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Win a DVD of NOVA’s Excellent “Earth From Space”
Satellites give us views of our planet’s constantly-changing systems as never seen before (Earth From Space, ©PBS)
Earth… our home planet, a brilliant “blue marble” tirelessly turning through space on an endless journey around the Sun and across the galaxy. Basically a ball of molten rock and metal, its relatively thin crust is mostly covered by a sea of liquid water as well as wrapped in a sea of air… and it’s the complex interaction between all of these things that have allowed life to evolve, thrive, and — so far, anyway — continue to exist on this one particular world.
But how exactly does this work? How, and why, do all of these different factors combine to make a habitable planet? Energy from the Sun, the movement of the atmosphere, the planet’s rotation, the constant churning of ocean currents, the upwelling of materials from deep inside the Earth… all of these play essential roles every day in the survival of nearly every living thing on our planet — including us. To truly understand life on Earth, we must first understand the complex interactions of these forces, and more.
Luckily we have satellites, our “eyes in the sky” that let us look at the entire world on a daily basis and measure and monitor many different processes like never before, letting us see the otherwise invisible big picture of Earth From Space.
The Colors of Saturn’s Northern Skies
Color-composite of Cassini images acquired on 27 Feb. 2013 (NASA/JPL/SSI/J. Major)
Bored by blue? Saturn’s skies sure do have a lot more colors, as seen here in a color-somposite made from raw Cassini images acquired on Feb. 27, 2013.
With spring progressing on Saturn’s northern hemisphere (a season that takes 7 1/2 Earth years to pass!) the upper latitudes gradually receive more sunlight and thus more solar energy, warming the planet’s atmosphere and driving the upper-level winds and storms.
Mercury’s Cratered Crescent (in Color!)
A view of Mercury from MESSENGER’s October 2008 flyby (NASA / JHUAPL / Gordan Ugarkovic)
Every now and then a new gem of a color-composite appears in the Flickr photostream of Gordan Ugarkovic, and this one is the latest to materialize.
This is a view of Mercury as seen by NASA’s MESSENGER spacecraft during a flyby in October 2008. The image is a composite of twenty separate frames acquired with MESSENGER’s narrow-angle camera from distances ranging from 18,900 to 17,700 kilometers and colorized with color data from the spacecraft’s wide-angle camera. (North is to the right.)
Click the image for a closer look, and for an even bigger planet-sized version click here. Beautiful!
Our Electric Earth at Night: the “Black Marble”
Suomi NPP satellite image of North and South America at night
In daylight our big blue marble is all land, oceans and clouds. But the night is electric.
This image of North and South America at night is a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012. The new data was mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet.
The nighttime view was made possible by the new satellite’s “day-night band” of the Visible Infrared Imaging Radiometer Suite. VIIRS detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires, and reflected moonlight. In this case, auroras, fires, and other stray light have been removed to emphasize the city lights.
Although the view looking down from space is of a sparkling show, the downside of course is light pollution over major metropolitan areas which impede the view of the night sky from the ground. (Find out more at the International Dark Sky Association site.)
Read more (and watch a video of these nighttime images of Earth) below:
Mercury’s Sufferingly Sulf’rous Surface
The rugged terrain surrounding Mercury’s Vivaldi basin may be rich in sulfur
Named for the 17th-century Venetian composer, the southern half of Mercury’s Vivaldi basin is seen in this image acquired on August 26 by NASA’s MESSENGER spacecraft. The 213-km (132-mile) -wide crater’s smooth floor is contrasted by the incredibly rugged terrain beyond its outermost ring — a result of the ejected material that was flung out from the impact site and emphasized by the low angle of illumination.
Recent findings from the MESSENGER mission have revealed variations in Mercury’s surface composition due to volcanism that occurred at different times, as well as a surprising concentration of elements rich in magnesium and sulfur — much more, in fact, than any of the other terrestrial planets.
Our Sharpest (Ground-Based) View of Pluto Yet:
Pluto and its largest moon, Charon, seen by the Gemini North telescope on Mauna Kea (Gemini Observatory)
Real planet, dwarf planet, KBO… who cares? What matters here is that astronomers from NASA, NOAO and the Gemini Observatory have created the sharpest image of Pluto ever made with ground-based observations — and developed a new way to verify potential Earth-like exoplanets at the same time. Not too shabby, I’d say.
Rhapsody on an Impact Event: Mercury’s Rachmaninoff Crater
The peak-ringed interior of Mercury’s Rachmaninoff crater
Rachmaninoff is a spectacular double-ring basin on Mercury, and this color view is one of the highest resolution color image sets acquired of the basin’s floor. Visible around the edges of the frame is a circle of mountains that make up Rachmaninoff’s peak ring structure. The color of the basin’s floor inside the peak-ring differs from the darker material outside of it, and contains concentric troughs formed by extension (pulling apart) of the surface, likely as the molten surface solidified and cooled in the wake of the initial impact event.
This image was acquired as a high-resolution targeted color observation by MESSENGER on July 31, 2012. See a wider-angle view of the 140-km-wide Rachmaninoff crater here.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
