{"id":19124,"date":"2025-11-03T23:58:53","date_gmt":"2025-11-03T22:58:53","guid":{"rendered":"https:\/\/www.oavda.it\/uncategorized\/astronomia-da-fantascienza-5"},"modified":"2026-05-23T20:22:27","modified_gmt":"2026-05-23T18:22:27","slug":"astronomia-da-fantascienza-5","status":"publish","type":"post","link":"https:\/\/www.oavda.it\/en\/news-en\/astronomia-da-fantascienza-5","title":{"rendered":"Astronomia da fantascienza \ud83d\udc49 -5"},"content":{"rendered":"<h3><span style=\"color: #ffcc00\">*Sci-fi Astronomy, edited by Camilla Pianta*<\/span><\/h3>\n<h2><span style=\"color: #ffcc00\"><b><em>Solaris<\/em>,<\/b><b> an inquiry into extraterrestrial life through the lens of science fiction<\/b><\/span><b><\/b><\/h2>\n<h2><b>\ud83d\udc7d<\/b><\/h2>\n<h3><em><span style=\"color: #ffcc00\"><b>What if searching for alien life helps us understand ourselves<\/b><\/span><\/em><em><span style=\"color: #ffcc00\"><b>?<\/b><\/span><\/em><\/h3>\n<h3><span style=\"color: #c0c0c0\"><strong>COUNTDOWN TO APRIL 2026, THE CENTENARY OF SCIENCE FICTION: -5<\/strong><\/span><\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/0\/03\/Flag_of_Italy.svg\/960px-Flag_of_Italy.svg.png\" alt=\"File:Flag of Italy.svg\" width=\"20\" height=\"13\" \/>\u00a0 <em><a href=\"https:\/\/www.oavda.it\/astronomia-da-fantascienza\/centenario-della-fantascienza\">Clicca qui<\/a> per la versione italiana di questo articolo<\/em><\/p>\n<p>&nbsp;<\/p>\n<p><i><span style=\"font-weight: 400\">\u201cThe discovery of Solaris dated from about 100 years before I was born. The planet orbits two suns: a red sun and a blue sun. For 45 years after its discovery, no spacecraft had visited Solaris. At that time, the Gamow-Shapley theory\u2014that life was impossible on planets which are satellites of two solar bodies\u2014was firmly believed. The orbit is constantly being modified by variations in the gravitational pull in the course of its revolutions around the two suns. [&#8230;] A few decades later, however, observations seemed to suggest that the planet\u2019s orbit was in no way subject to the expected variations: it was stable, as stable as the orbit of the planets in our own solar system.<\/span><\/i><i><span style=\"font-weight: 400\">\u201d<\/span><\/i><\/p>\n<p><span style=\"font-weight: 400\">Published in 1961, <\/span><i><span style=\"font-weight: 400\">Solaris<\/span><\/i><span style=\"font-weight: 400\"> is nowadays acknowledged as one of the most important science fiction novels ever written, and arguably the most significant of the genre authored by a continental European \u2014 the Polish <strong><span style=\"color: #99ccff\">Stanis\u0142aw Lem<\/span><\/strong> (1921\u20132005) \u2014 in the past century. The story follows astronaut Chris Kelvin, who is dispatched to a space station orbiting the planet Solaris, located in the constellation of Aquarius. He is neither a physicist, nor an engineer, nor an astronomer, as one might expect: he is a psychologist. Indeed, the task of investigating this mysterious world tests the Earthly explorers not merely on a scientific level, but, above all, on a human one. Solaris is almost utterly covered by a gelatinous ocean in perpetual motion, whose properties are so inexplicable as to suggest a formless sentient intelligence capable of influencing its surroundings. Some believe that this influence governs the planet\u2019s remarkably stable orbit around its two suns, a trajectory that, according to the laws of gravity, ought not to be admissible. Other equally anomalous phenomena are likewise attributed to the ocean, including disturbances of the minds of those aboard the station, as for instance the materialisation of figures from their past \u2014 faithful recreations of the dead or long forgotten. Sent to uncover the nature of the events occurring on the station, Kelvin soon finds himself unprepared for what he encounters: his confrontation with Solaris radically transforms not only his understanding of life, but also his perception of himself.<\/span><\/p>\n<p><span style=\"font-weight: 400\">When Lem devised <\/span><i><span style=\"font-weight: 400\">Solaris<\/span><\/i><span style=\"font-weight: 400\">, he could not have foreseen that, just three decades later, beginning in the 1990s, astronomical research would confirm the existence of the alien worlds long imagined by science fiction. These worlds are known as exoplanets, the technical term used to designate planets beyond the Solar System. Although none of the more than 6,000 exoplanets discovered to date harbour an entity as unfathomable as Solaris\u2019 ocean, the observed physical properties are so diverse and peculiar that they compel reviewing theoretical models for planetary formation and evolution. Much like Kelvin, in reality too, these alien worlds continue to astonish us\u2026<\/span><\/p>\n<p><span style=\"font-weight: 400\"><strong><span style=\"color: #99ccff\">Giuseppe Galletta<\/span><\/strong>, professor of astronomy and astrobiology at the University of Padua, provides a scientific perspective on the alien worlds envisioned by Lem. His research concentrates on the study of exoplanets and the conditions that could render them habitable. Astrobiology \u2014 a discipline at the intersection of astronomy, geology, chemistry, and biology \u2014 addresses these exact questions: how planets form, what chemical elements they contain, and how they might sustain life<\/span><span style=\"font-weight: 400\">.<\/span><\/p>\n<figure id=\"attachment_18112\" aria-describedby=\"caption-attachment-18112\" style=\"width: 1200px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-18112\" src=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio.png\" alt=\"\" width=\"1200\" height=\"600\" srcset=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio.png 2000w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio-300x150.png 300w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio-1024x512.png 1024w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio-768x384.png 768w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio-1536x768.png 1536w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio-24x12.png 24w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio-36x18.png 36w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-solaris-nord-lem-sellerio-48x24.png 48w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><\/a><figcaption id=\"caption-attachment-18112\" class=\"wp-caption-text\">On the left, the cover of the first Italian translation of <em>Solaris<\/em> (Editrice Nord, 1973). Source: <a class=\"ng-star-inserted\" href=\"https:\/\/www.equilibrilibreria.it\/product\/solaris-lem-stanislaw-editrice-nord-1973\/\" target=\"_blank\" rel=\"noopener\" data-hveid=\"0\" data-ved=\"0CAAQ_4QMahgKEwixkPSB-s6UAxUAAAAAHQAAAAAQ_wE\">https:\/\/www.equilibrilibreria.it\/product\/solaris-lem-stanislaw-editrice-nord-1973\/<\/a> In the center, a portrait of the author Stanis\u0142aw Lem. Source: <a class=\"ng-star-inserted\" href=\"https:\/\/www1.wdr.de\/radio\/wdr5\/sendungen\/zeitzeichen\/zeitzeichen-stanislaw-lem-100.html\" target=\"_blank\" rel=\"noopener\" data-hveid=\"0\" data-ved=\"0CAAQ_4QMahgKEwixkPSB-s6UAxUAAAAAHQAAAAAQgAI\">https:\/\/www1.wdr.de\/radio\/wdr5\/sendungen\/zeitzeichen\/zeitzeichen-stanislaw-lem-100.html<\/a> On the right, the cover of the most recent Italian translation of <em>Solaris<\/em> (Sellerio, 2013). Source: <a class=\"ng-star-inserted\" href=\"https:\/\/www.doppiozero.com\/grandezza-di-stanislaw-lem\" target=\"_blank\" rel=\"noopener\" data-hveid=\"0\" data-ved=\"0CAAQ_4QMahgKEwixkPSB-s6UAxUAAAAAHQAAAAAQgQI\">https:\/\/www.doppiozero.com\/grandezza-di-stanislaw-lem<\/a><\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">\u201cThere are several techniques that enable us to determine the presence of an exoplanet, derive its fundamental physical properties \u2014 such as mass, radius, density, atmospheric composition, and orbital period \u2014 and evaluate its potential habitability. Among these, we mention four in particular: the radial velocity method, the transit method, direct imaging, and gravitational microlensing,\u201d Galletta explains. The radial velocity method involves measuring the tiny variations in the speed at which a star moves along the observer\u2019s line of sight, caused by the gravitational pull of an orbiting planet. This oscillatory motion produced a Doppler shift in the spectral lines of the star\u2019s light: as the star approaches, the lines shift towards the blue (shorter wavelengths); instead, if it recedes, they shift towards the red. Since the magnitude of this effect depends on the inclination of the orbit relative to the line of sight, it is possible to infer the planet\u2019s minimum mass. On the other hand, the transit method tracks the drop in a star\u2019s brightness when a planet passes across its visible disc, partially obscuring it. The depth and duration of the transit provide an estimate of the planet\u2019s radius: when combined with the mass obtained through the radial velocity method, this yields its average density, a key parameter for distinguishing between gaseous and rocky planets.