Universe Today

March 24, 2009December 24, 2015 by Ian O'Neill

Mars Express Finds Rusty Evidence to Red Planet’s Wet Past

Aram Chaos region of Mars as imaged by the OMEGA instrument on board ESA's Mars Express (ESA)

[/caption]

The picture of Mars’ wet history is gradually becoming more comprehensive. This time, new observations by the European Space Agency’s Mars Express satellite have revealed concentrations of sulphates and ferric oxides in the 175 mile-wide (280 kilometres) Aram Chaos region, an ancient crater basin. Although the true nature of these compounds remain elusive, it could reveal past atmospheric precipitation, otherwise known as rain and snow…

Artist's impression of Mars Express (ESA)

It is the mother of all planetary jigsaw puzzles, piecing together the geological and atmospheric evidence to better understand Martian history. Although we have hypothesised for some time about the presence of water in the regolith, it wasn’t until the Mars Phoenix Lander touched down in the Martian arctic in May 2008, dug a trench and detected water ice that we had proof of the existence of water on the surface. Observations made by the lander helped too, as it saw broken, regular shapes of a permafrost layer in the surrounding landscape (suggesting quantities of ice below the surface), and there is tantalizing evidence that liquid water brines may also exist at very low atmospheric pressures (with the help of perchlorate salts). It doesn’t stop there, Phoenix also confirmed that atmospheric ice may get large enough to fall as snow in arctic regions.

Now, from Mars orbit, the ESA Mars Express has used its OMEGA instrument (a.k.a. the Visible and Infrared Mineralogical Mapping Spectrometer) to map an equatorial region to gain clues about Martian history. The results beamed back to Earth are both exciting and a little peculiar.

It is well known that Mars is covered in ferric oxides, contained within the dust that blankets much of the planet. This is the compound that gives Mars its characteristic red hue. However, looking deep into the crater of Aram Chaos, there is a four-fold increase in the spectral signature of ferric oxides. This has led ESA scientists to believe this is indicative of a specific concentration mechanism. On Mars, ferric oxides are usually found with sulphates, but in this location, strong winds have blown away the lighter sulphates, leaving the ferric oxides behind, allowing the Mars Express spectrometer to measure the high concentrations.

On Earth, we commonly know ferric oxide as rust. Rust forms when there is a reaction between iron and atmospheric oxygen, facilitated by the presence of water.

“They have accumulated in dark deposits at the bottom of sulphate cliffs,” said Stephane Le Mouelic of the University of Nantes in France. This suggests that the ferric oxides have been uncovered by eolian (wind) erosion before being eroded themselves, dropping to the bottom of sulphate enriched cliffs. Driven by Martian winds, the ferric oxides went on to enrich dunes in the region.

Opportunitys blue berries, or ferric oxide deposits (NASA) — Opportunity's blue berries, or ferric oxide deposits (NASA)

It turns out the ferric oxide accumulation processes are not exclusive to Aram Chaos. According to observations by Mars rover Opportunity, there are ferric oxide concentrations in Meridiani Planum about 1000 km (600 miles) away. Also, Valles Marineris, about 3000 km (1900 miles) away appears to have similar deposits.

This is an intriguing study and it is possible that other regions will show similar accumulation processes, but are covered by other material. “OMEGA is sensitive to the first hundreds of microns of the surface. So, a layer of Martian dust just one millimeter thick will hide the signature from us,” said Marion Masse, also of the University of Nantes. Although OMEGA is restricted to hunting for ferric oxide deposits only in regions where rock is exposed due to wind action, this could be an important method to seek out how and where ferric oxides got deposited. Although scientists are keeping an open mind as to how these deposits formed, it could be due to atmospheric precipitation (rain or snow) or it could be down to volcanic ashes or glacial deposits.

Source: Astronomy.com

March 24, 2009December 24, 2015 by Tammy Plotner

International Year of Astronomy Live Telescope

Notice something new here on Universe Today? That’s right… There’s a new International Year of Astronomy logo in the right hand column and a video. If you’re wondering what “Galactic TV” is all about, then step inside…

The International Year of Astronomy 2009 is a global effort initiated by the International Astronomical Union (IAU) and UNESCO to help the citizens of the world rediscover their place in the Universe through the day- and night-time sky, and thereby engage a personal sense of wonder and discovery. Here at Universe Today, we believe in those goals set forth by the IYA founders, so we teamed together to give our readership something you’ll find nowhere else on Earth (or the web) – a live view of the Cosmos via a remote telescope.

