Category: Planet Content


Neptune: The Mystic


Neptune is the furthest planet from the sun and was the only planet to be discovered using mathematics instead of observation.  It is nearly identical to Uranus, except for its atmosphere, which has notable weather patterns.  It even had a Great Dark Spot, similar to the Great Red Spot on Jupiter.  However, unlike the Great Red Spot, Neptune’s spot forms and dissipates once every few years.  It has been observed with different sizes and shapes, and at one point was even the same size as the Earth.  Neptune’s extremely dynamic storm systems are also noteworthy considering its winds reach speeds of close to 600 meters per second (almost supersonic)! Like Uranus, Neptune’s season lasts approximately 40 years, resulting in cloud bands that regularly increase in size.  The planet is names after the Roman god of the sea, perfectly fitting for a planet that is composed primarily of ice and is blue in appearance.  An interesting fact to point out-Neptune will complete its first full orbit since its discovery on July 12, 2011, only four months from now.

The music for Neptune is very static and one-dimensional, which seems to contradict the mythological characteristic as god of the sea.  Gustav Holst was not aiming to write music that depicted the sea, however, because in his opinion Neptune should be portrayed as mystical and whimsical.  What sets Neptune apart from the other pieces in the movement is the use of actual voices at the end of the piece to provide a first-of-its-kind fade-out ending.  At first, the women’s chorus was not distinguishable from the instruments, but upon closer listening, it was easy to hear the faint sound of the voices.  The voices sounded quite haunting, and the fact that they blended in with the music so well and were “hidden” provides a perfect “mystical” experience.  Other than that though, nothing about this piece particularly stood out, and it was a weak ending for Holst’s most famous work.




Neptune has an unusual instrumentation, with the main body of the orchestra, which is usually the focus of the audience’s attention, playing second fiddle to the melodic percussion instruments, like the celesta – an instrument I had actually never seen before and had to go look up (and then realized it is used all over the place, but that every performance I have been involved in personally had been rewritten to substitute the glockenspiel for the rare and expensive celesta). Another unusual instrumentation is the choir that sneaks in at minute 4:15. It seems rather fitting that the last, furthest instruments would become the first in a piece about the furthest planet. The choice of featuring a choir is interesting as well, the voices sliding over each other, echoed by the slides on the harps, lending an ethereal, unanchored quality to the music. I remember reading somewhere that Holst originally intended for the choir to be hidden out of view of the audience. There would have been no hiding that there was a choir once they took over the movement, but his intention was that when they first snuck in, the audience would slowly become aware of a sound that seemed to emerge from nowhere, and for a moment before they were able to identify what it was, it would create the surreal experience of a disembodied presence within the symphony hall. We can only imagine that to an audience unaware this sleight of hand was coming, the unearthly chords the choir sings at the climax of their section must have only prolonged that moment of surreality, refusing to let the audience relinquish their instinctual adrenaline and terror to the recognition of something human and familiar. It must have been a very disturbing experience to the first audience on opening night.

Little is still known about Neptune. It’s thick hydrogen-rich atmosphere makes it difficult to see beyond the uppermost cloud layers. Like with the other Jovian planets, there is believed to be no surface to speak of, but a gradual increase in density from gas to liquid to molten heavy metals. Two fascinating aspects of Neptune are that its magnetic field seems to be produced not by the planet’s core, but by the rotation of the fluid mantle, and that it has the only moon in the solar system with a retrograde orbit. Scientists can do no more than speculate on explanations for either. Until technology improves and allows us to better evaluate the planet, Neptune will remain a mystery.





Move over, Gustav Holst: the solar system gets a whole new groove

February 1st, 2011 Leave a comment Go to comments

Today the International Year of Astronomy’s 365 Days of Astronomy podcast show is featuring a program I recorded about an album, Planets, by the New York City band One Ring Zero. I did it on my own time, as a labor of love for IYA’s excellent and important effort to promote understanding of science, astronomy, and the night sky. But ORZ’s music turns out to have deep connections to NASA and its mission to understand and appreciate the universe. So here is the podcast on 365 Days of Astronomy about Planets, One Ring Zero’s thoughtful and fresh take on the “music of the spheres.” What’s it got to do with NASA? Read on. . .

365 days of astronomy show banner

It’s a perfect time to give the solar system a new groove. NASA has decreed 2011 the “year of the solar system.” Stardust NExT encounters Comet Tempel 1 on February 14. MESSENGER enters orbit around Mercury on March 18. Dawn begins its approach to asteroid Vesta in May. Next comes the launch of the Juno spacecraft to Jupiter in August, the launch of GRAIL to map the gravitational field of the Moon in September, and the launch of a roving science lab named “Curiosity” to Mars in November.