<\/span><\/p>\n<p><span style=\"font-weight: 400\">Direct imaging is a more recent and complex approach, which aims to separate the light from the planet from the much more intense light from the nearby star. Once isolated, the radiation emitted or reflected by the planet can be observed directly and analysed using high-resolution spectroscopy to ascertain its atmospheric chemical composition, albedo and surface temperature. Finally, gravitational microlensing \u2014 a phenomenon predicted by <span style=\"color: #99ccff\"><b>Albert Einstein<\/b><\/span><\/span>&#8216;s ge<span style=\"font-weight: 400\">neral relativity in which the light from a distant star is deflected and amplified by the presence of a massive body along the line of sight \u2014 allows astronomers to discover small-mass planets that would otherwise escape detection by the radial velocity or transit methods. When a planet and its host star pass in front of a background star, the light from the latter experiences a temporary brightening (better called magnification), whose shape is a function of the planet\u2019s mass.<\/span><\/p>\n<p><span style=\"font-weight: 400\">By integrating these detection techniques, exoplanets can be classified according to their internal composition. Rocky planets, like Earth, possess dense cores and solid crusts, while gas giants, like Jupiter and Saturn, feature vast hydrogen and helium envelopes enclosing reduced-size rocky or metallic cores. Between these extremes lie super-Earths and mini-Neptunes: the former are planets more massive than Earth but smaller than Neptune, with surface gravity sufficient to retain a substantial atmosphere and maintain liquid water on a large scale, whereas the latter have dense atmospheres rich in volatile gases<\/span><span style=\"font-weight: 400\">.<\/span><\/p>\n<figure id=\"attachment_18121\" aria-describedby=\"caption-attachment-18121\" style=\"width: 1500px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-18121\" src=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa.png\" alt=\"\" width=\"1500\" height=\"600\" srcset=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa.png 5000w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-300x120.png 300w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-1024x410.png 1024w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-768x307.png 768w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-1536x614.png 1536w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-2048x819.png 2048w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-24x10.png 24w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-36x14.png 36w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/collage-galletta-esa-48x19.png 48w\" sizes=\"auto, (max-width: 1500px) 100vw, 1500px\" \/><\/a><figcaption id=\"caption-attachment-18121\" class=\"wp-caption-text\">On the left, Giuseppe Galletta. Source: courtesy of the author. On the right, summary diagram of the main methods for detecting exoplanets. From top left, clockwise: transit photometry; transit timing variation; direct imaging; astrometry; microlensing; radial velocity. Credit: ESA. Source: <a class=\"ng-star-inserted\" href=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2019\/12\/Exoplanet_detection_methods\" target=\"_blank\" rel=\"noopener\" data-hveid=\"0\" data-ved=\"0CAAQ_4QMahgKEwixkPSB-s6UAxUAAAAAHQAAAAAQlgI\">https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2019\/12\/Exoplanet_detection_methods<\/a><\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">This classification is not an end in itself, though: rather, it serves as a tool to assess whether an exoplanet could be habitable \u2014 that is, whether it might support complex life, at least of a cellular type, similar to the Earth\u2019s. \u201cThe factors that defines the habitability of an exoplanet are the following: its distance from the host star, the orbital stability and dynamics of the planetary system, atmospheric thickness, the presence of a liquid solvent like water, geological activity and geochemical recycling \u2014 which preserve the chemical elements indispensable for life \u2014, the existence and duration of a magnetic field shielding the planet from stellar radiation, and a time window suitable for the emergence and survival of microorganisms,\u201d Galletta elaborates. A planet\u2019s distance from its star dictates the energy it receives, and consequently its surface temperature and the physical state of any water present. If the planet is too close, it is exposed to ionising stellar radiation, responsible for the loss of volatile atmospheric gases, while if it is too far, it freezes, with water turning to ice. The range of distances that theoretically allows an exoplanet to support liquid water on its surface in a stable manner identifies the so-called circumstellar habitable zone.