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We knew that, if the Webb telescope could make it to the L2 Lagrange Point in one piece and deploy properly, this would be an exciting season for astronomers–but, even so, the parade of stunning new images from outer space are marvelous and demand comment. Today’s treasure is a picture of Planet Neptune and its moons as imaged by the near-infrared camera on Webb. The ice giant Neptune is made of strange cold things with a great pall of methane gas over them. Methane gas is very opaque to infrared light (which it absorbs) and so the planet looks like a frosty, haunted bowling ball with glass rings.
Ever since Pluto got demoted to “dwarf planet”, Neptune is the outermost world of our solar system. Yet the great gas giants…or even the trans-Neptunian objects like Eris and Haumea get all of the attention. No space craft has even visited Neptune since Voyage II rolled by in 1989 (the first and last time a probe entered the Neptune system).
Aside from the spectral rings, the image shows some bright sparks in a line along Neptune’s Tropic of Capricorn (which is not called that, but you get the idea). These bright spots are caused by high altitude methane clouds which are made of methane ice (which reflects infrared light better than methane gas does).
The full Webb photo has a striking focal point! Pulling back we see that Neptune’s largest and strangest moon Triton outshines the giant world it orbits. This is because Triton (which is named for the Greco-Roman deity Neptune’s merman super-son) is covered in a sheet of frozen nitrogen which reflects 70% of the sunlight which strikes it–so Triton glows like an aquamarine star in this photo. Ultimately Triton might well turn out to be be more interesting than Neptune: it is the only large moon in the solar system with a retrograde orbit (an orbit opposite of the planet’s rotation). Such an unusual orbit suggests that the moon was a little world captured by the ice giant long ago.
Triton is larger than Pluto and is one of five moons in the solar system known to be geologically active (the others being Io, Europa, Titan, and Enceladus). Voyager II spotted geysers of nitrogen gas venting from the moon. Clearly cryovolcanic activity is taking place below the strange patchwork of old ice (as explained in this confusing yet compelling map/diagram) and lakes of liquid water may exist below the moon’s crust.
I am going to keep staring at images of our strange far-off neighbor world, but I can’t wait to see what Webb photographs next!
Did you know it has been 30 years since a spacecraft swung by Neptune? Voyager II was the first and last spacecraft to visit the strange ice world which (with the demotion of Pluto) is the outermost planet of our solar system. A ball of gas, ice, rock and iron 17 times the size of Earth, Neptune is the third most massive planet and is the most dense of all the giant planets. However we know surprisingly little about this distant neighbor–a fact which was vividly demonstrated this week when astronomers discovered an unexpected new moon orbiting the planet. This new moon brings the tally of Neptune’s moons to 14. Mark Showalter, a researcher at the SETI institute in California, discovered the little satellite accidentally, while working on another project and the new body was confirmed with the Hubble Space telescope (which is also still out there, by the way).
Neptune’s largest moon is the retrograde Triton. The second largest moon is Proteus, an irregular polyhedron with a diameter of 420 kilometers, named after the shape-shifting old man of the sea. The new moon, which is named “Hippocamp”, after a seahorse like Greek sea monster (above) has a diameter of about 20 kilometers (about the length of Manhattan) and seems to have been formed from ejecta left over from when some primordial body slammed into Proteus.
Astronomers have spent comparatively little time studying Uranus and Neptune compared to the other planets of the solar system–which is somewhat ironic since most of the exoplanets we are finding are ice giants. It seems like they might be noticing this gap in their knowledge. A new mission to the ice giants is the third top mission priority in a vote-based ranking of proposed probe missions (by astrophysicists…nobody asked me what I want *cough* balloon mission to Venus’ atmosphere). Hopefully we will get our act together and launch a modern robot out to the big blue ice worlds in the not-too-distant future.
