For the average stargazer, Mercury might look like a dull, grey blob in space.
But up close, it's a different story. Thanks to images from NASA's Messenger probe, the solar system's innermost planet looks iridescent blue with patches of sandy-colored plains with strands of grayish white. Early images released by NASA have even shown purples and aquamarine -- a truly psychedelic planet.
The different colors represent differences in Mercury's composition.
The blue hues, for example, are younger parts of the planet while the darker sections represent areas that have long been exposed to the planet's harsh environment. The yellowish, tan-colored regions are "intermediate terrain."
Mercury also hosts brighter and smoother terrain known as high-reflectance red plains. One example can be seen towards the upper right, where there is a prominent patch that is roughly circular. This is the Caloris basin, an impact crater thought to have been created by an asteroid collision during the solar system's early days.
Launched in 2004, Messenger spent the past four years in orbit around the closest planet to the sun -- a first in the history of planetary exploration -- working behind a sunshade to endure temperatures higher than 600 degrees Fahrenheit while beaming back more than 10 terabytes of data from a suite of sophisticated instruments.
The images were taken before Messenger ended its orbit around Mercury in late April, crashing into the planet's surface. The probe managed to extend its mission by several weeks, after the spacecraft executed the first of a series of engine burns designed to lift the probe's orbit slightly.
The investigation of Mercury will be continued by ESA's BepiColombo, due for launch in 2017. BepiColombo, a mission in partnership with the Japan Aerospace Exploration Agency (JAXA), comprises two orbiters, ESA's Mercury Planetary Orbiter and JAXA's Mercury Magnetospheric Orbiter, which will reach Mercury together in 2024.
for more features.