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Planetary Science

¨  Why is Mars red?
¨  Can I find treasure with the GRS?
¨  What is the correct way to give coordinates on Mars?
¨  Is Pluto a planet?
¨  Jane Luu's discovery of the Kuiper Belt
¨  What causes the dark spots on Mars to change with the seasons?
  What type of schooling must you have to become a planetary geologist?
  Time till results return for rocks sent to Schoolhouse Rocks program
  Are results from the Schoolhouse Rocks program released yet?
  How does hematite prove that water was once on Mars?
  My rock is too large to send to the Schoolhouse Rocks project
  Will you return rocks sent to the Schoolhouse Rocks geology project?

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Why is Mars red?

ANSWER from Roger Herzler on 1 October 2005:
That is due to iron oxide, which is also called rust.  The Martian soil has a high iron content and that has rusted over the years to produce the oranges and reds that are so prominent on its surface.  Of course, this iron oxide had to form and that is good evidence that Mars probably had at least water vapor in its atmosphere.

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Can I find a treasure with the GRS?

ANSWER from Michelle Mock on 28 September 2005:
If you are a scientist and you are talking about the the Gamma Ray Spectrometer aboard the Mars Odyssey spacecraft, the answer is: ABSOLUTELY!

The GRS has detected a wealth of information!  According to the instrument website, "Mars is richer in volatiles, which is indirect evidence for the planet having had lots of water in the past."

Michelle Mock
Imagiverse Educational Consortium

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Looking at different maps of Mars I noticed that some have the longitude increasing towards the West and on others it increases towards the East.  What is the correct way to give the coordinates of a point on Mars?

ANSWER from Stephanie Wong on 27 September 2005:
The "prime meridian" of Mars runs through the middle of the small crater Airy-0, which is located in the larger crater Airy.  Traditonally, the longitudes were numbered to the East (0° to 360°W), the coordinates being based on the "planetographic" system.  These coordinates were in reference to the surface of the planet.  More recently, it has been the trend to use a "planetocentric" (with reference to the center of the planet) system with coordinates going east.  Both systems are approved by the International Astronomical Union.  But, any Mars map created since 2002 will probably been planetocentric going east.



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Is Pluto a planet?

ANSWER from Stephanie Wong on 25 May 2005:
Whether a celestial object is a planet is a question of preference.  Roughly-speaking, a planet is a few thousands of kilometres in diameter, with enough gravity to make it spherical, orbiting a star, but not large enough to have its own nuclear reactions.  The planets of the solar system are believed to have formed where they are today, accreting from the materials in that part of the solar system.  Pluto, however, has features that indicate it is part of the Kuiper Belt, objects in our solar system that orbit in an area that extends out from Neptune.  These are generally icy bodies that are a source for comets.  The differing features of these from planets is that they are usually small and have eccentric orbits.  In earlier times, these Kuiper Belt objects were too small and far away to be seen.  The large bodies that we could see, we called planets.  The ones in the inner solar system are rocky and not too big. The ones farther away are gas giants, very large and made largely of hydrogen and helium gas.  Pluto was the last of the 9 planets to be discovered.  Being a tiny body of rock and ice, it certainly does not fit the characteristics that the other outer planets have.  But, seeing that it was the "next" body out from Neptune, it was natural at the time to designate it a planet.  Since then, however, we have begun to find other objects of similar size and make-up to Pluto, and that they are part of this new class called Kuiper Belt Objects.  If these comet-like bodies are similar to Pluto, then one might beg the question why not call them planets as well?  So, the debate of whether Pluto is a planet is born.  If we keep calling it a planet, then it and possibly many other yet-to-be found bodies could be called planets.  If we do not call it a planet, and just a big Kuiper Belt object, then our traditional notion of 9 planets is gone.  Since we do not have a definite definition of a planet, it is a question of preference.  There have been attempts by people to create black-and-white criteria for something to be called a planet, but again, that means we will arbitrarily choose sides.  It is like saying whether a piece of rock is a piece of sand or a pebble.  Believe it or not, Pluto is now firmly established as a Kuiper Belt object, and it doesn't look like people are ever going to "dethrone" it as the 9th planet anytime soon.

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Hello Dr. Luu.  I am in 8th grade at the Jefferson Middle School in Wisconsin.  We are studying you and what you discovered.  Can you tell me what you discovered?

