Friday, January 27, 2023

Laser Pulses Divert Lightning Strikes


This graphic shows the central part of a thunderstorm where air is moving upward rapidly (up-draft), as the cloud accumulates a negative charge (electrons) creating lightning. Temperatures in this cloud range from +5 to -13 degrees Fahrenheit / -15 to -25 degrees Celsius. (Graphic Sources: Wikipedia.org, By U.S. Government, National Weather Service - http://www.lightningsafety.noaa.gov/science/science_electrification.shtml (in August 2019, https://www.weather.gov/safety/lightning-science-scienceintro), Public Domain, https://commons.wikimedia.org/w/index.php?curid=53463755)

By Glenn A. Walsh

Reporting for SpaceWatchtower

Scientists in Switzerland have now demonstrated that laser pulses can divert lightning strikes. As the first major improvement to Benjamin Franklin's Lightning Rod, this has the potential to provide much greater protection to large infrastructure such as launch-pads and airports.

The experiment took place from 2021 July 21 to September 30 on Santis Mountain, on the northeastern tip of the Swiss Alps, using a green, infrared laser. At the summit of the mountain (altitude 8,200 feet / 2,500 meters), the laser was mounted near a 407 -foot / 124-meter telecommunications tower (which has its own Lightning Rod) and aimed at passing storm-clouds in the sky.

By firing the laser rapidly, in short, intense pulses (1,000 times per second), during thunderstorms, they were able to create a path for the lightning to specifically avoid striking the tower's tip (where the traditional Lightning Rod is located). In this experiment, lightning avoided the tower's tip four times within six hours.

Normally, this tower is struck by lightning about 100 times in one year. During the trial period, lightning struck the tower 12 times, while the laser was not being used.

Hence, the unpredictability of lightning strikes can lead to billions of dollars of damage each year, as well as occasional lives lost. So, finding a modern improvement to the Lightning Rod could save resources, as well as some lives.

This research was led by physicist Aurelien Houard of the French National Center for Scientific Research's Applied Optics Laboratory in Paris. The scientists' findings were published in the 2023 January 16 edition of the scientific journal Nature Photonics.

According to the published study, “Although this research field has been very active for more than 20 years, this is the first field-result that experimentally demonstrates lightning guided by lasers.” With only a couple exceptions, previous work had only occurred in physics laboratories, since 1974.

Past attempts at field tests of laser deflection of lightning in New Mexico (2004) and Singapore (2011) had not been successful. Although the reason for the past failures is not certain, the researchers speculate that the laser beams in the past experiments had not been as rapid as the laser pulses in the Swiss experiment.

Lightning is an electrostatic discharge (generated by the friction of ice clumps and rain drops in storm-clouds), within a cloud, between two clouds, or between the cloud and the ground. As negatively-charged electrons gather at a storm-cloud's base and attract a ground's positive charge, the electrons begin to overcome air resistance causing the ionization of air in a charged flow or path to the ground – a lightning bolt. This dissipates and temporarily neutralizes the charge with the release of approximately a gigajoule of energy.

Every second about a hundred lightning flashes can be found some place on our planet, or between clouds.

Lightning Rods protect buildings and other structures by providing a path for the electrical charge to more easily reach the ground, rather than traveling through the air for the entire distance. But, the protection is limited, due to the height of a Lightning Rod.

To extend the protection from lightning, the new laser pulses are used to provide a new pathway to the ground. The laser beam rapidly heats air molecules, which creates a channel of less dense air and an easier pathway to the ground. Whether a traditional Lightning Rod, or this new system of laser pulses, electricity always wants to follow the path of least resistance.

Lightning bolts release a wide range of electromagnetic radiation including radio waves (which can be heard as crackling and / or a large clap on AM and Short-Wave radios), light waves, and X-Rays. Lightning causes thunder, the sound from a shock wave in the vicinity of the electrical discharge, as air experiences a sudden increase in pressure.

Many people are aware of the “5-second rule”. When you see a lightning strike, count each second until thunder is heard. When you divide the total number of seconds between lightning and thunder by five, the result is an approximate distance in statute miles of the lightning bolt (and often the center of the thunderstorm) from your current location.

Earth is not the only planet with lightning. Jupiter and Saturn have been observed with lightning strikes, with major lightning bolts seeming to be common on Jupiter. Although not confirmed, NASA and Russian space probes suggest that lightning may also exist in the very dense and toxic atmosphere of Venus.

