Monday, August 10, 2020

Annual Perseid Meteor Shower Peaks Tue. Night / Early Wed. Morning

    
A short, cropped video-clip of a Perseids meteoroid (at the bright head of the "shooting-star" trail) entering the Earth's atmosphere in slow-motion (x0.1). The meteoroid measured about 0.39-inch / 10 milimeters. This video, aimed at the Constellation Camelopardalis, was taken from Berlin on 2019 August 14.
(Image Sources: Wikipedia.org, By Bautsch - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=81371519)

By Glenn A. Walsh
Reporting for SpaceWatchtower

This year's Perseid Meteor Shower, which peaks Tuesday evening / early Wednesday morning, is considered the best meteor shower of the year. And, this peak could stretch into Wednesday evening / early Thursday morning.

The peak of the Perseid Meteor Shower, this year, actually occurs Wednesday Morning, 2020 August 12 at 9:00 a.m. Eastern Daylight Saving Time (EDT) / 13:00 Coordinated Universal Time (UTC). However, the best time to watch most meteor showers, including this year's Perseids, is always between local midnight and dawn, when the Earth is rotating into the meteor shower.

At the peak time, sometimes up-to 50-to-100 meteors could possibly be seen per-hour, if observing conditions are ideal. Depending on your location, weather conditions, and the condition of your eye-sight, seeing 50-to-60 meteors per-hour would be more likely.

As most meteors are often dim, it is best to view a meteor shower away from city lights, which cause a brightening of the sky at night, and hence, the dimmest meteors are often missed. And, you want to go out ahead of time, before you start actual viewing of meteors, to get your eyes accustomed to the dark sky. Dark-adapting your eyes for meteor watching could take up-to one half-hour.

For the Perseid Meteor Shower at this time, the Moon will be in a Waning Crescent Phase, having just passed the primary lunar phase of Last Quarter the previous day (Tuesday, 2020 August 11) at 12:45 p.m. EDT / 16:45 UTC. Although the Moon will be visible for most of the early Wednesday morning hours, there should not be quite as much reflected sunlight from the Moon to obscure the dimmer meteors. Try not to look directly at the Moon, so it does not hinder your dark-adapted eye-sight.

Actually, some meteors from the Perseid Meteor Shower can be seen as early as mid-July and as late as late August (~July 17 to August 24); but they are few and far between. Most Perseid meteors can be seen three-to-five days before and three-to-five days after the peak time, which is considered, approximately, between August 9 and 14 each year.

Viewers in the Northern Hemisphere are fortunate that the Perseid Meteor Shower arrives during the Summer month of August, when temperatures are comfortable for night-time viewing. However, some locations (such as in the mountains) could be cooler in the early-morning hours. So, be sure to check your local weather forecast (with NOAA Weather Radio, local radio or television, or the Internet) and bring a sweater or jacket with you if your location has a cooler forecast.

Be aware that sometimes August can be very humid with poor seeing conditions. And, the closer to the horizon, the worse the seeing conditions could be.

Binoculars and telescopes are not very useful for finding meteors. Meteors streak across the sky in a very brief period of time, too short to aim binoculars or a telescope. So, the best way to view a meteor shower is to lie on the ground (perhaps on a blanket, sheet, or beach-towel—or possibly in a reclining beach or lawn-chair), in an area with a good view of the entire sky (with few obstructions such as buildings, trees or hills, perhaps at a higher elevation), and keep scanning the entire sky with your naked-eyes (one-power).

Meteor showers appear to emanate from a radiant point in the sky. For the Perseid Meteor Shower, the radiant appears to be within the Constellation Perseus, named for the hero of Greek mythology. However, you should not, necessarily, be looking only at Perseus, when looking for meteors in this shower. Meteors can appear in any part of the sky at any time. In fact, looking towards Perseus may not result in finding the best meteors, as meteors coming from the apparent radiant may be seen for a shorter time in the sky.

A meteor shower normally consists of dust particles related to a comet. Each time a comet approaches the Sun, the comet loses dust particles following the melting of ice on the comet. These dust particles, called meteoroids, continue to follow the same orbit as the comet and form a meteoroid stream. Each year, as the Earth orbits the Sun, the Earth passes through several of these meteoroid streams, becoming Earth's meteor showers.

