Thursday, March 19, 2020

Spring Begins at the Vernal Equinox Late Thursday Night

   http://buhlplanetarium.tripod.com/pix/graphics/solsticeimage008.png
This diagram shows the position of the Earth, in relation to the Sun, at the time of the Vernal Equinox at the official beginning of the season of Spring in the Earth's Northern Hemisphere (Autumn in Earth's Southern Hemisphere), as well as the other equinox and solstices of the year.
(Graphic Source: ©1999, Eric G. Canali, former Floor Operations Manager of 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) and Founder of the South Hills Backyard Astronomers amateur astronomy club; permission granted for only non-profit use with credit to author.)

By Glenn A. Walsh
Reporting for SpaceWatchtower

Spring begins late Thursday evening at the moment of the Vernal Equinox in Earth's Northern Hemisphere. In the Southern Hemisphere of Earth, this marks the astronomical beginning of the season of Autumn. And, Saturday marks "Galactic Tick Day," which celebrates our Solar System's travel around the Milky Way Galaxy.

                                                Vernal Equinox on Earth

The Vernal Equinox occurs on Earth at precisely: 11:50 p.m. Eastern Daylight Saving Time (EDT) on Thursday Evening, 2020 March 19 / 3:50 Coordinated Universal Time (UTC) on Friday Morning, 2020 March 20.

As the diagram at the beginning of this blog-post demonstrates, on the day of Equinox the Sun appears directly overhead at local Noon on the Equator. At the moment of Equinox, the Northern and Southern Hemispheres of Earth are illuminated equally. And, the time of Equinox is the only time when the Earth Terminator (dividing line on Earth between daylight and darkness) is perpendicular to the Equator.

This, and the reason for seasons on Earth in the first place, is due to the fact that Earth rotates on its axis, which is tilted at a 23.439281-degree angle from the plane of the Earth's orbit around the Sun, which is part of the Ecliptic of our Solar System. As the Earth revolves around the Sun, this axial tilt causes one hemisphere of the planet to receive more direct solar radiation during that hemisphere's season of Summer and much less direct solar radiation a half-year later during that hemisphere's season of Winter. As mentioned, during an Equinox (about half-way between Summer and Winter, and about half-way between Winter and Summer) both planetary hemispheres receive an equal amount of solar radiation.

Although "Equinox" in Latin means equal-night, the day of the Equinox does not actually have an equal amount of daylight and nightfall, as it appears on the Earth's surface. If the Sun was just a pin-point of light in our sky, as all other stars appear, day and night would be equal.

But, because the Sun is a disk, part of the Sun has risen above the horizon before the center of the Sun (which would be the pin-point of light); so there are extra moments of light on the Equinox. Likewise, part of the Sun is still visible, after the center of the Sun has set.

Additionally, the refraction of sunlight by our atmosphere causes sunlight to appear above the horizon, before sunrise and after sunset.

March 16 marked the Equilux ("equal-light"), the actual day with equal hours and minutes of the Sun above the horizon, and equal hours and minutes of the Sun below the horizon. The Equilux occurs twice each year, approximately 3-to-4 days before the Vernal Equinox and 3-to-4 days after the Autumnal Equinox (Equilux on September 25, while the Autumnal Equinox is ~ September 22 or 23).

An urban legend that has been making the rounds for decades, now exacerbated by the Internet and Social Media, has it that eggs can be stood on their ends only during an Equinox, whether the Vernal Equinox in the Spring or the Autumnal Equinox in the Fall. This is completely false!

Depending greatly on the size and shape of the particular egg, eggs can be stood on their ends any day of the year! Astronomy has nothing to do with whether an egg can stand on its end. If an egg can stand on its end on the Equinox (and, due to the shape and size of some eggs, this is not even possible), it can stand the same way any other day of the year.

In the last few years, with the help of the Internet and Social Media, another urban legend has become prevalent. Now it is claimed that brooms can stand, on their own, on their bristles, only on an Equinox day. This is also false! Again, as with eggs, if a broom can stand on its bristles by itself (this usually only works with newer brooms, with more even and stiff bristles) on an Equinox, it can do so any day of the year!

In ancient times, the Vernal Equinox was considered the beginning of the new calendar year. This was when most of Western Civilization used the Julian Calendar, and the Vernal Equinox occurred on March 25, later observed by Christians as the Feast of the Annunciation (observed nine full months before Christmas Day). As part of the Gregorian Calendar reform, in October of 1582, Pope Gregory XIII chose the Feast of the Circumcision of Christ (January 1) as the beginning of the New Year in the Roman Catholic Church's Liturgical Year.