Thanks to Internet magic, Universe Today, Northern and Southern Galactic and Warren Rupp Observatory have teamed together to base a small telescope in the southern hemisphere and broadcast a live television image of what the telescope is seeing through the eyepiece camera. Around 09:00 UT, (which is local dark time in Central Victoria, Australia) broadcasting will begin – and will continue non-stop until either daylight or clouds happen. If you tune in and there’s no image, that can only mean one of three things – it’s either clouded out, it’s daylight, or the connection has reached its limits of viewers and you’ll just have to try back in few minutes.

If you’ve ever wondered what southern sky gems look like, now is your chance to see them just as they appear at the moment. All you have to do is click on “LIVE Remote Cam” below the IYA logo. While these aren’t Hubble views, the small telescope and Stellacam are providing very clear looks at objects like you’ll see on the small screen replay of Omega Centauri! Check out this larger version…

If you miss out on a live broadcast of the International Year of Astronomy telescope, don’t despair. Each time the telescope is in operation we’ll take a video recording of each object, add some Wikipedia information and store it in the IYA “Live” Telescope Library! Broadcasts from the telescope will continue for the entire 2009 year and will feature everything from galaxies to double stars.

The International Year of Astronomy 2009 is a global celebration of astronomy and its contributions to society and culture and marks the 400th anniversary of the first use of an astronomical telescope by Galileo Galilei. The aim of the Year is to stimulate worldwide interest, especially among young people, in astronomy and science under the central theme “The Universe, Yours to Discover”. What better way to celebrate than to enjoy this virtual telescope and discover the beauty with your own eyes?

Rock on….

March 24, 2009December 24, 2015 by Nancy Atkinson

Follow the Lunar and Planetary Science Conference at AC LIVE

Dr. Pamela Gay from Astronomy Cast is attending the Lunar and Planetary Science Conference this week and is blogging from the conference. You can catch her updates at Astronomy Cast Live . She’s already posted some very interesting reports on how the Martian north pole region — where the Phoenix lander sits — may currently be habitable, and the debate on how planets should be classified. Great stuff — check it out!

March 24, 2009December 24, 2015 by Nancy Atkinson

Bathroom Works, Power’s On: ISS Now Ready for Crew of Six

Can we get a quote on how it feels to finally be working?

[/caption]
The International Space Station’s complex water recycling system which includes a balky urine processing assembly, now appears to be working in fine fashion after the ISS/shuttle crew installed a new distillation centrifuge unit over the weekend. After initial tests and checkout, (including a sound test to record what types of vibrations the unit was creating – hence the microphone), astronauts ran a water sample through the system and no problems were reported. “We had great success with the operation of the urine processor assembly,” said Lead Flight Director for the mission, Kwatsi Alibaruho at the mission status briefing. “We were able to perform the full processing cycle of about 70 pounds of urine that has been washed through the urine processor and has been converted into clean water. So we’re very excited about that.” Having a working water/urine recycling system is critical for NASA’s plans to increase the station crew size from three to six in late May.

The water recycling system converts water collected through condensate and urine into potable water for drinking, crew hygiene and oxygen generation. The urine processor was installed during a shuttle flight last November, but the vacuum distillation assembly centrifuge malfunctioned and eventually failed.

Alibaruho said the new assembly is performing well with no anomalies so far. “In fact, we got a report from the crew that all-around performance of that unit was much better from a vibration perspective and an acoustic perspective,” he said, “so that gives us some indication that that new distillation assembly that we flew up is in good shape and quite healthy. So we’re very excited about that activity today.”

The STS-119 shuttle crew will take four samples of processed water back to Earth to be analyzed by specialists to see if the entire system can be cleared for use by the crew.

Astronauts Steve Swanson and Ricky Arnold connected bolts to permanently attach the S6 truss segment to S5. Credit: NASA

The other consumable need for increasing the crew size, as well as increasing the amount of science that can be done by a bigger crew is more electrical power. That need was met with the installation of the S6 truss and the last set of solar arrays. During the three mission EVA’s, astronauts plugged in power and data connectors to the newly installed S6 truss, prepared a radiator to cool it, opened boxes containing the new solar arrays and deployed the Beta Gimbal Assemblies containing masts that support the solar arrays.
One problem arose, however, that two spacewalks couldn’t fix. An external cargo carrier mechanism failed to deploy. This has no immediate impact on space station assembly, Alibaruho said. The jammed carrier, intended to support pallets carrying spare parts and other equipment will likely be repaired by the station crew or astronauts on an upcoming assembly flight.

