Australian icebreaker nearing Akademik Shokalskiy ship in Antarctica

View from the Akademik Shokalsky a day ago
from the NYTimes.com 

Nearly a week ago, the Russian ship, Akademik Shokalskiy ship became trapped in ice in the Antarctic. The ship is an ice-strengthened expedition vessel, currently carrying both tourists and scientists studying environmental change near Cape de la Motte, about 1,700 miles south of Hobart, Tasmania. Strong winds pushed the ice pack against the ship, with ice thicknesses around 10 m. Earlier a Chinese vessel, the Xue Long attempted the rescue, but was frustrated by thick ice over the weekend.

The Russian icebreaker Krasin leading
an American supply ship into McMurdo Station
from Wiki here.

     Now, the Australian icebreaker, the Aurora Australis, is only 11 nautical miles from the ship and nearing a rescue. At the moment, the link above shows the view from the ships webcam! So, how do icebreakers work? The primary job of the icebreaker is to crush the icpack and move it aside whiteout becoming stuck itself. According to Marshall Brain on "How Stuff Works", an icebreaker has characteristics that help it do this: (1) a high-strength hull; (2) a large mass to help it maintain momentum so that it doesn't get stuck itself; and (3) power to overcome the drag of the crushed ice. Must be a noisy place!
     Here's a bit more from Wiki: The icebreakers push straight into the ice, breaking up the ice, sometimes even driving its bow onto the ice surface so that the weight of the ship helps break up the ice. The design of the hull is such that the broken ice is then directed around or under the vessel. The design is also optimized to minimize damage to the propellers and other parts of the icebreaker itself. Icebreakers have variously been steam-powered, diesel -powered, and nuclear-powered. They have been designed to function on rivers (e.g., in Europe) as well as on the open ocean. The photo shown next is of a successful rescue.

On the fluid dynamics of gold, as in "gold, incense, and myrrh" this Holiday Season!

Gold leaf temples in Bagan, Myanmar
from http://images.smh.com.au/2012/01/27/2919441/art-Burma-Bagan-Temples-420x0.jpg

OK, so gold (a precious metal), frankinense (aperfume or incense), and myrrh (an oil) were given to Kings and other important persons in biblical times. Why? Gold, perhaps representing kingship; incense symbolizing a priestly role, and myrrh, a symbol of death and embalming.
     Well, let's stick to a more-or-less geological topic here, and look at the unique properties of gold, a substance so soft that it almost qualifies for discussion on this blog of "geology in motion." That is, let's look at how gold leaf is produced. It's a long involved process, involving human labor that has changed little in 5,000 years since artsans in Egypt recognized the ductility and its possibility for use. On this website, is the statement that the amount of gold that would fit inside a tennis ball is enough to cover (gold-leaf covered) the dome of the capital building in Atlanta, Georgia!

(In researching this, I discovered a Wiki article on the "Georgia Gold Rush" that might e of interest to the readers.

The Atlanta Georgia capital. The gold leaf was
added in 1958, with native gold leaf
from nearby Lumpkin  County,
where one of the
first American Gold Rushes occurred
in the 1830's.

Paraphrasing and quoting from here, the basic process is this:
Gold is typically mixed with an alloy such as silver or copper to make a grade of gold described by the "carat" system. Goldbeaters typically make 23 carat gold.
     The gold, along with its added alloy metals, are melted in a furnace, and then poured into a cast to make a bar. This bar is then put through a series of rollers, adjusted repeatedly until the bar becomes a sheet 1/1000 of an inch thick.
     But, this is not the end of the process. The gold is then cut into one-inch squares and beaten on large blocks of marble and granite, and, amazingly, ends up with a sheet that is only 1/2500,000 inch thick.
     Along the way, the gold has been cut into one-inch squares and been beaten by hammers. The first stage is referred to as the "cutch."  In it, about 150 skins (formerly ox intestines, but now, Mylar or parchment) surround the gold to hold it together during the beating. Finding something that can withstand the repeated pounding was a challenge. Blocks of marble and granite are used, sometimes placed onto the top of a tree trunk or set deep into the ground to create resiliency. The beaters spend an hour, using a 15-pound hammer and striking the gold about 70 times per minute, while also rotating and turning over the gold alloy packets to ensure uniformity in the expansion. Then, the beaten gold alloy is carefully removed and put into second packets of skins which are beaten for about there hours.
     At this point, the gold is thin enough that the cutter can simply blow on it to move it. (More details here because I'm skipping some.) Basically, at this point there still remains 3-4 hours of beating with an 8-pound hammer, to get pieces that are 1/250,000 thick. After this process, the result is 3.0x3.3/8 inch squares of leaves in tissue paper books that contain 25 leaves.
     Here's a video that shows parts of the process.
Happy Holidays!

