; traces of it in the past, and water today.

Water leaves traces in a bunch of ways. There are minerals that can only form when there’s water around, and there are geologic formations that water can form. I look for both kinds of evidence for water.

Some of the minerals I’ve found that require water are hematite and carbonates. Hematite can form without water, as it has all over Mars. But what I found that shows there must have been water are called hematite spherules. These are tiny spheres of hematite, embedded in a martian rock. They’re more commonly called “blueberries”. They could have formed as concretions, which only form when there’s liquid water, but the blueberries still don’t definitively prove the existence of water on Mars. There are other ways they could have formed, like as martian tektites.

There are other minerals that can only form with water, such as carbonate minerals like calcite and limestone. The Spirit rover has found evidence of carbonates in the Gusev Crater. You know what this means? Water! Rovers rock!

Channels on Mars were discovered a long time ago, yet exogeologists are still debating how they were made. One theory says that the channels are riverbeds, so they would have been made by water. But another says that the channels were made by lava. I’m still trying to decipher the history of the channels. But I’m hopeful that water had something to do with it.

The Phoenix rover took part in the search for water. It looked for water as part of its mission, and actually found some! I’ll say it again, rovers ROCK!

I’ve found lots of evidence for water on Mars, but I need more proof before I can say for sure that any large amounts of it existed on Mars. I think that “follow the water” is a great goal for the Mars program. I’ll have to keep searching!

Is Pluto a Planet?

Posted by Petra on 1st April 2010 in Petra's Blog

I figured this would make an appropriate April Fool’s Day post… :)

Whether Pluto is a planet or not is a topic that’s had a lot of controversy since the term “planet” was defined. According to the new definition, a planet must: (1) orbit the Sun, (2) be basically round, and (3) have “cleared the neighborhood” around its orbit. Pluto fits all the requirements except for having cleared the area. Since it’s not a satellite of something else, it’s now considered a dwarf planet.

Pluto has been considered a planet for long enough now though that many people are upset by reclassifying Pluto as a dwarf planet.

I wonder if getting a better idea of what Pluto is like will help settle the debate? The New Horizons probe’s mission is planned to explore the Kuiper Belt and Pluto. It’s scheduled to arrive on July 14, 2015, making a flyby. That’s pretty soon considering how long of a mission it is to get there! I can’t wait to find out what it sees. Meanwhile, the Hubble Space Telescope got some good photographs of Pluto changing seasons, and New Horizons made a flyby of Jupiter.

What do I think? I believe that dwarf planets should be considered a specific type of planet, like terrestrial planets and gas giants. They should be considered just as important as any other planets. But there’s a good reason for changing the definition of “planet”; there are so many dwarf planets still being discovered that the number of planets in the Solar System would be hard to keep track of. Besides, we need a way to distinguish between planets and asteroids, and dwarf planets are somewhere in between. No matter what the definition of planet is though, Pluto is still an important member of the Solar System.