Microscopy, by definition, is the science of using a microscope to observe objects that are unseen by the naked eye. However, astronomical objects such as planets, moons and comets or asteroids are easily identifiable in the night sky, yet scientists are increasingly relying on microscopic methods to investigate their composition, structure, and determine their origins. Whether this is via extra-terrestrial exploration with satellites, landers or rovers, or by studying returned astromaterials in the laboratory itself, the use of microscopy within the diverse field of planetary science is quickly becoming the norm. Correlating multiple microscopic and spectroscopic methods within the scanning electron microscope (SEM) when studying meteorites allows us to extend the spectrum from nano or micro-scale imaging at one end, all the way up to the astronomical scale at the other. For example, the Mars Science Laboratory (MSL) rover, Curiosity, landed in Gale Crater; a region that had been heavily investigated using satellite data from previous mission Mars Odyssey. Using similar infrared microscopic methods in the laboratory, we can distinguish the same compositions within Martian meteorites as those directly observed on the Martian surface.Recent studies (e.g. Stephen et al. 2014; King et al. 2018) have combined traditional SEM imaging and analysis (energy-dispersive spectroscopy - EDS, electron-backscatter diffraction – EBSD, wavelength-dispersive spectroscopy – WDS) with micro Fourier transform infrared (μFT-IR) to inform the varied geological histories of meteorite parent bodies, including aqueous alteration on both asteroids and planets. Further studies combine SEM & TEM imaging with other X-ray techniques at varying scales, i.e. X-ray microscopy (XRM) or X-ray tomography (XRT), to help classify new meteorites and examine potential parent bodies throughout the Solar System (MacArthur et al. 2019).Non-destructive, microscopic methods allow for detailed investigation through multiple volumes that would otherwise be inaccessible without damaging the specimens themselves; a crucial consideration when working with limited material from an extra-terrestrial source. Correlating microscopy techniques across instruments, scales and disciplines is perhaps one of the best approaches to studying these astromaterials, and fully unravelling their geological history, as well as their journey to Earth.References:King et al. (2018) Investigating the history of volatiles in the solar system using synchrotron infrared micro-spectroscopy' Infrared Physics and Technology 94, 244-249.MacArthur et al. (2019) Mineralogical constraints on the thermal history of Martian regolith breccia Northwest Africa 8114, Geochimica et Cosmochimica Acta 246, 267-298.Stephen et al. (2014) Mid-IR mapping of Martian meteorites with 8-micron spatial resolution, Meteoritics and Planetary Science, pp A381.
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