28 February 2011

ILLUSTRATED: THE CRAB NEBULA THROUGH TIME

M1: The Crab Nebula, captured by the Hubble Space Telescope, 2009. Credit: NASA, ESA.

Towards the end of my book DEEP BLUE HOME I wrote about the cave paintings of Mexico's Baja Peninsula—truly a wonder of the world—including an image of the Crab Nebula supernova from the year 1054.

[O]ne of the most modest paintings on view anywhere in Baja California: a small depiction in ochre of a childlike sun, with lines radiating from a circle, nestled beside the outline of another circle more than half filled with ochre pigment.

North American rock art depicting the Crab Nebula supernova, circa 1054. Illustration: Harry W. Crosby, from The Cave Paintings of Baja California.


  
You can see the art I'm describing on the far left in the image above: 

The story of this image has a long lineage, and the starting place for its rediscovered meaning dates back to the year 1054, when Chinese astronomers noted a guest star in the constellation Taurus and recorded that its glow was visible in the daytime sky for twenty-three days and in the nighttime sky for six hundred fifty-three days.
Little more thought was given to this celestial light for a long time. It was not noted in 1731 when the English doctor and astronomer John Bevis first observed a nebulous cloud within our own Milky Way galaxy nor, more than a century later, when another English astronomer named it the Crab Nebula. The visit of the guest star was nearly forgotten until the early twentieth century, when—working backward in time to calculate the rate of expansion—astronomers surmised that the Crab Nebula was the remains of the 1054 supernova observed by ancient astronomers.

The crablike sketch made in 1844 by William Parsons, 3rd Earl of Rosse, for which the nebula was named. Image courtesy Wikimedia Commons.
























And:
Later the American astronomer William Miller calculated that the 1054 supernova appeared in western North America in dazzling conjunction with a crescent moon. He correlated this sight to two pieces of prehistoric rock art in Arizona, each depicting a star beside a crescent moon. Later astronomers found strikingly similar rock art of conjunct stars and crescents at other sites in the American Southwest. In 1971 the explorer Harry Crosby, traveling by mule in the Sierra de San Francisco, came upon this image of a star and a moon—the only painting of its kind in the murals of Baja California, which he later surmised was also an image of the 1054 supernova.

Chaco Canyon, 1054 supernova rock art. Photo via.

Astronomy Picture of the Day (APOD) describes the Crab Nebula as "the mess left after a star explodes," filled with mysterious filaments:

The filaments are not only tremendously complex, but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion. In the nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second. 

Crab Pulsar Wind Nebula, 2008. Credit: NASA.

  
This deep x-ray image of the Crab Pulsar taken from the orbiting Chandra Observatory provided the first clear view of the ghostly edges of the pulsar's wind nebula. From APOD:

The pulsar's energy accelerates charged particles, producing eerie, glowing x-ray jets directed away from the poles and an intense wind in the equatorial direction. Intriguing edges are created as the charged particles stream away, eventually losing energy as they interact with the pulsar's strong magnetic field.


It's astonishing to think how much we've seen—and learned to see—in less than the blink of a universe. Of course the real timeline of events is even more profound. Back to my excerpt:

The 1054 supernova occurred 6,300 years before anyone on Earth witnessed it. The explosion dismantled a star more than 37,000 trillion miles away from us. The blast radiated as much energy as our sun will emit in the course of its life, and its light traveled at the fastest speed possible, the speed of light itself, yet it still took more than sixty centuries to get here.

Credit: Danny LaCrue & the ESA/ESO/NASA Photoshop FITS Liberator.
 
The beautiful mess of the Crab Nebula.

