100 Years – 100 Objects: Jeremejevite

The Houston Museum of Natural Science was founded in 1909 - meaning that the curators of the Houston Museum of Natural Science have been collecting and preserving natural and cultural treasures for a hundred years now. For this yearlong series, our current curators have chosen one hundred exceptional objects from the Museum’s immense storehouse of specimens and artifacts—one for each year of our history. Check back here frequently to learn more about this diverse selection of behind-the-scenes curiosities—we will post the image and description of a new object every few days.

This description is from Joel, the Museum’s President and Curator of Gems and Minerals. He’s chosen spectacular objects from the Museum’s mineralogy collection, which includes some of the most rare and fascinating mineral specimens in the world, that we’ll be sharing here – and at 100.hmns.org- throughout the year.

Jeremejevite

Jeremejevite. Mile 72 near Swakopmund, Namibia

Blue jeremejevite is among the rarest of gem minerals and has been found at only two localities, both of them in Namibia. Crystals from the original Namibian find in 1973 remain the finest known examples of the species. This 5.5-cm specimen is the best of the matrix specimens recovered. The presence of multiple crystals makes it unusual.

Marvel at the world’s most spectacular collection of natural mineral crystals in the Cullen Hall of Gems and Minerals at the Houston Museum of Natural Science.

You can see more images of this fascinating artifact – as well as the others we’ve posted so far this year – in the 100 Objects section at 100.hmns.org.

Partial Eclipse of the Eclipse: Report from Shanghai

In July 2009, I had a rare opportunity to travel with an HMNS sponsored tour group to the path of a solar eclipse. That eclipse occurred the morning of July 22, 2009, and was visible in Asia and the Pacific. Unfortunately, clouds marred the event as seen from our location just outside Shanghai. But since the clouds did not completely hide the eclipse, we were able to witness some of its effects.

Eclipsed? Not totally.
Creative Commons License photo credit: James Jordan

Solar eclipses occur when the Moon passes between the Sun and the Earth and casts its shadow on the Earth.  The shadow itself, called the umbra, is the region in which the Moon completely blocks the Sun.  Anyone in the Moon’s umbra experiences a total eclipse of the Sun.  As the Moon passes in front of the Earth, its shadow traces a path across the Earth’s surface; this is the ‘path of totality’.  To see a total solar eclipse, one must travel to a place on the path of totality.  As it happens, last month’s path covered parts of India, the Himalayas, China, and the open Pacific.

In an interesting coincidence, the Moon is about 400 times smaller than the Sun and about 400 times closer.  Thus, the Moon and Sun appear to be about the same size (just over 1/2 degree across) in our sky.  However, the Moon had been at perigee (closest approach to Earth) on July 21, making it slight larger than usual in our sky.  Further, every year in early July (July 3 in 2009) the Earth is as far as possible from the Sun (called aphelion).   These factors combined to make the New Moon of July 22 8%  larger than the Sun in our sky.  Thus, this is the longest eclipse of the 21st century, lasting 6 minutes and 39 seconds when seen on the centerline at local noon.

This was the latest eclipse in Saros cycle 136.  Astronomers in ancient Babylon noticed that similar solar and lunar eclipses recurred every 18 years, 10, 11, or 12 days, and 8 hours.  This corresponds to 223 lunations.  (One lunation is the period from one New Moon to the next–about 29.5 days).  The 10, 11, or 12 days depend on how many leap years are in the 18 year period.  In 1691, Edmund Halley applied the name ‘saros’ to this cycle, based the ‘SAR,’ a Babylonian unit of measure.  It turns out that the unit for keeping track of eclipses in Babylon was not the SAR, but Halley’s term stuck.  Cycle 136, then includes the eclipses of  July 11, 1991, June 30, 1073, and June 20, 1955.  Future eclipses in this cycle will occur on August 2, 2027, August 12, 2045, and so on.  As eclipses of cycle 136 occur further and further from aphelion, they won’t be quite as long as this year’s.  There won’t be a longer total solar eclipse until June 13, 2132.  That’s when a different saros cycle, #139, begins to occur near aphelion.

The Shanghai Tourism Administration estimates that over 13,000 overseas visitors traveled to Shanghai to watch the eclipse.  Along with hundreds of other eclipse chasers, our group left Shanghai proper to observe the eclipse from the Yangshan Deep Water Port, a small island southeast of the city itself.   To understand why, refer again to the July 2009 path of totality.  Drawn on the eclipse path on that map is a black Sun with small rays, indicating a point on the open water southeast of Japan.  This is the point of maximum eclipse, where the eclipse occurred at local noon and lasted the full 6 minutes and 39 seconds.  At other places on the path, totality was slightly shorter.  A few folks actually sailed the Pacific in order to be near that point.  We, however, opted for the convenience of observing on land.  Shanghai was the place in the path of totality closest to the point of maximum eclipse while still on the Asian mainland.

Also, note the blue line drawn down the middle of the path of totality.  Observing on that line, as opposed to the northern or southern edges of the path, gives you a longer eclipse.  Shanghai, although well within the path, is somewhat north of the blue centerline.  Moving from Shanghai itself to Yangshan island to the southeast put us closer to the centerline.  This gave us 5 minutes, 57 seconds of totality as opposed to about 5 minutes even in Shanghai.

eclipse 1
Photo from Shanghai, 2009 solar eclipse

As it turns out, there was another benefit from observing from Yangshan.  July 22, 2009 was rainy in Shanghai.  At Yangshan, however, it was simply overcast.  And just when we were beginning to think we’d miss the entire event, the clouds began to thin out in spots, allowing us occasional glimpses of the partially eclipsed Sun.

Unfortunately, those thinner clouds were not with us during totality.  We missed seeing the beautiful corona around the totally eclipsed Sun.  We could not see the planets and the brighter stars against the mid-day twilight sky.  And we could not watch the Moon’s shadow approach and then leave us  making shadow bands on the ground as it did so.  However, we did notice how much darker and cooler it got during totality.  After all, an overcast sky at night or in twilight is much darker than an overcast sky in broad daylight.  Cheers and whistles rose from Yangshan as darkness fell at 9:37 am and lasted until 9:43 am local time.

eclipse 2
Photo from Shanghai, 2009 solar eclipse

Literally seconds after totality was over, the clouds once again became thin enough for us to see the Sun through them.  As we watched the Sun come out of eclipse, we gave thanks for having avoided the rain and for being able to see as much as we saw, although we wished the clouds had thinned a little earlier to give us a glimpse of totality.

Would you like to have a similar experience?  Well, the path of the next total solar eclipse, on July 11, 2010, scarcely touches land at all, although it does pass over exotic Easter Island.  On November 13, 2012, totality is visible from northern Australia.

Can’t afford to leave the country to see an eclipse?  The Moon’s shadow crosses the United States on Monday, August 21, 2017.  The path of totality for that eclipse passes roughly from Salem, Oregon to Charleston, South Carolina.  How about a total eclipse right here in Texas?  Mark April 8, 2024, on your calendars.  On that date the Moon shadow first touches land near Mazatlan, Mexico, then sweeps right across the center of Texas before heading off to the northeast.  Folks in Dallas, Austin, and the western part of the San Antonio area see a total eclipse on that date; Houston experiences a deep partial eclipse.  The really young can look forward to May 11, 2078.  On that date, the Moon’s shadow passes just south of the upper Texas coast on its way to New Orleans and Atlanta.  Houstonians again experience a very deep partial eclipse.

The Moon’s shadow, then, will visit North America several times in the 21st century.  Maybe you can go observe the rare and beautiful spectacle of a solar eclipse, with better luck than I had in Shanghai. 

Send help now!

In theory, archaeologists set out on their digs with specific goals in mind. They want to find out when a site was occupied and what people were doing at that time. They also want to know the bigger picture: how did people at the site they are digging interact with those living elsewhere?
In practice this does not always mean that they know what they will unearth.  In that regard, I have often compared archaeology to fishing; people tend to go where they think they will catch (or, in the case of archaeologists, find) something.  The discovery described below is a good example of this.

untitled
Creative Commons License photo credit: procsilas

Cambridge University  professor John MacGinnis recently commented on one of his finds, a small clay tablet with cuneiform writing on it. The tablet, which dates back to the final years of the Assyrian Empire, was found at the site of Tushan in Southeast Turkey. This site is known today as Ziyaret Tepe; several archaeological teams have undertaken excavations there.

 The tablet contains a message written by an Assyrian army commander facing imminent danger from invading Babylonian forces.  His message is a raw plea for help. “Death will come out of it! No one will escape! I am done!” 
 
What is this all about?
The year is 630 BC and Tushan, considered to have been the administrative capital of the northern province of the Assyrian Empire, is threatened by the Babylonians. From the brief cuneiform text, it appears that the citizens knew all too well this was happening. Many fled, among those specialists in weapons manufacturing. This is what caused the commander to lament: “Nobody mentioned in this letter, not one of them is here! How can I command?”  His premonitions proved to be correct: the city fell.

Assyrian door gaurd
Creative Commons License photo credit: glyn_nelson

Yet the Assyrians had had a great run for a long time. Centered on the capital city of Ashur (Assur), located on the west bank of the river Tigris in northern Mesopotamia, the Empire’s roots date back to 1800 BC. Its zenith occurred during the 13th century BC, during the reign of king Tukulti-Ninurta I (1244–1208 B.C.). As with all empires, decline eventually set in and by the time we reach 630 BC, the Assyrian Empire was but a shadow of its former self.  The Babylonians were systematically conquering them.

Through this tablet, we get a glimpse of what people experienced at that time. Archaeologists  value this highly: when we read history, we often forget that real people were part of these events and that to them these developments were more than just of academic interest. To me, this cry for help still packs a punch, even after more than two and a half millennia have gone by.

100 Years – 100 Objects: Conus adamsonii

The Houston Museum of Natural Science was founded in 1909 – meaning that the curators of the Houston Museum of Natural Science have been collecting and preserving natural and cultural treasures for a hundred years now. For this yearlong series, our current curators have chosen one hundred exceptional objects from the Museum’s immense storehouse of specimens and artifacts—one for each year of our history. Check back here frequently to learn more about this diverse selection of behind-the-scenes curiosities—we will post the image and description of a new object every few days.

Conus rhodendron - srop

This description is from Tina, the museum’s associate curator of malacology. She has chosen a selection of objects that represent the most fascinating shells and animals in the Museum’s collections, that we’ll be sharing here – and at 100.hmns.org- throughout the year.

Broderip, 1836

Commonly called the “Rhododendron Cone” this rare species is easily distinguishable from any other species of Conidae.  They live on the seaward sides of coral reefs and are difficult to find in their habitats because of the rough ocean currents outside the reefs.  Occasionally they can be found inside the protective coral reefs in lagoons.  Possibly these have been washed over the reef by strong storms.  French Polynesia is the eastern border of its range which extends westward to the Coral Sea area.

You can see more images of this fascinating artifact – as well as the others we’ve posted so far this year – in the 100 Objects section at 100.hmns.org