Posted on by Anne Minard

Does Enceladus Harbor a Liquid Ocean? Reasonable Minds Disagree

Image of Enceladus from Cassini. Credit: NASA/JPL/Space Science Institute

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Two papers in the journal Nature this week come down on opposite sides of the question about whether Saturn’s moon Enceladus contains a salty, liquid ocean.

One research team, from Europe, says an enormous plume of water spurting in giant jets from the moon’s south pole is fed by a salty ocean. The other group, led out of the University of Colorado at Boulder, contends that the supposed geysers don’t have enough sodium to come from an ocean.  The truth could have implications for the search for extraterrestrial life, as well as our understanding of how planetary moons are formed.

The Cassini spacecraft first spotted the plume on its exploration of the giant ringed planet in 2005. Enceladus ejects water vapor, gas and tiny grains of
ice into space hundreds of kilometers above the moon’s surface.

The moon, which orbits in Saturn’s outermost “E” ring, is one of only
three outer solar system bodies that produce active eruptions of dust
and vapor. Moreover, aside from the Earth, Mars, and Jupiter’s moon
Europa, it is one of the only places in the solar system for which
astronomers have direct evidence of the presence of water.

The European researchers, led by Frank Postberg of the University of Heidelberg in Germany, are reporting  the detection of sodium salts among the dust ejected in the Enceladus plume. Postberg and colleagues have studied data from the Cosmic Dust Analyzer (CDA) onboard the Cassini
spacecraft and have combined the data with laboratory experiments.

They say the icy grains in the Enceladus plume contain
substantial quantities of sodium salts, hinting at the salty ocean
deep below.

The results of their study imply that the concentration of sodium chloride in the ocean can be as high as that of Earth’s oceans and is about 0.1-0.3 moles of salt per kilogram of water.

But the Colorado study suggests a different interpretation.

Nicholas Schneider, of CU-Boulder’s Laboratory for Atmospheric and Space Physics, and his colleagues say high amounts of sodium in the plume should give off the same yellow light that comes off street lights, and that the world’s best telescopes can detect even a small number of sodium atoms orbiting Saturn.

Schneider’s team usied the 10-meter Keck 1 telescope and the 4-meter Anglo-Australian telescope, and demonstrated that few if any sodium atoms existed in the water vapor. “It would have been very exciting to support the geyser hypothesis. But it is not what Mother Nature is telling us,” said Schneider.

One suggested explanation for the contrasting results, said Schneider, is that deep caverns may exist where water evaporates slowly. When the evaporation process is slow the vapor contains little sodium, just like water evaporating from the ocean. The vapor turns into a jet because it leaks out of small cracks in the crust into the vacuum of space.

“Only if the evaporation is more explosive would it contain more salt,” he said. “This idea of slow evaporation from a deep cavernous ocean is not the dramatic idea that we imagined before, but it is possible given both our results so far.”

But Schneider also cautions that several other explanations for the jets are equally plausible. “It could still be warm ice vaporizing away into space. It could even be places where the crust rubs against itself from tidal motions and the friction creates liquid water that would then evaporate into space,” he said.

“These are all hypotheses but we can’t verify any one with the results so far,” said Schneider. “We have to take them all with, well, a grain of salt.”

Lead photo caption: Image of Enceladus from Cassini. Credit: NASA/JPL/Space Science Institute

Sources: Press releases from CU Boulder and the University of Leicester, via Nature and Eurekalert (a news service through the American Association for the Advancement of Science).

Posted on by Nancy Atkinson

Buzz is the Man With a Plan for NASA

Buzz on the Moon. Credit: NASA

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Buzz Aldrin is approaching 80 years of age, and he’s decided it’s not time to mince words. Not only is he rapping about what he accomplished during his astronaut career, but in today’s online version of Popular Mechanics Buzz wrote an article outlining what he believes NASA’s path and vision should be — for the next few years and into the next few decades. He’s a man with a plan, and he calls it the “Unified Space Vision.” He will present his plan to the Augustine Commission, an independent council appointed by President Obama to review NASA’s human spaceflight objectives.