The Earth's gravity then attracts many of these meteoroids to fall to Earth, and they are viewed by people as meteors, as they burn-up, often high in the atmosphere. Most are extremely small and burn-up completely. From time-to-time, larger particles enter the atmosphere and create brilliant displays known as fire-balls. If these particles are large enough, they may not completely burn-up and land on Earth as a meteorite.

Meteors can be seen any night of the year, although they are not predictable and are rare outside of one of the annual meteor showers. The vast majority of meteors that can be seen during the Perseid Meteor Shower originate from the Comet Swift-Tuttle, which has an orbital period of 133 years, leaving behind a trail of dust and grit. Comet Swift-Tuttle was discovered in 1862 and last returned for viewing in 1992.

Comet Swift-Tuttle measures about 16 miles / 25 kilometers across, much larger than the object that is thought to have fallen to Earth which resulted in the extinction of the dinosaurs (about 6 miles / 10 kilometers across) approximately 66 million years ago (after living on Earth for about 165 million years!).

Comet Swift-Tuttle will make a very close approach to the Earth in the year A.D. 4479. Scientists are now studying whether some day Comet Swift-Tuttle could impact the Earth. Comet Swift–Tuttle has been described as "the single most dangerous object known to humanity".

So, the time for viewing is right, and the less moonlight is great. And, of course, with the warm weather most of us experience in the Northern Hemisphere, this time of year, what could be better for viewing meteors?

Of course, meteor showers, like all celestial observations, are weather-permitting. Even a few clouds could obscure quite a few meteors.

If the weather in your area does not permit direct viewing outdoors of this meteor shower, it is possible (but not guaranteed) you may be able to use Google, Yahoo, Bing, Lycos, or your favorite Internet search engine to find special web-casts of the meteor shower at one or more sites on the Internet.

A cautionary note for those who find it necessary to watch the meteor shower on the Internet. The video camera, used for each web-cast, can only aim at one part of the sky at a time. Hence, do not expect to see as many meteors as you might see with your own eyes outside. Outdoors, you can easily scan the entire sky for meteors, while a camera aimed at one area of the sky will only be able to see the meteors that enter that particular field-of-view.

Internet Links  to Additional Information ----

Perseid Meteor Shower: Link >>> https://en.wikipedia.org/wiki/Perseids

Comet Swift-Tuttle: Link >>> https://en.wikipedia.org/wiki/Comet_Swift%E2%80%93Tuttle

Constellation Perseus: Link >>> https://en.wikipedia.org/wiki/Perseus_%28constellation%29

Meteor Shower: Link >>> https://en.wikipedia.org/wiki/Meteor_shower

Meteor: Link >>> https://en.wikipedia.org/wiki/Meteoroid#Meteor

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

Meteorite: Link >>> https://en.wikipedia.org/wiki/Meteoroid#Meteorites

Fifth largest fragment of the meteorite which struck Barringer Meteor Crater near Winslow, Arizona, which was displayed (1939 to 1991) at the original Buhl Planetarium and Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science and technology museum from 1939 to 1991. Today, this meteorite is displayed on the second floor of Pittsburgh's Carnegie Science Center, next to the Henry Buhl, Jr. Planetarium:
Link >>> http://buhlplanetarium2.tripod.com/Buhlexhibits.htm#meteorite

Related Blog-Posts ---

"Tonight's 'Meteor Outburst' w/Web-Casts: 150 Years After Comet-Meteor Shower Link Found." Thur., 2016 Aug. 11.

Link >>> https://spacewatchtower.blogspot.com/2016/08/tonights-meteor-outburst-wweb-casts-150.html

 

"Great Perseid Meteor Shower Peaks Wed. Night w/ Web-Casts." Wed., 2015 Aug. 12.

Link >>> https://spacewatchtower.blogspot.com/2015/08/great-perseid-meteor-shower-peaks-wed.html

 

"Perseid Meteor Shower Peaks in Sky & Web-Casts." Tue., 2014 Aug. 12.

Link >>> https://spacewatchtower.blogspot.com/2014/08/perseid-meteor-shower-peaks-in-sky-web.html

 

"Perseid Meteor Shower Peaks Sun., Mon. Nights." Sat., 2013 Aug. 10.

Link >>> https://spacewatchtower.blogspot.com/2013/08/perseid-meteor-shower-peaks-sun-mon.html


Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
              Monday, 2020 August 10.

