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Pluto (Photo from NASA’s New Horizons mission)
As promised we are dedicating today’s post to the New Horizons spacecraft. The unmanned robot probe (which is the size of an unwieldy motorcycle) flew past Pluto at 7:49 a.m. EST, traveling at nearly 50,000 kilometers per hour (31,000 mph). At its nearest approach, the craft was only 1200 kilometers (7500 miles) above Pluto’s surface—closer to Pluto than Brooklyn is to Botswana.
Because of the shape and size of the solar system, the telemetry of the mission, and the niceties of radio-communication, NASA did not receive the information dump from the spacecraft until 00:53 GMT Wednesday which is uh…approximately right now! So I haven’t had any time to groom the Pluto data! Today’s post is thus more of a laurel. But the information does exist—the craft survived and completed its mission. We have a trove of knowledge about Pluto to help scientists understand the nature of the solar system—or to conceive of what kinds of new questions to ask about other planetary systems. Maybe I’ll be desperately writing another post tomorrow if scientists unexpectedly find canals on Pluto or discover that Nyx is really a giant egg or something, but most likely this data will take a long time to process and understand. Such is the nature of science (and most worthwhile pursuits). So what is the purpose of this post?
I have never been unduly upset about the designation “dwarf planet” for things like Pluto, Ceres, Eris, and Haumea. However I did grow up with “My very educated mother just served us nine pizzas” (a much snappier mnemonic than “My very educated mother just served us nothing”), and the idea of Pluto as the final planet still holds undeserved weight in my subconscious. I have thus been taking NASA’s self-congratulatory PR announcements seriously when they say “we complete the initial reconnaissance of the planets.” That sounds right to me. Humankind has gathered a great deal of information about the solar system. Now it is time to brainstorm some new objectives before the fickle public loses its interest and wanders off.
This graphic is old…What next?
There is a national consensus that we should be spending all of our money on expensive cell phones and vastly overpriced (yet disturbingly ineffectual) medical care. The space age is reckoned to be over—and space should now be left to the likes of Elon Musk and other James Bond villain-ish mega billionaires. I think this is wrong, wrong, wrong, wrong, ever so wrong. Now that we have some ideas about what is out there we should use our hard-won knowledge to do tremendous things! My favorite next step is an atmospheric mission to Venus. Let’s send some cool space blimps to sit in the high atmosphere of our sister planet and maybe launch some weird little drones and smaller balloons into the atmosphere. We could find out whether a floating colony is even feasible. Plus it would be like the Montgolfier brothers and the Wright brothers all over—on another world!
Oooh! Can we use a donut-shaped balloon?
The idea of a human mission to Mars and a submarine mission to Europa also have great merit—but I see them as more difficult and with less practical purpose. What are your favorite ideas about what to do next? This seems like a good moment to at least talk about the direction we are headed, even as we sip champagne and dance joyously about what we have done.
“Champagne in Space” by Jshinncreative on DeviantArt
Artist’s redition of New Horizons approaching Pluto and Charon
After years and years and years of waiting, NASA’s New Horizons mission is officially in its “flyby” stage. As I write, the robot probe is desperately snapping pictures and taking readings of Pluto and its moon Charon. The closest pass-by will arrive next Tuesday when New Horizons will be a mere 12,500km from the dwarf planet.
Hmm, I can sort of see a heart, a whale, and a donut (Photo courtesy of NASA, New Horizons)
Today’s post serves to alert you to keep your eyes peeled next week! I will be eagerly awaiting news of the developments and I will relay them to you as quickly as possible–although Pluto is 320 light minutes away from us (give or take a few hundred million kilometers) so nobody is going to be caught up in real time. In the meantime, New Horizons is already learning more about the dwarf planet than we have ever known before: this is a mission to a world almost wholly unknown to us despite the fact that we are neighbors in the same star system! Pluto has a distinctive reddish pinkish hue and features an array of high-contrast features (presumably composed of layers of exotic ices) which, to human eyes, superficially resemble familiar shapes. Most notable is a large cardiod-shaped feature in the southern hemisphere unsurprisingly dubbed “the heart”. There is also a planet sized stain resembling a whale and a smaller stain which looks like a donut. No doubt we will get a better idea about these bright/dark areas during the close-up approach next week. Right now I hope people are appreciating my artistic prescience!
Mister SETI (Wayne Ferrebee, 2012, oil on panel)
The main thing which is currently striking to scientists (who have better things to worry about then whether methane ice looks like a whale) is how dissimilar Pluto is from its moon Charon. The two objects are closer size-wise than any other planet/moon system in the solar system, yet Charon is completely unlike Pluto in appearance and make-up. The moon, which is named after the ferryman of the underworld, is gray and nearly featureless and has no atmosphere (I should have mentioned that Pluto does have an atmosphere—at least at this phase of its strange orbit).