The original Lightning Rod was invented in 1750 by American Founding Father Benjamin Franklin of Pennsylvania, who is considered America's first true scientist. While a lightning bolt may strike a Lightning Rod, the actual purpose of a Lightning Rod is to bleed-off excess electrical charge to the ground where the excess charge is dissipated, so the charge does not build-up to a dangerous lightning strike.

So, this new laser system would, indeed, be used to attract lightning strikes, when a Lightning Rod does not, or is not close enough to, bleed-off enough electrical charge. With extreme weather becoming more prevalent, due to Climate Change, this new type of protection from lightning could be used to protect many more tall structures.

Internet Links to Additional Information ---

Published Research - Abstract & Main Article: "Laser-guided lightning":

 Link >>> https://www.nature.com/articles/s41566-022-01139-z?utm_medium=affiliate&utm_source=commission_junction&utm_campaign=CONR_PF018_ECOM_GL_PHSS_ALWYS_DEEPLINK&utm_content=textlink&utm_term=PID100052172&CJEVENT=b24eceef9d8f11ed817f3b8a0a82b836

Laser: Link >>> https://en.wikipedia.org/wiki/Laser

Lightning: Link >>> https://en.wikipedia.org/wiki/Lightning

Lightning Rod: Link >>> https://en.wikipedia.org/wiki/Lightning_rod 

Benjamin Franklin Invents Lightening Rod: Link >>> https://www.fi.edu/history-resources/franklins-lightning-rod

Tesla Coil (Artificial Lightning): Link >>> https://buhlplanetarium2.tripod.com/Buhlexhibits.htm#teslacoil 

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss          

               Friday, 2023 January 27.


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Glenn A. Walsh, Informal Science Educator & Communicator                                                               (For more than 50 years! - Since Monday Morning, 1972 June 12):
Link >>> http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: Link >>> http://buhlplanetarium.tripod.com/fotz/
SpaceWatchtower Editor / Author: Link >>> http://spacewatchtower.blogspot.com/
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), America's fifth major planetarium and Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania, the fourth of only five libraries where both construction and endowment funded by famous industrialist & philanthropist Andrew Carnegie.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh: Link >>>  http://www.planetarium.cc  Buhl Observatory: Link >>>  http://spacewatchtower.blogspot.com/2016/11/75th-anniversary-americas-5th-public.html
* Adler Planetarium, Chicago: Link >>> http://adlerplanetarium.tripod.com
* Astronomer, Educator, Optician John A. Brashear: Link >>> http://johnbrashear.tripod.com
* Andrew Carnegie & Carnegie Libraries: Link >>> http://www.andrewcarnegie.cc

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html

 

Wednesday, January 11, 2023

$4.48 Million Mars Exhibit Opens in Pittsburgh

               

Meteorite from the planet Mars, on display as part of the new exhibit, Mars: The Next Giant Leap, at The Carnegie Science Center in Pittsburgh. A Moon rock, found during the 1971 mission of Apollo 15, is also on display; one of the astronauts to land on the Moon during this mission was James B. Irwin, a native of the Beechview section of Pittsburgh.

(Image Source: Friends of the Zeiss; Photographer: Glenn A. Walsh)

(More photographs of exhibit at this link: Link >>> https://andrewcarnegie.tripod.com/csc/pix/mars/ )

 By Glenn A. Walsh

Reporting for SpaceWatchtower

Late last year, a new, 7,400 square-foot / 2,255.52 square-meter exhibit, titled, Mars: The Next Giant Leap, opened in The Carnegie Science Center in Pittsburgh. Divided in seven experiential zones, the exhibit focuses on future human exploration of, and possible settlement on, the Red Planet.

The new exhibit, which cost an estimated $4.48 million, includes a slice of a meteorite that scientists believe came from the planet Mars. The rock, from which the meteorite slice came from, probably fell to Earth after being knocked off of Mars by a larger meteorite or asteroid which hit Mars in the distant past.

Also displayed is a Moon rock (Lunar Sample #15499), on loan from NASA for at least five years, collected by Apollo 15 astronauts in 1971. One of the Apollo 15 astronauts to land on the Moon was James B. Irwin, a native of the Beechview section of Pittsburgh.

Other meteorites are on display, nearby, in the lobby of the Henry Buhl, Jr. Planetarium. One large meteorite, which the public can touch, is the fifth largest fragment of the large meteorite that created Meteor Crater in Arizona; this particular meteorite, Property of the City of Pittsburgh, was first displayed at Pittsburgh's original Buhl Planetarium and Institute of Popular Science in 1939. Another meteorite on display was collected by University of Pittsburgh Professor William Cassidy, during one of his expeditions to Antarctica.

Mars Closest Approach to Earth & Opposition

Mars: The Next Giant Leap opened to the public on Saturday, 2022 November 19, shortly before the bi-annual close approach of Mars to the Earth. Actually, Earth and Mars reach the closest point to each other every two years and two months.

The planet Mars was at its closest approach to Earth on Wednesday, 2022 November 30 at 9:00 p.m. Eastern Standard Time (EST) / December 1 at 2:00 Coordinated Universal Time (UTC). Mars was at its brightest in Earth's night sky at a Visual Magnitude of -1.8 with the Martian disk appearing as large as 17.2 seconds-of-arc in diameter. At that time, Mars was just 4.5 light-minutes away (distance of 0.544 Astronomical Unit / 50,567,959 statute miles / 81,381,241.409 kilometers).

Mars was in Opposition (with the Earth lying directly between Mars and the Sun - Mars visible all-night-long, approximately local sunset to local sunrise) on Thursday, 2022 December 8 at 1:00 a.m. EST / 6:00 UTC. The one week difference between Mars' closest approach to Earth and Mars' Opposition is due to the asymmetric nature of the Martian orbit.

The Red Planet appeared fairly close to the December Full Moon (“Cold Moon” on Wednesday, 2022 December 7 at 11:08 p.m. EST / December 8, 4:08 UTC). In fact, the Moon completely covered the planet Mars, in what astronomers call an Occultation, on Wednesday, 2022 December 7 at 11:00 p.m. EST / December 8 at 4:00 UTC. Amazingly, this occurred when Mars and Earth's Moon were both opposite the Sun and 100 per-cent illuminated by the Sun, but far enough north of the Ecliptic that there was no Lunar Eclipse / Eclipse of the Moon.

This Lunar Occultation was visible, weather-permitting, in most of the United States (except Alaska), Canada, Greenland, northwestern portion of Mexico, Svalbard (archipelago part of Norway), much of Europe, western portion of Russia, and a portion of northern Africa. For other observers, Mars was in Conjunction with the Full Moon (Mars 0.5 degree south of the Moon).

Today, Mars is still bright in the evening sky, but through much of the month Mars' brightness is beginning to wane. Although it will still be pretty bright at the end of January, the brightness will be 50 per-cent dimmer than at the beginning of the month as Earth and Mars separate. Look for Mars high in the east in evening twilight, and in the south later in the night, weather-permitting.

Again, there will be another Lunar Occultation of Mars late on Monday Evening, 2023 January 30 at 11:00 p.m. EST / January 31 at 4:00 UTC (Moon Phase: Waxing Gibbous). This Occultation will be visible, weather-permitting, in the southern portion of the United States, Mexico, Central America, Caribbean, northern section of South America, and most of Polynesia (but not New Zealand). Other areas will see Mars as little as 0.1 degree north of the Moon.

                    

A simulated Martian landscape, where visitors can control miniature Mars rovers, while trying to search for evidence of past life.

(Image Source: Friends of the Zeiss; Photographer: Glenn A. Walsh)

(More photographs of exhibit at this link: Link >>> https://andrewcarnegie.tripod.com/csc/pix/mars/ )

Exhibit Experiential Zones

The Carnegie Science Center used focus groups of students and North Side, Pittsburgh residents, as well as seeking input from local business leaders, to help design the new exhibit. In the focus groups, questions such as “Why go to Mars?” and “How do you form a new society on the planet?” were asked by the participants. Future input from Science Center visitors will help further develop parts of the exhibit.

The following are the seven experiential zones of the new exhibit ---

  • View from Mars – This zone provides images of the Martian landscape and perspectives of Earth. It talks about how robotic exploration of Mars, as well as science-fiction and pop-culture, has influenced our view of the Red Planet.

  • Climatology – This zone looks at how climates produce the conditions for life to arise. This area considers the climate systems of Mars and Earth, the abilities of each to sustain life, and what similar conditions may be found on the two planets. This zone includes a meteorite scientists believe originated on Mars.