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400\">For this reason, the position of the habitable zone hinges on both the brightness and evolutionary stage of the star and the planet\u2019s atmosphere, which can expand or shrink it through albedo and the greenhouse effect. For example, a main-sequence star such as the Sun radiates energy at an almost constant rate for billions of years, thereby stabilising the habitable zones of its planets. By contrast, a red giant star, which is larger and more luminous, shifts the habitable zone to greater distances, causing previously temperate planets to become inhospitable. Finally, a red dwarf star, having very low luminosity, confines the habitable zone to regions close to the star, where planets may undergo tidal locking and be thus irradiated on a single hemisphere.<\/span><\/p>\n<p><span style=\"font-weight: 400\">However, it is not sufficient for a planet to reside within the habitable zone: its orbit must also remain stable over time to safeguard climatic equilibrium. Large variations in eccentricity, due to gravitational perturbations from neighbouring planets or companion stars, can create thermal gradients that temporarily evaporate or freeze water; a variable inclination of the planet\u2019s rotational axis can trigger abrupt seasonal shifts; and orbital resonances, resulting from interactions with moons or other nearby planets, can alter the distribution of volatile gases in the atmosphere. The implication is that the likelihood of developing an environment suited to the onset of biological life is higher in orderly planetary systems (those not subject to strong gravitational perturbations or frequent climatic disturbances). In addition, a moderately dense atmosphere guarantees pressure and temperature values compatible with the persistence of liquid water and acts as a barrier against ionising stellar radiation reaching the surface. An atmosphere that is too thin, as on Mars, promotes heat loss and the evaporation of liquids \u2014 of which only traces remain today in the form of riverbeds or ancient ocean basins; one that is too thick, as on Venus, leads to extreme temperatures, the planet being perpetually shrouded by an impenetrable blanket of clouds and aerosols. A planet&#8217;s capacity to retain its original atmosphere is mainly linked to the existence of a magnetic field generated by its dynamo. The magnetic field plays a key role in deflecting charged particles from the stellar wind, engendering a protective shield around the planet \u2014 the magnetosphere \u2014, such to secure the thermal and chemical conditions necessary for the survival of organic molecules<\/span>.<\/p>\n<figure id=\"attachment_18115\" aria-describedby=\"caption-attachment-18115\" style=\"width: 1056px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-18115\" src=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-scaled.jpg\" alt=\"\" width=\"1056\" height=\"600\" srcset=\"https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-scaled.jpg 2560w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-300x170.jpg 300w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-1024x581.jpg 1024w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-768x436.jpg 768w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-1536x872.jpg 1536w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-2048x1163.jpg 2048w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-24x14.jpg 24w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-36x20.jpg 36w, https:\/\/www.oavda.it\/wp-content\/uploads\/2025\/11\/habitable-zone-48x27.jpg 48w\" sizes=\"auto, (max-width: 1056px) 100vw, 1056px\" \/><\/a><figcaption id=\"caption-attachment-18115\" class=\"wp-caption-text\">Artist&#8217;s impression of the circumstellar habitable zone. If a planet is too close to its star, it will be too hot and water, if present, will evaporate. If a planet