27 February 2011

SUNDAY POETRY: "BEACH GLASS"



While you walk the water’s edge,   
turning over concepts
I can’t envision, the honking buoy   
serves notice that at any time   
the wind may change
the reef-bell clatters
its treble monotone, deaf as Cassandra   
to any note but warning. The ocean,   
cumbered by no business more urgent   
than keeping open old accounts   
that never balanced,
goes on shuffling its millenniums   
of quartz, granite, and basalt.
                                              It behaves
toward the permutations of novelty   
driftwood and shipwreck, last night’s   
beer cans, spilt oil, the coughed-up   
residue of plastic—with random   
impartiality, playing catch or tag   
or touch-last like a terrier,
turning the same thing over and over,   
over and over. For the ocean, nothing   
is beneath consideration.
                                       The houses
of so many mussels and periwinkles   
have been abandoned here, it’s hopeless   
to know which to salvage. Instead   
I keep a lookout for beach glass   
amber of Budweiser, chryoprase   
of Almadén and Gallo, lapis   
by way of (no getting around it,   
I’m afraid) Phillips’
Milk of Magnesia, with now and then a rare   
translucent turquoise or blurred amethyst   
of no known origin.
                              The process
goes on forever: they came from sand,   
they go back to gravel,
along with the treasuries
of Murano, the buttressed
astonishments of Chartres,
which even now are readying
for being turned over and over as gravely   
and gradually as an intellect   
engaged in the hazardous   
redefinition of structures   
no one has yet looked at.

21 February 2011

CORAL CONUNDRUM

(Photograph of Acropora pulchra by Albert Kok at nl.wikipedia, courtesy Wikimedia Commons.)

I had the good fortune to meet Greta Aeby last April at her lab on Hawaii's Coconut Island—that tiny gem in Kaneohe Bay that was filmed for the show open of Gilligan's Island—now home to the Hawaii Institute of Marine Biology

I was planning to write about Greta's work on coral diseases for a new Mother Jones article. Then the Deepwater Horizon rearranged the known world and I never got to write that piece. 


(Coconut Island. Via HIMB.) 

Now I see that Greta is lead author of a new paper in PLoS ONE, assessing the causes of tumorlike diseases afflicting corals in the Indian and Pacific Oceans. Coral cover in those waters has declined  by about 1 percent per year for the last 20 years, increasing to 2 percent between 1997 and 2003.

So what's doing that?

This paper outlines the first broad-scale assessment of how nine "predictors of interest" correlate with tumorlike diseases. You can see the predictors in the table below.



The nine predictors fall into three broad categories:

  • biological factors: population abundance of affected corals
  • human factors: human population
  • environmental factors: warming waters, surface ultra-violet radiation

Statistical models were used to examine the prevalence of two coral diseasesAcropora growth anomalies and Porites growth anomalies. These diseases manifest like tumors. They're easy to identify in the field and not easily confused with anything else.


(Porites growth anomaly at top, and Acropora growth anomaly at bottom. Images courtesy PLoS ONE DOI: 10.1371/journal.pone.0016887)

The team surveyed for growth anomaly diseases on 937 reefs from 13 regions across the Indo-Pacific between 2002 and 2008. They examined corals at the genus level.

The results:

  • The Acropora growth anomaly was most associated with Acropora abundance—that is, the more Acropora corals, the more Acropora disease too
  • The Porites growth anomaly was associated with Porites abundance, but also with nearby human populations—that is, the more people, the more disease too

Which basically means that the growth anomaly diseases are likely communicable, and the the Porites version is also likely related in some fashion to an environmental co-factor or two: pollution, eutrophication, habitat fragmentation, and/or direct introduction of novel pathogens into the ecosystems.

Might there be a similar correlation for human health?



(Survey sites. Image: PLoS ONE DOI:10.1371/journal.pone.0016887)

Meantime, the heavily populated coasts suffering the most Porites growth anomalies are also home to many of the 500 million people most immediately dependent on coral reefs. The authors note:

As human densities and environmental degradation increase globally, the prevalence of coral diseases like [Porites growth anomalies] could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

Or... halted perhaps by declines in human density below thresholds required for disease establishment

This is not an impossible reality beginning sometime this century if—as projected—our population peaks and then naturally falls as more women become literate wage-earners. (For more about that, see my article The Last Taboo.)

But can coral reefs—or the people dependent on them—hold out until then? It's sort of a Catch-21st century. 



Finally, for your enjoyment, an incredibly gorgeous video of captive corals. Though the porno soundtrack is a puzzler.

The paper:

ResearchBlogging.org
Aeby, G., Williams, G., Franklin, E., Haapkyla, J., Harvell, C., Neale, S., Page, C., Raymundo, L., Vargas-Ángel, B., Willis, B., Work, T., & Davy, S. (2011). Growth Anomalies on the Coral Genera Acropora and Porites Are Strongly Associated with Host Density and Human Population Size across the Indo-Pacific PLoS ONE, 6 (2) DOI: 10.1371/journal.pone.0016887

I ♥ open access papers.

15 February 2011

SONG FOR THE BLUE OCEAN SYMPOSIUM

For anyone in the Corvallis area, I'll be appearing at the Song for the Blue Ocean Symposium at Oregon State University this Friday and Saturday.

Friday:

  • Teaching a workshop—Science and Social Networking: Blogging with a Purpose. 
Saturday:

  • My plenary address—Our Deep Blue Home. 
  • Sitting on the panel—Oceans, Science, and Advocacy: A Conversation about the Moral Responsibilities that Come with Expertise—along with Carl Safina, Rick Steiner, Bruce Menge, and Courtney Campbell, moderated by Kathleen Dean Moore.
  • Presenting with Kelly Benoit-Bird—a recent MacArthur Fellow whose work I wrote of in Mother Jones The BP Cover UpScience and Stories through Oceans of Sound.
There are many exciting speakers and presentations. You can see the complete schedule here.

Free and open to all. How cool is that?

13 February 2011

SUNDAY POETRY: "AT MELVILLE'S TOMB"


Often beneath the wave, wide from this ledge
The dice of drowned men’s bones he saw bequeath
An embassy. Their numbers as he watched,
Beat on the dusty shore and were obscured.


And wrecks passed without sound of bells,
The calyx of death’s bounty giving back
A scattered chapter, livid hieroglyph,
The portent wound in corridors of shells.


Then in the circuit calm of one vast coil,
Its lashings charmed and malice reconciled,
Frosted eyes there were that lifted altars;
And silent answers crept across the stars.


Compass, quadrant and sextant contrive
No farther tides ... High in the azure steeps
Monody shall not wake the mariner.
This fabulous shadow only the sea keeps.

*Thanks to my friends Howard and Michele Hall for sharing their amazing sperm whale video on Vimeo.

12 February 2011

CRYPTICAL

(Mimic octopus. Via WebEcoist.)

(Hiding in the City—Dragon Series, No. 4 of 10 panels. 2010. Liu Bolin.)

(Flounder. Photo: Moondigger, courtesy Wikimedia Commons.)

(Hiding in the City No. 87. 2009. Liu Bolin.)


(Cuttlefish. Photo: Raul654, courtesy Wikimedia Commons.)


(Striped pyjama squid, Sepioloidea lineolata. Photo: Richard Ling, courtesy Wikimedia Commons.)

























(Crab spider. Photo:池田正樹 masaki ikeda, courtesy Wikimedia Commons.)























(Coral crab. Photo: Nhobgood, courtesy Wikimedia Commons.)

 (Teatro alla Scala. 2010. Liu Bolin.)


(Dead leaf butterfly. Via Museum of Life + Science.)



(Hiding in the City No. 94—In the Woods, 2010. Liu Bolin.)
  

07 February 2011

JANUARY SEA ICE

Credit: NASA.
Despite record cold in the US and Europe this winter, the Arctic has experienced unusual warmth. Sea ice has been slow to grow.

The red line in the image above shows the average January sea ice extent from 1979 through 2000. The white marks the average Arctic sea ice concentration for January 2011—the lowest measured extent since satellite record keeping began.

Photo by Pink floyd88 a, courtesy Wikimedia Commons.
From the Earth Observatory page:

The National Snow and Ice Data Center [NSIDC] offered two possible explanations. One reason is the Arctic Oscillation (AO), a seesaw pattern of differences in atmospheric pressure. In "positive" mode, the AO includes high pressure over the mid-latitudes and low pressure over the Arctic, setting up wind patterns that trap cold air in the far North. In "negative" mode, air pressure isn’t quite as low over the Arctic and isn’t quite as high over the mid-latitudes. This enables cold air to creep south and relatively warm air to move north.

Credit: NASA.
Continuing from the Earth Observatory:
Another factor in the low Arctic sea ice extent could be that the areas of open ocean were still releasing heat to the atmosphere. Due to its bright appearance, sea ice reflects most of the Sun’s light and heat back into space. Dark ocean water, by contrast, absorbs most of that energy and reinforces the melting process.
 
Photo by Rear Admiral Harley D. Nygren, NOAA Corps, ret., courtesy Wikimedia Commons.
NASA and the NSIDC report too that the the summer Arctic melt season is getting significantly longer:

This trio of images [below] shows changes between 1979 and 2007 in the average date of melt onset in the spring (left), the first autumn freeze (center), and the total average increase in the length of the Arctic sea ice melt season. The color scales show the trends in days per decade. Red indicates trends consistent with warming: earlier melt onset, later freezes, and longer total melt season. White indicates little or no change. The maps are based on satellite observations of microwave energy radiated from the ice.

Credit: NASA.
Those summer and winter trends bode poorly for species dependent on sea ice. The new paper in Polar Biology that got a fair amount of press last week describes the effects in 2008 on one polar bear who made an epic iceless swim and lost nearly a quarter of her body weight, as well as her cub, to the meltwaters. Here's the abstract:

Polar bears (Ursus maritimus) prefer to live on Arctic sea ice but may swim between ice floes or between sea ice and land. Although anecdotal observations suggest that polar bears are capable of swimming long distances, no data have been available to describe in detail long distance swimming events or the physiological and reproductive consequences of such behavior. Between an initial capture in late August and a recapture in late October 2008, a radio-collared adult female polar bear in the Beaufort Sea made a continuous swim of 687 km [427 miles] over 9 days and then intermittently swam and walked on the sea ice surface an additional 1,800 km [1,118 miles]. Measures of movement rate, hourly activity, and subcutaneous and external temperature revealed distinct profiles of swimming and walking. Between captures, this polar bear lost 22% of her body mass and her yearling cub. The extraordinary long distance swimming ability of polar bears, which we confirm here, may help them cope with reduced Arctic sea ice. Our observation, however, indicates that long distance swimming in Arctic waters, and travel over deep water pack ice, may result in high energetic costs and compromise reproductive fitness. 

Photo by Martha de Jong-Lantink at Flickr.
The paper:

  • George M. Durner, John P. Whiteman, Henry J. Harlow, Steven C. Amstrup, Eric V. Regehr and Merav Ben-David. Consequences of long-distance swimming and travel over deep-water pack ice for a female polar bear during a year of extreme sea ice retreat. 2011. Polar Biology. DOI: 10.1007/s00300-010-0953-2.

03 February 2011

BURIAL AT SEA

Seems to me that minus the embalming chemicals and coffins, burial at sea is a sensible solution to our current conundrum of more people, fewer cemeteries, dwindling land availability, and increasing air pollution and mercury contamination (think dental fillings) from cremations. 

Why not—if we so desire—let our bodies go unclothed into the deep, to feed a foodweb running short of big bodies?

Or if you'd rather commit your ashes to Davy Jones Locker, how about via The Shell (above)—from Lots Design of Sweden—a biodegradeable paper urn? Submarine to the great beyond.


Another solution is offered by Hong Kong architect Tin Shun But. His Columbarium at Sea is a concept for a floating mausoleum designed for the storage of funerary urns. Or you could visit for the purpose of scattering ashes offshore.

From Arch Daily:
The columbarium is about a journey from the land to the floating resting ground, which represents the transformation of the human body into ashes. A place of collective memories, the ashes of the deceased are scattered or buried in urns. "The goal is to create an experience of 'moving on to the next'—a synthesis between horizon and the datum of the ocean celebrating the lives that are buried in this space or scattered in the sea," explained the designer.

Would make a great scifi set.


(All images from Arch Daily. More here.)

The Norse, or Vikings, performed burials at sea in the course of their long oceanic voyages. 

They also buried great kings and chieftains ashore in their own ships. A few of these ship burials have been located, excavated, and restored over the years.

Hard to imagine anything more beautiful than the sleek lines of these ancient vessels.

























(Top two images: Excavation c.1904 and restoration of Norway's Oseberg ship. Bottom two: Excavation c.1880 and restoration of Norway's Gokstad ship. All courtesy Wikimedia Commons.)

In The Rusiyyah, Ahmad Ibn Fadlan, a 10th-century Arab travel writer, witnessed a Viking ship burial/cremation. His tale is surely one of the more hair-raising accounts ever committed to the written word, complete with a description of a Norse version of suttee.

Here's a snippet, translated by James E. Montgomery:

When their chieftain dies, his family ask his slave-girls and slave-boys, "Who among you will die with him?" and some of them reply, "I shall." Having said this, it becomes incumbent upon the person and it is impossible ever to turn back. Should that person try to, he is not permitted to do so. It is usually slave-girls who make this offer. 
When that man whom I mentioned earlier died, they said to his slave-girls, "Who will die with him?" and one of them said, "I shall." So they placed two slave-girls in charge of her to take care of her and accompany her wherever she went, even to the point of occasionally washing her feet with their own hands. They set about attending to the dead man, preparing his clothes for him and setting right all he needed. Every day the slave-girl would drink and would sing merrily and cheerfully.

On the day when he and the slave-girl were to be burned I arrived at the river where his ship was. To my surprise I discovered that it had been beached and that four planks of birch (khadank) and other types of wood had been erected for it. Around them wood had been placed in such a way as to resemble scaffolding (anābīr). Then the ship was hauled and placed on top of this wood. They advanced, going to and fro uttering words which I did not understand, while he was still in his grave and had not been exhumed.

Then they produced a couch and placed it on the ship, covering it with quilts Byzantine silk brocade and cushions Byzantine silk brocade. Then a crone arrived whom they called the "Angel of Death" and she spread on the couch the coverings we have mentioned. She is responsible for having his sewn up and putting him in order and it is she who kills the slave-girls. I myself saw her: a gloomy, corpulent woman, neither young nor old.

When they came to his grave, they removed the soil from the wood and then removed the wood, exhuming him in the izār in which he had died. I could see that he had turned black because of the coldness of the ground. They had also placed alcohol, fruit and a pandora (ṭunbūr) beside him in the grave, all of which they took out. Surprisingly, he had not begun to stink and only his colour had deteriorated. They clothed him in trousers, leggings (rān), boots, a qurṭaq, and a silk caftan with golden buttons, and placed a silk qalansuwwah with sable on his head. They carried him inside the pavilion on the ship and laid him to rest on the quilt, propping him with cushions...

 It gets gory. You can read on here.


(Ship burial of Igor the Old in 945. Henryk Siemiradzki, 1843-1902.)

A much better idea, seems to me, is the divers' take on a ship burial offered by Eternal Reefs. Cast your cremains into a concrete artificial reef. Then sink it offshore for marine life to colonize.

In no time at all, corals and other invertebrates will happily adhere to your hereafter.