Stînea+Monica

Einstein was enthralled by light. Even as a teenager he pondered its properties. At 16, he imagined what it would be like to chase, catch up with, and ride on a light beam. When he started thinking more seriously about light, he questioned the thinking of his day—that it traveled through a medium dubbed "ether," and that its speed was determined by how fast its source moved through this mysterious substance. Einstein realized that the speed of light—about 186,000 miles per second—is constant whether it comes from a moving source such as a speeding car's headlights or an unmoving source such as a ceiling light. But here's the catch: The speed of light is constant only in a vacuum, a place where there's no matter, like the vast emptiness of space. Here on Earth, the speed of light can slow down. To see if you can identify what ordinary objects in your house can kick light into a lower gear, click on the [|image] at left.—//Karen Hartley//  Note: This feature originally appeared, in slightly different form, on NOVA's "Einstein Revealed" Web site, which has been subsumed into the "Einstein's Big Idea" Web site. **Hubble Space Telescope ** ||   The Hubble Space Telescope as seen from [|Space Shuttle //Columbia//] during Servicing Mission 3B ( [|STS-109] ) || **General information ** || ** [|NSSDC ID] ** ||  [|1990-037B] || **Organization ** ||  [|NASA] / [|ESA] / [|STScI] || **Launch date ** || 24 April 1990 || **Mission **** length ** || 18 years, 10 months, and 15 days elapsed || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Deorbited ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Likely between 2013 and 2021 [|[1]] || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Mass ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">11,110 kg (24,500 lb) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Type of orbit ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Near-circular [|low Earth orbit] || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Orbit height ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">559 km (347 mi) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Orbit period ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">96–97 minutes || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Orbit velocity ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">7,500 m/s (17,000 mph) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Acceleration due to gravity ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">8.169 m/s2 (26.80 ft/s2) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Location ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Low Earth orbit || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Telescope style ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|Ritchey-Chretien] reflector || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|Wavelength] ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|Optical], [|ultraviolet] , [|near-infrared] || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Diameter ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">2.4 m (94 in) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Collecting area ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">approx. 4.5 square metres (48 sq ft) [|[2]] || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|Focal length] ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">57.6 metres (189 ft) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Instruments ** || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|NICMOS] ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">infrared camera/spectrometer || **//<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|ACS] //**<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">  || //<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">optical survey camera //<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> (mostly failed) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|WFPC2] ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">wide field optical camera || **//<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|STIS] //**<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">  || //<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">optical spectrometer/camera //<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> (failed) || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|FGS] ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">three fine guidance sensors || **<span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Website ** || <span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [] [] [] [] || <span style="font-size: 12pt; color: blue; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-no-proof: yes;"> <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> <span style="font-size: 12pt; font-family: 'Times New Roman'; text-decoration: none; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; text-underline: none; mso-no-proof: yes;"> <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Miracle cure. <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">"When I woke up just after dawn on September 28, 1928, I certainly didn't plan to revolutionize all medicine by discovering the world's first antibiotic, or bacteria killer," Fleming would later say, "But I guess that was exactly what I did." [|[2]]. <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">By 1928, Fleming was investigating the properties of [|staphylococci]. He was already well-known from his earlier work, and had developed a reputation as a brilliant researcher, but quite a careless lab technician; he often forgot cultures that he worked on, and his lab in general was usually in chaos. After returning from a long holiday, Fleming noticed that many of his culture dishes were contaminated with a fungus, and he threw the dishes in disinfectant. But subsequently, he had to show a visitor what he had been researching, and so he retrieved some of the submerged dishes that he would have otherwise discarded. He then noticed a zone around an invading fungus where the bacteria could not seem to grow. Fleming proceeded to isolate an extract from the mold, correctly identified it as being from the //[|Penicillium]// genus, and therefore named the agent [|penicillin]. <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">He investigated its positive anti-bacterial effect on many organisms, and noticed that it affected bacteria such as staphylococci, and indeed all [|Gram-positive] pathogens ([|scarlet fever], [|pneumonia], [|meningitis], [|diphtheria]) but unfortunately not [|typhoid] or [|paratyphoid], for which he was seeking a cure at the time. It also affected [|gonorrhoea], although this condition is caused by a Gram-negative pathogen. <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Fleming published his discovery in 1929 in the British Journal of Experimental Pathology, but little attention was paid to his article. Fleming continued his investigations, but found that cultivating penicillium was quite difficult, and that after having grown the mould, it was even more difficult to isolate the antibiotic agent. Fleming's impression was that because of the problem of producing it in quantity, and because its action appeared to be rather slow, penicillin