is too far, it will be too cold and water, if present, will freeze. Stars have very different sizes, masses, and temperatures. Smaller, cooler stars with a lower mass than the Sun (M-type dwarfs) have a habitable zone closer to the star compared to the Sun (a G-type dwarf); larger, hotter stars with a higher mass than the Sun (A-type dwarfs) have a habitable zone farther from the star. Credit: NASA\/Kepler Mission\/Dana Berry. Source: <a class=\"ng-star-inserted\" href=\"https:\/\/www.nasa.gov\/image-article\/habitable-zones-of-different-stars\/\" target=\"_blank\" rel=\"noopener\" data-hveid=\"0\" data-ved=\"0CAAQ_4QMahgKEwixkPSB-s6UAxUAAAAAHQAAAAAQvAI\">https:\/\/www.nasa.gov\/image-article\/habitable-zones-of-different-stars\/<\/a><\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">Specifically, certain macromolecules are pivotal for Earth-like life: proteins, which serve as enzymes and structural supports, and nitrogenous bases, the chemical building blocks of nucleic acids, which encode and transmit biological information. The formation, assembly, and functioning of these polymer chains demand the presence of a liquid solvent on the planetary surface. This chain of processes is sustained by the planet\u2019s geological activity, which recycles carbon, nitrogen, phosphorus, and other vital nutrients, thereby preventing the depletion of the chemical resources that constitute organic molecules. Phenomena such as plate tectonics, volcanism and heat exchange between the planet&#8217;s core and mantle regulate climatic equilibrium through long-term cycles, fostering biological evolution over timescales of millions or billions of years. In particular, the carbonate\u2013silicate cycle modulates the atmospheric concentration of carbon dioxide, so that the surface temperature stays within the critical range for the conservation of liquid water. The carbonate\u2013silicate cycle comprises four phases: erosion, in which silicate rocks are chemically altered by carbonic acid (H<\/span><span style=\"font-weight: 400\">\u2082<\/span><span style=\"font-weight: 400\">CO<\/span><span style=\"font-weight: 400\">\u2083<\/span><span style=\"font-weight: 400\">), produced by the dissolution of atmospheric carbon dioxide in rainwater; sedimentation, involving the transport and deposition of carbonate minerals such as calcite in oceanic sediments; subduction, during which the oceanic crust and carbonate sediments are progressively drawn into the mantle as tectonic plates move; and the release of new carbon dioxide during volcanic eruptions.<\/span><\/p>\n<p><span style=\"font-weight: 400\">But what do we mean by \u201clife,\u201d based on our current understanding of alien worlds? Galletta comments: \u201cIf we consider the exoplanets observed so far, the concept of life must be interpreted more flexibly than the traditional Earth-centric definition. A living being can be described as a system able to keep a coherent internal organisation \u2014 that is, one that resists spontaneous decay due to entropy \u2014 as it exchanges energy and matter with its environment, responds to external stimuli, and, ideally, evolves through adaptations or modifications over time. Habitability factors are the criteria on which astrobiology relies to hypothesise life, also under conditions very different from those on Earth. The search for life on exoplanets centres primarily on the so-called biosignatures \u2014 traces of chemical elements (like oxygen, methane, ozone, or water vapour) that can only be detected via high-resolution spectroscopy and are regarded as potential indicators of biological activity. Now, Solaris, with its immense ocean that gives it an almost sentient appearance, represents an extreme case of an alien world. Now, Solaris, with its vast ocean that gives it an almost sentient appearance, represents a limit case of an alien world. In astrobiological terms, conceiving anything even remotely comparable would entail imagining a planet situated within the habitable zone of a stable star, with a dominant fluid component capable of underpinning complex chemical processes. In fact, exoplanets with oceans of exotic substances, dense and dynamic atmospheres, and severe temperatures and pressures have already been discovered. Nevertheless, there are no recognised physico-chemical mechanisms that would allow an entire planet to be transformed into an organism intelligent enough to control its own orbit or to impinge on the psyche of its inhabitants.