  • Martian Garden - Greening of the Red Planet is the focus of this zone. Sustainability and resource management are vital for the survival of humans, and whatever other animals are brought to Mars. Three Pods show Soiless Growing (very little soil exists on Mars), Soil Growing, and Biotechnology on Mars.

  • Martian Living – This zone looks at life on Mars, from the viewpoint of possible Mars settlers. This area looks at technology needed to support human living on Mars. This area includes a Moon rock (Lunar Sample #15499), on loan from NASA for at least five years, which was collected by the two astronauts who landed on the Moon in 1971 during the mission of Apollo 15; one of these astronauts was James B. Irwin, a native of the Beechview section of Pittsburgh. This area also talks about possible challenges from Martian Living such as a weakened or lost human immune system (from a sterile environment), how bones may become denser and more brittle (due to lower gravity), and whether more prevalent DNA mutations (from DNA damage caused by greater Cosmic Rays) could turn setters into a new species—true Martians!

  • Dream Big: Space – This zone includes an imagined Martian settlement, which exhibit visitors can help design. Visitors' input will be immediately displayed on a digital model, and over-time may be added to the physical model. This area asks several questions about possible future Martian settlements, including, “In an isolated world, will we guarantee the right to return to Earth?”

  • Pittsburgh in Mars – This zone looks at humanity's future in Outer Space. In particular, it shows how Pittsburgh academic and corporate research is helping move humans into Outer Space and onto Mars. This area includes profiles of NASA Space Shuttle Astronaut Mike Fincke, University of Pittsburgh Engineering Professor Albert To, Carnegie Mellon University Robotics Professor Howie Choset, Carnegie Mellon University (CMU) Lead Systems Engineer Siri Maley (CMU's IRIS Rover to travel to the Moon; IRIS is Siri spelled backwards!), Carnegie Mellon University Civil and Environmental Engineering Professors Burcu Akinci and Mario Berges, Carnegie Mellon University Creative Technologist Angelica Bonilla Fominaya (spacesuit user interface), Howmet Aerospace Vice President Markus Heinimann, Arconic Corporation (aluminum-lithium low-weight, alloy plates for NASA spacecraft), and Kennametal Corporation (metal-cutting tools for NASA spacecraft).

  • Search for Life – Scientists believe that, at one time, the Martian climate was similar to Earth's current climate. So, Mars is one of the most logical places to look for evidence of past life in our Solar System. This also looks at possible life impacts on climate. In this area, visitors can control miniature Martian rovers on a simulated Martian landscape, in a search for signs of life.

More on The Carnegie Science Center.

The Carnegie Science Center is located on the Lower North Side of Pittsburgh, on the North Shore of the Ohio River about a mile from Downtown Pittsburgh's Golden Triangle. The Science Center building is located between Acrisure Stadium (home of the Pittsburgh Steelers and the University of Pittsburgh Panthers football teams) and Rivers Casino and Hotel. The Carnegie Science Center is about a block south of the Allegheny Light Rail Rapid Transit Station (served by the "T" Red, Blue, and Silver Lines) of Pittsburgh Regional Transit (a.k.a. Port Authority of Allegheny County Transit). Two parking lots are available for visitors coming by automobile.

The Carnegie Science Center is open six days a week, 10:00 a.m. to 5:00 p.m. Eastern Time, Wednesday through Monday; the building is closed on Tuesday. Admission charges are --- Adults: $20; Senior Citizens (age 65 and greater): $15; Children (ages 3 to 12): $12; and Toddlers (age 2 and under): No Charge.

Adjacent to this Mars exhibit, on the second floor of The Carnegie Science Center, is the recently renovated Henry Buhl, Jr. Planetarium. On the day of the author's visit (Wednesday, 2022 November 23), four planetarium sky shows and one laser-light concert were performed for the public in the planetarium theater: “Story Time Under the Stars” (11:00 a.m. - geared to ages 6 and younger and their families), “Two Small Pieces of Glass” (12:00 Noon), “Stars Over Pittsburgh” (1:00 p.m.), “Laser Galactic Odyssey” (2:00 p.m.), “Beginner's Guide to the Universe” (3:00 p.m.), and “Big Astronomy” (400 p.m.). Each show lasts about a half-hour, and all planetarium shows are included in the General Admission Fee; laser-light shows (such as the 2:00 p.m. show) require an additional admission ticket.

