MESSENGER tagged posts

The origin of Mercury, the closest planet to the sun, is mysterious in many ways. It has a metallic core, like Earth, but its core makes up a much larger fraction of its volume—85% compared to 15% for Earth.

The NASA Discovery-class MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging) mission, and first spacecraft to orbit Mercury, captured measurements revealing that the planet also strongly differs chemically from Earth. Mercury has relatively less oxygen, indicating that it formed from different building blocks in the early solar system. However, it has proven difficult to precisely pin down Mercury’s oxidation state from available data.

In a new st...

Scientists have long known that Earth and Mercury have metallic cores. Like Earth, Mercury’s outer core is composed of liquid metal, but there have only been hints that Mercury’s innermost core is solid. Now, in a new study, scientists report evidence that Mercury’s inner core is indeed solid and that it is very nearly the same size as Earth’s solid inner core.

Some scientists compare Mercury to a cannonball because its metal core fills nearly 85% of the volume of the planet. This large core – huge compared to the other rocky planets in our solar system – has long been one of the most intriguing mysteries about Mercury...

Though Mercury may look drab to the human eye, different minerals appear in a rainbow of colors in this image from NASA’s MESSENGER spacecraft. Credit: NASA/Johns Hopkins University APL/Carnegie Institution of Washington

Mercury’s crust is thinner than anyone thought, new mathematical calculations reveal. A planetary scientist has used careful mathematical calculations to determine the density of Mercury’s crust, which is thinner than anyone thought. Mercury is small, fast and close to the sun, making the rocky world challenging to visit. Only one probe has ever orbited the planet and collected enough data to tell scientists about the chemistry and landscape of Mercury’s surface. Learning about what is beneath the surface, however, requires careful estimation.

After the probe’s mission end...

Scientists used models along with earlier findings from the MESSENGER mission to shed light on how certain types of comets influence the micrometeoroids that preferentially impact Mercury on the dawn side of the planet. Here, data from the Mercury Atmosphere and Surface Composition Spectrometer, or MASCS, instrument is overlain on the mosaic from the Mercury Dual Imaging System, or MDIS. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers...