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Today (June 30th) is asteroid day.  For this auspicious (yet anxious-making) holiday, I have been saving two asteroid-related miniature stories ripped from the headlines.

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First, we return to the dwarf planet Ceres, the largest object in the asteroid belt.  We need to revisit the bright spots upon the dwarf planet’s surface.  Ever since the New Horizons spacecraft began to approach the little world, these glistening spots have fascinated the astronomy community.  Initially scientists thought that the spots were composed of hydrated magnesium sulfate (a substance quite similar to the Epsom salts sold for bathing and foot-soaking), however it now seems like the shiny patches are made of something else entirely.  According to astronomers, the particular chemical in these glistening patches actually turns out to be sodium carbonate–a salt formed from carbon.  On Earth, this chemical usually forms in evaporitic conditions–when water evaporates from a lake, sea, or hot springs.  This seems to indicate that the geology of Ceres is more complicated than initially thought—instead of a big ice crystal which has always been the same, the miniature planet has undergone changes: surface water evaporated to leave these mysterious chemical deposits.  Hopefully finding out about Ceres’ past can teach us more about how planets form (or don’t form).

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Second, we turn our eyes back closer to Earth to take in the newly discovered “second moon” a tiny asteroid about the size of the great pyramid of Giza which seems to be orbiting Earth.  This new asteroid, called 2016 HO3, is not really a true moon but a quasi-satellite: it sometimes loops around our planet because Earth and the little rock both orbit the sun on a similar circuit.  The asteroid orbits the sun in 365.93 days (just slightly longer than Earth’s orbit of 365.24 days). Thus, for the next few hundred years it will act like a true moon as our orbits converge. The rock is about 40 meters (130 feet) across by 100 meters (328 feet) wide.  It is a bit strange to think about it up there hidden in the darkness, but it is a fairly comforting asteroid day story.  2016 HO3 is never destined to hit Earth.  The really bad asteroids seem to be the ones we don’t know about (so it is time to keep our eyes on the skies and learn more).

The Mountain on Ceres (Dawn Space Probe, NASA)

The Mountain on Ceres (Dawn Space Probe, NASA)

Now that the Dawn spacecraft has actually reached the dwarf planet Ceres, Ferrebeekeeper has been writing less about it!  Today we will remedy that with a spectacular photo taken from the robot probe.  Remember the strange reflected light from Ceres which the world was so fascinated by?  Well now that Dawn is a mere 1500 kilometers (900 miles) from Ceres, we have discovered that the reflections come from a huge glistening mountain—a strange anomaly on the puckered cratered terrain of the dwarf world.   This mound is likely made of some sort of ice and is about the same size as Mount McKinley—the highest mountain in North America (approximately 6,000 meters (20,000 feet) tall).  Geologists (or I guess I should say astrophysicists) are baffled by why the mountain is there—but I am sure that theories will be forthcoming.

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Pundits and media personalities talk about this singular ice mountain as a pyramid (possibly to get hits), but to me it looks like a huge limpet made of ice.  Here is a 360 degree panoramic sweep around of the mountain (which needs a name!).  I wonder what other odd things are hiding in less plain sight on the little world.

Artist's redition of New Horizons approaching Pluto and Charon

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)

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)

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).

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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.

Time lapse photo of the movement of 2012 VP113 (color digitally added)

Time lapse photo of the movement of 2012 VP113 (color digitally added)

Astronomers today announced the discovery of a new dwarf planet at the edge of the solar system. Until the appropriate nomenclatural bodies settle on a snappier name, the tiny body will be known by the unwieldy moniker of 2012 VP113. The little planetoid is estimated to measure about 450 kilometers in diameter (so it is much smaller than other plutoids like Haumea (which is approximately 2,000 km x 1,500 km x 1,000 km). Speaking of Haumea, which has a mysterious pink spot, the new object (which I’ll call VP113, for short) is also suspected to be light pink because radiation causes the frozen gases to decay to that color.