Exhibits in the Henry Buhl, Jr. Planetarium Lobby include the fifth largest meteorite fragment (iron-nickel meteorite weighing 746 pounds / 340 kilograms) from Arizona's Barringer Meteor Crater. Visitors are encouraged to touch this meteorite. Also on display is a smaller meteorite found in Antarctica by University of Pittsburgh Professor William A. Cassidy.

In the Henry Buhl, Jr. Planetarium Lobby, visitors can also determine their weight on Mars, as well as their weight on Earth, the Moon, and Venus, on the historic Fairbanks-Morse Planetary Weight Scale. As the Arizona meteorite fragment and the Fairbanks-Morse scale were both originally displayed at the dedication of the original Buhl Planetarium and Institute of Popular Science on Tuesday Evening, 1939 October 24, both are the Property of the City of Pittsburgh.

On Saturday, 2022 October 15 just four blocks north of The Carnegie Science Center, a $2.7 million Moonshot Space Museum, regarding robotic missions to the Moon, opened. The museum is adjacent to, and operated by, Astrobotic Technology, Inc., which plans to send a robotic rover to the Moon this year. Near the end of this blog-post is the link to a blog-post describing the new Moonshot Space Museum.

  

The planet Mars, as displayed in a classic, display-case exhibit in the Hall of the Universe (1950s to 1994) at the original Buhl Planetarium and Institute of Popular Science / Buhl Science CenterAmerica's fifth major planetarium and Pittsburgh's science and technology museum from 1939 to 1991.

.(Image Source: Friends of the Zeiss; Photographer: Francis G. Graham, Professor Emeritus of Physics, Kent State University)

Mars Often Featured at the Original Buhl Planetarium

The predecessor of The Carnegie Science Center was the original Buhl Planetarium and Institute of Popular Science (a.k.a. Buhl Science Center), America's fifth major planetarium and Pittsburgh's science and technology museum from 1939 to 1991. The original Buhl Planetarium building, now used by the Children's Museum of Pittsburgh, is located in Allegheny Center, one mile northeast of The Carnegie Science Center.

Mars was often the topic of science programming at the original Buhl Planetarium.

For decades (1950s to 1994), a classic, display-case exhibit showing the planet Mars was displayed in the Hall of the Universe of the original Buhl Planetarium. This exhibit showed the topography of Mars, as determined by telescopic images of Mars taken in the 1950s.

Two weight scales at the original Buhl Planetarium helped visitors determine what they would weigh on Mars: Fairbanks-Morse Planetary Weight Scale (in addition to Mars, visitors could determine their weight on Earth, Earth's Moon, and Venus on this scale); Toledo Planetary Weight Scale (three additional Toledo scales allowed visitors to determine their weight on Earth, the Moon, and Jupiter). The historic Fairbanks-Morse scale (Property of the City of Pittsburgh) continues to be available to the public in the Henry Buhl, Jr. Planetarium Lobby on the second floor of The Carnegie Science Center.

From time-to-time, the Buhl Planetarium sky show performance, in the original Theater of the Stars, would be about Mars. This includes a show titled, “The Red Planet Mars” in April of 1988, ahead of the Perihelic Opposition of Mars on 1988 September 28 (closest approach to Earth: 1988 September 22). The historic Zeiss II Planetarium Projector (Property of the City of Pittsburgh), which presented all planetarium sky shows from 1939 to 1991, is now on static display in the Space Place exhibit in The Carnegie Science Center's first-floor Atrium Gallery.

“Mars in 3-D”, a popular motion picture produced by NASA, was often shown to the general public in Buhl Planetarium's Little Science Theater (250-seat Lecture Hall); each visitor attending the film was given a pair of 3-D glasses to view the production. This 1979 film included 3-D images of Mars, taken by the Viking 1 and Viking 2 spacecraft, beginning in the Summer of 1976.

Mars was often the featured object shown to the public, particularly when Mars was close to Earth, in the original Buhl Planetarium Astronomical Observatory. Buhl's Astronomical Observatory was open for public observing every Friday evening 7:30 to 10:30 p.m. Eastern Time (ET), weather-permitting, year-round---also, some Thursday, Saturday, and Sunday evenings, weather-permitting, during the months of November through February (except the evenings of Christmas Eve and Christmas Day, when the building was closed) each year.

In addition to the opening of Mars: The Next Giant Leap exhibit on November 19, November 19 also marked the 81st anniversary (Wednesday Evening, 1941 November 19) of the Astronomical Observatory at the original Buhl Planetarium and Institute of Popular Science. The Astronomical Observatory's primary instrument was a rather unique, and now historic, 10-inch Siderostat-type Refractor Telescope (Property of the City of Pittsburgh).

