Above: On ancient Mars, water carved channels and transported sediments to form fans and deltas within lake basins. Examination of spectral data acquired from orbit show that some of these sediments have minerals that indicate chemical alteration by water. Here in the Jezero Crater delta, sediments contain clays and carbonates. Credit: NASA/JPL-Caltech/MSSS/JHU-APL
The most recent issue of Free Astronomy Magazine (January-February 2020) is available for your reading and downloading pleasure at www.astropublishing.com (click the link to go directly to the issue).
Feature articles this month include (1) a great read on the history of the discovery of the (dwarf) planet Pluto, (2) SOFIA confirming the collision of two planets in an old star system, and (3) details about the landing site selection of Jezero Crater for Mars 2020 (with an image from the article featured about and downloadable from www.jpl.nasa.gov…PIA23239).
For those wanting a quick look at what the issue has to offer, the Table of Contents is reproduced below.
Above: This illustration shows what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Credit: SETI Institute.
Slightly late to the posting game – the January-February issue of Free Astronomy Magazine is available for your reading and downloading pleasure. Highlights from the original content (h/t Michele Ferrara) include an excellent introduction to panspermia and the wonderful ways in which small, dense solar systems (like TRAPPIST-1, one of the only solar systems with its own website – www.trappist.one) might serve as test beds for better understanding if such an explanation is applicable to ourselves and our Earth – either from a local source (Mars?) or from the greater beyond.
Above: ESA’s Mars Express has used radar signals bounced through underground layers of ice to identify a pond of water buried below the surface. This image shows an example radar profile for one of 29 orbits over the 200 x 200 km study region in the south polar region of Mars. The bright horizontal feature at the top corresponds to the icy surface of Mars. Layers of the south polar layered deposits – layers of ice and dust – are seen to a depth of about 1.5 km. Below is a base layer that in some areas is even much brighter than the surface reflections, while in other places is rather diffuse. The brightest reflections from the base layer – close to the centre of this image – are centred around 193°E/81°S in all intersecting orbits, outlining a well-defined, 20 km wide subsurface anomaly that is interpreted as a pond of liquid water. Image Credit: ESA/NASA/JPL/ASI/Univ. Rome; R. Orosei et al 2018.
I'm also pleased to report a promotion from contributing translator to contributing author this month with the publication of the cover story "A Possible Subglacial Lake On Mars." For the local record, a PDF of the article (with cover and edition TOC) is available for direct download at 5FAM2018_dgallis.pdf and I can now say that my work has been published in over three languages (four, to be exact, including English, Spanish, French, and Italian).