Even when it is closest to the sun, the little planetoid is still 12 billion kilometers (7.4 billion miles) distant from our home star–but at the farthest extent of its orbit 2012 VP113 is a whopping 70 billion kilometers (44 billion miles) from Sol. That’s almost a thousandth of a light year! The irregular orbit takes 44,000 Earth years to complete—which means one year there is a very long time!

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You might be wondering why I am taxing your brain with obscure snowballs, but, astronomers are very interested in VP113 because of what it might reveal about the origins of the solar system. In 1951, the Dutch-born astronomer, Gerard Kuiper, predicted the existence of a vast cloud of icy objects at the remote edge of the solar system. The Kuiper belt has indeed been discovered—it is a belt of dust and icy objects approximately between Neptune and Pluto. In 1950, a Dutch astronomer, Jan Hendrik Oort revived an idea from the 1930s (from Estonian Ernst Öpik) that there was a huge spherical cloud of comets, vapor, and icy planetoids at the edge of the solar system—beyond even the orbits of miniature planets Eris, Sedna, and VP113. [I don’t know why all the scientists who theorized about the solar system’s icy edges were northern Europeans].

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The discovery of VP113 proves the existence of the inner Oort cloud and provides astronomers with a source of information about the objects in the Oort cloud. Additionally the extremely strange orbits of VP113 and Sedna begin to suggest that an alien star disturbed the Oort cloud in the past—or that there may still be an Earth sized planet at the true edge of the solar system.

Ceres (optimized image from the Hubble Space telescope)

Today’s post topic is located in the depths of space far far away from the bats, pumpkins, and haunted deserts I have been writing about for October. The dwarf planet Ceres is located in the midst of the asteroid belt between Jupiter and Mars.  The only dwarf planet in the inner solar system, Ceres is only 950 km (590 miles) in diameter, but it is sufficiently large to have become spherical from its own gravity (and it is by far the largest asteroid). Named after Ceres (Demeter), the mythological goddess of growing things whose daughter was abducted by Hades and who gave the secrets of agriculture to humankind through the farmer Triptolemus, the dwarf planet was discovered in 1801 by Italian astronomer Giuseppe Piazzi, a Roman Catholic priest of the Theatine order.  Ceres was the first asteroid to be discovered and it comprises a third of the asteroid belt’s total mass.

A comparison of the sizes of the Earth, Moon, and Ceres

The nebular hypothesis proposes that the solar system formed as a great cloud of space dust and gas coalesced into a disk which then further coagulated into small clumps, then into planetesimals, then into moon-sized planetary embryos, and finally into planets. Ceres is one of the few (or maybe the only) planetary embryos which formed four and a half billion years ago but somehow did not get smushed together with other like bodies to form a planet or hurled off into deep space. The dwarf planet probably consists of a rocky core surrounded with an icy mantle of frozen water.  Ceres is believed to contains 200 million cubic kilometers of water–more fresh water than in all the lakes, rivers, clouds, swamps, ponds (and everything else) on Earth. The Hubble telescope has photographed several mysterious surface features on Ceres including a dark spot believed to be a crater (now informally named after Piazzi) and several bright spots, the nature of which is unknown.

Image of the bright spots on Ceres (taken by the Hubble Space telescope)

Astronomers are profoundly curious about Ceres and hope to better understand the history of the solar system by examining this surviving planetary embryo.  Additionally, the chemical makeup of Ceres is similar to that of Earth. Scientists seeking extraterrestrial life have concentrated on Europa and Mars, but Ceres is next on their short list.

Astronomers will soon have some of their answers about Ceres.  The asteroid probe Dawn is currently orbiting the asteroid Vesta–but its mission there is scheduled to end in July of 2012.  At that point Dawn will power up its ion thrusters and fly to Ceres. In February of 2015 Dawn will enter permanent orbit around the little planet and we will finally have some of our answers.

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