Image: False-color image of Earth highlights plant growth

Mar 10, 2014 by Holli Riebeek
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

On Aug. 3, 2004, NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft began a seven-year journey, spiraling through the inner solar system to Mercury. One year after launch, the spacecraft zipped around Earth, getting an orbit correction from Earth's gravity and getting a chance to test its instruments by observing its home planet.

This image is a view of South America and portions of North America and Africa from the Mercury Dual Imaging System's wide-angle camera aboard MESSENGER. The wide-angle camera records light at eleven different wavelengths, including visible and infrared light. Combining blue, red, and green light results in a true-color image from the observations. The image substitutes infrared light for blue light in the three-band combination. The resulting image is crisper than the natural color version because our atmosphere scatters blue light. Infrared light, however, passes through the atmosphere with relatively little scattering and allows a clearer view. That wavelength substitution makes plants appear red. Why? Plants reflect near-infrared more strongly than either red or green, and in this band combination, near-infrared is assigned to look red.

Apart from getting a clearer image, the substitution reveals more information than natural color. Healthy plants reflect more near- than stressed plants, so bright red indicates dense, growing foliage. For this reason, biologists and ecologists occasionally use infrared cameras to photograph forests.

Explore further: Image: A storm of stars in the Trifid nebula

add to favorites email to friend print save as pdf

Related Stories

Space Image: North American Nebula

Oct 19, 2011

This swirling landscape of stars is known as the North America Nebula. In visible light, the region resembles North America, but in this image infrared view from NASA's Spitzer Space Telescope, the continent ...

Image: A storm of stars in the Trifid nebula

Jan 30, 2014

(Phys.org) —A storm of stars is brewing in the Trifid nebula, as seen in this view from NASA's Wide-field Infrared Survey Explorer, or WISE. The stellar nursery, where baby stars are bursting into being, ...

Image: Infrared image of Saturn's rings

Jan 22, 2014

(Phys.org) —Although it may look to our eyes like other images of the rings, this infrared image of Saturn's rings was taken with a special filter that will only admit light polarized in one direction. ...

Asteroid zips by Orion nebula

Aug 26, 2013

(Phys.org) —This image shows the potentially hazardous near-Earth object 1998 KN3 as it zips past a cloud of dense gas and dust near the Orion nebula. NEOWISE, the asteroid-hunting portion of the Wide-field ...

Image: Spitzer's Orion

Jan 16, 2014

(Phys.org) —Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away.

Recommended for you

Asteroid 2014 SC324 zips by Earth Friday afternoon

9 hours ago

What a roller coaster week it's been. If partial eclipses and giant sunspots aren't your thing, how about a close flyby of an Earth-approaching asteroid?  2014 SC324 was discovered on September 30 this ...

Who owns space?

9 hours ago

The golden age of planetary exploration had voyagers navigating new sea routes to uncharted territory. These territories were then claimed in the name of the monarchs who had financed the expeditions. All ...

User comments : 0