A NASA Discovery mission to conduct the first orbital study
of the innermost planet
NASA logo carnegie institution logo JHU APL logo

Why Mercury?
The Mission
News Center
Science Operations
Who We Are
Related Links

Download iPhone/iPad app Explore orbital data with quickmap Question and Answer End of Orbit Insertion Where is MESSENGER? Where is Mercury now? Subscribe to MESSENGER eNews

First Detection of Magnesium in Mercury's Exosphere
Click on image to enlarge.
First Detection of Magnesium in Mercury's Exosphere
Release Date: October 30, 2008
Topics: MASCS, Mercury Flyby 2, NASA Press Conference 10/29/2008

Date Acquired: October 6, 2008
Instrument: Mercury Atmospheric and Surface Composition Spectrometer (MASCS)

Of Interest: The histogram in this figure represents a typical MASCS observation in the tail region of Mercury’s exosphere from magnesium atoms. These MASCS measurements mark the first time that magnesium has been detected in Mercury’s exosphere. In contrast to emissions from sodium and calcium, magnesium emission occurs at a wavelength that is in the ultraviolet part of the spectrum. Magnesium has not been observed from ground-based telescopes partly because it emits at ultraviolet wavelengths, which are completely obscured by Earth’s atmosphere. Because these atoms primarily originate at the surface of Mercury, the detection of magnesium in the exosphere provides evidence that magnesium is a component of surface material, something that has been expected for years but until now had not been proven. As with calcium and sodium, the distribution of magnesium in Mercury’s exosphere is a result of the processes that release the magnesium atoms from the surface and can provide valuable clues to the relative importance of each process.

Credit: NASA/University of Colorado/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

For information regarding the use of MESSENGER images, see the image use policy.


   Top  | Contacts
© 1999-2015 by JHU/APL