Autumnal equinox, September 23, 2015

September 23, 2015

You can only get this shot on two days each year.

I was sad to discover most of my U.S. history students (juniors) didn’t know what an equinox is. So the autumnal equinox always offers a teaching moment that ticks off the teacher raters.

Summer 2015 ended at 4:15 a.m., September 23.

This is what an equinox looks like, from 2013 photos.

From Astronomy Picture of the Day: Earth at Equinox. From the Russian meteorological satellite Elektro-L

From Astronomy Picture of the Day: Earth at Equinox. From the Russian meteorological satellite Elektro-L

Explanation from NASA:

Equinox Earth
Image Credit: Roscosmos / NTSOMZ / zelenyikot.livejournal.com
Courtesy: Igor Tirsky, Vitaliy Egorov Explanation: From a geostationary orbit 36,000 kilometers above the equator, Russian meteorological satellite Elektro-L takes high-resolution images our fair planet every 30 minutes. But only twice a year, during an Equinox, can it capture an image like this one, showing an entire hemisphere bathed in sunlight. At an Equinox, the Earth’s axis of rotation is not tilted toward or away from the Sun, so the solar illumination can extend to both the planet’s poles. Of course, this Elektro-L picture was recorded on September 22nd [2013], at the northern hemisphere’s autumnal equinox. For a moment on that date, the Sun was behind the geostationary satellite and a telltale glint of reflected sunlight is seen crossing the equator, at the location on the planet with satellite and sun directly overhead (5MB animated gif).

Wait. Animated .gif?  Cool!

The Earth at equinox, 2013; from Russan space program, via NASA.

The Earth at equinox, 2013; from Russan space program, via NASA.

The autumnal equinox is at 8:22 GMT or 4:22 am EDT on Wednesday. The two satellite images below from the European Meteosat show the sun angle on Earth from June 22 near the summer solstice and then today at the same time.  Notice the sun angle has changed dramatically, and the High Arctic is no longer seeing 24 hour daylight.

June 22 2015 from Meteosat.

Below is today at the same time.

Seviri Sep22

More:

Yes, this is mostly an encore post. Fighting ignorance requires patience.

Yes, this is partly an encore post. Fighting ignorance requires patience.


September 23, 1858: DON’T wash your hands!

September 23, 2015

Ignaz Semmelweiss

Dr. Ignaz Semmelweis

This is one of the classic stories of public health, an issue that most U.S. history and world history texts tend to ignore, to the detriment of the students and the classroom outcomes.

This is the story as retold by Christopher Cerf and Victor Navasky in The Experts Speak:

In the 1850s a Hungarian doctor and professor of obstetrics named Ignaz Semmelweis [pictured at left] ordered his interns at the Viennese Lying-in Hospital to wash their hands after performing autopsies and before examining new mothers. The death rate plummeted from 22 out of 200 to 2 out of 200, prompting the following reception from one of Europe’s most respected medical practitioners:

“It may be that it [Semmelweis’ procedure] does contain a few good principles, but its scrupulous application has presented such difficulties that it would be necessary, in Paris for instance, to place in quarantine the personnel of a hospital during the great part of a year, and that, moreover, to obtain results that remain entirely problematical.”

Dr. Charles Dubois (Parisian obstetrician), memo to the French Academy
September 23, 1858

Semmelweiss’ superiors shared Dubois’ opinion; when the Hungarian physician insisted on defending his theories, they forced him to resign his post on the faculty.

Gotta wonder what Dr. Dubois would make of the suits and sanitation procedures required today for health professionals who treat Ebola victims.

More: 

Yes, this is mostly an encore post. Fighting ignorance requires patience.

Yes, this is mostly an encore post. Fighting ignorance requires patience.


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