<\/span><\/p>\n<p><span style=\"font-weight: 400\">In <\/span><i><span style=\"font-weight: 400\">Solaris<\/span><\/i><span style=\"font-weight: 400\">, Lem constructs a fictional world that is at once disturbing and fascinating, inviting the reader to question the nature of life and consciousness in alien contexts. The novel<\/span><span style=\"font-weight: 400\">\u00a0calls to mind that the unknown is not confined to cosmic distances: the true mystery dwells in our inability to comprehend it fully. Every observed exoplanet is an enigma akin to Solaris, a <\/span><i><span style=\"font-weight: 400\">sui generis<\/span><\/i><span style=\"font-weight: 400\"> reality to be delved into without prior assumptions or absolute certainties. Lem\u2019s planet thus mirrors scientific curiosity and humility, configuring as a literary provocation that foreshadows the true challenges of astrobiology. After all, the endeavour to find extraterrestrial life takes the shape of an exploration of the universe as well as an introspection of the boundaries of human knowledge, carried out in the inexhaustible hope of pushing them further<\/span><span style=\"font-weight: 400\">.<\/span><a href=\"https:\/\/buonacausa.org\/cause\/riccardopozzobon\"><span style=\"font-weight: 400\"><br \/>\n<\/span><\/a><\/p>\n<p><em>Nus, 3 November 2025 &#8211; English version published on 23 May 2026<\/em><\/p>\n<p>&nbsp;<\/p>\n<p><span style=\"text-decoration: underline;color: #ffcc00\"><b>Astroglossary<\/b><\/span><\/p>\n<p><span style=\"font-weight: 400\"><strong>circumstellar habitable zone<\/strong>: the region surrounding a star where a planet\u2019s surface temperature allows liquid water to persist over long periods.<\/span><span style=\"font-weight: 400\"><br \/>\n<\/span><span style=\"font-weight: 400\"><strong>volatile gases<\/strong>: chemical substances that, at a given temperature and pressure, readily transition into a gaseous state through evaporation or sublimation and can contribute to a celestial body\u2019s atmosphere. Examples include water (H<\/span><span style=\"font-weight: 400\">\u2082<\/span><span style=\"font-weight: 400\">O), carbon dioxide (CO<\/span><span style=\"font-weight: 400\">\u2082<\/span><span style=\"font-weight: 400\">), methane (CH<\/span><span style=\"font-weight: 400\">\u2084<\/span><span style=\"font-weight: 400\">), ammonia (NH<\/span><span style=\"font-weight: 400\">\u2083<\/span><span style=\"font-weight: 400\">), molecular nitrogen (N<\/span><span style=\"font-weight: 400\">\u2082<\/span><span style=\"font-weight: 400\">), molecular oxygen (O<\/span><span style=\"font-weight: 400\">\u2082<\/span><span style=\"font-weight: 400\">), molecular hydrogen (H<\/span><span style=\"font-weight: 400\">\u2082<\/span><span style=\"font-weight: 400\">), and sulphur dioxide (SO<\/span><span style=\"font-weight: 400\">\u2082<\/span><span style=\"font-weight: 400\">).<\/span><span style=\"font-weight: 400\"><br \/>\n<\/span><span style=\"font-weight: 400\"><strong>tidal locking<\/strong>: a gravitational phenomenon that can occur when a planet orbits very close to its star. The star\u2019s gravitational pull exerts differential forces on the planet, gradually slowing its rotation until it matches the orbital period (synchronous rotation). As a result, one hemisphere permanently faces the star, continuously receiving radiation and becoming extremely hot, while the opposite hemisphere cools down, sometimes reaching freezing temperatures.<\/span><span style=\"font-weight: 400\"><br \/>\n<\/span><span style=\"font-weight: 400\"><strong>dynamo<\/strong>: the motion of electrically conductive materials within a planet\u2019s liquid core.<\/span><\/p>\n<p><span style=\"text-decoration: underline\"><strong><span style=\"color: #ffcc00;text-decoration: underline\">Short bio<\/span><\/strong><\/span><\/p>\n<p><span style=\"font-weight: 400\">Giuseppe Galletta is an Italian astrophysicist and astrobiologist, and a professor of astronomy and astrobiology at the University of Padua. With a degree in physics, he has devoted his career to research and scientific dissemination, publishing over a hundred articles in international journals. In the 1970s, he identified a new category of galaxies with elongated structures and discovered the existence of galaxies with polar rings. In the 1980s, he revealed the phenomenon known as \u201ccounter-rotation\u201d in disc galaxies. In 2004, he directed the LISA (Italian Laboratory for Astrobiological