March 23, 2009December 24, 2015 by Nancy Atkinson

Former Astronaut To Take Social Media to New Heights

Scott Parazynski during his attempt to climb Mt. Everest. Credit: OnOrbit.com

[/caption]
In 2008, astronaut Scott Parazynski came within 24 hours of reaching the summit of Mt. Everest when a painful back injury forced him to abandon his climb. Now, Parazynski is on his way back for another attempt at summitting the world’s highest mountain peak. But this time, he wants to take the rest of the world with him. If everything works as planned, Parazynski will blog, podcast, vodcast and more during the climb, and he even wants to Twitter from the summit. “I want to tell the story of exploration here on Earth and the corollaries it has with space exploration,” Parazynski told Universe Today before he left for Kathmandu, Nepal. “They are both very hostile, unforgiving environments that require a lot of training, a lot of gear, and a lot of thought. The intent is to share the story with as many people as we can, particularly young people.” Parazynski and his team have even agreed to take questions from readers of Universe Today and answer them during their climb.

Parazynski has teamed up with the Challenger Centers for Space Science Education and the Boy Scouts of America to offer educational activities in association with his trek, and is working with various scientists to do field science along the way.

“We’ll be collecting data for astrobiologists, looking for extremophile life,” Parazynski said. “If you understand how extremophiles live, you might be able to understand how life may have once evolved on Mars, or may still exist on Mars.”

As an astronaut, Parazynski was part of 5 space shuttle missions; his last mission to the International Space Station included a daring repair of the ISS’s solar panels.

Parazynski will also be testing some NASA-derived hardware, taking along a prototype lunar geology camera and other hardware for extreme environments. “Up high on the mountain there are limestone formations, which are wonderful places to look for fossilized life,” he said,” and we’ll also look for melt water and primitive forms of life there; algae lichens, etc. If liquid water exists even for brief periods on Mars it may be in similar conditions to what we’ll find on Mt. Everest. We hope to bring samples back for scientists to look at.”

To help Parazynski, he has enlisted the help of a couple of “media sherpas;” Keith Cowing from NASAWatch and Miles O’Brien, former CNN correspondent. Cowing will definitely be at the base camp, coordinating the media blitz, while O’Brien is still working out his schedule, but hopes to be there as well.

“Scott has the chance to something interesting and wants to share it with as many people as possible,” said Cowing. “This is participatory exploration, where we’ll bring as many people as possible to where we’re going. This is enabled by high end internet connection capable of streaming video. The idea is to open up a vista of participation to a very large audience.”

Cowing said they will have access to email to answer as many questions as possible, and Universe Today will be one of the venues supplying questions from readers. “We’ll be Twittering, videocasting, podcasting, Skyping, emailing, SMSing, blogging , you name it. We’re using every gizmo we’ve got and every avenue of interaction with people, giving them the opportunity to see what it’s like to live in a tent at 17,600 feet.”

The entire expedition will take between 6 -10 weeks, depending on the weather and health of the climbers. Parazyski said it will take several weeks just for the climbers’ bodies to acclimate to the decreased amount of oxygen at those heights. The peak of Mount Everest is 8,848 meters (29,028 feet) above sea level. “We’ll be going up and down to get body used to the conditions,” he said. “Essentially what happens, you need to increase your body’s oxygen carrying capacity, and grow more red blood cells. Your blood chemistry changes to enable you to exchange oxygen more efficiently and that just takes time.” Parazynski, an MD, will be the official physician for the group.

The Discovery Channel will also be part of the climb, with hopes of creating a documentary of the expedition for their “Everest: Beyond the Limits” series. Cameras will be mounted on the climbers to take video of the experience.

Parazynski is part of a team of 23 climbers. Another team will also be part of the climb, and there will be an additional 20 or 30 climbers to help create the documentary.

The climb officially starts in early May. You can follow the climb via OnOrbit.com/Everest. Parazynski’s whereabouts can also be followed on Google Earth, via his SPOT, a GPS location and message device, which is a commercial sponsor of the climb. The expedition is completely privately funded.

