Well, the moving truck finally brought our stuff to us in Virginia, and that meant it was time to organize and shelve all of our books. How to do it? By subject? By author? By color? By sum of all ISBN digits? By how loud the book is when dropped from 4.5 feet? Well being the giant academic nerd that I am, I suggested “why not just use the Library of Congress?” We did.
Now really, even though my family has a lot of books, we don’t have nearly enough to call what we have “a library,” and so the Libraray of Congress system isn’t exactly a perfect fit, but it made the decision for us, and it was both a little fun, and turned up a couple of surprises along the way. Here are a couple that stood out while we were sorting and shelving:
Anthony Bourdain, the opinionated trash-talking chef and travel guide of No Reservations (among other shows) has written a number of books about his career and experiences as a chef and world traveler. Where does the LoC put his books? Why TX – Home Economics of course!
The Physics of Christmas by Roger Highfield gets put into GT - Manners and Customs, as the subject has been determined to be 1. Christmas and then 2. Science. Also in the G section (subsection GF - Human ecology. Anthropogeography) are the The Worst Case Scenario Survival Handbook line of books. Except, oddly enough, The Worst Case Scenario Survival Handbook: Work Which ends up in PN - Literature (General).
Historical creative non-fiction also end up in weird places. The creative non-fiction The Perfect Storm by Sebastian Junger gets sorted into QC – Physics, and Seabiscuit: An American Legend by Laura Hillenbrand goes into SF - Animal husbandry, Animal science.
Now I’m not a librarian, nor do I have any training in library science. I’m not knocking the classification system here at all – in fact I may have even been poorly informed by the various search engines I used to look up the LoC classifications for my books that didn’t have them printed on the copyright page. I’m just an astronomer with a couple bookcases of books who is rather amused by where this classification scheme puts some of them. With that disclaimed I’ll sign off with one last placement oddity: The Pursuit of Happyness by Chris Gardner (now a movie starring Will Smith) gets filled under HG – Finance.
Monday, July 30, 2012
Friday, July 20, 2012
And then there were five…
134340 Pluto has a new moon, bringing the distant dwarf planet’s collection of satellites to 5. No official name for the little guy yet, but this 10 to 25 km piece of (more than likely) ice takes about 20 days to orbit Pluto at a distance of about 42,000 km, placing it between Charon (the largest and innermost know moon) and Nix. With the New Horizons probe on the way to Pluto, the little world’s family of moons continues to grow.
Pluto’s first satellite, Charon was discovered by James Christy in 1978. He noticed a “bump” in the images of Pluto that changed position (and even disappeared) from image to image. Since then studies of Charon has allowed for much better mass measurements of Pluto, as well as revealing information about the moon itself. Charon is, in relation to its parent, the largest object we consider a “moon.” Charon’s diameter is about half that of Pluto, with 12% the dwarf planet’s mass. Compare that to the Earth-Moon system: our Moon is about a quarter the diameter of the Earth in size with only 1.2% of the mass of the Earth, and our Moon is abnormally large compared to most planetary satellites (e.g. Saturn’s largest moon Titan is about than .02% the mass of Saturn!). Charon is so massive compared to Pluto that it causes Pluto to actually orbit a point ouside of itself in space. Really Pluto-Charon could be considered a double dwarf planet (or a binary Kuiper Belt Object) as they both orbit around a point partway between each other.
Charon and Pluto are also tidally locked to one another, Pluto’s rotation, the rotation of Charon and the the orbit of Charon all take the same amount of time, roughly 6 days, 9 hours. This situation results Pluto and Charon always “facing” each other. Charon will always be in the same place in the sky for an observer on Pluto (and the other way around too!).
The rest of Pluto’s family of satellites are more recent discoveries. The dwarf planet had been under detailed study to prepare for the New Horizon’s mission, which was launched in 2006, and is scheduled to fly-by Pluto and its moons in 2015. By blocking the light from the bright sources of Pluto and Charon, the region near Pluto may be searched for additional, small and faint bodies. In 2005 a team conduced a search for companions of Pluto using the Hubble Space Telescope and discovered two new satellites of Pluto, later officially designated Nix and Hydra. In 2011 a 4th moon of Pluto was discovered, “P4” Which brings us up to today, with the recent announcement that a 5th moon of Pluto, “P5” had been identified through HST images. All four of these newer moons are pretty small, with the largest one, Hydra, between 60 to 170 km across, while the smallest moon, the newly discovered “P5,” being only 10-25 km in diameter. Quite a bit of the uncertainty in size comes from not knowing how reflective these moons are. If they have very dark surfaces, they will be larger than if they had very reflective surfaces since these size estimates are based on how bright the sunlight is that has reflected off of their surface and been collected by our telescopes.
Of interest is the relationship that the orbits of Pluto’s moons have with each other. They are all very close to mean motion resonances with the Pluto-Charon system. From closest P5, Nix, P4, and Hydra are almost in a 1:3:4:5:6 resonance with the Pluto-Charon. That means that every 6th time Charon orbits Pluto, P5 will have completed 5 orbits, Nix will complete 4, P4 will have completed 3 and Hydra will have finished one orbit of Pluto. Details are being studied right now, but it seems as though none of them are in a “perfect” resonance – but the orbital dynamics of the Pluto system are getting very interesting indeed.
In fact a colleague of mine, Dr. Alex Parker at the Harvard–Smithsonian Center for Astrophysics, has made a wonderful demonstration of how close to resonance these moons are. By translating their orbital frequency into sound, and boosting it by 29 octaves (to be in the auditory range) Dr. Parker has turned the Plutonian orbits into “music”. One can visit his SoundCloud page: http://soundcloud.com/alexhp-1/plutos-five-moons and hear the slight difference between a perfect resonance, and what we have measured the Plutonian system to be in. Seriously, check it out – it is super cool.
Pluto’s system of five moons. Pluto and Charon are added into this composite image from a different source – the light from them needs to be blocked in order to make out the much fainter satellites.
Now you see me now you don’t: The “bump” that would become known as Charon is visible to the upper right of Pluto in the first image, but not in the second.
Charon and Pluto are also tidally locked to one another, Pluto’s rotation, the rotation of Charon and the the orbit of Charon all take the same amount of time, roughly 6 days, 9 hours. This situation results Pluto and Charon always “facing” each other. Charon will always be in the same place in the sky for an observer on Pluto (and the other way around too!).
The rest of Pluto’s family of satellites are more recent discoveries. The dwarf planet had been under detailed study to prepare for the New Horizon’s mission, which was launched in 2006, and is scheduled to fly-by Pluto and its moons in 2015. By blocking the light from the bright sources of Pluto and Charon, the region near Pluto may be searched for additional, small and faint bodies. In 2005 a team conduced a search for companions of Pluto using the Hubble Space Telescope and discovered two new satellites of Pluto, later officially designated Nix and Hydra. In 2011 a 4th moon of Pluto was discovered, “P4” Which brings us up to today, with the recent announcement that a 5th moon of Pluto, “P5” had been identified through HST images. All four of these newer moons are pretty small, with the largest one, Hydra, between 60 to 170 km across, while the smallest moon, the newly discovered “P5,” being only 10-25 km in diameter. Quite a bit of the uncertainty in size comes from not knowing how reflective these moons are. If they have very dark surfaces, they will be larger than if they had very reflective surfaces since these size estimates are based on how bright the sunlight is that has reflected off of their surface and been collected by our telescopes.
Of interest is the relationship that the orbits of Pluto’s moons have with each other. They are all very close to mean motion resonances with the Pluto-Charon system. From closest P5, Nix, P4, and Hydra are almost in a 1:3:4:5:6 resonance with the Pluto-Charon. That means that every 6th time Charon orbits Pluto, P5 will have completed 5 orbits, Nix will complete 4, P4 will have completed 3 and Hydra will have finished one orbit of Pluto. Details are being studied right now, but it seems as though none of them are in a “perfect” resonance – but the orbital dynamics of the Pluto system are getting very interesting indeed.
