U.S. News - holiday-calendar

Dec

2011

3:51am, EST

Pearl Harbor from above, 1941-2011

GeoEye

A satellite picture of Pearl Harbor, acquired by the GeoEye-1 satellite on Sept. 24, shows the USS Missouri docked at Battleship Row as a museum ship, with its bow pointing toward the USS Arizona memorial at lower right. The wreck of the Arizona can be seen below the white memorial, barely visible beneath the water's surface.

By Alan Boyle, Science Editor, NBC News

Seventy years after a "date which will live in infamy," this satellite image of Pearl Harbor shows the symbols of a war's beginning and end.

The symbol of the end is more evident: The USS Missouri sits at its dock at Ford Island in the Hawaiian harbor, serving as a museum ship. In 1945, the "Mighty Mo" was the stage for the formal Japanese surrender at the end of World War II. After almost a half-century of service, the battleship was decommissioned for good in 1992 and took its place on Pearl Harbor's Battleship Row in 1998.

The Missouri wasn't even afloat on Dec. 7, 1941, when Japanese airplanes bombed the harbor and drew the United States into the war. But the battleship Arizona was. In the picture above, snapped by the GeoEye-1 satellite, the outlines of the Arizona are barely visible at upper right, beneath the surface of the water. The USS Arizona Memorial is the white structure sitting above the ship.

GeoEye-1, a polar-orbiting satellite operated by the GeoEye commercial venture, focused on Pearl Harbor on Sept. 24 from a height of 423 miles as it sped over the scene at 17,000 mph.

The scene was quite different in 1941, on what President Franklin Roosevelt dubbed a day of infamy. The aerial photograph you see below, taken from U.S. Navy archives, shows the wreckage in the harbor on Dec. 10, 1941, three days after the attack. Dark trails of oil stream from the dead and damaged ships. From this altitude, you get a sense of the attack's toll on the U.S. fleet, but not of the human cost: 2,390 Americans killed, 1,178 wounded.

U.S. Navy

This aerial photograph of Pearl Harbor's Battleship Row was captured on Dec. 10, 1941, after the Japanese attack. The sunken USS California is at upper left. The capsized Oklahoma and the Maryland are at left center, the sunken West Virginia and the lightly damaged Tennessee are at lower center, The sunken Arizona is at lower right, in the same position where it lies today. Dark streaks of oil stream from the damaged vessels.

Today, veterans, family members and dignitaries are gathering at Pearl Harbor to commemorate the 70th anniversary. Flags are flying at half-staff. And Americans are looking back at the events of 1941 from a remote perspective, as if from a great height.

These views of Pearl Harbor serve as a somber entry in the Cosmic Log Space Advent Calendar, which puts a spotlight on views of Earth from outer space every day from now until Christmas. Click on the links below for more about Pearl Harbor Day, as well as other images from the calendar:

Pearl Harbor coverage:

More space views from the calendar:

Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Holiday calendar: Santa's shrinking domain

By Alan Boyle, Science Editor, NBC News

Few places on Earth have more of a connection to the holiday season than the North Pole: After all, that's where Santa Claus hangs his hat. That's the address most kids write on their Christmas letters. Even NORAD lists that locale as Santa's home base.

But if I were Santa, I'd start thinking about real estate: Over the years, satellite measurements have pointed to a shrinkage in ice extent and thickness in the Arctic, due to rising temperatures. In September, experts at the National Snow and Ice Data Center reported that Arctic sea ice had declined to its second-lowest level in the past 32 years, and researchers at the University of Bremen in Germany said the ice coverage had fallen even below the 2007 minimum. This report from the European Space Agency helps put the issue in perspective.

With the approach of northern winter, the ice is returning. The picture above, based on data from NASA's Aqua satellite, shows the maximum and minimum extent of Arctic ice this year. ESA has an animation that illustrates the annual fluctuation in a moving way. Santa shouldn't have to worry about shrinking sea ice between now and Christmas. But once the holiday rush is over, he might want to keep an eye on msnbc.com's Environment coverage. There may well be a "new normal" in the Arctic from now on.

Today's Arctic offering is part of the Cosmic Log Space Advent Calendar, which provides a daily view of Earth from space from now until Christmas. Check out these previous entries on the calendar, as well as other space-themed Advent calendars online. And check in again on Sunday for the next visual treat.