On the Edge of Tyagaraja

Here’s a rather interesting view from orbit around the innermost planet: Mercury’s Tyagaraja crater, the interior of which is seen here in an oblique-angled image acquired by the MESSENGER spacecraft on November 12, 2011 (and released August 16, 2013.)

This view looks west across the northern portion of the 97-kilometer (60-mile) -wide crater, and shows some of its large central peaks, terraced walls, and bright erosion features called hollows that are spread across a wide swath of its interior.

First seen by MESSENGER in 2011, hollows are thought to indicate an erosion process unique to Mercury because of its composition and close proximity to the Sun. The lack of craters within hollows seems to indicate that they are relatively young features… in fact, they may be part of a process that continues today.

This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury’s surface at resolutions much higher than the 200-meter/pixel morphology base map.

Enhanced-color image of Tyagaraja crater acquired on Sept. 29, 2011. Its large hollow field is highlighted.
Enhanced-color image of Tyagaraja crater acquired on Sept. 29, 2011. Its large hollow field is highlighted.

Tyagaraja is named after Kakarla Tyagabrahmam, an 18th-century composer of classical Indian Carnatic music.

Read more on the MESSENGER website here.

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

Mercury Shows Off Its Reds, Whites, and Blues

At first glance, the planet Mercury may bear a striking resemblance to our own Moon. True, both are heavily-cratered, airless worlds that hide pockets of ice inside polar shadows… but there the similarities end. In addition to being compositionally different than the Moon, Mercury also has surface features that you won’t find on the lunar surface — or anywhere else in the Solar System.

The picture above, part of an 11-color targeted image acquired by MESSENGER on April 25, 2013, shows the varied terrain found within the 97-kilometer-wide Tyagaraja crater located near Mercury’s equator. The reds, blues, greens, and oranges, much more saturated than anything we’d see with our own eyes, correspond to surface materials of different compositions… and the brightest spots within the crater are features called “hollows” that are truly unique to Mercury, possibly resulting from the planet’s close interaction with the solar wind.

First noted in September of 2011, hollows have been identified across many areas of Mercury. One hypothesis is that they’re formed by the sublimation of subsurface material exposed inside larger craters. Being so close to the Sun and lacking a protective atmosphere, Mercury is constantly being scoured by the solar wind — a relentless stream of charged particles that’s actively “sandblasting” exposed volatiles from the planet’s surface!

Read more about hollows here.

A previous MESSENGER image of hollows inside Tyagaraja crater
A previous MESSENGER image of hollows inside Tyagaraja crater

The reddish spot at the center of the crater in the top image is likely material surrounding a pyroclastic vent, which appear red and orange in MDIS images. The dark material that appears bluish is something called “low reflectance material” (LRM).

The image was acquired as a targeted high-resolution 11-color image set. Acquiring 11-color targets is a new MESSENGER campaign that began in March and utilizes all of the Wide-Angle Camera’s 11 narrow-band color filters. Because of the large data volume involved, only features of special scientific interest are targeted for imaging in all 11 colors.

Full of geologically interesting features the crater was named for Kakarla Tyagabrahmam, an 18th century composer of classical South Indian music.

The first spacecraft to establish orbit around Mercury in summer 2011, MESSENGER is capable of continuing orbital operations until early 2015.

Read more on the Johns Hopkins University APL MESSENGER site here.

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