Simulations) project, a Martian environment simulator designed to study the survival of microorganisms on the red planet. He is a member of leading international astronomy and astrobiology societies and the author of three popular science books: <\/span><i><span style=\"font-weight: 400\">Astrobiologia: le frontiere della vita<\/span><\/i><span style=\"font-weight: 400\"> (2005, Hoepli), <\/span><i><span style=\"font-weight: 400\">Astrobiologia. La ricerca della vita nello spazio <\/span><\/i><span style=\"font-weight: 400\">(2021, Padova University Press), and <\/span><i><span style=\"font-weight: 400\">Schizzi di cosmologia<\/span><\/i><span style=\"font-weight: 400\"> (2025, Padova University Press).<\/span><\/p>\n<p><span style=\"text-decoration: underline;color: #ffcc00\"><b>References<\/b><\/span><\/p>\n<p><a href=\"https:\/\/www.sellerio.it\/it\/catalogo\/Solaris\/Lem\/5491\"><span style=\"font-weight: 400\">Stanis\u0142aw Lem, <\/span><i><span style=\"font-weight: 400\">Solaris<\/span><\/i><span style=\"font-weight: 400\">, translated by Vera Verdiani, editor Francesco M. Cataluccio, Sellerio editore, 2013<\/span><\/a>, in Italian<\/p>\n<p><a href=\"https:\/\/www.isfdb.org\/cgi-bin\/title.cgi?1330320\">Internet Speculative Fiction Database: <span style=\"font-weight: 400\">Stanis\u0142aw Lem, <\/span><i><span style=\"font-weight: 400\">Solaris<\/span><\/i>, every edition<\/a><\/p>\n<p><a href=\"https:\/\/www.galletta.it\/gg\/it\/\">Giuseppe Galletta&#8217;s website<\/a><\/p>\n<p><a href=\"https:\/\/www.galletta.it\/gg\/it\/astrobiologia2021\/\">Giuseppe Galletta, <em>Astrobiologia. La ricerca di vita nello spazio<\/em>, Padova University Press, 2021<\/a>, in Italian. The book is available on the publisher&#8217;s website for free in digital format, and for purchase in print.<\/p>\n<p><a href=\"https:\/\/science.nasa.gov\/exoplanets\/\">NASA&#8217;s website about exoplanets<\/a><\/p>\n<p><a href=\"https:\/\/nexsci.caltech.edu\/\">NASA Exoplanet Science Institute<\/a><\/p>\n<p class=\"display-3\"><a href=\"https:\/\/exoplanet.eu\/home\/\">Encyclopaedia of exoplanetary systems<\/a>, European-based website online since February 1995<\/p>\n<p><a href=\"https:\/\/openexoplanetcatalogue.com\/\">Open Exoplanet Catalogue<\/a>, an open-contribution decentralized database<\/p>\n<p><a href=\"https:\/\/www.poloniaeuropae.it\/fantascienza-e-filologia-solaris-in-italia\/\">Luigi Marinelli, <em>Fantascienza e filologia: Solaris in Italia<\/em>, 26 marzo 2024<\/a>, in Italian<\/p>\n<p>Featured image: <a href=\"https:\/\/victo-ngai.mysupadupa.com\/products\/solaris\"><em>Solaris Variant<\/em>, Victo ngai<\/a>, official licensed silkscreen posters commemorating Andrei Tarkovsky\u2019s 1972 movie <em>Solaris<\/em> based on the novel by Stanis\u0142aw Lem.<\/p>\n<p>&nbsp;<\/p>\n<p>\ud83d\udc49 <em><a href=\"https:\/\/www.oavda.it\/astronomia-da-fantascienza\/centenario-della-fantascienza\">Click here<\/a><\/em>\u00a0for other articles of the series\u00a0<em>Sci-fi Astronomy<\/em>, edited by Camilla Pianta<\/p>\n","protected":false},"excerpt":{"rendered":"<p>*Sci-fi Astronomy, edited by Camilla Pianta* Solaris, an inquiry into extraterrestrial life through the lens of science fiction \ud83d\udc7d What if searching for alien life helps us understand ourselves? COUNTDOWN TO APRIL 2026, THE CENTENARY OF SCIENCE FICTION: -5 \u00a0 Clicca qui per la versione italiana di questo articolo &nbsp; \u201cThe discovery of Solaris dated [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":18110,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[327,322,330],"tags":[],"class_list":["post-19124","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-iniziative-archivio","category-news-en","category-sci-fi-astronomy"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Astronomia da fantascienza \ud83d\udc49 -5 - Osservatorio Astronomico della Regione Autonoma Valle d&#039;Aosta<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.oavda.it\/en\/news-en\/astronomia-da-fantascienza-5\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Astronomia da fantascienza \ud83d\udc49 -5 - Osservatorio Astronomico della Regione Autonoma Valle d&#039;Aosta\" \/>\n<meta property=\"og:description\" content=\"*Sci-fi Astronomy, edited by Camilla Pianta* Solaris, an inquiry into extraterrestrial life through the lens of science fiction \ud83d\udc7d What if searching for alien life helps us understand ourselves? 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