Parazynski is now a “former” NASA astronaut. He announced two weeks ago that he left NASA to work in private industry, at Wyle Labs in Houston. “I had a wonderful experience in the role of astronaut, but now it’s time to pursue other opportunities.”

One other hope for this expedition is to have people participating both on this Earth and off. “If the stars align and everything works just right, we hope to have a satellite phone call between our group and the Hubble repair space shuttle mission,” Parazynski said. Of course, that would depend on if the Hubble mission launches during Parazynski’s climb.

Despite Parazynski’s wish to share his experience with the world, he admits there’s also a strong personal element to this climb. “I went almost the entire way last year and came within 24 hours of summitting,” he said. “It is something I’ve thought of and dreamt about every day since I left the mountain last May, wondering what that last 24 hours will be like, and what it will be like to complete one of the great aspirationa of my entire life.”

Follow OnOrbit.com/Everest for complete coverage. You can follow Parazynski’s Twitter feed, too, SPOTScott, and the OnOrbit Everest Twitter feed. We’ll post regular updates here on Universe Today, along with reminders to submit questions for Parazynski, Cowing and O’Brien by posting your questions in the comments section.

March 23, 2009December 24, 2015 by Fraser Cain

What Are Volcanoes?

[/caption]
Volcanoes are mountains. But unlike most mountains in the world, formed from folding continental plates, uplift and erosion, volcanoes are created when material from inside the Earth escapes to the surface. Let’s answer the question, “what are volcanoes”.

As you probably know, the ground you’re standing on is the Earth’s crust. It varies in depth between 10 km under the oceans and 30 km beneath the continental plates. Beneath the crust is a vast region called the Earth’s mantle. The mantle is made up of molten rock called magma. At the boundaries between continental plates, volcanic vents can open up, where magma and gasses from inside the Earth can escape.

When it’s still underground, the molten rock is called magma. Although most of the Earth’s mantle is solid, it can create pockets of liquid which escape from underneath through weaknesses in the Earth’s crust. After it escapes to the surface, it’s called lava. Lava has different levels of viscosity – how easily it flows downhill. The least viscous (easy flowing) lava creates shield volcanoes. The lava can flow for great distances in huge rivers, and creates wide volcanoes with gently sloping sides. The most viscous (thickest) lava piles up around the volcanic vent created the familiar cone-shaped volcanoes.

The simplest volcanoes where a single vent breaks through a weakness in the crust, releasing lava, ash and rocks. After being blasted out of the vent, it piles up around on the surface, allowing the volcano to grow up quickly. Some of the largest, most familiar volcanoes are composite, or stratovolcanoes. These are built up of multiple layers of ash and lava, and can have vast networks of vents.

The word volcano comes from the island of Vulcano in the Mediterranean Sea off Sicily. Ancient people thought that this island was the chimney of the forge of Vulcan, the Roman god of blacksmithing.

We have written many articles about volcanoes for Universe Today. Here’s an article about the biggest volcano on Earth, and here’s one about the tallest volcano.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.

March 23, 2009December 24, 2015 by Nancy Atkinson

Colbert Wins ISS Naming Contest

[/caption]
NASA obviously underestimated the awesome power of the Colbert. In an online contest to name a new module for the International Space Station, NASA suggested a few names, but then provided the possibility for write-in suggestions. Comedian Stephen Colbert won in a landslide, beating out NASA’s obvious top suggestion, Serenity by over 40,000 votes. But NASA has not said if they will heed the public’s wishes. Nearly 1.2 million votes were cast when the voting ended last Friday. Colbert has been in the lead for some time, and a few weeks ago NASA’s Associate Administrator for Space Operations Bill Gerstenmaier joined Colbert on his Comedy Central show to address the possibility of actually naming the module. “Will you now commit to naming that module Colbert if I win your online vote?” Colbert asked Gerstenmaier.

“Well, we’re going to have to go think about that as we get all the votes and we see where we are,” Gerstenmaier responded. See the video below:

The Colbert Report

Mon – Thurs 11:30pm / 10:30c

Space Module: Colbert – William Gerstenmaier

comedycentral.com

Colbert Report Full Episodes

Political Humor

Mark Sanford

NASA said it reserves the right to choose an appropriate name. Agency spokesman John Yembrick said NASA will decide in April, but will give top vote-getters “the most consideration.”