ANSWER from Bonnie Walters on 9 September 2004:
I have portrayed Dr. Luu for two years through our school's Women in History program.  I also met and interviewed her for Imagiverse.  She is a fascinating person to study and I'm glad your class is doing so.

Dr. Luu discovered the first Kuiper Belt Object (KBOs) with her colleague, David Jewitt, in 1992.  She was very, very excited to make this discovery.  They had searched for 5 years!  Think of it... 5 years with no results to show.  It took incredible patience and perserverence to keep on looking.  People came up to them saying, "There's nothing out there, you're nuts to keep looking."  Since then, at least 500 KBOs have been found.

Here are some links for information on the Kuiper Belt.  The first is David Jewitt's Kuiper Belt page:

NASA's Solar System Exploration Page will give you more information and resources:

Finally, I always use Bill Arnett's, The Nine Planets for starting out any research:

OK, for Dr. Luu's information, of course you can use our interview at Imagiverse:

Here's a link from an online enclyclopedia:

This is a referral to her in a Science Fair Project Bank:

Good luck on your research!

Bonnie J. Walters
NASA/JPL Solar System Ambassador

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What causes the dark spots on Mars and what causes the dark spots to change with the seasons?

ANSWER from Stephanie Wong on 11 July 2004:
Mars has high winds that often cause vast amounts of dust to be picked up into the air.  These dust storms can grow to continental sizes that sweep over the entire planet.  Therefore, surface features as seen from a telescope can vary widely within a matter of weeks (or days!).  Depending on the season, dust storms may become more frequent, and thus there might be some "spots" that may seem more prevalent at a given time of year.

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What type of schooling must you have to become a planetary geologist?  Do you need to have a certain degree, and how long would it take to receive the degree?

ANSWER from Chris Herd on 23 June 2004:
I recommend starting with a Bachelor of Science degree in geology.  Even though most universities, especially in Canada, do not offer planetary geology courses in their geology programs, the way we understand the geology of other planets is by first understanding our own.  So the more geology of different types that you are exposed to (igneous, sedimentary, metamorphic, groundwater, glacial, mineralogy, etc.), the better.

Once you get a B.Sc. (which takes about 4 years), then it's time to find a university that offers a graduate program in planetary geology.  This would involve a Masters of Science (M.Sc.), which typically takes 2 to 3 years.

At this point you will probably know what kind of geology you like best, and so you want to look for ways to do that kind of geology on other planets - volcanoes on Mars, for example.  You will have to apply to the programs, and find out what different profs are working on, because you will have to do a research project for the Masters.  You should ask yourself, Do I want to work on data from missions?  Or do I want to work on rocks (meteorites)?  This will help you decide what schools to apply to.

After the M.Sc., then you will have to decide whether you want to get a Ph.D.  This involves a project that is bigger in scope than the M.Sc., and so takes longer - typically 4 years.  Whether you do a Ph.D. depends on what you want to do: a Ph.D. means you are a Dr. of planetary geology, so you could get a job as a university professor (teaching and doing research), or as a government scientist (doing research) for NASA, for example.  A Masters wouldn't allow you to work as a prof, but more jobs might be open to you, whether it's in government or one of the up-and-coming space companies.

So by the time you get a Ph.D., you might have been in school for ten years after high school.  But if you ask me, it's worth it.

Chris Herd
Assistant Professor of Mineralogy
Department of Earth & Atmospheric Sciences
University of Alberta, Canada

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We sent a rock in several weeks ago and we were wondering approximately how long it takes before it shows up on the web page and how long it will take to get the certificate in the mail.

ANSWER from Michelle Mock on 6 March 2004:
I just came back from an Mars Educator Workshop at Arizona State University and this subject came up.  The Schoolhouse Rocks project has received some 2,500 rocks from around the world and more are coming every day.  They are working as quickly as they can to analyze rocks and post the information on the web, so it is hard to estimate a time-frame for you.  Keep checking:

They are posting a variety of different rocks from different places around the world.  You might see something similar to your rock in the meantime.  While you wait, you could try to make some predictions about how your rock's spectra will compare with other similar rocks.

Phil has been signing all the certificates himself so try to be patient.  Phil and all the other Mars scientists are getting very little sleep lately, trying to keep up with all the fascinating discoveries of the two rovers.  It is an exciting and very busy time for all of them!