The original Buhl Planetarium / Buhl Science Center also displayed a Moon Rock, collected by the Apollo astronauts, for the general public twice. The first time was in the Spring of 1970, shortly after the beginning of the manned lunar landings. The second time was in the Summer of 1989, in commemoration of the 20th anniversary of the Apollo 11 landing.

ADDENDUM - More Photographs of the new Mars: The Next Giant Leap Exhibit:

Link >>> https://andrewcarnegie.tripod.com/csc/pix/mars/

Internet Links to Additional Information ---

Mars: The Next Giant Leap Exhibit at The Carnegie Science Center:

Link >>> https://carnegiesciencecenter.org/exhibits/mars/

Photographs of some additional exhibits at The Carnegie Science Center:

Link >>> https://andrewcarnegie.tripod.com/csc/photoalbum.html

Mars: Link >>> https://en.wikipedia.org/wiki/Mars

The Carnegie Science Center: Link >>> https://carnegiesciencecenter.org/

Historic Buhl Planetarium & Institute of Popular Science / Buhl Science Center:

Link >>> http://www.planetarium.cc/

NASA  Apollo 15  Astronaut James B. Irwin, Pittsburgh native who landed on Moon:

Link >>> https://buhlplanetarium2.tripod.com/bio/Pghastronauts.html#irwin

Related Blog-Posts ---

"Moonshot Space Museum Opens in Pittsburgh." Thur., 2022 Oct. 20.

Link >>> https://spacewatchtower.blogspot.com/2022/10/moonshot-space-museum-opens-in.html

"Science Museums Rebound After Worst of Pandemic." Tue., 2022 Sept. 27.

Association of Science & Technology Centers (ASTC) 2022 Conference in Pittsburgh

Link >>> https://spacewatchtower.blogspot.com/2022/09/science-museums-rebound-after-worst-of.html


NASA Astronaut & Beechview Native James B. Irwin

"Pittsburgh Museum Displays Historic Apollo 11 Moon Mission Artifacts." Wed., 2018 Oct. 24.


"Mars Rover Sees Mystery Rock Suddenly Appear." Mon., 2014 Jan. 20.

By Francis G. Graham, Professor Emeritus of Physics, Kent State University
Reporting for SpaceWatchtower

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss          

               Wednesday, 2023 January 11.


                             Like This Post?  Please Share!

           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
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gaw

Glenn A. Walsh, Informal Science Educator & Communicator                                                               (For more than 50 years! - Since Monday Morning, 1972 June 12):
Link >>> http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: Link >>> http://buhlplanetarium.tripod.com/fotz/
SpaceWatchtower Editor / Author: Link >>> http://spacewatchtower.blogspot.com/
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), America's fifth major planetarium and Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania, the fourth of only five libraries where both construction and endowment funded by famous industrialist & philanthropist Andrew Carnegie.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh: Link >>>  http://www.planetarium.cc  Buhl Observatory: Link >>>  http://spacewatchtower.blogspot.com/2016/11/75th-anniversary-americas-5th-public.html
* Adler Planetarium, Chicago: Link >>> http://adlerplanetarium.tripod.com
* Astronomer, Educator, Optician John A. Brashear: Link >>> http://johnbrashear.tripod.com
* Andrew Carnegie & Carnegie Libraries: Link >>> http://www.andrewcarnegie.cc

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html

 

Sunday, January 1, 2023

Leap-Second to Make-Way for Leap-Minute?

 

Time.gov screen-shot from the last Leap-Second inserted in the civil time scale. In this case, displayed is Coordinated Universal Time (UTC), used internationally and by scientists. This time was equivalent to 6:59:60 p.m. Eastern Standard Time (EST) on Saturday Evening, 2016 December 31. (Image Sources: National Institute of Standards and Technology, Wikipedia.org, By US Government / NIST - Screen Grab from web display of www.time.gov, Public Domain, https://commons.wikimedia.org/w/index.php?curid=54655717)

By Glenn A. Walsh

Reporting for SpaceWatchtower

For the last 50 years, some calendar years have ended with a Leap-Second, an additional second added to keep clocks in-sync with the slowing rate of the Earth's rotation. However, scientists have decided to end the practice of adding Leap-Seconds, by or before 2035.