Science and astronomy, the NASA missions to the inner and outer planets, and the art and culture associated with astronomy and the night sky all fueled One Ring Zero’s inspiration for the album. The band’s leaders, Joshua Camp and Michael Hearst, explained it better than I could in an interview last year with SEED Magazine:

Seed Magazine: Can you tell us a bit about how you came up with the idea for this album?

Joshua Camp: It started when the International Astronomical Union decided to demote Pluto to a dwarf planet.  At the time, we had just finished our album Wake Them Up, and hadn’t begun any other projects.  The news of Pluto’s demotion was shocking, inspiring, and funny, which led to us write and record a song about it.

Michael Hearst: Yes, at that point, it dawned on us that maybe we should write songs for all of the planets. After all, it had been just about 100 years since Gustav Holst had composed his song cycle. Our knowledge of the solar system has changed since then, with many new discoveries. Of course, music has also changed since then.  At the same time, Holst’s The Planets was a big inspiration for us. It’s such an epic and entertaining piece—it seemed almost daunting to try and do what he had already done so well.  And yet, the challenge was what really sparked our interest.

Actually, Holst’s The Planets is the reason I ended up doing this podcast. I discovered Holst in the 1980s, when I was a college intern in the Link Planetarium in Binghamton, New York. At one point, we were developing a new show titled “Mission to Mars,” and my boss Jay Sarton mentioned the Holst composition Mars, Bringer of War. We used it for the scene in the show where humans blast off into space to explore Mars. I’ve been a big fan of The Planets ever since.

Holst composed this music almost a century ago, during the dark days of world war one. Each of its seven parts are named for one of seven planets: Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Holst was an amateur astrologer, and he intended his orchestral suite to convey the astrological influence of the planets. The piece was first performed with a full orchestra in 1919.

Now fast-forward a century to Brooklyn, home base of One Ring Zero. Gustav Holst died in 1934, but if he were alive today, he might find the band’s version of the solar system bewildering. It’s an eclectic and quirky journey from Mercury to Pluto, with influences as diverse as gypsy violin, Pink Floyd and David Bowie, Electric Light Orchestra, and even klezmer.

I decided to kick off the interview by having a little fun with Hearst, demanding that he explain where he got the nerve to take on Holst’s masterwork.

GOGBLOG: Let’s see…Holst’s The Planets, enduringly popular, they say; influential; widely performed  and the subject of numerous recordings. Much beloved by astronomy and space fans the world over. And you, Mr Popular Music Guy, think you have what it takes to meet Gustav Holst. To you I say, sir, how dare you! How do you comment?

HEARST: Well, you’re welcome to say that. In many ways it’s sort of an homage to Holst; it was inspired by him. We’re certainly not trying to compete against what he created, which was fantastic and very much the inspiration for our work. However, with all due respect, it has been just about a hundred years.

GOGBLOG: He started writing it, composing it, in the middle of world war one!

HEARST: Yeah, exactly. The other big difference is his is based on astrology, where ours is much more based on astronomy.

GOGBLOG: Right, he was trying to capture the astrological influence…

HEARST: Yeah, apparently he used to even read his friends’ horoscopes for fun.


HEARST: Nothing wrong with that, but that was his kind of angle.

GOGBLOG: An astrological hobbyist.

HEARST: Whereas Joshua and I are much more geeks, and inspired by all things science.  [A] slightly different angle.

In fact, Hearst says that as a result of this project, he became a bit junkie for NASA TV from the space station and for the stunning imagery of the Cassini mission to Saturn.

One Ring Zero’s video (below) for the song Venus should give you a pretty good idea of what the album is about.

Yes, that is gypsy violin and an accordion you hear in the song. But is the other sound the sound of Holst spinning in his grave?





Saturn posts

Saturn is an impressive planet, even though it’s not quite the grandiosity of Jupiter. The extensive and bright ice rings surrounding the planet make it an object of fascination for many people. Although Jupiter has some ring activity going on, Saturn has more. It is very interesting to know that we may be seeing the rings of Saturn at a particularly bright period and that they will wane over the next several million years. It is a bit mind-blowing to think about how short and yet how long a time-span these rings are particularly bright due to impacts with Saturn’s icy moons. We are lucky, in a sense, to exist in this time so as to see the rings in a bright state.

That Saturn has Titan as its moon is also of intense interest. Titan seems to be another possibility for finding life outside of Earth in our solar system. The fact that it has such a dense atmosphere and liquid (even if it’s not water)on its surface is exciting. Its weather patterns which are similar to those on Earth also add to the excitement. I hope that we are able to find out a whole lot more about this planet-like moon in my lifetime.

As for Holst’s music regarding Saturn: It starts out so slowly and quietly that it almost seems ominous—like something is creeping forward. It doesn’t seem to pick up much at all until the slow growth in dynamics which begins about half-way through the piece. This gradual increase in volume and intensity doesn’t reach its climax for a couple minutes after it begins; it plods along like an elephant walks.In fact, the pace is relatively slow and steady all the way through. I could almost describe the feeling of the piece as vaguely sinister, but I’m a on the fence on that. I’m not convinced of it being sinister, but it is definitely eerie. It reminds me of the hands of time marching forward wearily and slowly, which is appropriate if Saturn is the bringer of old age. The part at the end after the momentary break in music does sound a lot more hopeful and bright. It’s lovely, really. I can envision new life—as if the piece goes from old age into new life.

NASA update Cassini

NASA’s Cassini spacecraft has successfully completed its closest flyby of Saturn’s moon Rhea, returning raw images of the icy moon’s surface.

Pictures of the Rhea surface taken around the time of closest approach at 4:53 a.m. UTC on Jan. 11, 2011, which was 8:53 p.m. PST, Jan. 10, show shadowy craters at a low sun angle. A portrait of bright, icy Rhea also captures Saturn’s rings and three other moons clearly visible in the background.

Images obtained by Cassini’s imaging science subsystem show an old, inert surface saturated with craters, just like the oldest parts of Earth’s moon. But there appear to be some straight faults that were formed early in Rhea’s history, which never developed the full-blown activity seen on another of Saturn’s moons, Enceladus.

The flyby of Rhea also presented scientists with their best available chance to study how often tiny meteoroids bombard the moon’s surface. Scientists are now sifting through data collected on the close flyby by the cosmic dust analyzer and the radio and plasma wave science instrument. They will use the data to deduce how often objects outside the Saturn system contaminate Saturn’s rings, and to improve estimates of how old the rings are.

Scientists using Cassini’s fields and particles instruments are also looking through their data to see if they learned more about Rhea’s very thin oxygen-and-carbon-dioxide atmosphere and the interaction between Rhea and the particles within Saturn’s magnetosphere, the magnetic bubble around the planet.

At closest approach, Cassini passed within about 69 kilometers (43 miles) of the surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

For more information about the Cassini-Huygens mission, visit and .

Media contact:
Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.


Surprise Hidden in Titan’s Smog: Cirrus-Like Clouds

Saturn and Titan Titan, the largest of Saturn’s moons, is about to slip behind the planet in this portrait captured by the Cassini spacecraft in 2008. Credit: NASA’s Jet Propulsion Laboratory

Titan seen behind Saturn's rings The blurring effects of Titan’s aerosol are obvious in this image, where the orange moon peeks from behind two of Saturn’s rings. Small, battered Epimetheus, another of Saturn’s 62 moons, appears just above the rings. Credit: NASA/JPL/Space Science Institute
› Larger image

Titan Titan’s northern half, where it’s early spring, appears slightly darker than the southern half, where it’s early fall, in this image taken on March 22, 2010. Like Earth, Titan has four distinct seasons, each of which lasts about seven of Earth’s years. Credit: NASA/JPL/Space Science Institute
› Larger image Every day is a bad-air day on Saturn’s largest moon, Titan. Blanketed by haze far worse than any smog belched out in Los Angeles, Beijing or even Sherlock Holmes’s London, the moon looks like a dirty orange ball. Described once as crude oil without the sulfur, the haze is made of tiny droplets of hydrocarbons with other, more noxious chemicals mixed in. Gunk.

Icky as it may sound, Titan is really the rarest of gems: the only moon in our solar system with an atmosphere worthy of a planet. This atmosphere comes complete with lightning, drizzle and occasionally a big, summer-downpour style of cloud made of methane or ethane — hydrocarbons that are best known for their role in natural gas.

Now, thin, wispy clouds of ice particles, similar to Earth’s cirrus clouds, are being reported by Carrie Anderson and Robert Samuelson at NASA’s Goddard Space Flight Center in Greenbelt, Md. The findings, published February 1 in Icarus, were made using the Composite Infrared Spectrometer (CIRS) on NASA’s Cassini spacecraft.