When you get information about your rock, please write back to Imagiverse and share what you learned!  We want to know!

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I realize the Schoolhouse Rocks program most likely is inundated with enormous piles of rocks as children (including my own) are sending treasures from all over the world.

For my students who are participating in this program, the big question is how soon will information be posted on the web and or how soon are we likely to hear back regarding the composition of our non-Mars rocks.  Maybe an update could be added to the JPL site describing this program so this question could be answered for all the kids and classes that are participating.

As we patiently wait, keep up your excellent work of inspiring the next generation of planetary scientists.

ANSWER from Michelle Mock on 20 February 2004:
It is great to hear that your students are participating in the Schoolhouse Rocks project!  Samples from around the world have already begun to be posted at:

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On the matter of grey
hematite or the coarse-grained hematite, found on Mars, how does this prove that there once was water on the planet?  Hematite is a iron oxide mineral usally found near bodies of water on Earth. However, the strong depletion of iron on Mars coupled with the place it was discovered (close to one of the poles) suggests that the cold frozen CO2 could have enriched the iron with oxygen, release the frozen CO2 into the atmosphere and the bombardment of nitrogen could have created these rocks.

ANSWER from Michelle Mock on 28 January 2004:
The grey hematite on Mars is located in Terra Meridiani, on the equator of Mars (very close to 0 latitude and 0 longitude).  It was not discovered near the poles.  The existence of hematite in this area does not in itself prove that there was water on Mars.  However, since the time that hematite was first discovered (with the Mars Global Surveyor spacecraft's TES instrument), the Odyssey spacecraft has found clear evidence of water ice on the planet.  See:

On Earth, grey hematite is formed in water.  Using that as an analog for Mars, scientists believe that hematite on Mars must have also formed in long standing water.  That is what they hope to confirm.

The rover opportunity has now landed at the site where the hematite was discovered from orbit.  Scientists are very excited about this because now they are at a place where they will be able to find out a lot more and test some of their hypotheses.  At Meridiani Planum in Terra Meridiani, Opportunity has already found some incredible things that have never been seen before on Mars.  The surface is almost devoid of rocks and the soil is unlike anything previously seen on Mars at previous landing sites.  There are layered rocks close to where the rover has landed and those layered rocks will be investigated as soon as the rover rolls off the landing platform.

So much science is happening at Mars, I cannot give you a more precise answer to your question.  Follow the rovers as they investigate Mars through updates at http://marsrovers.jpl.nasa.gov/ .  Check out the press briefings on NASA TV (http://www.nasa.gov/).  I am sure there will be all kinds of new and exciting information coming at us over the next several months.

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I have a rock for you to analyze at the Schoolhouse Rocks program but it is larger than 6".  How can I break it to send you a smaller piece?  When I throw it at the ground it just chips.

ANSWER from Michelle Mock on 17 January 2004:
We asked Sheri Klug from ASU Mars K-12 Education Outreach and she told us that larger rocks can be sent to the Schoolhouse Rocks program at the sender's expense, or you can choose a smaller rock.  Neither Sheri nor Imagiverse suggest you try to break rocks on your own.  Please don't throw rocks on the ground or attempt to break them if you do not have the training to do so.  You are risking injury to yourself and others and we don't want to see anyone get hurt!

If you have a college or university nearby, you may be able to find a geologist who is willing to break your rock for you.  If you do, you might want to write down what the geologist tells you about the rock and then compare that information with the analysis you get back from ASU.

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I found a rock several years ago that fascinated me.  This stone is extremely dense, non magnetic, and has what looks like the remains of a molten crust on it's surface.  When I look at it, I think,"Mars!"  I'd hate to part with this unique stone, but I'm very curious as to its composition.  If I send the stone to Dr. Phil Christensen at the Mars Space Flight Facility of Arizona State University, would it be possible for the stone to be returned after analysis?

ANSWER from Sheri Klug on 16 January 2004:
Thank you for your interest.  I would suggest, in your case, that you take your rock specimen to a university near you for examination.  You could contact the geology department within the university to find out who would be the appropriate contact.  The Schoolhouse Rocks program is not set up to return special samples.

Sheri Klug
ASU Mars Education Program

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Last Updated:
15 October 2005

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