The Vernal Equinox continues to be considered the beginning of the New Year, or an important holy day, in several other places on Earth ---

* Beginning of New Year (using the Solar Calendar) - Nowruz: Afghanistan and Iran / Persia.
* Holy Day for adherents of the Zoroastrian Religion (the three Magi, who the Christian Bible reports visited the Christ Child after following the Star of Bethlehem / Christmas Star, were adherents of the Zoroastrian Religion).
* Holy Day for adherents of the Bahá'í Faith: Baha'i Naw-Ruz, one of nine holy days of the Bahá'í Faith.

NASA and the European Space Agency (ESA) observe Sun-Earth Day on or near the Vernal Equinox. This is a joint educational program started in 2000, to popularize the knowledge about the Sun, and the way it influences life on Earth, among students and the public. This is part of Solar Week, which is the calendar week that includes the Vernal Equinox.

The first week of Spring, beginning with the Vernal Equinox, has been declared by physicians as Medicine Cabinet Clean-Up Week. To avoid prescription drug abuse, particularly important at this time of the opioid crisis, physicians encourage everyone to get rid of unused and no-longer-needed medications and other drugs, which may have lingered in the household, as part of an annual Spring cleaning. Several states have prescription drug take-back locations, where these drugs can be dropped-off.

The week of the Vernal Equinox is the also the beginning of the National Cherry Blossom Festival held each year in Washington, DC, which begins on March 20. This festival commemorates the 1912 gift of 3,000 cherry trees from the Mayor of Tokyo to the City of Washington. The festival runs through April 12 this year.

However, due to the Coronavirus / COVID-19, the annual 2020 National Cherry Blossom Festival Parade® (April 4) and Petalpalooza® (April 11) have been canceled, while other events have been postponed. Of course, the Washington Cherry Blossoms should still be in bloom, during this time period.

                                                "Galactic Tick Day"

Saturday, 2020 March 21 marks "Galactic Tick Day," which celebrates our Solar System's travel around the Milky Way Galaxy. It takes 230 million years for our Solar System to make one revolution around the Milky Way. The Galactic Tick Day occurs once every 1.7361 years, marking each 1 centi-arc-second of travel (i.e. "tick") in this trek.

Internet Links to Additional Information ---

Vernal Equinox: Link >>> https://en.wikipedia.org/wiki/March_equinox

Season of Spring: Link >>> http://en.wikipedia.org/wiki/Spring_%28season%29

Equinox: Link >>> http://en.wikipedia.org/wiki/Equinox

Earth's Seasons: Link >>> http://en.wikipedia.org/wiki/Season

Tilt of a Planet's Axis: Link >>> http://en.wikipedia.org/wiki/Axial_tilt

National Cherry Blossom Festival: Link >>> https://nationalcherryblossomfestival.org/

News Release - National Cherry Blossom Festival Cancellations & Postponements:

Galactic Tick Day: Link >>> http://galactictick.com/

Hubble Space Telescope image of Galaxy UGC 12158, a spiral galaxy which is thought to resemble our Milky Way Galaxy in appearance:

Related Blog Post ---

Winter Begins Late Sat. Night; Ursid Meteor Shower Sun. Night.” Fri., 2019 Dec. 20.


Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
              Thursday, 2020 March 19.

                             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 ?
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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 >

Monday, March 16, 2020

NASA Public Design Contest: Venus Rover Obstacle Avoidance Sensor


Artist's concept (2020 February 21) of a proposed wind-powered, Venus Rover probe, being considered for a future launch.
(Image Sources: NASA, Wikipedia.org, By NASA/JPL-Caltech - https://www.jpl.nasa.gov/images/venus/20200221/Rover-2-16.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=87366612)

By Glenn A. Walsh
Reporting for SpaceWatchtower

After several successful probes and rovers sent to the Planet Mars, NASA is now starting to design a rover to probe the hostile surface of the Planet Venus. NASA's Jet Propulsion Laboratory (JPL) is offering a $15,000 prize for the successful entry in a public contest to design an obstacle avoidance sensor for this Venus rover.

Venus is known as Earth's “sister” planet, as Venus is just a wee bit smaller than the Earth (with a similar mass and gravity) and approaches closer to Earth than any other planet. However, that is where the similarities end. Venus is shrouded with opaque and highly-reflective clouds of sulfuric acid, in an extremely dense atmosphere (densest atmosphere of the four terrestrial planets in our Solar System), consisting of more than 96% carbon dioxide (CO2) which has created a run-away Greenhouse Effect on the planet.

Venus' atmospheric pressure at the planet's surface is 92 times stronger than the pressure on Earth's surface (roughly the pressure found 3,000 feet / 900 meters under the oceans on Earth). NASA notes that this great pressure could easily crush a nuclear-powered submarine.