In fact a colleague of mine, Dr. Alex Parker at the Harvard–Smithsonian Center for Astrophysics, has made a wonderful demonstration of how close to resonance these moons are. By translating their orbital frequency into sound, and boosting it by 29 octaves (to be in the auditory range) Dr. Parker has turned the Plutonian orbits into “music”. One can visit his SoundCloud page: http://soundcloud.com/alexhp-1/plutos-five-moons and hear the slight difference between a perfect resonance, and what we have measured the Plutonian system to be in. Seriously, check it out – it is super cool.
Sunday, July 8, 2012
Off the air for a week or so.
A Sky Full of Rocks will resume its normally sporadic schedule later this month. I’m moving across the country and will be at the whim of when the cable folks show up to the new place. That said, cool stuff is happening, from the CERN / Higgs Boson stuff on the 4th of July, to the MSL Curiosity Rover’s landing on Mars on August 6th, and bunch of things between then too.
Tuesday, July 3, 2012
Flag Day - The Updating!
Turns out I’ve already got an update to my Flag Day! post from a little bit ago. I had speculated that like Pathfinder, the flag decals on the Mars Exploration Rovers, Spirit and Opportunity, were under the camera-mast, and thus not imaged by the rovers. Boy was I wrong!
These two steel spheres (diameters 7.5 and 12 cm respectively) were carried to the Moon by the Soviet Union’s Luna-2 spacecraft. Each of these spheres was filled with a an explosive designed to fragment them like a very large grenade, showering the Lunar surface with the little pentagonal pennants that the spheres were crafted out of. It is really unlikely that any of these little medals survived. On September 13, 1959 Luna-2 didn’t land gently on the Moon, but rather plowed into it at over 3 km/s. The energy generated by the impact of a 400kg spacecraft at the speed would generate enough heat to vaporize steel. One of the ideas behind the explosives inside the spheres was to try and remove some of the impact velocity, and thus allow at least some of them to survive. It’s possible but, in my opinion, unlikely that they made it through the impact intact.
Here’s the flag on the instrument deployment device (IDD), the rover’s “arm” on Opportunity. All that dust on the instrument is left over from using its rock abrasion tool (sort of a grinder/drill) on the exposed rocks during Opportunity’s 31st Martial day.
I also missed an obvious “2-fer” on Spirit! Beyond the decal on the IDD, Spirit also carried with it a memorial to the crew of the Space Shuttle Columbia, STS-107.
The above memorial plaque carries the US flag, along with the names of the Astronauts who were lost on the Columbia. If you look closely you can see an additional Israeli flag next to the name of Ilan Ramon, Israel’s first astronaut.
As a bonus here’s a shot of the first “nationally branded” object deployed to the surface of the Moon
These two steel spheres (diameters 7.5 and 12 cm respectively) were carried to the Moon by the Soviet Union’s Luna-2 spacecraft. Each of these spheres was filled with a an explosive designed to fragment them like a very large grenade, showering the Lunar surface with the little pentagonal pennants that the spheres were crafted out of. It is really unlikely that any of these little medals survived. On September 13, 1959 Luna-2 didn’t land gently on the Moon, but rather plowed into it at over 3 km/s. The energy generated by the impact of a 400kg spacecraft at the speed would generate enough heat to vaporize steel. One of the ideas behind the explosives inside the spheres was to try and remove some of the impact velocity, and thus allow at least some of them to survive. It’s possible but, in my opinion, unlikely that they made it through the impact intact.
The first Soviet Moon probe, Luna-1, also carried a similar sphere, but missed the moon (Luna-1 passed within 6,000 km of the Moon on January 4, 1959), and is now in a 450 day orbit about the Sun.
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