Posts Tagged ‘solar system’

Hang On, Philae!

Posted by Zoe on 12th November 2014 in Exogeology, Main Page

Could you land on a comet? Normally, the force of gravity holds a lander to the surface of a larger body, like a planet or a moon. The less mass an object has, the less gravity pulls you toward it. Comets are small. Gravity won’t do you a lot of good, so you would need to hang on tight.

That’s what Philae is doing. The European Space Agency (ESA) sent a spacecraft named Rosetta to Comet 67P/Churyumov–Gerasimenko, and Rosetta carried a dishwasher-sized probe called Philae, which was to land on the comet. The comet is about the size of a mountain, which may seem big, but think how small a mountain is in comparison to a planet! The Philae lander had to come equipped with screws in its feet and harpoons to grasp the surface.

Philae detached from Rosetta early this morning (09:03 GMT, 02:03 Arizona time) and began its descent. Curiosity had seven minutes of terror landing on Mars, but Philae took seven hours from separation to landing. At 16:03 GMT, ESA heard from the little lander. Philae had successfully touched down! But remember those harpoons? They didn’t work. Philae is clinging on by the screws in its feet, but it’s there.

Philae's view of the comet. Courtesy ESA.

Philae’s view of the comet. Courtesy ESA.

Philae will photograph and analyze the comet for the next two and a half days. If it gets enough sunlight for power, it can keep going for an “extended phase” lasting until March 2015—four whole months of comet science! After that, the comet will be closer to the sun and Philae will probably be too hot to work. Comet 67P/Churyumov-Gerasimenko will also heat up as it gets closer to the sun, so we might be able to see it active, with ices sublimating (turning from solid to gas) and creating the tails of gas and dust comets are famous for. Maybe the most exciting reasons to study a comet up close are that we get to see way, way back in history, and we get to learn about the far, far off outer solar system. Here’s wishing Philae just the right amount of sun.

Is landing on a comet even possible? Yes, but it’s tricky. Hang on tight, Philae!

More information:

Rosetta main website

Rosetta blog

Comet 67P/Churyumov-Gerasimenko

Timeline, instruments, and and landing details from Emily Lakdawalla

Bad Astronomy’s coverage, part one and part two

NPR story

ESA’s photographs


Exogeology ROCKS! Episode 11

Posted by Zoe on 2nd July 2014 in Exogeology, Main Page

In this episode of Exogeology ROCKS! I get to answer a few viewer questions:
How are planets made?
Are there gemstones on other planets?
Where is the closest black hole?

Good questions! Here are my best answers.

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!

Exogeology ROCKS! Episode 5

Posted by Zoe on 15th April 2012 in Main Page

I’m pleased to announce the fifth episode of Exogeology ROCKS! In this episode, we hear from Professor Geoff Marcy, Professor of Astrophysics at University of California, Berkeley. Professor Marcy tells us about the search for exoplanets—planets which orbit around other stars.

How are exoplanets found? Are there other Earth-like planets? Could there be aliens on them? Find out the answers to these questions and more in Exogeology ROCKS! Episode 5.

You can watch the previous four episodes here.

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.

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!

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!