Posts Tagged ‘planet’

More like Earth than Ever: Kepler-452b

Posted by Zoe on 2nd August 2015 in Exogeology, Main Page

Are there any other Earths out there? Is there another planet like ours, maybe one where we could live? One goal in the search for exoplanets, planets orbiting stars other than our own sun, is to find Earth-like planets. NASA’s Kepler mission just found the closest match yet!

This planet is called Kepler-452b. It’s not exactly a catchy name, but it’s informative: the name tells us the planet was found by the Kepler mission, and gives a number to the star system and a letter to each object. This planet got the letter “b” because it’s the second object found in the system, after the star.

What does it mean to say Kepler-452b is the closest match found to Earth? It’s fairly close in size to Earth, its sun is a similar star to ours, and it’s in what we call the habitable zone.

Artist's concept of newly-discovered exoplanet Kepler-452b. Image Credits: NASA Ames/JPL-Caltech/T. Pyle

Artist’s concept of newly-discovered exoplanet Kepler-452b. Image Credits: NASA Ames/JPL-Caltech/T. Pyle

A planet in its star’s habitable zone? We’ve found a few, but that’s still pretty cool—or rather, just the right amount cool for liquid water to potentially exist on the planet. This is the definition of the habitable zone. Without liquid water, we wouldn’t find a planet habitable, and in order to have liquid water, a planet would need to be warm enough for water not to freeze and cold enough for water not to boil. The temperature on the surface of a planet depends largely on its distance from its sun. The closer they are, the warmer the planet is. However, being not too close to and not too far from its star doesn’t tell you everything about a planet. It could be large or small, and made of all sorts of different materials. It could be dense and rocky like Earth or Mercury, or it could be fluffy and gaseous like Jupiter or Neptune.

So, being in the habitable zone isn’t enough to make a planet habitable. It would be hard to live on a planet without a surface you could stand on, so if you’re looking for a new planet to inhabit, pick out a rockier one. The size of the planet would also make a difference. The smaller a planet is, or even a moon for that matter, the harder it is to hold on to an atmosphere. Less mass means less gravity, which means less pull on the gases which make up an atmosphere. Gas particles can fly away over time until there are hardly any left. More mass means more pull, so it’s harder for particles to escape. So, more massive planets are more likely to have a thick atmosphere.

What about Kepler-452b? Where does this recent discovery fit in? It’s 60% larger than Earth in diameter, which is actually pretty close in size. For comparison, Kepler-452b is about 1.6 times the diameter of Earth, and Earth is about 1.9 times the diameter of Mars. Kepler-452b is considered a super-Earth in size. That’s what we call planets near in size to Earth, but on the large side.

While we know all this about Kepler-452b, there is also a lot we don’t know. We don’t know exactly what it looks like. We don’t know how close it is to actually being habitable. We certainly don’t know its whole story—yet. As technology improves, telescopes get better, and we think up cleverer ways to learn more about far-off places, we keep finding out more and more about distant worlds like this one.

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!

Speech on Why Exogeology ROCKS!

Posted by Zoe on 28th July 2012 in Main Page

You’ve heard that exogeology rocks, but just what is exogeology? Why does it rock?

I recently gave a speech on just that: Why Exogeology ROCKS!

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!

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

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.

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!

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!

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.

The Solar System

Posted by Petra on 30th March 2010 in Petra's Blog

You’re probably wanting to know, just what is it that exogeologists do? What do they look at? Why? And what do they find there? Well, let me start by giving you a tour of the Solar System.

The Solar System is a big place, and there’s still a lot we don’t know about it. But we do know where to start looking. We’ve found eight planets, some dwarf planets, comets, and numerous asteroids.

In our solar system we have, in order from the Sun: Mercury, Venus, Earth, and Mars, the inner or “terrestrial” (Earth-like) planets. These are all rocky planets that have similar geology to Earth. Then there is the asteroid belt, a ring of asteroids (big chunks of rock in a ring between the inner and outer planets) orbiting the Sun. And next out there are Jupiter, Saturn, Uranus, and Neptune, the outer or “jovian” (Jupiter-like, the gas giants) planets. And much further out, there is the Kuiper belt, a ring of asteroids and dwarf planets like Pluto and Eris.  There also comets, which have orbits that take them very far from the Sun for years, and then for a short time bring them into the inner solar system. Comets are made of ice and rock, and are sometimes called “dirty snowballs” because of their composition.

And what about the Moon? Well, exogeologists also study Earth’s moon, as well as other planets’ moons. The Moon is covered in craters, made by meteorites (asteroids and other space rocks that hit another object). There are dark areas on the moon that don’t have many craters though, and those are called maria. A mare is a place where a large meteor hit and molten lava seeped up through cracks made by the impact, which then cooled to become one of the dark maria we see on the moon today.

Some of the other planets have moons too, in fact, Jupiter has 63 and Saturn has over 200! Moons can be very different from each other. Some have atmospheres (like Saturn’s Titan), and some are just asteroids and are strange shapes and have lots of craters (Like Mars’ two moons, Phobos and Deimos).

There are lots of planets to explore, and that’s what I do! I like finding out new information about everything in the solar system!