Scrolling Down Martian Landscape

The highest-resolution panorama ever taken by a rover illuminates unprecedented detail of the red planet’s surface.

“Studying whether there’s life on Mars or studying how the universe began, there’s something magical about pushing back the frontiers of knowledge. That’s something that is almost part of being human, and I’m certain that will continue.” –Sally Ride

Lunar Topographic Orthophotomap (LTO) Series

Publisher: Defense Mapping Agency
Scale: 1:250,000
Projection: Transverse Mercator

Lunar Topographic Orthophotomap (LTO) Series.

Egypt Looters Ransack Archaeological Sites | @pritheworld

Since Hosni Mubarak’s government fell last year, many of Egypt’s museums have been looted.

And the looting has gone beyond museums — now criminals are digging up archaeological sites and stealing their treasures.

Anchor Marco Werman speaks with Carol Redmount, an archaeologist at the University of California, about her efforts to stop the looting in Egypt.

Redmount described the looters stealing from El-Hibeh’s archaeological dig as “essentially a gang of criminals, headed by a master criminal, who escaped from jail after the revolution.”

via Egypt Looters Ransack Archaeological Sites | @pritheworld.

Photo Gallery: Parts with Tin Whiskers

What are Tin Whiskers?

Tin whiskers are electrically conductive, crystalline structures of tin that sometimes grow from surfaces where tin (especially electroplated tin) is used as a final finish.  Tin whiskers have been observed to grow to lengths of several millimeters (mm) and in rare instances to lengths in excess of 10 mm.  Numerous electronic system failures have been attributed to short circuits caused by tin whiskers that bridge closely-spaced circuit elements maintained at different electrical potentials.

 

Tin whiskers are not a new phenomenon.  Indeed, the first published reports of tin whiskers date back to the 1940s and 1950s. Tin is only one of several metals that is known to be capable of growing whiskers.  Other examples of metals that may form whiskers include some tin alloys, zinc, cadmium, indium, antimony, silver among others . 

 

People sometimes confuse the term “whiskers” with a more familiar phenomenon known as “dendrites” commonly formed by electrochemical migration processes.  Therefore, it is important to note here that whiskers and dendrites are two very different phenomena. A “Whisker” generally has the shape of a very thin, single filament or hair-like protrusion that emerges outward (z-axis) from a surface.  “Dendrites”, on the other hand, form in fern-like or snowflake-like patterns growing along a surface (x-y plane) rather than outward from it.  The growth mechanism for dendrites is well-understood and requires some type of moisture capable of dissolving the metal (e.g., tin) into a solution of metal ions which are then redistributed by electromigration in the presence of an electromagnetic field.  While the precise mechanism for whisker formation remains unknown, it is known that whisker formation does NOT require either dissolution of the metal NOR the presence of electromagnetic field

via Photo Gallery: Parts with Tin Whiskers.

Paradoxes of set theory – Wikipedia, the free encyclopedia

Paradoxes of the Supertask

In set theory, an infinite set is not considered to be created by some mathematical process such as “adding one element” that is then carried out “an infinite number of times”. Instead, a particular infinite set (such as the set of all natural numbers) is said to already exist, “by fiat”, as an assumption or an axiom. Given this infinite set, other infinite sets are then proven to exist as well, as a logical consequence. But it is still a natural philosophical question to contemplate some physical action that actually completes after an infinite number of discrete steps; and the interpretation of this question using set theory gives rise to the paradoxes of the supertask.

[edit]The diary of Tristram Shandy

Tristram Shandy, the hero of a novel by Laurence Sterne, writes his autobiography so conscientiously that it takes him one year to lay down the events of one day. If he is mortal he can never terminate; but if he lived forever then no part of his diary would remain unwritten, for to each day of his life a year devoted to that day’s description would correspond.

via Paradoxes of set theory – Wikipedia, the free encyclopedia.

IMSLP/Petrucci Music Library: Free Public Domain Sheet Music

IMSLP stands for International Music Score Library Project. The logo is a capital letter A, taken from the very first press-printed book of polyphonic music, theHarmonice Musices Odhecaton, published in 1501. Its printer, Ottaviano Petrucci, is this library’s namesake.

Browse scores

IMSLP/Petrucci Music Library: Free Public Domain Sheet Music.

cdli – penn museum

View the Nippur Collection

Penn tablets by period:

   Late Uruk (ca. 3400-3000 BC)
   Proto-Elamite (ca. 3100-2900 BC)
   Early Dynastic I-II (ca. 2900-2700 BC)
   Early Dynastic IIIa (ca. 2600 BC)
   Early Dynastic IIIb (ca. 2500-2350 BC)
   Old Akkadian (ca. 2350-2200 BC)
   Lagash II (ca. 2200-2100 BC)
   Ur III period (ca. 2100-2000 BC)
   Old Assyrian (ca. 2000-1900 BC)
   Early Old Babylonian (ca. 2000-1800 BC)
   Old Babylonian (ca. 1800-1600 BC)
   Middle Babylonian (ca. 1500-1000 BC)
   Middle Assyrian (ca. 1500-1000 BC)
   Neo-Assyrian (ca. 1000-600 BC)
   Neo-Babylonian (ca. 1000-540 BC)
   Achaemenid (ca. 540-330 BC)
   Hellenistic (ca. 330-140 BC)
   Uncertain date

Penn tablets by provenience (only major sites):

   Abu Hatab
   Babylon
   Drehem
   Fara
   Girsu
   Kültepe
   Malyan
   Nippur
   Tell Billa
   Umma
   Ur

Penn tablets by text genre:

   Administrative texts
   Legal texts
   Literary texts
   Omina
   Lexical texts
   Mathematical texts
   School texts
   Scientific texts
   Royal/Monumental texts

Search all CDLI inscriptions


The tablet to the right (CBS 16106) contains on the top surface the impression of a diorite brick stamp said, in the neo-Assyrian inscription on the reverse surface, to have been found by a scribe in Naram-Sin’s palace in Agade, the capital of the Old Akkadian empire (ca. 2300 and 700 BC, respectively). The lower image offers a mirrored representation of the original stamp, in the orientation in which it would have been read in lines from top to bottom, and from right to left (click image to be directed to the text’s corresponding CDLI page).

via cdli – penn museum.