So just what does Buzz have in mind?

Buzz writes, “It’s a blueprint that will maintain U.S. leadership in human spaceflight, avoid a counterproductive space race with China to be second back to the moon, and lead to a permanent American-led presence on Mars by 2035 at the latest. That date happens to be 66 years after Neil Armstrong and I first landed on the moon—just as our landing was 66 years after the Wright Brothers’ first flight.”

Buzz has proposed other plans in the past, but this one is different, so he’s not just singing an old tune. It’s also well thought-out and it has many facets that will appeal to both the Moon lovers, the Mars huggers and the asteroid devotees, as well as those of us that like big rockets and small space planes. Buzz’s plan has something for everyone – those that are practical and those that are dreamers.

Buzz wants to avoid the gap between the shuttle and Constellation, so he suggests stretching out the six remaining shuttle flights – not adding any, but flying just one mission each year until 2015. In the meantime he thinks the troubled Ares rockets should be scrapped and Orion should be fast-tracked by using Delta IV Heavy or the Atlas V satellite launchers, upgraded for human flight.

He also thinks NASA should take advantage of the upstart commercial space companies and upgrade the Commercial Orbital Transporation Services (COTS) program to include more flights and more companies.
Buzz says his medium-term plan is simple. “Scrap our go-it-alone lunar program and let international partners—China, Europe, Russia, India, Japan—do the lion’s share of the planning, technical development and funding.” Buzz wants to call off Space Race II with the Chinese and work together.

NASA's current plan for Constellation. Credit: NASA
NASA's current plan for Constellation. Credit: NASA

He has some other ideas about the types of space vehicles to use – perhaps a mini shuttle based on the scrapped Crew Return Vehicle that the space station was going to use as a lifeboat, and instead of using an Ares I and Ares V, just use a mid-range “Ares-III,” as medium sized rockets would be an more efficient way to transport crew and cargo to the Moon.

The way to get to Mars, Buzz says, is to use comets, asteroids and Mars’ moon Phobos as incremental points to Mars. “No giant leaps this time,” Buzz writes. “More like a hop, skip and a jump. For these long-duration missions, we need an entirely new spacecraft that I call the Exploration Module, or XM.”

Unlike the Orion capsule, which is designed for short flights around the Earth and to the moon, the XM would be a big honkin’ rocket, and would include radiation shields, artificial gravity and food-production and recycling facilities necessary for a spaceflight of up to three years. Once launched, it would remain in space. The XM would carry attached landers designed for Phobos or Mars and an Orion capsule for astronauts returning to Earth.

An the astronaut explorers on these big ships would be like pilgrims and pioneers of old: Buzz thinks the one-way to Mars idea is the way to go. Those that want to go to Mars should commit to staying there permanently.

Check out Buzz’s complete plan in his article on Popular Mechanics. (It will also be published in the August edition of the print version of Popular Mechanics.) He’s got some ideas that are sure to prompt discussion.

Posted on by Anne Minard

Mysterious “Blobs” Are Windows Into Galaxy Formation

Credit: Left panel: X-ray (NASA/CXC/Durham Univ./D.Alexander et al.); Optical (NASA/ESA/STScI/IoA/S.Chapman et al.); Lyman-alpha Optical (NAOJ/Subaru/Tohoku Univ./T.Hayashino et al.); Infrared (NASA/JPL-Caltech/Durham Univ./J.Geach et al.); Right, Illustration: NASA/CXC/M.Weiss

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Astronomers say they’ve discovered the “coming of age” of galaxies and black holes, thanks to new data from NASA’s Chandra X-ray Observatory and other telescopes. The new discovery helps resolve the true nature of gigantic blobs of gas observed around very young galaxies, and sheds light on the formation of galaxies and black holes.

The findings, led by Jim Geach of Durham University in the UK, will appear in the July 10 issue of The Astrophysical Journal.

About a decade ago, astronomers discovered immense reservoirs of hydrogen gas — which they named “blobs” – while conducting surveys of young distant galaxies.  The blobs are glowing brightly in optical light, but the source of immense energy required to power this glow and the nature of these objects were unclear.