would not be important in treating infection. Fleming also became convinced that penicillin would not last long enough in the human body (//in vivo//) to kill bacteria effectively. Many clinical tests were inconclusive, probably because it had been used as a surface antiseptic. In the 1930s, Fleming’s trials occasionally showed more promise,[|[3]] and he continued, until 1940, to try and interest a chemist skilled enough to further refine usable penicillin. <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Fleming soon abandoned penicillin, and not long after Florey and Chain took up researching and mass producing it with funds from the U.S and British governments. They started mass production after the bombing of Pearl Harbor. When D-day arrived they had made enough penicillin to treat all the wounded allied forces. <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">DNA **<span style="font-size: 13.5pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">First Publication ****<span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> [|Discovery of the DNA Double Helix] ** || <span style="font-size: 12pt; font-family: 'Times New Roman'; text-decoration: none; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; text-underline: none; mso-no-proof: yes;"> <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;"> An early sketch of the DNA [|double helix]. || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|William Astbury] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Oswald Avery] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Francis Crick] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Erwin Chargaff] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Jerry Donohue] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Rosalind Franklin] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Phoebus Levene] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Linus Pauling] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Erwin Schrödinger] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Alec Stokes] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|James Watson] || <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">[|Maurice Wilkins] ||
 * <span style="font-size: 12pt; font-family: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US;">Accidental discovery – Fleming’s Penicillin **

ENIAC Comparison with other early computers
// Main article: [|History of computing hardware]// Mechanical and electrical computing machines have been around since the 19th century, but the 1930s and 1940s are considered the beginning of the modern computer era. Defining characteristics of some early digital computers of the 1940s (In the [|history of computing hardware])   || **Name**  || **First operational**  || **Numeral system**  || **Computing mechanism**  || **[|Programming]** || **[|Turing complete]** || May 1941 || [|Binary] || [|Electro-mechanical] || Program-controlled by punched [|film stock] || Yes ([|1998])  || 1942 || [|Binary] || [|Electronic] || Not programmable—single purpose || No || February 1944 || [|Binary] || [|Electronic] || Program-controlled by patch cables and switches || No || May 1944 || [|Decimal] || [|Electro-mechanical] || Program-controlled by 24-channel [|punched paper tape] (but no conditional branch) || No || June 1944 || [|Binary] || [|Electronic] || Program-controlled by patch cables and switches || No || ** ENIAC ** ** (US) ** || July 1946 || [|Decimal] || [|Electronic] || Program-controlled by patch cables and switches || Yes || June 1948 || [|Binary] || [|Electronic] || [|Stored-program] in [|Williams cathode ray tube memory] || Yes || ** Modified ENIAC ** ** (US) ** || September 1948 || [|Decimal] || [|Electronic] || Program-controlled by patch cables and switches plus a primitive read-only stored programming mechanism using the Function Tables as program [|ROM] || Yes || May 1949 || [|Binary] || [|Electronic] || [|Stored-program] in mercury [|delay line memory] || Yes || October 1949 || [|Binary] || [|Electronic] || [|Stored-program] in [|Williams cathode ray tube memory] and [|magnetic drum] memory || Yes || November 1949 || [|Binary] || [|Electronic] || [|Stored-program] in mercury [|delay line memory] || Yes || The ABC, ENIAC and Colossus all used [|thermionic valves (vacuum tubes)]. ENIAC's registers performed decimal arithmetic, rather than binary arithmetic like the Z3 or the Atanasoff-Berry Computer. Until 1948, ENIAC required rewiring to reprogram, like the Colossus. The idea of the stored-program computer with combined memory for program and data was conceived during the development of the ENIAC, but it was not implemented at that time because World War II priorities required the machine to be completed quickly, and it was realized that 20 storage locations for memory and programs would be much too small. You Tube []
 * The German [|Z3] (shown working in May 1941) was designed by [|Konrad Zuse] . It was the first general-purpose digital computer, but it was electromechanical, rather than electronic, as it used [|relays] for all functions. It computed logically using binary maths. It was programmable by punched tape, but lacked the conditional branch. It was destroyed in a bombing on Berlin in December 1941.
 * The American [|Atanasoff–Berry Computer] (ABC) (shown working in summer 1941) was the first electronic computing device. It implemented binary computation with [|vacuum tubes] but was not general purpose, being limited to solving systems of linear equations. It also did not exploit electronic computing speeds, being limited by a rotating [|capacitor] drum memory and an input-output system that was intended to write intermediate results to paper cards. It was manually controlled and was not programmable.
 * The [|British] [|Colossus computers] (used for [|cryptanalysis] starting in 1943) were designed by [|Tommy Flowers] . The Colossus computers (of which ten were built) were digital, all-electronic, and could be reprogrammed by rewiring, but they were dedicated to code breaking and not general purpose.[|[13]]
 * [|Howard Aiken] 's 1944 [|Harvard Mark I] was programmed by punched tape and used relays. It performed general math functions, but lacked any branching.
 * The ENIAC was, like the Z3 and Mark I, able to run an arbitrary sequence of mathematical operations, but did not read them from a tape. Like the Colossus, the operations happened at electronic speed. The ENIAC combined full, Turing complete programability with electronic speed.
 * [|Zuse] [|Z3] ** ** (Germany) **  ||
 * [|Zuse] [|Z3] ** ** (Germany) **  ||
 * [|Atanasoff–Berry Computer] ** ** (US) **  ||
 * [|Atanasoff–Berry Computer] ** ** (US) **  ||
 * [|Colossus Mark 1] ** ** (UK) **  ||
 * [|Colossus Mark 1] ** ** (UK) **  ||
 * [|Harvard Mark I – IBM ASCC] ** ** (US) **  ||
 * [|Harvard Mark I – IBM ASCC] ** ** (US) **  ||
 * [|Colossus Mark 2] ** ** (UK) **  ||
 * [|Colossus Mark 2] ** ** (UK) **  ||
 * [|Manchester Small-Scale Experimental Machine] ** ** (UK) **  ||
 * [|Manchester Small-Scale Experimental Machine] ** ** (UK) **  ||
 * [|EDSAC] ** ** (UK) **  ||
 * [|EDSAC] ** ** (UK) **  ||
 * [|Manchester Mark 1] ** ** (UK) **  ||
 * [|Manchester Mark 1] ** ** (UK) **  ||
 * [|CSIRAC] ** ** (Australia) **  ||
 * [|CSIRAC] ** ** (Australia) **  ||