King Cake (Wayne Ferrebee, 2012, oil on canvas)
In the Northern hemisphere today is the summer solstice—the longest day of the year. Here in Brooklyn, the Saturday closest to the solstice (which, this year, happens to also be the solstice) is the occasion of the Mermaid Parade, a great festival to Neptune, the Roman god of the ocean. Revelers gather in Coney Island which is a famous beach by the Atlantic Ocean. Artists, mummers, and lovers of the ocean dress as sea creatures, mermaids, and oceanic beings and parade down Surf Avenue before proceeding through Luna Park and to the beach. As a Brooklynite, I thought I should likewise celebrate Neptune and the glorious beginning of summer—which I am doing by showing one of my paintings. The title of this work is “King Cake” and everything you see is some sort of king. There is King Neptune, a king salmon, the king of herring, a king vulture, and a princely crown. The colorful torus-shaped cake is known as a king cake, which is eaten down south during carnival season. When the cake is consumed, the person who receives the piece with the baby baked inside is given a golden coin…or maybe sacrificed to the ancient gods (depending on one’s denomination and traditions). Carnival and Mardi Gras are not celebrated in Brooklyn: instead we have the mermaid parade on the summer solstice! Hail Poseidon! Hail summer!
Fontana del Tritone
(Gian Lorenzo Bernini ca.1624-1643, Piazza Barberini, Rome)
Triton (the moon) and tritons (the gastropods) are named after…Triton, a Greek sea god who was the son of Poseidon (king of the sea) and his wife Amphitrite (herself a daughter of the ocean titans Nereus and Doris). Triton was portrayed as a mighty merman who carries a musical conch with which he calms the seas…or whips them into a frenzy.
Triton lived with his parents in a golden palace beneath the waves (according to Hesiod). He has a few cameo appearances in classical mythology (most notably in the story of Jason and the Argonauts) but he is generally overshadowed by his mighty father. In late antiquity and the Renaissance, Triton came to be a sort of progenitor of mermaids and mermen (a role which he occupies in Disney’s “animated film The Little Mermaid”).
Triton and Ariel (from “The Little Mermaid”)
Geologists know that oceans and seas are indeed ever-changing and protean. Whenever I think of Triton, I imagine how the oceans of the world will be entirely different in a few hundred million years (just as today’s oceans are no longer the Tethys or the Panthalassic Ocean). Neptune’s reign will end and the oceans and seas will change–and yet they will really be the same great world-sea as they have been since the beginning.
Neptune’s Moon Triton photographed by Voyager 2 (NASA)
It is absolutely freezing here in Brooklyn—a great vortex of bitter Arctic air has swirled south across huge swathes of the nation. The temperature here is 9° Fahrenheit (or -13° Celsius). Imagine how much worse things are in Minnesota, where it is -14° Fahrenheit (or -25° Celsius). Brrr! It hurts my fingers to write about it–even in my overheated study (well—bedroom, really). Now truly stretch your mind from the frozen heartland of America to the edge of the planetary solar system. The largest moon of the ice giant Neptune is the moon Triton, discovered in 1846 by English astronomer/brewer William Lassell, and named for the son of Poseidon. On the surface of Triton temperatures plunge to 36…which is to say 36 K (Kelvin). To translate that is -237° Celsius or a bone chilling -395° Fahrenheit.
Artist’s rendering of an ice volcano on Triton with Neptune in the background (NASA)
Triton is a strange moon. It is the seventh largest moon in the solar system and it is the only large moon to orbit its planet in a direction opposite from the planet’s rotation (which is called a retrograde orbit). Since there is no model for retrograde moons forming from accretion disks, Triton must be a captured object from the Oort cloud—and, indeed, the moon is extremely similar in composition to Pluto and other dwarf planets of the Solar system’s distant periphery. Despite the extreme cold of Triton’s surface, the moon is geologically active. Like Earth, the moon is probably differentiated into layers: a core, a mantle, and a crust. The crust is formed of ice: frozen water, methane, and nitrogen. A large polar cap covers the southern pole, but much of the rest of the moon is a“cantaloupe” surface of melted and refrozen ice. The surface is (geologically) young. Cryovolcanic activity and tidal forces have kept the ice active. Cryovolcanoes were first spotted on Triton during the Voyager 2 flyby in 1989 (the first time such phenomenon were ever observed). Because of tidal warming (caused by gravitational interaction with Neptune), Triton may have once had a liquid ocean beneath the crust, but this has likely solidified assuming that there is no radioactive decay from the rocky core.
A size comparison of Earth, Earth’s moon, and Triton
Triton is closer to Neptune than the Earth’s moon is to Earth…and Neptune is seventeen times more massive than Earth. This doesn’t bode well for the long term future of Triton. Within the next three and a half billion years, the moon will either be pulled into Neptune’s surface and swallowed or it will be ripped to pieces and form a spectacular ring structure like Saturn’s.
The Bailey Fountain (beautifully photographed with the arch behind it by Wally Gobetz)
I love fountains and my home, New York City, is an excellent place to witness all manner of lovely ornamental waterworks. No doubt other bloggers have extolled Manhattan’s many famous fountains, so I thought I would briefly write about my favorite fountain in Brooklyn, the Bailey Fountain, which is located at Grand Army Plaza at the north end of Prospect Park. The fountain lies beyond the huge triumphal arch which celebrates the victorious conclusion of the American Civil War. Both fountain and arch lie on a traffic island surrounded at all times by dangerous rivers of vehicles.
Wisdom and Felicity form the Bailey Fountain (another fine photo by Wally Gobetz)
The Bailey Fountain was conceived of during the late nineteen twenties but it was built in 1932. The tension between these two very different eras is noticeable in the ferocity and severity of the classical figures. The fountain seems to be an allegory of abundance however the individual figures look like they instead portray greed, abandon, and resignation. The fountain is the work of architect Edgerton Swarthout and the bronze sculptures were crafted by Eugene Savage. I think the final work might transcend what either had initially intended.
The Bailey Fountain (photo from “Tugster: a Waterblog”)
Bailey fountain portrays a pair of magnificent bronze nudes standing on the deck of a ship. The two respectively represent wisdom and felicity. I assume the man is wisdom and the woman is felicity, but it is not easy to tell because she does not look happy and he does not look wise. Although they both look powerful the figures seem wan and resigned. Additionally, although they are connected, their backs are forever turned to each other. A besotted Nerues, the “old man of the sea” sprawls on the prow as grim Tritons sound horns and writhe on both sides of the boat. Strange frog and fish faces spew white water around the tormented figures. The boat and its inhabitants represent humankind and the figures in the water represent chance and the forces of nature. When contemplating the fountain it is easy to pitch your mind back to the time of the great depression and see Nereus and his fierce watery compatriots as the unquenchable greed, panic, and other raw group passions which spawned the hardships of that era.
FFigure of King Neptune from the Bailey Fountain (www.nyc-architecture.com)
The Bailey fountain replaced a bizarre Victorian electric water show which was the rainbow-colored high-pressured wonder of its time (but which did not hold up well since it combined early electrical technology, 19th century plumbing, and Brooklyn winters). I first saw the Bailey fountain in the mid-nineties when it was broken and dry: large portions of the work were painted the same aqua blue as swimming pools. The plaza seemed deserted except for the eternal traffic, the sinister vine covered trees, and a huge tribe of rats. Great hunks of granite pavement had been broken apart by frost heave (or some other urban force) and melancholy pervaded the scene. A lone homeless person sidled up and sadly informed me that the fountain was haunted and, in the lugubrious twilight, I half believed him. Today, however, the fountain has been restored, and you can contemplate its enigmatic meaning in a much more pleasant surrounding.
Bronze triton from the Bailey Fountain (photo from “Tugster: a Water Blog”)
ferrebeekeeper 