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Flux Capacitor Day

Posted Thursday, 5 November 2026

The premise of the 1985 film Back to the Future is that time travel (in a direction other than into the future) is possible. In the movie, the mad scientist character Dr. Emmett Brown (Christopher Lloyd) tells the story of how he invented the "flux capacitor" on this day in 1955.

Dr. Emmett Brown with a diagram of the flux capacitorThat was the day I invented time travel. I remember it vividly. I was standing on the edge of my toilet hanging a clock, the porcelain was wet, I slipped, hit my head on the edge of the sink, and when I came to I had revelation. A vision. A picture in my head. A picture of this. This is what makes time travel possible. The flux capacitor.

A capacitor is an electronic device for storing separated electric charges. Capacitors are used in power supplies (to reduce fluctuations in DC voltages), condenser microphones, MEMS accelerometers (like those found in game controllers or car airbag triggers), and random access computer memory (RAM).

The word flux has many meanings, but in physics flux is the "rate of flow" of some quantity through an area. The thing "flowing" could be a fluid (like air or water), some form of energy (like heat, light, or radio waves), or a field (gravitational, electric, or magnetic). In the case of fields, however, the idea of "flow" is more poetic than literal.

The phrase "flux capacitor" is an example of a portmanteau — two different ideas joined together. Portmanteau is itself a portmanteau of the French words portez (to carry) and manteau (coat). Portmanteau makes sense as a word since it refers to a bag or case used to carry clothing — what I would call luggage. In contrast, "flux capacitor" is nonsense. It’s an example of science fiction technobabble. If you say it with enough conviction it almost sounds real, but that doesn’t make it so.

https://glennelert.us/news/?p=626

Ivy Mike: First thermonuclear weapon test (1952)

Posted Saturday, 31 October 2026

Date: 1 November 1952 (7:15 AM New Zealand Standard Time)
Code name: Ivy Mike
Type: two-stage fusion
Yield: 10.4 million tons of TNT
Location: Enewetak Atoll, Marshall Islands (Note the obvious deep hole in the lagoon where the island of Elugelab used to be.)

https://glennelert.us/news/?p=2648

Tsar Bomba: Most powerful nuclear weapon test (1961)

Posted Friday, 30 October 2026

Date: 30 October 1961
Code name: Tsar Bomba (Царь бомба)
Type: air drop, two-stage fusion
Yield: 50 megatons of TNT
Location: Novaya Zemlya, Russia

https://glennelert.us/news/?p=623

Nedelin disaster (1960)

Posted Saturday, 24 October 2026

The Nedelin Distaster occurred on this day in 1960 at the Baikonur Cosmodrome in Kazakhstan. A two-stage R-16 ICBM prototype exploded on the launch pad killing over 100 engineers, technicians, and military personnel including the commander of the program Mitrofan Nedelin. The second stage of the rocket accidentally fired, which caused the first stage below it to explode. The disaster occurred during preflight operations as the rocket was being worked on and while dignitaries milled about on the launch pad.

https://glennelert.us/news/?p=373

Mole Day

Posted Friday, 23 October 2026

Mole Day commemorates the international unit for amount of material. A mole is like a dozen (12) or a gross (144). It’s a name for a number of things. One mole of anything consists of 6.02214076 × 1023 of those things. The mole was originally chosen so that the mass of a mole of something in grams is the same value as the mass of one of those things in atomic mass units. One mole of water consists of 6.02214076 × 1023 water molecules and weighs approximately 18 g since one water molecule weighs…

 H2  +  O 
 2(1 proton)  +  1(8 protons + 8 neutrons) 
 2 atomic mass units  +  16 atomic mass units 
 18 atomic mass units 

The number 6.02214076 × 1023 is known as Avogadro’s constant in honor of the Italian chemist Lorenzo Romano Amedeo Carlo Avogadro, Count of Quaregna and Cerreto (1776–1856) who conceived of this scheme for quantifying amounts of material in 1811. He never calculated the constant himself (probably because he used up all the space in his lab log writing his incredibly long name). That was first done by the Austrian chemist Josef Loschmidt (1821–1895) in 1865.

Avogadro’s constant is a number that’s so large it’s difficult to comprehend. The only things that anyone would ever measure in moles would be tiny — atoms or molecules. When applied to everyday objects, the results are ridiculous.

Mole Day was started by a group of chemistry teachers in the 1980s as a way to raise awareness about chemistry. The Mole Day website is run by a US tax-exempt organization registered in the State of Wisconsin called the National Mole Day Foundation, Inc. IRS records published at watchdog.net indicated assets in excess of $30,000 in 2015. All that money couldn’t buy a sense of humor, however.

  1. What is Avogadro’s favorite kind of music?
  2. Rock ‘N’ Mole

    Meh.

    The best joke on Mole Day is the choice of the day itself. Mole Day begins every year at 6:02 AM on October 23. If one uses the American style of writing dates with the month preceding the day, that’s 6:02 10/23. There is no equivalent to Mole Day in Europe where the tradition is to write the day before the month. There is no 10th day in the 23rd month since there is no 23rd month in Europe or anywhere else in the universe as we currently know it. Mole Day ends at 6:02 PM on the same day, which is another witticism that wouldn’t work in Europe where 6:02 PM would be written 18:02.

    I feel sorry for the Europeans missing out on this great event. There is a serious deficiency in nerd-related holidays outside the US. Even π Day (3/14) doesn’t work for them. Of course, we can all enjoy Powers of Ten Day (10/10), which was two weeks ago (or fifty weeks away). The only other days I know of with international numerical significance are the Square Root Days (4/4/16, 5/5/25, 6/6/36, etc.).

    Physicists have it a lot easier than the mathematicians and chemists. We have Newton’s birthday (December 25th) which always seems to be filled with lots of celebration.

    https://glennelert.us/news/?p=543

    Trans-Siberian Railroad completed (1916)

    Posted Sunday, 18 October 2026

    Train service between St. Petersburg (then known as Petrograd) in the west and Vladivostok in the east began on this day in 1916 (October 18 in the Gregorian calendar, October 5 in the old Julian calendar). It is still the longest continuous rail line in the world.

    Source: University of South Florida

    https://glennelert.us/news/?p=4418

    596: First Chinese nuclear weapon test (1964)

    Posted Friday, 16 October 2026

    Date: 16 October 1964 (3:00 PM China Standard Time)
    Code name: 596
    Type: plutonium fission
    Yield: 22 thousand tons of TNT
    Location: Lop Nur, Xin Jiang, China

    https://glennelert.us/news/?p=606

    Chuck Yaeger breaks the sound barrier (1947)

    Posted Wednesday, 14 October 2026

    On October 14, 1947, in the rocket powered Bell X-1, Capt. Charles E. Yeager flew faster than sound for the first time.

    Source: NASA

    https://glennelert.us/news/?p=4407

    Time zones adopted in the US (1883)

    Posted Sunday, 11 October 2026

    The first five standardized time zones of the US and Canada went into effect on this day in 1883. The agreement reached by the General Time Convention (later known as the American Railway Association) was designed to simplify railway scheduling.

    https://glennelert.us/news/?p=522

    Powers of Ten Day

    Posted Saturday, 10 October 2026

    Celebrate the powers of 10 on the tenth day of the tenth month.

    • books
    • films
      • Cosmic Zoom. Eva Szasz. National Film Board of Canada (1968). Starts in the Ottawa River near the Parliament of Canada. No numbers or narration — probably because they didn’t want to make one version in French and another in English.
      • Powers of Ten. Charles and Ray Eames (1977). Narrated by Philip Morrison. The most famous film of this type. Starts in Burnham Park near Soldier Field in Chicago.
        • Eames Office. The Eames Office is dedicated to communicating, preserving, and extending the work of Charles and Ray Eames. The Eames Office also posted info about the film at powersof10.com for a while. As of 2024 it is now a website run by "a team of experts committed to publish legit info".
        • YouTube. The official Charles and Ray Eames channel.
      • Cosmic Voyage. National Air and Space Museum. Smithsonian Institution (1997). Narrated by Morgan Freeman. Starts in the Piazza San Marco in Venice.
      • The Known Universe. American Museum of Natural History (2009). Starts in the Himalayas. Zooms out and back, but not really in. Completely computer generated, but based on the latest astronomical and geographic data.
    • interactive web pages
      • Cell Size and Scale. Genetic Science Learning Center. University of Utah (no date). Zoom in from the size of a coffee bean to the size of a carbon atom. A nice, simple interactive JavaScript (at least, that’s what I think it is).
      • Scale of the Universe. Cary Huang and Michael Huang (2010). A nicely illustrated, interactive webpage with swirly, distracting new age music. Now Adobe Flash-free.
      • Secret Worlds: The Universe Within. Michael W. Davidson. Florida State University (1995–2013). A Java applet in the style of the Eames film, centered on a tree in near the National High Magnetic Field Laboratory in Tallahassee, Florida.

    https://glennelert.us/news/?p=516

    Rudolph Diesel’s body found (1913)

    Posted Saturday, 10 October 2026

    Rudolph Diesel, of diesel engine fame, was last seen alive 29 September 1913 aboard the steamship Dresden en route from Antwerp to London. Eleven days later the crew of the Coertsen found his decomposed body floating in the North Sea. Circumstances leading to Diesel’s death remain a mystery.