Based on the new data and theoretical arguments, Geach and his colleagues show that heating of gas by growing supermassive black holes and bursts of star formation, rather than cooling of gas, most likely powers the blobs. The implication is that blobs represent a stage when the galaxies and black holes are just starting to switch off their rapid growth because of these heating processes.  This is a crucial stage of the evolution of galaxies and black holes – known as “feedback” – and one that astronomers have long been trying to understand.

“We’re seeing signs that the galaxies and black holes inside these blobs are coming of age and are now pushing back on the infalling gas to prevent further growth,” said coauthor Bret Lehmer, also of Durham.  “Massive galaxies must go through a stage like this or they would form too many stars and so end up ridiculously large by the present day.”

Chandra and a collection of other telescopes including Spitzer have observed 29 blobs in one large field in the sky dubbed “SSA22.” These blobs, which are several hundred thousand light years across, are seen when the Universe is only about two billion years old, or roughly 15 percent of its current age.

In five of these blobs, the Chandra data revealed the telltale signature of growing supermassive black holes – a point-like source with luminous X-ray emission. These giant black holes are thought to reside at the centers of most galaxies today, including our own.  Another three of the blobs in this field show possible evidence for such black holes.  Based on further observations, including Spitzer data, the research team was able to determine that several of these galaxies are also dominated by remarkable levels of star formation.

The radiation and powerful outflows from these black holes and bursts of star formation are, according to calculations, powerful enough to light up the hydrogen gas in the blobs they inhabit. In the cases where the signatures of these black holes were not detected, the blobs are generally fainter. The authors show that black holes bright enough to power these blobs would be too dim to be detected given the length of the Chandra observations.

Besides explaining the power source of the blobs, these results help explain their future. Under the heating scenario, the gas in the blobs will not cool down to form stars but will add to the hot gas found between galaxies. SSA22 itself could evolve into a massive galaxy cluster.

“In the beginning the blobs would have fed their galaxies, but what we see now are more like leftovers,” said Geach.  “This means we’ll have to look even further back in time to catch galaxies and black holes in the act of forming from blobs.”

Sources/more information: the Chandra sites at Harvard and NASA.

Posted on by Nancy Atkinson

Gemini VI

Gemini 7
This photograph of the Gemini 7 spacecraft was taken from the hatch window of the Gemini 6 spacecraft during rendezvous and station keeping maneuvers at an altitude of approximately 160 miles on December 15, 1965. Credit: NASA

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Gemini VI ended up launching after Gemini VII, making it the fifth manned mission of Project Gemini. The astronauts on board were Walter M. Schirra Jr., Commander and Thomas P. Stafford, Pilot.

The mission launched on Dec. 15, 1965 at 8:37 am EST, and the two-man capsule reached at altitude of 311.3km. The crew made 16 orbits and their flight lasted 1 Day, 1 hour, 51 min, 24 seconds.

The crew of Gemini VI, Stafford and Schirra. Credit: NASA
The crew of Gemini VI, Stafford and Schirra. Credit: NASA

The original flight plan called for the Gemini VI to rendezvous with an Agena target vehicle in space to test out rendezvous and docking procedures. However the Agena launched on October 25 blew up on the way to orbit. After much discussion, NASA decided to launch Gemini VII first and have Gemini VI rendezvous the Gemini VII spacecraft. This required a quick one week turnaround of the launch pad, something NASA had never done before.

Gemini VII launched on Dec. 4, 1965 but the first launch attempt for Gemini VI on Dec. 12 was aborted, as the Titan II rocket ignited and then shut down a second later. As commander, Schirra had the option of ejecting the crew to safety, but he waited it out and did not pull the abort handles. That decision allowed a quick second launch attempt on Dec. 15 that went perfectly.