Unlike Titan’s brownish haze, the ice clouds have the pearly white appearance of freshly fallen snow. Their existence is the latest clue to the workings of Titan’s intriguing atmosphere and its one-way “cycle” that delivers hydrocarbons and other organic compounds to the ground as precipitation. Those compounds don’t evaporate to replenish the atmosphere, but somehow the supply has not run out (yet?).

“This is the first time we have been able to get details about these clouds,” says Samuelson, an emeritus scientist at Goddard and the co-author of the paper. “Previously, we had a lot of information about the gases in Titan’s atmosphere but not much about the [high-altitude] clouds.”

Puffy methane and ethane clouds had been found before by ground-based observers and in images taken by Cassini’s imaging science subsystem and visual and infrared mapping spectrometer. Compared to those clouds, these are much thinner and located higher in the atmosphere. “They are very tenuous and very easy to miss,” says Anderson, the paper’s lead author. “The only earlier hints that they existed were faint glimpses that NASA’s Voyager 1 spacecraft caught as it flew by Titan in 1980.”

Out on a Limb

Even before Voyager 1 reached Titan, scientists knew the moon was wrapped in a thick atmosphere that probably contained hydrocarbons. Part of that atmosphere, Voyager found, is a haze so smothering that it hides every bit of the moon’s surface.

Only a small amount of visible light penetrates this haze, or aerosol, so studies rely on instruments that operate at wavelengths beyond human sight. This is how Voyager learned that Titan’s atmosphere is made mostly of nitrogen, as is Earth’s. Unlike Earth’s atmosphere, though, Titan’s has neither oxygen nor water to speak of. Instead, it contains small amounts of organic materials, including members of the hydrocarbon family such as methane, ethane and propane.

Voyager also picked up indications that Titan’s stratosphere, the second-lowest layer of its atmosphere, harbored “ices made from some exotic organic compounds,” Samuelson says. “At the time, that was about all we could tell.”

Fast-forward a quarter-century to mid-2006, past decades of research conducted from telescopes, past Cassini’s arrival at Saturn, past the European Space Agency’s Huygens probe landing on Titan and taking the first pictures of the surface, past the discovery of the methane and ethane clouds. At this point, Cassini continues to orbit Saturn and visit Titan and other moons periodically.

More than a half-dozen hydrocarbons have been identified in gas form in Titan’s atmosphere, but many more probably lurk there. Researchers worldwide are looking for them, including Anderson and Samuelson, who are using the CIRS (pronounced “sears”) instrument on Cassini.

Pinpointing the altitudes where such gases turn into ices is painstaking work. The researchers scan up and down the atmosphere, pausing at each altitude to catalog a slew of signals that have to be teased apart later so that the molecules can be identified. “You can learn a lot about a compound, even if you have no idea what it is, by looking at how it is distributed vertically,” says Anderson. “Where does it accumulate? Where does it dissipate? How thick is the boundary? Is there layering going on?”

Anderson and Samuelson start a series of observations near Titan’s north pole, at roughly the same latitudes Voyager looked at, 62 °N and 70 °N. On Earth, these would fall just inside and outside the ring for the Arctic Circle.

The team focuses on the observations made when CIRS is positioned to peer into the atmosphere at an angle, grazing the edge of Titan. This path through the atmosphere is longer than the one when the spacecraft looks straight down at the surface. Planetary scientists call this “viewing on the limb,” and it raises the odds of encountering enough molecules of interest to yield a strong signal.

It works. When the researchers comb through their data, they succeed in separating the telltale signatures of ice clouds from the aerosol. “These beautiful, beautiful ice clouds are optically thin, and they’re diffuse,” says Anderson. “But we were able to pick up on them because of the long path lengths of the observations.”

In addition to spotting the clouds, the researchers gather enough information to measure the sizes of the ice particles. The results get reported in a January 2010 Icarus paper by Anderson, Samuelson, their Goddard colleague Gordon Bjoraker and Richard Achterberg, a University of Maryland staff member working at Goddard.

“That was convincing evidence,” Anderson says. “What Voyager had seen was real.”

That Sinking Feeling

Clouds on Titan can’t be made from water because of the planet’s extreme cold. “If Titan has any water on the surface, it would be solid as a rock,” says Goddard’s Michael Flasar, the Principal Investigator for CIRS.

Instead, the key player is methane. The action starts high in the atmosphere, where some of the methane gets broken up and reforms into ethane and other hydrocarbons, or combines with nitrogen to make materials called nitriles. Any of these compounds can probably form clouds if enough accumulates in a sufficiently cold area.

