Free Astronomy Magazine January-February 2023

8 JANUARY-FEBRUARY 2023 ASTRO PUBLISHING N ASA’s Perseverance rover puts its robotic arm to work around a rocky outcrop called “Skinner Ridge” in Mars’ Jezero Crater. Composed of multiple images, this mosaic shows layered sedimentary rocks in the face of a cliff in the delta, as well as one of the locations where the rover abraded a circular patch to analyze a rock’s composition. [NASA/JPL-Cal- tech/ASU/MSSS] A close-up view of an engineering model of SHERLOC (Scanning Habitable Environments with Raman & Lumi- nescence for Organics & Chemicals), one the instruments aboard NASA’s Perseverance Mars rover. Located on the end of the rover’s robotic arm, this instrument features an auto- focusing camera (pictured) that shoots black-and-white im- ages used by SHERLOC’s color camera, called WATSON (Wide Angle Topographic Sensor for Operations and eNgi- neering), to zero in on rock textures. SHERLOC also has a laser, which aims for the dead center of rock surfaces de- picted in WATSON’s images. The laser uses a technique called Raman spectroscopy to detect minerals in microscopic rock features; that data is then superimposed on WATSON’s images. These mineral maps help scientists determine which rock samples Perseverance should drill so that they can be sealed in metal tubes and left on the Martian surface for a future mission to return to Earth. [NASA/JPL-Caltech] framework of the A/T/C/G bases. In proteins, the formation of a peptide bond between two amino acids re- sults in the removal of an oxygen- hydrogen (OH) fragment from a car- bon on one molecule and a single hydrogen from a nitrogen on an- other to also form a departing H 2 O molecule. In both the reliance on proteins as catalysts and the formation of pep- tide bonds in proteins and phospho- diester bonds in DNA, Nature relies on a key ingredient − liquid water. It is within liquid water that the pep- tide chain has the freedom to flop, spin around bonds, fold and unfold into different geometries on the way to its favored geometry, jiggle and undulate to modify the shape of its molecular binding pocket, and allow for the delivery and removal of whatever molecules are being modified that might be floating in