The primary objective was to rendezvous with Gemini-VII, which was accomplished successfully, making it the first manned rendezvous controlled entirely by the self-contained, on-board guidance, control, and navigation system. This system provided the crew of Gemini 6 with attitude, thrusting, and time information needed for them to control the spacecraft during the rendezvous. The two spacecraft came within 16 meters.

Secondary objectives were to stationkeep with Gemini VII, conduct visibility tests for rendezvous and evaluate reentry guidance capability. The crew had three planned experiments, but the Radiation in Spacecraft experiment was unable to be done because stationkeeping with Gemini VII interfered with it.

Gemini VI splashed down on December 16, 1965, landing at 23 degrees 35 minutes North and 67 degrees 50 minutes West, missing its target landing location by only 12.9 km. The crew was recovered by the USS Wasp, which had the crew onboard in 66 minutes.

NASA’s Gemini VI history page.

More images from Gemini VI.

Posted on by Mark Mortimer

Book Review: Observing the Night Sky with Binoculars

Observing the Night Sky with Binoculars

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With warmer weather returning to the Earth’s northern hemisphere, we can again venture forth under the night sky for pleasant star gazing. If you’re just beginning this pastime and are planning to rely upon binoculars, then you should also consider Stephen O’Meara’s book, “Observing the Night Sky with Binoculars – A Simple Guide to the Heavens“. It will have you comfortably cruising the night’s starry sphere in no time with its straightforward techniques and handy mnemonics.

In a simple but effective layout, the book starts by providing background information. In particular, it has details on what’s good to look for and how to find it. Whether bright stars and variable stars, pink stars and blue stars, or galaxies and clusters, it gives the reader a set of distinctive parameters. Then, by describing the use of averted eyes, star charts and monthly calendars, it prepares the reader for getting the most from their night time sleuthing.

After this brief baselining, the book settles in to a monthly-specific rendition of what’s exciting and where to find it. Without getting hung up on whether a constellation, asterism or sign of the zodiac, it prepares the reader for locating common stellar appearances that occur in the mid-northern latitudes. Then, as if to urge on the reader, the text adds some star lore like the T Coronae Borealis being a recurring novae that flared in 1866 and 1946. And for those less inclined to the physical particulars, the text also includes artistic and historical pieces. Many snippets of related poetry begin chapters and epic Greek stories illustrate how star patterns influenced early cultures. Thus, each month broadens the reader’s understanding of night time skies and their knowledge of sky’s influence in earlier ages.

Also, clear illustrations appear throughout. Most drawings have an angular scale (i.e. one fist being about 10 degrees) for the reader to get their bearing. And, traces on photographic images should aid the reader to make order of what can be a very daunting, busy night time scene. Given these and the book’s focus upon having the reader enjoy their viewing time should prove an effective enticement for anyone rousing from a long winter’s nap.

So, don’t dismiss that little spark of interest when newly seeing a bright star in the evening sky. Grab binoculars and Stephen O’Meara’s book, ‘”Observing the Night Sky with Binoculars – A Simple Guide to the Heavens” to begin an adventure exploring an unlimited realm.

Posted on by Nancy Atkinson

Buzz Aldrin Raps with Snoop Dog About Apollo 11

Buzz Aldrin and Snoop Dog. Credit: FunnyorDie.com

Some things you just have to see to believe. Apollo 11 astronaut Buzz Aldrin recently cut a hip-hop song along with rappers Snoop Dogg and Talib Kweli. The website Funny Or Die has the music video of the song, “Rocket Experience. They also have the “making of” video of Buzz’s song. Quincy Jones and Soulja Boy also make appearances. It’s fun to watch, and Buzz really lets it all hang out – he’s a very cool dude! And let’s face it, everyone wants to see Buzz Aldrin rapping about traveling in space, right? My favorite part is when Buzz is rapping while standing next to the famous cardboard cut-out of him standing on the Moon. (I have one of those…) Enjoy the video!

Also available: Download the song “Rocket Experience” on iTunes. A portion of the proceeds from the song sales of” Rocket Experience” will go to ShareSpace Foundation, to further benefit and support the work of the National Space Society, the Planetary Society and the Astronaut Scholarship Foundation.