Colbert urged viewers of his Comedy Central show, “The Colbert Report” to write in his name. Colbert received 230,539 votes.

He said “Serenity” is not a name for a space station module, but for an air freshener.

Serenity took 70% of votes for NASA’s suggested names, with Legacy, Earthrise and Venture getting just a small percentage of the votes. NASA has said contests like this one are a way to get the public involved with space exploration.

Anyone want to place bets on what the module’s name will actually be?

For more information about the Node 3 module, read our original post about the naming contest.

Source: MSNBC, NASA

March 23, 2009December 24, 2015 by Fraser Cain

Most Active Volcanoes

Most volcanoes are dormant. They erupted millions of years ago, but then the Earth’s plate tectonics closed the vent or caused it to drift away. But some volcanoes are still active and erupt on a regular basis. Here are a list of the most active volcanoes in the world.

The most active volcano on Earth is Kilauea volcano on Hawaii. It’s the most recent of a series of volcanoes that created the Hawaiian archipelago of islands. They formed as a string of islands because the Pacific plate is slowly moving over the Hawaii hotspot. That’s why the islands of Kauai and Oahu are no longer active, but Kilauea is. This volcano only rises 1,247 meters above sea level, but it’s still growing. 90% of the surface of Kilauea is less than 1,100 years old, and there were 45 eruptions of the volcano in the 20th century alone. Even in 2008, there were explosive eruptions from Kilauea.

The second most active volcano in the world is Mount Etna, a composite volcano on the east coast of Sicily. It’s the largest active volcano in Europe, with an altitude of 3,329 meters. It’s in an almost constant state of eruption, but despite this, its flanks support extensive vineyards and orchards. Over the last few thousand years, it has experienced many eruptions. Ash from its eruptions have been found as far away as Rome, 800 km away. There are more than 300 volcanic vents across Mount Etna, ranging in size from small holes to massive craters, hundreds of meters across.

The third most active volcano is Piton de la Fournaise, which is French for the “Peak of the Furnace”. This is a shield volcano on the eastern side of Renunion island in the Indian Ocean. It has erupted in 2006, 2007 and in 2008 – with more than 150 eruptions since the 17th century. Piton de la Fournaise is referred locally as “le Volcan”, and stands at a height of 2,631 meters tall. It has many craters and cinder cones inside the volcano’s caldera and around its outer flanks.

We have written many articles about volcanoes for Universe Today. Here’s an article about how the dinosaurs might have been killed by both volcanoes and asteroids, and how they helped slow the ocean warming trend.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.

References:
USGS Volcanoes Page: Kilauea
NASA Earth Observatory
USGS Volcanoes Page: Piton de la Fournaise

March 23, 2009January 24, 2021 by Fraser Cain

Universe Today Turns 10

Hey everyone, I just wanted to inform you of a little anniversary. I started up Universe Today exactly 10 years ago today, on March 23rd, 1999. Since very few of you know the actual story of Universe Today, I thought I’d regale you with it on this 10-year anniversary.

I was living in Vancouver at the time, working as a project manager in an Internet company. We were helping clients develop websites, but I felt that I didn’t have enough personal experience developing and maintaining a website to really give good advice. I was thinking I should run a website on the side about a topic I was passionate about… but what subject?

On one business trip I stopped at a Barnes and Nobles, browsed through the books section and picked up The Case for Mars by Bob Zubrin, and Pale Blue Dot by Carl Sagan – I gobbled them up, front to back in a single sitting. I had always been interested in space and astronomy, and was out every clear night as a teenager with my 4″ telescope. I realized that this was the topic that I was most interested in, and I was excited enough about the subject matter that I could keep the website going with my busy job and total lack of spare time.

I started brainstorming domain names; unfortunately space.com was taken. I started mashing together spacey names with other words, and then checked to see what was available. In the end, Universe + Today was open, so I went with that. I hacked together a site with my terrible HTML skills and even worse graphic abilities, but I knew that the purpose of the site would be the articles updated on a daily basis.

Here’s a link to the Wayback Machine to show you what the site used to look like. And here’s a link to the first article, reposted in WordPress.

My goal for Universe Today was to teach myself about space and astronomy… by teaching others. Each day I went though all of the breaking news, wrote a quick summary, and then linked out to the originating sources. And this was how things went for years and years. Over time, I learned more and more about space and astronomy, and was able to put this knowledge back into the website. I covered lunar eclipses live, interviewed astronomers and astronauts, and eventually learned how to write longer and better articles.

The website’s traffic and number of subscribers continued to grow. About 3 years ago, the advertising revenue from Google and other advertisers was enough that I could work on Universe Today full time – thanks to a hardworking wife who understands that we need to do what we love to be truly happy (she works in a toy store). Over the last few years, I brought on a team of writers to help get the news out faster and better than what I was doing alone. I’m indebted to Nancy, Ian, Nick, Tammy, Mark, and our newest team member, Anne.

10 years from when I started Universe Today, we’ve now got almost 45,000 RSS subscribers, and receive close to 2 million page views a month. I’m able to pick the brains of an astrophysicist twice a week with our Astronomy Cast podcast. I’ve met professional astronomers, astronauts, and Nobel laureates. I’m a member of a wonderful community of space bloggers, and call many of them my best friends.

It’s funny how a hobby can turn into so much more.

Who knows where we’ll all be in 10 more years? I know what I’ll be doing, though – working on Universe Today; covering the New Horizons close encounter with Pluto, the launch and first images from the James Webb Space Telescope, and reporting on astronauts returning to the Moon.

I can’t wait to tell you all about it.

March 23, 2009December 24, 2015 by Anne Minard

Moonshadows on Saturn’s Rings Are Harbingers of Spring

[/caption]

Moonshadows on Saturn’s rings are foretelling the planet’s equinox, when the sun will be exactly aligned with the planet’s equator and rings — and then will shift north from the southern hemisphere, kickstarting northern spring.

NASA’s Cassini spacecraft has captured, for the first time, the tell-tale moonshadows – sort of like groundhogs on Earth.

moonshadow2 — Click to play the short movie. Credit: NASA/JPL/Space Science Institute

The image above is a still from a movie, from Cassini’s hour-long observation of the shadow of the small moon Epimetheus.

Like Earth and most of the other planets, Saturn’s spin axis is tilted relative to its motion around the sun. So the sun, seen from Saturn, cycles from the southern hemisphere to the north and back again. A full sweep of seasonal changes on Saturn and its rings and moons takes a Saturnian year, equal to 29.5 Earth years. Thus, about every 15 Earth years, or half-Saturn-year, the sun passes through the plane containing the planet’s rings.

During these times, the shadows of the planet’s rings fall in the equatorial region on the planet. And the shadows of Saturn’s moons external to the rings, especially those whose orbits are inclined with respect to the equator, begin to intersect the planet’s rings. When this occurs, the equinox period has essentially begun, and any vertical protuberances within the rings, including small embedded moons and narrow vertical warps in the rings, will also cast shadows on the rings. At exactly the moment of equinox, the shadows of the rings on the planet will be confined to a thin line around Saturn’s equator and the rings themselves will go dark, being illuminated only on their edge. The next equinox on Saturn, when the sun will pass from south to north, is Aug. 11, 2009.

Because of these unique illumination circumstances, Cassini imaging scientists have been eager to observe the planet and its rings around the time of equinox. Cassini’s first extended mission, which began on July 1, 2008, was intended to gather observations during this time. Hence its name: Cassini Equinox Mission.

More than just pretty pictures, the observations could reveal any deviations across the rings from a perfectly flat wafer-like disk. Saturn’s ring system is wide, spanning hundreds of thousands of miles or kilometers. But the main inner rings (called A, B and C) are perhaps only 10 meters (30 feet) thick, and they are sometimes obscured from view inside thicker outer rings.

“We hope that such images will help us measure any vertical warping in the A and B rings,” said John Weiss, an imaging team associate from the Space Science Institute in Boulder, Colorado. “Because we know how big the moons are, and where they are in their orbits around Saturn when they cast these shadows, we have all the information we need to infer any substantial vertical structure that might be present.”

On Jan. 8, Epimetheus, a small moon 113 kilometers (70 miles) across, was the first moon observed casting a shadow onto the outer edge of the A ring. Next Pan, 30 kilometers (20 miles) across and orbiting within the rings, was caught casting a shadow on the A ring on Feb. 12. Eventually, more moons will cast shadows on the rings and all shadows will grow longer as exact equinox approaches.

Source: Cassini Imaging Central Laboratory for Operations (CICLOPS)