What is a Leap-Second ?

As mentioned, a Leap-Second is an additional second inserted into the civil time scale (which had been converted to the more accurate and consistent Atomic Time), to keep our clocks close to the time as determined by the Earth's rotation rate. The Leap-Second is used to keep Atomic Time synchronized with Astronomical Time or Universal Time.

As of 2022 December, Atomic Time has been between 15 and 20 milliseconds ahead of Astronomical Time. One millisecond is one-thousandth of one second.

Actually Leap-Seconds were designed to be either positive or negative, depending on the uncertain nature of the Earth's rotation. However, to-date, only 27 positive Leap-Seconds have been inserted into the civil time scale since 1972, the last one added on 2016 December 31.

Also, the Leap-Second was designed to be added or subtracted from the civil time scale on either June 30 or December 31, or both. One Leap-Second was added both on June 30 and December 31 in the first year it was instituted, 1972. Although most Leap-Seconds have been added on December 31, 11 Leap-Seconds have been inserted on June 30, the last added on 2015 June 30.

Sometimes, when a Leap-Second is added on December 31, the famous New York City Times Square Ball-Drop holds the ball for an additional second, for the Leap-Second. However, this is just for show. The Leap-Second, whether inserted on June 30 or December 31, is always added at 23:59:60 Coordinated Universal Time (UTC - time used internationally and by scientists), which is the equivalent of 6:59:60 p.m. Eastern Standard Time (EST).

The Times Square Ball-Drop harkens back to the early days of marine navigation. Time Balls, mostly at astronomical observatories and other significant marine navigation-related buildings, would drop each day at local Noon, so ships off-shore could accurately set their chronometers. To determine the accurate Longitude at sea. mariners must have the accurate time.

Why Have a Leap-Second in the First Place ?

Astronomers in the 19th century used the stars to tell-time. A special Meridian Transit Telescope would be used to determine the precise time when a star had returned to the same location in the sky, the following day. Samuel Pierpont Langley, a future Secretary of the Smithsonian Institution, sold the precise time to the railroads via telegraph transmission beginning in 1869, when he was Director of Pittsburgh's Allegheny Observatory. This led to the creation of geographic Time Zones in 1883.

However, the Earth's rate of rotation on its axis (which causes day and night), measured by astronomers, is not as consistent as the more accurate time created by our atomic clocks. So, it was decided in 1972 to change the clocks, to more agree with the Earth's rotation, which is measured as Astronomical Time or Universal Time (UT or UT1). Coordinated Universal Time (UTC) is then converted to the civil time scales of the world, such as Eastern Time (ET) and the other 23 world time zones.

This was fine for the last 50 years. When the Earth's rate of rotation slowed to the point where Atomic Time was ahead by 0.9 second, a Leap-Second would be added to remedy the discrepancy. Actually, the Leap-Second is usually added once Atomic Time is ahead by 0.6 second, so the discrepancy does not approach the one second deviation. When a Leap-Second is added, automatically clocks come to be ahead of Astronomical Time by 0.4 second; so, the next Leap-Second would not be added until clocks lose an additional 1.0 second of time.

An organization called the International Earth Rotation and Reference Systems Service (IERS) makes the decision when a Leap-Second needs to be added (or subtracted), six months before implementation. In addition to notifying other scientists and the media of the decision, U.S. National Institute of Standards and Technology short-wave radio stations WWV (Fort Collins, Colorado) and WWVH (Kekaha, Hawaii), which broadcast precise time-of-day signals to the general public, transmit an hourly announcement of the Leap-Second change to take-place.

Why Eliminate Leap-Seconds Now ?

Remember the “Y2K” scare of 1999? Moving from “99” to “00”, on computers which represented the year with only two digits, was predicted to confuse and compromise some computer applications. Preparations and preventive measures were taken and few problems occurred. Regrettably, two-digit year expressions can still be found in some applications.

In the 21st century, Leap-Seconds have proven to be quite disruptive to computers, particularly with applications requiring time-stamping or time-critical process control. This includes cellular telephone networks and GPS (Global Positioning System), as well as aviation and satellite navigation systems – any system that requires precise time-keeping. System failures and anomalies can be caused by the insertion of a Leap-Second.

Scientists have been considering the elimination of the Leap-Second since 2015. On 2022 November 18 the final decision was made at a general conference in France of the International Bureau of Weights and Measures (BIPM), which is responsible for international time-keeping.