Posted on by aalla

Continental Drift Theory

Map showing some of the continents

In elementary school, every teacher had one of those pull-down maps of the world to teach geography. On occasion, I thought the largest land masses, known as continents, reminded me of pieces in a jigsaw puzzle. They just seemed like they should fit together, somehow. Not until I took Earth Science, in 8TH grade, did I discover my earlier idea was correct. My teacher explained about a phenomenon, known as, The Continental Drift Theory. He said that some German had the same idea I did.

The man my teacher mentioned, Alfred Wegener (Vay gen ner), developed The Continental Drift Theory in 1915. He was a meteorolgist and a geologist. His theory basically said that, at one time, there existed one large supercontinent, called, Pangea, pan, meaning all-encompassing, and, gea, meaning the Earth. He went on to suggest that, seismic activity, such as erthquakes, volcanic eruptions, and tsunamis, also called tidal waves, eventually created fissures, or cracks in the Earth. As these fissures became larger, longer, and deeper, 7 pieces of Pangea broke off and, over time, drifted to the places where they are now. These 7 large pieces of land are what we now call, continents. They are: North America; South America; Europe; Asia; Africa; Antarctica; and, Australia. Some people refer to the country as Australia, and the continent as, Oceania. They do this because there are other countries, such as New Zealand, included as a part of that particular continent.

At the time, people thought Wegener was, well, “nuts.” Only in the 1950s did people begin to take his idea seriously. According to the United States Geological Survey (the USGS), thanks to the use of the submarine and the technology developed during World War II, scientists learned a lot about the Ocean Floor. When they found out that it was not as old as the Crust, or Surface, of the Earth, sicentists had to ask themselves, “Why?”

The answers have to do with earthquakes, volcanoes, and magnetism. When the Earth cracks, molten magma, from the middle of the Earth, known as the Mantle, works its way to the surface, where it becomes known as, lava. That lava melts away some of the older layers; then, when the water cools that lava, it forms a new layer of Earth. For that reason, if scientists tried to determine the age of the Earth from samples taken from the Ocean Floor, they would be very wrong.

That same equipment also helped scientists recognize that heavy amounts of basalt, a volcanic rock that contains high amounts of iron, could throw compasses off course. This information provided one more pieces to the puzzle. Now, scientists recognize that the North and South Poles were not always where they currently are.

The Earth changes every day. Although we might not notice it, the continents move all the time. We don’t only revolve, or spin, around the Sun. We also drift across the surface of the planet.

The United States Geological Survey has some excellent information on this topic.

University Today has some other fabulous material about this and related topics, including Earth, Barely Habitable?, by Fraser Cain begin_of_the_skype_highlighting     end_of_the_skype_highlighting, and Interesting Facts About Planet Earth.

You can also read or listen to Episode 51: Earth, of Astronomy Cast, also produced by Universe Today.

Sources:
http://en.wikipedia.org/wiki/Continental_drift
http://www.ucmp.berkeley.edu/history/wegener.html
http://pubs.usgs.gov/gip/dynamic/historical.html

Posted on by Nancy Atkinson

LRO Successfully In Lunar Orbit; LCROSS Provides Flyby Video

LCROSS flyby video capture. Credit: NASA

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The Lunar Reconnaissance Orbiter fired its braking thrusters for 40 minutes early today, successfully inserting the spacecraft into orbit around the Moon. Over the next several days, LRO’s instruments will be turned on and its orbit will be fine-tuned. Then LRO will begin its primary mission of mapping the lunar surface to find future landing sites and searching for resources that would make possible a permanent human presence on the moon. Also, early Tuesday, the companion mission Lunar Crater Observation and Sensing Satellite (LCROSS) sent back live video as it flew 9,000 km above the Moon, as it enters its elongated Earth orbit, which will bring it on course to impact the Moon’s south pole in October.

