The choice of which type of electricity is called "positive" and which "negative" was made around 1750 by Ben Franklin, early American scientist and man of many talents. Franklin studied static electricity, produced by rubbing glass, amber, sulfur etc. with fur or dry cloth. ... Later, when electric batteries were discovered, scientists naturally assigned the direction of the flow of current to be from (+) to (-). ... Exploration" home page (index) Glossary . Official GSFC Home Page .. ...

... The choice of which type of electricity is called "positive" and which "negative" was made around 1750 by Ben Franklin, early American scientist and man of many talents (the stamp on the left commemorates his role as first US postmaster--and colonial postmaster before that). ... Franklin knew of two types of electric charge, depending on the material one rubbed. ... Later, when electric batteries were discovered, scientists naturally assigned the direction of the flow of current to be from (+) to (-...

Databases (NSDC) of the Natural Planetary Satellites. ... NSDC: Database of astrometric observations of Natural Planetary Satellites . ... They are thoroughly looking for observations in different sources, creating their owndatabases which are then mostly inaccessible to other researchers. ... In the file "content" with explications, the reference is given to the data source as well as the bibliographic reference. ... Data sources. ... Why a specific bibliographic database for Natural satellites? ...

... Satellites of the planets are assigned a provisional designation (indicating year of discovery) by the Central Bureau for Astronomical Telegrams ( CBAT ) upon satisfactory demonstration of the existence of a new object. ... In the past, Comets were first given a provisional designation, consisting of the year and a lowercase letter indicating the order of discovery in the year (e.g., 1994a was the first comet discovered or recovered in 1994, 1994b the second, etc.) ... Names .. ...

Supernova 2009js in NGC 918 . This page is devoted to information on Supernova 2009js in NGC 918 . Basic information on this SN, including the last reported brightness, on this Supernova can be found on the main page . Information on the original web pages for many of these images can be found on the updates and links web pages. Discovered independently by Lick Observatory Supernova Search (USA) and Koichi Itagaki (Japan). ... 2009/10/11.44 . 17.2 . ... Joseph Brimacombe . ...

The database contains references to the papers, data files and links to the Internet resources related to measurements and calculations of the optical constants in the wavelength interval from X-rays to radio domain. ... References to some useful books and reviews on the subject (e.g. the classical handbooks edited by E.D.Palik) and links to Internet collections of optical constants and personal WWW pages with related software were also placed in the database. You have arrived at our welcome page. ...

Image credit: Michael Nolan, Arecibo Observatory. These radar images of near-Earth asteroid 2001 SN263 were obtained on 2008 Feb 12 and 13. ... Image from Feb 12 . ... First near-Earth triple asteroid discovered by Arecibo Observatory . ... was discovered this week by astronomers at the sensitive radar telescope at Cornell University?s Arecibo Observatory in Puerto Rico. ... For example, Arecibo has discovered more than half of the near-Earth binary asteroid systems discovered since 1999. ...

... I am developing an Informed Prefetching and Caching system as part of the kernel in which it is very important that the memory assigned to hold the data does not get swapped to disk. Without any thought to swapping I used vmalloc() to assign memory to the data structures of the Informed prefetching system. ... I later realized that most probably the pages assigned using vmalloc() were getting swapped to the disk and when I referenced them, they were brought from the disk rather than memory. ...

... Higgs, 1989; DRAO 1991. ... 12-13 RA (hours) 15-16 RA (min) 18-22 RA (sec) (XX.XX) 24-28 RA error (sec) (XX.XX) ( blank = unknown ) 30 Sign of declination 31-32 DEC (degrees) 34-35 DEC (arcmin) 37-40 DEC (arcsec) (XX.X) 42-45 DEC error (arcsec) (XX.X) ( blank = unknown ) 47 Epoch of coordinates (1=B1950, 2=J2000, 3= unknown ) 49 Type of position determination (1=rough estimate, 2=centroid, 3=peak, 4=fitted Gaussian, 5= unknown ) 51-56 Flux #1 ( variable format ) 58-62 Error in ...

This document describes how number input can be given to tasks which request numbers from Hermes. ... list selection The following constants are implemented: pi 3.14159.... c speed of light (SI) h Planck (SI) k Boltzmann (SI) g gravitation (SI) s Stefan-Boltzman (SI) m mass of sun (SI) p parsec (SI) BLANK Universal undefined value The following mathematical functions are implemented: abs(x) absolute value of x sqrt(x) square root of x sin(x) sine of x asin(x) inverse sine ...

... There is also an edge-on view of the asteroid belt here . This video was created by Scott Manley. ... View of the solar system showing the locations of all the asteroids starting in 1980. ... Notice how the pattern of discovery follows the Earth around its orbit. ... At the beginning of 2010 a new discovery pattern becomes evident, with discovery zones in a line perpendicular to the Sun-Earth vector. ... An edge-on view of the asteroids . ... Other asteroid and comet animations by Scott Manley . ...

... PUL2 catalog contains original absolute proper motions of 59646 stars in 149 fields with galaxies. ... Mean errors of relative proper motions in PUL2 catalog is 5.5 mas/year. ... The external mean error of one relative proper motion of a bright star of PUL2 catalog is 9 mas/year for both of coordinates. ... After issue of UCAC2 catalog, we decided to improve accuracy of proper motions, using Pul-3 coordinates (of 1950s) as the first epoch, and UCAC2 coordinates as the second epoch. ...