With a mean surface temperature of +863 degrees Fahrenheit / +462 degrees Celsius / +735 degrees Kelvin, Venus is by-far the hottest planet in the Solar System, despite the fact that Mercury is the closest planet to the Sun. And, NASA adds that this heat “can turn lead into a puddle.”

These planetary conditions have made a surface study of Venus very challenging. Both the United States and Russia have had limited success landing probes on Venus. In fact, while the United States has had greater success with probes to the Martian surface, Russia, before dissolution of the Union of Soviet Socialist Republics, had concentrated on Venusian landers with notable successes.

The Russian Venera 7 probe became the first spacecraft to soft-land on Venus on 1970 December 15, which stayed in contact with Earth for 23 minutes. The Russian probes Venera 9 and Venera 10 landed and took the first surface photographs of Venus in October of 1975. The first color photographs of the Venus surface were sent back to Earth by the Soviet Venera 13 lander in 1981, which lasted on the surface for a record 127 minutes.

NASA had some success with the Pioneer Venus Multiprobe in 1978, when one of four small probes survived a landing on Venus. This probe transmitted data from the surface for more than an hour.

The last Earth probe to land on Venus was the Russian Vega 2 in 1985.

So, this new Venus rover project will be one of NASA's greatest challenges to-date. Called the Automation Rover for Extreme Environments (AREE), this probe will be designed to operate on the surface of Venus, not for an hour or two, but for months!

AREE is planned to be powered by the Venusian winds, which seem to be somewhat strong and fairly constant on the planet's surface. According to NASA, the extreme pressure on the surface of Venus means that the fairly low wind speeds would feel almost like gale-force winds here on Earth.

The challenge that the Jet Propulsion Laboratory has offered for consideration by the general public is to develop an obstacle avoidance sensor for the AREE rover. The “Exploring Hell: Avoiding Obstacles on a Clockwork Rover” challenge seeks a sensor to be incorporated into the final design of the Venus rover. This sensor would be the primary mechanism for the rover to detect and navigate around surface obstructions.

As of now, there is no time-line for when the AREE would be launched toward Venus. The Jet Propulsion Laboratory hopes that the successful development of a robust obstacle avoidance sensor will strengthen the case to return to Venus with a rover, sooner rather than later.

First prize for the winning entry will be $15,000. Second prize ($10,000) and third prize ($5,000) will also be awarded.

Entries are due 2020 May 29.

More information on this “Exploring Hell: Avoiding Obstacles on a Clockwork Rover” challenge:



Internet Links to Additional Information ---

Planet Venus: Link >>> https://en.wikipedia.org/wiki/Venus

Observations & Explorations of Venus:
Link >>> https://en.wikipedia.org/wiki/Observations_and_explorations_of_Venus

Automation Rover for Extreme Environments (AREE):
Link >>> https://en.wikipedia.org/wiki/Automaton_Rover_for_Extreme_Environments

Transit of Venus, 2004 & 2012, Viewed from Pittsburgh:
Link >>> http://venustransit.pghfree.net/

Related Blog Posts ---

"Extremely Close Conjunction of Venus & Jupiter Saturday Night." Sat., 2016 Aug. 27.

Link >>> http://spacewatchtower.blogspot.com/2016/08/extremely-close-conjunction-of-venus.html


"NASA Astronauts to Visit Venus Atmosphere Before Mars?" Mon., 2014 Dec. 29.

Link >>> http://spacewatchtower.blogspot.com/2014/12/nasa-astronauts-to-visit-venus.html


Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
              Monday, 2020 March 16.

                             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 >

Monday, March 2, 2020

Astro-Calendar: 2020 March / "Galactic Tick Day": March 21

   
March 21 marks "Galactic Tick Day," which celebrates our Solar System's travel around the Milky Way Galaxy; it takes 230 million years for our Solar System to make one revolution around the Milky Way. The Galactic Tick Day occurs once every 1.7361 years, marking each 1 centi-arc-second of travel (i.e. "tick") in this trek. More Information: Link >>> http://galactictick.com/
This image from the Hubble Space Telescope is of Galaxy UGC 12158, a spiral galaxy which is thought to resemble our Milky Way Galaxy in appearance. (Image Sources: NASA, European Space Agency, Wikipedia.org, By ESA/Hubble & NASA - http://www.spacetelescope.org/images/potw1035a/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=12385417)

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

 Related Blog Post ---

"Astro-Calendar: 2020 Feb. / Once-in-Century Palindrome: Feb. 2"

Saturday, 2020 February 1.

Link >>> https://spacewatchtower.blogspot.com/2020/02/astro-calendar-2020-feb-once-in-century.html


Source: Friends of the Zeiss.
              Monday, 2020 March 2.

                             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 >