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           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
            Link >>> https://twitter.com/spacewatchtower

        Astronomy & Science Links: Link >>> http://buhlplanetarium.tripod.com/#sciencelinks

                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < spacewatchtower@planetarium.cc >.

gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: < http://buhlplanetarium.tripod.com/fotz/ >
SpaceWatchtower Editor / Author: < http://spacewatchtower.blogspot.com/ >
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >

Thursday, August 6, 2020

Female Astrophysicist Helped Build 1st Atomic Bomb

                           Leona Woods.jpeg
           Photograph of Leona Woods Marshall at the University of Chicago on 1946 December 2.
(Image Sources: Wikipedia.org, By Argonne National Laboratory - Leona Woods Marshall Libby, Uranium People, pp. 182-183, Public Domain, https://commons.wikimedia.org/w/index.php?curid=25600002)

By Glenn A. Walsh
Rep. 5orting for SpaceWatchtower

Today marks 75 years since the first use of nuclear weapons in war-time, the culmination of the American Manhattan Project (named for the Manhattan District of the U.S. Army Corp of Engineers). It was at 8:16 a.m. Japan Standard Time (JST) on the morning of 1945 August 6 [Aug. 5, 7:16 p.m. Eastern War Time (EWT) / Aug. 5, 23:16 Coordinated Universal Time (UTC)] that the United States dropped the first atomic bomb on Hiroshima, Japan.

One of the very few female scientists who worked on the Manhattan Project went on to become a researcher in high-energy physics, astrophysics, cosmology, and diatomic molecular spectroscopy.

Leona Woods, later known as Leona Woods Marshall Libby, was the youngest (at age 23) and only female member of Enrico Fermi's team at the University of Chicago that built and experimented with the world's first artificial nuclear reactor. During the experimentation, Leona Woods was instrumental in the construction and then utilization of Geiger counters for analysis. When the first nuclear reactor went critical on 1942 December 2, she was the only woman present.

Leona Woods worked with Enrico Fermi on the Manhattan Project until 1943. Then in 1944, Leona Woods Marshall, with her first husband John Marshall (who was the great-great-great-grandson of US Supreme Court Justice John Marshall), moved to Hanford, Washington to work with the nuclear reactor creating plutonium for the Manhattan Project.

They helped solve the problem of xenon-135 "poisoning" at the  plutonium production site, which had stopped production. Leona Marshall also supervised the construction and operation of Hanford's plutonium production reactors.

She had been selected for the Manhattan Project due to her expertise in creating vacuums needed for boron trifluoride counters, for measuring neutrons and creating a nuclear chain reaction.

Leona Woods is considered the most accomplished of the few women working on the Manhattan Project. She had graduated high school in 1934 at age 14 and earned a B.S. degree in chemistry from the University of Chicago in 1938 at age 19.

Leona Woods completed her graduate work in chemistry in 1942. Her graduate supervisor was the future Nobel Laureate Robert S. Mulliken (who had been taught at the University of Chicago by Nobel Laureate Robert A. Millikan).

After World War II, she became a fellow at Erico Fermi's Institute of Nuclear Studies at the University of Chicago. In 1957 after a separation from her husband, she went to work at the Institute for Advanced Study at Princeton University in Princeton, New Jersey; at the time she was a single mother. The next year she became a fellow at the Brookhaven National Laboratory on New York's Long Island.

At New York University, she became an associate professor of atomic and nuclear physics in 1962.

From 1964 to 1970, she was a research professor in astrophysics and cosmology, as well as high-energy physics, at the University of Colorado. She also became a staff member at the RAND Corporation, a position she maintained until 1976.

In 1966, she divorced John Marshall and married Nobel Laureate Willard Libby. Willard Libby won the 1960 Nobel Prize in Chemistry for his contributions to the team that developed radio-carbon-14 dating, a process which revolutionized archeology and paleontology.

In 1973, Leona Woods Marshall Libby joined her husband at the University of California at Los Angeles as a visiting professor of environmental studies, engineering, engineering archaeology, mechanical aerospace, and nuclear engineering. Like her husband, she was a strong advocate for food irradiation as a way to kill harmful bacteria; she supported relaxing regulations on the use of food irradiation.

Over her life-time, she published more than 200 scientific papers. This included papers and books on early atomic research and environmental issues, as well as astrophysics topics.

In 1982, she edited Willard Libby's papers and published, with Rainer Berger, The Life Work of Nobel Laureate Willard Libby. Her husband had died two years earlier.

A 1969 paper she wrote was titled, Creation of an Atmosphere for the Moon, which she wrote for the RAND Corporation. In 1980, she wrote The Upside Down Cosmology and the Lack of Solar Neutrinos. She also published a paper titled, Venusian Geography.

Her last paper, produced in 1984, was on quasi-stellar objects or quasars.

She died at age 67, of an anesthesia-induced stroke, on 1986 November 10. She had been born on 1919 August 9.

Leona Woods Marshall Libby always felt that developing the atomic bomb was necessary, particularly since the Germans were working on the same project. She was also very concerned with the realistic expectation of a great loss of American soldiers and sailors had an invasion of Japan been considered necessary.

Regarding the advancement of nuclear science, she once said, “You can’t stop it. How can you stop it? You’re going to tell a guy like [Muammar] Gaddafi, ‘Don’t buy that bomb from the Israelis,’ or wherever you’re going to buy it? You can tell him, and he’s going to do—I mean you cannot stop the wheels. That’s my view. And again, the do-gooders and the crying on shoulders, these guys have got blue-eyed optimism that is not useful.”

Internet Links to Additional Information ---

More on Leona Woods Marshall Libby:
Link 2 >>> https://www.lindahall.org/leona-

Astronomy & World War II

woods/ 

Oral History Interview (1986) - Leona Woods Marshall Libby:

Related Blog Posts ---

"Requirement for World War II D-Day: Full Moon !" Thur., 2019 June 6.

Link >>> https://spacewatchtower.blogspot.com/2019/06/requirement-for-world-war-ii-d-day-full.html


"Astronomy & World War II." Sun., 2014 Sept. 7.

Link >>> https://spacewatchtower.blogspot.com/2014/09/astronomy-world-war-ii.html


Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
              Thursday, 2020 August 6.

                             Like This Post?  Please Share!

           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
            Link >>> https://twitter.com/spacewatchtower

        Astronomy & Science Links: Link >>> http://buhlplanetarium.tripod.com/#sciencelinks

                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < spacewatchtower@planetarium.cc >.

gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: < http://buhlplanetarium.tripod.com/fotz/ >
SpaceWatchtower Editor / Author: < http://spacewatchtower.blogspot.com/ >
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >

Saturday, August 1, 2020

Astro-Calendar: 2020 August / 1st SpaceX Crew Dragon Splash-down Aug. 2


NASA astronauts Robert Behnken and Douglas Hurley (shown during a pre-flight test on 2020 March 30) will return to Earth on the SpaceX Crew Dragon on Sunday Afternoon, August 2, weather-permitting. The first splash-down of a crewed American spacecraft, since the Apollo-Soyuz Test Project on 1975 July 24, is planned to occur on the Crew Dragon Demo-2 flight, after leaving the International Space Station (ISS) on the evening of Saturday, August 1.
More Information & Video Coverage of the Return to Earth including Undocking from the Space Station & Spash-down: 
Link >>> http://buhlplanetarium4.tripod.com/astrocalendar/2020.html#spacex2
(Image Source: NASA)

Astronomical Calendar for 2020 August ---
Link >>> http://buhlplanetarium4.tripod.com/astrocalendar/2020.html#aug

 Related Blog Post ---

"Astro-Calendar: 2020 July / 50 Years of Video Calling."

Wednesday, 2020 July 1.

Link >>> https://spacewatchtower.blogspot.com/2020/07/astro-calendar-2020-july-50-years-of.html


Source: Friends of the Zeiss.
              Saturday, 2020 August 1.

                             Like This Post?  Please Share!

            More Astronomy & Science News - SpaceWatchtower Twitter Feed:
            Link >>> https://twitter.com/spacewatchtower

        Astronomy & Science Links: Link >>> http://buhlplanetarium.tripod.com/#sciencelinks

                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < spacewatchtower@planetarium.cc >.

gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: < http://buhlplanetarium.tripod.com/fotz/ >
SpaceWatchtower Editor / Author: < http://spacewatchtower.blogspot.com/ >
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >