December 2011

Posted by Ellen

At the end of November, when it came time to assess the results of a shaveless month, some of the 'staches sported by men of the USS Ingraham were of the Sharpie variety.

Posted by Ellen

Some babies are just born to pay attention. Here in this 1892 portrait we have the future mayor of Wadena, Minnesota, Bernard Burch, and his sister, the future Mrs. Edna Chesnut.

Posted by Ellen

The satellite view of Philadelphia in infrared, from a few days ago, led some people to ask for more false-color imagery of our planet. Here we've got a river delta in the tundra of eastern Siberia, where the River Lena empties into the Arctic Ocean. The image is from mid-summer, when the plants of the tundra were bursting with new growth, thanks to twenty-four hours a day of sunlight. The color scheme here is different from that of the Philadelphia scene but still not closely related to the colors a human eye would detect. The data displayed comes from three sensors on the Landsat satellite: one that detects infrared energy, another that detects near-infrared energy, which is very sensitive to the chemicals associated with growing vegetation, and a third sensor that picks up a part of the visible spectrum. Vegetation is green, exposed rock or soil is pink, wet soil (mud) is purple, and ice is blue.

Even in mid-summer, the sea ice floats close to shore. It will take another month or two for most of the ice to melt and/or wash out to sea, but as soon as it does freezing temperatures will return and ice formation will begin again.

The innumerable ponds and distributary streams are typical of flat places throughout the Arctic tundra, where permafrost just below the surface impairs drainage. Meltwater and rainwater sit on top of the permafrost all summer long, breeding mosquitoes...... which don't show up in the satellite imagery.

Posted by Ellen

I always thought they were called sycamores, but no, the people who know these things tell me that city trees that look like sycamores are actually hybrid variants called London planes. Real sycamores, we are told, are too crooked to serve well as street trees, so things are what they are, and now that the old elm trees are no longer among us, we are left with London planes as kings of the sidewalks, with their fine white bark and annoying seed balls. This one is on South 21st Street in Philadelphia, near the corner of Kater Street.

The picture was taken about a year ago, when December was decidedly more wintry than has been the case thus far in 2011. But last year's decorations are up again, and the dusk is just as dark and just as early as I remember from 2010. Season's greetings are probably in order.

Posted by Ellen

It's been a while since we've served up puppies or babies in this space, so here's the Dobster, hopping about on two wet feet.

Posted by Ellen

The stars of the Milky Way rise out of the Mediterranean in this time-release photo taken on the beach at the edge of the Greek village of Elia, near Molaoi. The earthly lights in the distance at far right are from the port of Gytheio, a few kilometers away. The brightest part of the Milky Way galaxy, in the right center of the picture near the constellation of Sagittarius, is about 27,000 light-years away.

Posted by Ellen

Maybe the gingerbread man was in that Folger's coffee can?

Government photographer John Vachon immortalized this scene while he was doing his Farm Security Administration work in Minnesota and the Dakotas in the spring of 1940. But he didn't record any explanations.

Posted by Ellen

At about 9:30 in the morning on September 23, 1999, the Landsat 7 satellite swooped southward over eastern North America and captured this image of Philadelphia and environs.

Three of the Landsat sensors detected energy in the infrared part of the electromagnetic spectrum, completely invisible to the human eye. Data from these sensors is displayed here, with each of the three infrared bands assigned to one of the normal red-green-blue color bands so we at least have something to look at, even though the colors have nothing to do with normal vision.

Clicking on the picture brings up a bigger version, which shows much more detail.

We can tell right away that the rivers are black; infrared energy is completely absorbed by water, reflecting back nothing for the sensors to detect. And if we look along the river at lower left, we can make out the airport, with runways that are bright cyan in color. This white-to-bluish hue is also the color of roads, railroads, parking lots, and other paved surfaces.

Infrared data is especially useful for studying vegetation, which shows up in this color scheme as red, orange, or yellow. The brightest red patches represent vigorous herbaceous growth, such as healthy cropland in the midst of the growing season. There's little or no farmland in and around Philly, however, so the red patches we see here, such as in between the airport runways, are probably healthy weeds.

Patches of red coloration with a touch of an orange tint and some texture are forested areas, such as in parks or between the fairways of golf courses. Extremely vigorous grass, such as on the golf course fairways themselves, looks bright yellow in this view.

The brownish-to-grayish-to-bluish areas show mixed land cover: Landsat's sensors are averaging out the infrared signals from house roofs, pavement, lawns, shrubs, and trees in varying concentrations. Brownish areas are suburban, with lots of trees and grass; dark green to gray-blue areas are more urban, with a higher ratio of rooftops and pavement to vegetation.

Philadelphia has changed since this image was captured twelve years ago. Another stadium has been built near where the Schuylkill River empties out into the Delaware. In my neighborhood just south of Center City, the forested patch of land near the Schuylkill, which in 1999 was an abandoned and overgrown Old Sailors' Home is now a heavily developed condo complex. Even though the population of Philadelphia has shrunk dramatically over the past half-century and has just barely started growing again, land use patterns as viewed from outer space show ongoing urbanization.