   

A National Weather Service "Critical Weather Day" !! Winter Storm Gemini!

National weather service map for 12/22/2013. Significant colors are: pink in the midwest=winter storm warning. Blue surrounding the pink is winter weather advisory; bright blue up in east Minnesota=severe weather statement. Green to the east of this =flood warnings; rust color east of the green = flash flood warning; yellow = tornado watch. 

The news is full of weather alerts for the central and eastern U.S. and Christmas travel is already a problem in the eastern half of the U.S. The east is basking in spring-like warmth, while the midwest suffers from temperatures below average. We who live in the Pacific Northwest are experiencing mild conditions at the moment, but will get our turn next week when rain/snow return here.  The full National Weather Service report is here.
     Temperatures are in the 20's across Oklahoma (southwest end of the pink/blue area)  while, not all that far away, they are nearly 80 degrees across Mississippi (yellow rain pattern). A big frontal boundary separates these two regions. According to the NWS, the severe icing now occurring in Oklahoma-Missouri will transition to light and moderate snow tonight, and the ice threat shifts to lower Michigan and northern New England.  Flooding is a major concern in some areas where the rainfall is more typical of April and May than December. Melting snow will contribute to the flooding.
     And, as if this isn't enough, tornadoes and straight line winds will continue in the lower Mississippi valley and into the Ohio Valley, much further north than usual for this time of year. Here's a link to a 5:59 p.m. EST warning about the thunderstorms and tornadoes. If the prediction holds, storms will be affecting a broad range of the midwest and even over to Washington DC by Sunday night.
     In researching this, I discovered something new about the NWS. At about 8:30 a.m., the NWS Centers for Environmental Prediction declared a "Critical Weather Day" from their station in Milwaukee/Sullivan. In the affected area their offices are not to make any equipment of software changes that might affect the work flow, i.e., do nothing that will cause the system to fail in this critical time. It is also routinely put into effect during Presidential elections and inaugurations.
     Take care, friends and readers, if you are traveling the next few days!

Europa, emission from oxygen and hydrogen, and inferred jets of water

In the blue areas near the south pole of Europa, a satellite of Jupiter,
aural emissions from oxygen and hydrogen have been
detected by the Hubble Space Telescope. NASA image.

Just as we have aurora at the north pole because charged particles enter Earth's magnetic field, Europa has an aurora at its south pole because it is in the intense magnetic field of Jupiter. When atomic oxygen and hydrogen are excited by the magnetic field, they produce an aural glow that can be detected spectroscopically. The oxygen and hydrogen have been interpreted as being the products of water molecules torn apart by electrons along the magnetic field lines.

Top row: Images of the hemispheres
of Europa; other rows: combined images of
the hydrogen and oxygen emissions. This is
Figure 1 in the Science Express paper

   











The measurements were made from Hubble Space Telescope in December 2012, nearly a year before reported this week in Science Express and summarized in this NASA press release. The scientists involved (Lorenz Roth et al.) have stressed the need for caution because the Hubble Space Telescope was "pushed to its limits to see this very faint emission." Scientists are excited about this for two reasons. First, if confirmed, it would mean that Europa becomes the second moon spewing out water plumes (Enceladus is the other). Second, because there is good evidence that an ocean of liquid water exists under the surface of Europa, the plumes would be a way to sample its composition without having to drill through a thick crust. (The evidence for subsurface water is in the surface morphology and magnetometer measurements.)
     The plumes vary in intensity with the orbital position of Europa, but not in a way that is easily explained. They are active only when the moon is the farthest from Jupiter, instead of the more logical position closest to Jupiter.  The scientists postulate that the cracks that emit the water are closed when Europa is closest to Jupiter, and open when it is farthest away. The plumes extend up to about 125 miles altitude and the erupted "water" falls back onto the surface rather than escaping into space.  In the figure to the right, the detected "jets" in December 2012 are compared with 1999 and November 2012 images when the particles were not detected. In December 2012 the plume was near apocenter, and the other two times, close to pericenter, lending support to predictions of tidal modeling.