Hooray for New Horizons! Considering where it is and what it is currently doing, I almost find it hard to think of it as real, but it most assuredly is. Also hooray for us! We have some bad moments, but we can launch a highly functional robot out of Earth’s gravity well to the edge of the solar system! It isn’t a space colony on Venus—but it’s a start. Our arms are growing longer and our apprehension keener. I almost can’t wait for next week, yet somehow I think I’ll still manage to enjoy the weekend.
Artist’s conception of the New Horizons spacecraft flying past Pluto and Charon
More dramatic news from the far reaches of the solar system: NASA’s probe New Horizons has awakened from its nine year hibernation and is powering up to approach Pluto! Although it sounds like “New Horizons” is a boy band, NASA gave up on trying to launch every saccharine teenybopper act into the Kuiper belt (although that is a laudable goal): instead the probe is named after the fact that New Horizons is the first human spacecraft to explore the dwarf planet Pluto and its little moons Charon and Hydra. Launched in January of 2006, New Horizons set the record for the highest launch speed of a human-made object from Earth. The grand piano-sized spacecraft has spent the intervening years hurtling through the darkness of space–although it has periodically come to partial wakefulness to check in with mission control and to snap some dramatic flyby photos of famous locations along its trip (like this photo montage of Jupiter and Io). The craft also used Jupiter’s gravity well to increase its velocity.
Composite image of Jupiter and Io as photographed from New Horizons (NASA)
Since the time the probe was launched, astronomers have discovered two new miniature moons of Pluto: Kerberus and Styx. This means that New Horizons mission planners were forced to assess the possibility of a catastrophic collision with unseen debris or dust left over from these satellites. Computer models suggest that the likelihood of such an accident is remote, but, just in case, NASA has added two dramatic contingency plans for the mission. In one emergency plan, the probe’s satellite dish acts as a dust shield, in the other, the craft drops dangerously close to Pluto, where atmospheric drag has presumably cleared the surrounding space of particles. These worst case plans will almost certainly not be needed, although we will learn more as New Horizons gets closer to the dwarf planet.
After flying past Pluto next July, New Horizons will hurtle into the Kuiper belt where NASA hopes the probe will rendezvous with an icy Kuiper belt object so that we can learn more about these enigmatic leftovers from the creation of the solar system. The coming 7 months should be filled with excitement as we learn more about the Pluto system!
The cornucopia is an ancient symbol of harvest abundance. It is commonly represented as a woven spiral basket overflowing with fruit, grains, vegetables, and other agricultural products. In America it is one of the symbols of Thanksgiving time (second only to the magnificent turkey). The wicker basket stuffed with fruits has become such a familiar image, that it is easy to overlook the Greco-Roman roots of the horn of plenty.
According to Greek legend, the cornucopia is the horn of Amalthea, the goat which served as foster mother to Zeus. In the benign version of the myth, young Zeus, unaware of his own strength, accidentally broke the horn off of the goat while he was playing with her. In the darker version, he slaughtered the goat when he reached manhood. From her hide he fashioned his impenetrable aegis. He gave her horn to the nymphs who had raised him, and this horn provided a magical eternal abundance of farm-raised food. In memory of her generosity, he set her image in the stars as the constellation Capricorn. There is yet another version of the cornucopia myth which Hercules broke the horn off of a river god and this became the original horn of plenty.
Infant Jupiter Fed by the Goat Amalthea (Jacob Jordaens, print)
Whatever its origin, the cornucopia remained a part of the classical pantheon. It is most frequently seen in the hands of Ceres/Demeter, the goddess of agriculture and grains. In Roman iconography the cornucopia was sometimes an attribute of Fortuna, the goddess of luck, and of the underworld god Pluto (who controlled the ground and thus was responsible for the gifts of the harvest).
Demeter holding a Cornucopia
I like the Hercules/river-god myth because it reflects on how important water is to agriculture, but I greatly prefer the myth of Zeus and his foster-mother which seems to embody the moral quandaries (and the promise of civilization) which are inherent in agriculture. The story—like that of Cain and Abel–hints at the replacement of hunting with herding and farming (indeed goats were the original domesticated animal). Some cornucopias are now made of baked goods which makes the symbolic transition even more apparent. The horn of plenty is an admirable symbol of humankind’s fundamental dependency on agriculture–which lies at the root of our civilization and our prosperity. I am glad the cornucopia has kept its relevance for all of these thousands of years and has not been replaced by some tamer symbol.
Artist's Interpretation of Sedna (Credit: Gemini artwork by Jon Lomberg)
After the discovery of Pluto in 1930, there was a long hiatus in discovering objects of comparable size. Then in 2003, a team of astronomers led by Mike Brown of Caltech discovered a distant icy sphere which was quickly heralded as “the tenth planet.” Mike Brown announced the discovery on his website along with his team’s rationale for naming the object. He wrote “Our newly discovered object is the coldest most distant place known in the Solar System, so we feel it is appropriate to name it in honor of Sedna, the Inuit goddess of the sea, who is thought to live at the bottom of the frigid Arctic Ocean.