The United States was one of the nations which voted to eliminate the Leap-Second. This is no surprise considering how dependent our nation has become to computer and other high-technology systems.

What Are Alternatives to the Leap-Second ?

At this conference, it was decided that by or before 2035, insertion of Leap-Seconds would end. When, exactly this would take place, and what would be the alternative, has not yet been determined. Another international conference in 2026 would need to iron-out those details.

It is anticipated that, without Leap-Seconds, the difference between Atomic Time and Astronomical Time would continue to increase, but not by an alarming rate. It is predicted that it would take 50-to-100 years before such a difference would add-up to one minute. It could take up-to five millenia for the difference to become as large as one hour!

So, what are possible alternatives? One idea is to add a Leap-Minute, when needed, every 50-to-100 years. Another alternative is similar, but instead of calling it a Leap-Minute, simply “smearing” the last minute of a particular year into two minutes. Again, so far no specific alternative has been endorsed by scientists.

Of course, this assumes that the Earth's rotation rate will continue slowing. But what if the Earth surprises us? If the Earth's rotation rate should suddenly speed-up, no change may be necessary or a negative Leap-Minute (subtracting a minute at the end of a year) could become necessary.

Scientists still have much to learn about the rotation rate of celestial bodies, including our own planet. Subtle changes could affect a planet's rotation rate. In the case of the Earth, the Moon's gravity which affects ocean tides could change, as the Moon very, very gradually moves farther from our planet each year.

The change in the distribution of the Earth's mass from shifts in our planet's molten interior, perhaps caused by greater volcanic activity, could affect the Earth's rotation rate. Some scientists suggest that Climate Change, with warmer air and melted water moving closer to the poles, may cause the Earth to spin faster!

Once Leap-Seconds no longer occur (by or before 2035), astronomers will need to adjust times, by a specific amount for the time period of their observations, to ensure that their telescopes and other instruments can find the star, planet, or other celestial body they wish to study. No doubt, astronomical almanacs will need to begin reporting on the time corrections needed by these scientists, as well as by amateur astronomers.

At any rate, there is no Leap-Second planned for the end of 2022. And, there may never be a Leap-Second again! We will just have to keep watching our time.

Internet Links to Additional Information ---

Leap-Second ---

(National Institute of Standards and Technology): Link >>> https://www.nist.gov/pml/time-and-frequency-division/leap-seconds-faqs

(Wikipedia): Link >>> https://en.wikipedia.org/wiki/Leap_second

International Atomic Time (TAI): Link >>> https://en.wikipedia.org/wiki/International_Atomic_Time

Astronomical Time >>> https://en.wikipedia.org/wiki/24-hour_clock

Universal Time (UT / UT1): Link >>> https://en.wikipedia.org/wiki/Universal_Time

Coordinated Universal Time (UTC):

Link >>> https://en.wikipedia.org/wiki/Coordinated_Universal_Time

Astronomical Time Balls: Link >>> https://en.wikipedia.org/wiki/Time_ball

Samuel Pierpont Langley: Link >>> https://johnbrashear.tripod.com/bio/LangleySP.htm

Related Blog-Posts ---

"Leap-Year to be Even Longer w/ Added Leap-Second!" Mon., 2016 July 11.


"Slowing Earth Rotation Rate Necessitates June 'Leap Second'." Tue., 2015 Jan. 27.

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss          

               Sunday, 2023 January 1.


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gaw

Glenn A. Walsh, Informal Science Educator & Communicator                                                               (For more than 50 years! - Since Monday Morning, 1972 June 12):
Link >>> http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: Link >>> http://buhlplanetarium.tripod.com/fotz/
SpaceWatchtower Editor / Author: Link >>> http://spacewatchtower.blogspot.com/
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), America's fifth major planetarium and Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania, the fourth of only five libraries where both construction and endowment funded by famous industrialist & philanthropist Andrew Carnegie.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh: Link >>>  http://www.planetarium.cc  Buhl Observatory: Link >>>  http://spacewatchtower.blogspot.com/2016/11/75th-anniversary-americas-5th-public.html
* Adler Planetarium, Chicago: Link >>> http://adlerplanetarium.tripod.com
* Astronomer, Educator, Optician John A. Brashear: Link >>> http://johnbrashear.tripod.com
* Andrew Carnegie & Carnegie Libraries: Link >>> http://www.andrewcarnegie.cc

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html