The cloud-forming temperatures occur in the “cold, cold depths of Titan’s stratosphere,” says Anderson. Researchers think that the compounds get moved downward by a constant stream of gas flowing from the pole in the warmer hemisphere to the pole in the colder hemisphere. There, the gas sinks.

This circulation pattern steals so much gas from the warmer hemisphere that researchers can measure the imbalance. The influx of all this gas gives the colder hemisphere more clouds. “At colder temperatures, more gas will condense anyway,” Anderson explains, “and on top of that, the atmosphere dumps a whole bunch of extra gas there.”

She and Samuelson think this is why the ice clouds were first spotted in the north. When Voyager flew by in November 1980, the north had just crossed from winter into spring. And the north was in mid-winter when the team conducted their early observations. (One Titan year lasts 29-1/2 Earth years, so spring came again to Titan’s north in August 2009.)

Still, the team figured, the south shouldn’t lack ice clouds; it should just have fewer of them. “For 30 years, Bob [Samuelson] had been saying that these clouds should exist in the southern hemisphere,” says Anderson, “so we decided to look.”

The team checked Titan’s southern hemisphere (at 58 °S latitude) and both sides of the equator (15 °N and 15 °S). Sure enough, they spotted clouds in all three locations. And as predicted, the clouds in the north were more plentiful — in fact, three times more plentiful — than those just south of the equator.

“The fact that the clouds are more enhanced at the cold polar region is a promising sign,” says Flasar. “It strengthens this idea that the molecules making up these clouds are being carried downward by this global circulation.”

Exotic Ices

Part of Titan’s allure has long been the organic compounds in the atmosphere, especially because some are thought to be involved in the events that led to life on Earth. One of those is cyanoacetylene, a member of the nitrile family. The compound’s distinctive signature made it the first to be picked up in the northern ice clouds by Voyager 1 and by Anderson and Samuelson.

To make a connection between these molecules and life isn’t the point for Anderson, though. “I just love ices and aerosols,” she says, “and Titan is this great natural laboratory for studying them.”

As the researchers continue to identify compounds in Titan’s atmosphere, the next likely candidate for an ice is hydrogen cyanide, a nitrile with an earthly reputation as a poison. In the aerosol, the team is investigating an intriguing feature in the data that seems to represent larger hydrocarbons than anybody has identified before, according to Samuelson. Early clues suggest the signature could indicate polycyclic aromatic hydrocarbons (PAHs), which typically get noticed on Earth as pollutants released by the burning of fossil fuels. In space, PAHs form in the regions where stars are born and die.

Each nugget of information like this is helping scientists piece together the life cycle and ultimate fate of Titan’s hydrocarbons, which never reenter the atmosphere via evaporation. “They fall to the surface, and it’s a dead end,” says Samuelson, “and yet Titan’s atmosphere still has methane in it. We are trying to find out why.”

The Great Switcheroo

At first, Titan’s frozen nitriles seem entirely unrelated to Earth clouds. Even putting aside their exotic ingredients, they form much higher in the atmosphere: at altitudes of about 30 to 60 miles (in the stratosphere) versus no more than 11 miles (in the troposphere) for nearly all Earth clouds.

But Earth does have a few polar stratospheric clouds that appear over Antarctica (and sometimes in the Arctic) during winter. These clouds form in the exceptionally cold air that gets trapped in the center of the polar vortex, a fierce wind that whips around the pole high in the stratosphere. This is the same region where Earth’s ozone hole is found.

Titan has its own polar vortex and may even have a counterpart to our ozone hole. The degree of similarity is intriguing, says Flasar, given the different compositions and chemistries of the stratospheric clouds on Earth versus Titan.

“We are starting to find out how similar Titan’s clouds are to Earth’s,” says Samuelson. “How do they compare? How do they not compare?”

The big test of scientists’ understanding of Titan’s atmosphere will come in 2017, when summer comes to the north and the south plunges into winter. “We expect to find a complete reversal in the circulation of gas then,” says Anderson. “The gas should start to flow from the north to the south. And that should mean most of the high-altitude ice clouds will be in the southern hemisphere.”

Other major changes are in store for Titan then, Flasar adds, including the disappearance of the fierce winds around the north pole. “The big question is: will the vortex go out with a bang or whimper?” he says. “On Earth, it goes out with a bang. It’s very dramatic. But on Titan, maybe the vortex just gradually fizzles out like the smile of the Chesire cat.”

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The CIRS team is based at NASA’s Goddard Space Flight Center in Greenbelt, Md., where the instrument was built.

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