It turns out that Sedna is only one of many similar snowball-like planetoids beyond Neptune. In fact, Ferrebeekeeper has already described the dwarf planet Eris (named after the Greek goddess of Strife) which is the largest currently known Kuiper belt object. Sedna was the first to be discovered since Pluto and it sparked a debate about such objects which ultimately resulted in Pluto’s downgrade to dwarf planet. Sedna also has some unique features which make it remarkable in its own right.
The orbit of Sedna (red) set against the orbits of Jupiter (orange), Saturn (yellow), Uranus (green), Neptune (blue), and Pluto (purple)
Sedna takes 11,400 years to complete its orbit around the sun and its bizarre highly elliptical orbit has given rise to much conjecture among astronomers. Although some astronomers believe it was scattered into a skewed orbit by the gravitational influence of Neptune, other astronomers believe it originated in the inner Oort cloud and was never close enough to Neptune to be affected by the giant’s gravity. Some scientists speculate that its lengthy orbit may have been caused by a passing star (perhaps from the sun’s birth cluster). A few theorists have gone one step further and conjectured that Sedna is from a different solar system and was captured by our Sun billions of years ago. A final school contends that Sedna is evidence of an unknown giant planet somewhere in the depths of space (!).
A photo of Sedna taken from a powerful telescope on Earth
We don’t know much about Sedna except that is probably 1,200–1,600 km in diameter and that its surface is extremely red. After Mars, Sedna is one of the reddest astronomical objects in our solar system. This color comes from the profusion of tholins covering the methane and nitrogen ice of which the little world is formed. Tholins are large, complex organic molecules created by the interaction of ultraviolet light on methane and other simple hydrocarbons. It is believed that early Earth (prior to obtaining an oxidizing atmosphere) was rich in Tholins and they are one of the precursors to the rise of life.
During my break from blogging, I visited the Getty Villa on the Malibu coast, which has a tremendous collection of Greco-Roman objects from the classical and pre-classical eras. One of the more lovely artworks in their collection was this first century Roman statue of Pluto carved from marble.
Statue of Pluto (Roman, ca. First Century, Marble)
The Getty’s label for this sculpture reads as follows:
Pluto (Hades to the Greeks) was the Roman god of the Underworld. He is depicted here in the guise of Plouton, a Greek deity associated with wealth and agrarian abundance. The mature bearded figure stands draped in a long cloak. A large cornucopia (now broken) rests in his left arm as a symbol of prosperity. Although sculpted in the Roman era, this statuette is modeled after a Greek work of the Hellenisitic period (323-31 BC)
Like Poseidon, Pluto/Hades was the older brother of Zeus. When he was born he was consumed by his father Cronus. Once rescued from that predicament by Zeus’ cunning, he joined his siblings in the terrible war against the Titans. When the Olympians were triumphant, Zeus gave Pluto suzerainty over the underworld, the dead, and all things within the ground.
Although Pluto appears in many myths, the most important story about him concerns the manner by which he obtained a spouse. The other deities feared and avoided Pluto, who was solitary and gloomy. The goddess Demeter, the goddess of growing things, had a radiant daughter named Persephone, a maiden of unsurpassed loveliness. One day, as Persephone was gathering flowers, Pluto opened a chasm in the world and drove up from the darkness in a chariot drawn by midnight black horses. The god of the underworld captured the trembling girl and bore her down to his opulent palace in the land of the dead. No longer a maiden, Persephone took no joy in the rich jewels and precious metals of Pluto’s great mansion. The only consolation to her was the dark garden of the underworld where she beguiled her time surrounded by the silent weeping shades of the dead.
Rape of Proserpine (Niccolò dell'Abbate, ca. 1571, oil on canvas)
Although Zeus had consented to this arrangement, even he was unprepared for Demeter’s wrath. She withdrew her gift of fertility from the world (a theme seen in both the story of Psyche and the myths concerning Oshun, an Afro-Brazilian love goddess) and everywhere people and animals starved. The world began to wither into a lifeless desert and Zeus was forced to send his messenger, Hermes (Mercury), to retrieve Persephone. But, while in the garden of the underworld, she had eaten four seeds of a pomegranate. Thereafter she was forced to return to the underworld for four months of the year to rule beside Pluto as queen of the dead.
Statues of Hades/Pluto are much less common than statues of the other Olympian deities. Greeks and Romans feared drawing his direct attention but they also feared to anger him by not sacrificing to him in worship. There were therefore a number of euphemisms for the deity such as “rich father” or “giver of wealth”. Additionally, since Pluto ruled all things under the ground, the Plouton identity, seen in the statue, came to be associated with wealth and with agricultural fertility–after all, gold and jewels came from the ground—as did life-giving crops. The Eleusinian Mysteries celebrated a more positive aspect of Pluto–as the god of wealth and the spouse of the life-giving Persephone. It was believed that initiates of these mysteries would enjoy Persephone’s favor in the underworld and would be granted access to the beautiful glowing fields of asphodel which she planted in the underworld.
ferrebeekeeper 