    https://glennelert.us/news/?p=366

    First North Korean nuclear weapon test (2006)

    Posted Thursday, 8 October 2026

    Date: 8 October 2006 (10:35 AM Korea Standard Time)
    Code name: unknown
    Type: plutonium fission
    Yield: less than one thousand tons of TNT
    Location: Kilchu-ŭp, North Hamgyŏng
    Earthquake magnitude: 4.3

    This test is thought to have been a fizzle. The second nuclear weapons test by North Korea on 25 May 2009 is thought to have been successful.

    https://glennelert.us/news/?p=500

    The Wright Brothers fly the first practical airplane (1905)

    Posted Monday, 5 October 2026

    The Wright Brothers completed the sixth and final flight in a series of “long duration” (20-40 minute) flights at Huffman Prairie, Ohio on 5 October 1905. The Wright Flyer III was the third powered aircraft built by the Wright Brothers and, although not the first airplane to fly, is generally considered the the first practical airplane.

    https://glennelert.us/news/?p=445

    Sputnik 1 launched (1957)

    Posted Sunday, 4 October 2026

    The world’s first artificial satellite was about the size of a basketball, weighed only 83 kg, and took about 98 minutes to orbit the Earth on its elliptical path. It was launched on this day, at this time in 1957.

    https://glennelert.us/news/?p=376

    STS-51-J Atlantis first flight (1985)

    Posted Saturday, 3 October 2026

    Space Shuttle Atlantis, named after the two-masted research vessel used by the Woods Hole Oceanographic Institution between 1930 and 1966, was the fourth space-qualified orbiter to join the fleet. In its construction and use of advanced technologies, Atlantis was very similar to its sister ship Discovery that joined the fleet a year earlier.

    https://glennelert.us/news/?p=3149

    Hurricane: First UK nuclear weapon test (1952)

    Posted Friday, 2 October 2026

    Date: 3 October 1952 (8:00 AM Western Australia Standard Time)
    Code name: Hurricane
    Type: plutonium fission
    Yield: 25 thousand tons of TNT
    Location: Monte Bello Islands, Australia

    https://glennelert.us/news/?p=377

    NASA founded (1958)

    Posted Thursday, 1 October 2026

    NASA became operational on 1 October 1958 — almost exactly one year after the Soviet Union launched Sputnik 1, the world’s first artificial satellite.

    https://glennelert.us/news/?p=359

    Rudolph Diesel last seen alive (1913)

    Posted Tuesday, 29 September 2026

    Rudolph Diesel, of diesel engine fame, was last seen alive around 10:00 PM on 29 September 1913 aboard the steamship Dresden en route from Antwerp to London. Eleven days later the crew of the Coertsen found his decomposed body floating in the North Sea. Circumstances leading to Diesel’s death remain a mystery.

    https://glennelert.us/news/?p=303

    First Chinese Space walk (2008)

    Posted Sunday, 27 September 2026

    Chinese astronaut Zhai Zhigang made the nation’s first spacewalk on this day in 2008 floating outside the Shenzhou VII spacecraft for 18 minutes as it orbited the earth. Another astronaut, Liu Boming, briefly poked his head and part of his body out of the module, becoming the second Chinese astronaut to touch outer space, while the third astronaut, Jing Haipeng, stayed behind in the re-entry module.

    Zhai ZhigangSource: Xinhua/Associated Press

    https://glennelert.us/news/?p=285

    Luna 16 lands on the Earth (1970)

    Posted Wednesday, 23 September 2026

    Luna 16 was the first robotic probe to land on the Moon and return a sample to Earth.

    https://glennelert.us/news/?p=264

    The Vela incident (1979)

    Posted Tuesday, 22 September 2026

    A double flash characteristic of a nuclear explosion was recorded by the US Department of Defense Vela 6911 satellite in the South Indian Ocean on this day in 1979. No government has officially taken credit for the event, but it is generally thought to have been a joint Israeli-South African test of a low-yield fission bomb.

    Further Reading (listed in reverse chronological order, just like a resume):

    Do your own independent research. Search for the phrase "South Africa" and the keyword "Nuclear" at the Central Intelligence Agency’s Freedom of Information Act Electronic Reading Room. It’s not easy to use, but there are a lot of interesting, original documents to peruse in this online archive. Also great for people who don’t like reading a lot since the CIA has a thing for censoring text. [As

    https://glennelert.us/news/?p=224

    Luna 16 leaves the moon (1970)

    Posted Monday, 21 September 2026

    Luna 16 was the first robotic probe to land on the Moon and return a sample to Earth.

    https://glennelert.us/news/?p=211