The two spacecraft reached the Moon four-and-a-half days after launch. LRO’s rocket firing began around 9:20 GMT (5:47 a.m. EDT) and ended at 10:27 GME (6:27 a.m. EDT), putting the spacecraft into an orbit tilted 30 degrees from the moon’s poles with a low point of 218 km (136 miles) and a high point of 3,000 km (1,926 miles). Over the next five days, additional rocket firings will put the spacecraft into the correct orbit for making its observations for the prime mission, which lasts a year — a polar orbit of about 31 miles, or 50 kilometers, the closest any spacecraft has orbited the moon.

Meanwhile, at 12:20 GMT (8:20 EDT) on Tuesday, LCROSS made a relatively close flyby of the Moon, sending back live streaming video. Watch the replay here.

LCROSS on its way to impact. Credit: NASA
LCROSS on its way to impact. Credit: NASA

LCROSS is now in its “cruise phase” and will be monitored by the mission operations team. During the flyby, the science team was able to obtain the data needed to focus and adjust the cameras and spectrometers correctly for impact.

LCROSS will never actually be lunar orbit, but is working its way to an elongated Earth orbit which will eventually bring it to the correct orientation for meeting up with the south pole of the Moon later this year. LCROSS will search for water ice on the moon by sending the spent upper-stage Centaur rocket to impact part of a polar crater in permanent shadows. The LCROSS spacecraft will fly into the plume of dust left by the impact and measure the properties before also colliding with the lunar surface.

Posted on by Tammy Plotner

Kid’s Astronomy: Bootes – The Ancient Herdsman


Hey, kids! Are you ready to spend another warm, northern summer evening out under the stars? Then perhaps you’d like to introduce yourself to the Celestial Farmer and his family. Before the Moon comes back and steals away our dark skies, begin when night falls and watch overhead for the appearance of a bright, orange-looking star. Congratulations! You’ve just found Arcturus and you’re on your way to learning our next constellation lesson. Now, sit back and listen to the voice of the wind and the night as it tells you a story…

Bootesurania“Some say that Bootes is the most ancient constellation in the sky, yet no one is quite sure where his legend came from. The set of stars that marks the ancient herdsman has played a role in many cultures and one of its first written histories belongs to “The Odyssey” – an epic poem by Homer written almost three hundred years ago. As a herdsman, he is accompanied by his working dogs, Asterion and Chara, who form the northern constellation of Canes Venatici. They are accompanied by the bright orange star called Arcturus, whose ancient name “Arktos” meant watcher of the bear. One legend says that egend says that Bootes was the son of Zeus and Callisto. Hera changed Callisto into a bear who was almost killed by Bootes when he was out hunting. Luckily, she was rescued by Zeus and he took her into the sky where she is now Ursa Major, the Great Bear.”

virgoAnother myth says Bootes was the son of Demeter, the goddess of agriculture. Supposedly he was placed among the stars for inventing the plow. It is also said that Bootes was a grandfather of Virgo, the goddess of the wheat or corn. Not far from the beautiful, bright, blue-white star that marks her crown is one of the most famous galaxies of all – the Sombrero. Perhaps it was Bootes who rescued the beautiful hair of Queen Berenices and placed it in the sky? After all, she gave up her long and lovely locks to see the safe return of her husband from war.”

hercules“The Romans called Bootes the Herdsman of the Septemtriones, that is, of the seven oxen represented by the seven stars of the Big Dipper, yet he is also associated with the constellation of Hercules, too. The ancient Greeks saw Hercules as a shepherd of great strength and a son to Bootes. He is most often pictured with a lion skin slung about his shoulders and holding an upraised club as he guards his flocks.”

We hope you had a wonderful time identifying these new constellations, but don’t go too far away… Because you’re about to learn some more!

Our awesome images are: Bootes map courtesy of Windows to the Universe, constellation chart courtesy History of Science Collections, University of Oklahoma Libraries, Bootes Uranometria, Virgo Image by Johfra Bosschart and Hercules Uranometria. We thank you!

Posted on by Nancy Atkinson

Carnival of Space #108 — Solstice Edition!

This week’s Carnival of Space is hosted by Ethan Siegal at Starts With a Bang.

Click here to read the Carnival of Space #108.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.