Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Original gray-scale image obtained from XMT. The section of the column cross-section shown is approximately 8 x 8 mm. The light gray objects are the sand grains, the dark gray is the water, and the white is the TCE blobs. A section of the column wall is present in the top of the image.
