Picture of the Day: First Global Image From a New NASA Satellite

By Rebecca J. Rosen

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In October, NASA launched a new satellite, loaded up with a set of instruments called the Visible Infrared Imager Radiometer Suite, more commonly referred to as VIIRS. We featured the first image from VIIRS, taken on November 21st, here. Today's Picture of the Day is the first global image from VIIRS, taken during the day of November 24th, from NPP's orbit 512 miles above Earth's surface. NASA explains the image:

Rising from the south and setting in the north on the daylight side of Earth, VIIRS images the surface in long wedges measuring 3,000 kilometers (1,900 miles) across. The swaths from each successive orbit overlap one another, so that at the end of the day, the sensor has a complete view of the globe. The Arctic is missing because it is too dark to view in visible light during the winter.

The NPP satellite was placed in a Sun-synchronous orbit, a unique path that takes the satellite over the equator at the same local (ground) time in every orbit. So, when NPP flies over Kenya, it is about 1:30 p.m. on the ground. When NPP reaches Gabon--about 3,000 kilometers to the west--on the next orbit, it is close to 1:30 p.m. on the ground. This orbit allows the satellite to maintain the same angle between the Earth and the Sun so that all images have similar lighting.

Below, recent Pictures of the Day:

Image: NASA.

This article available online at:

http://www.theatlantic.com/technology/archive/2011/12/picture-of-the-day-first-global-image-from-a-new-nasa-satellite/250326/