Free Astronomy Magazine March-April 2016

Editor in chief Michele Ferrara Scientific advisor Prof. Enrico Maria Corsini Publisher Astro Publishing di Pirlo L. Via Bonomelli, 106 25049 Iseo - BS - ITALY email info@astropublishing.com Internet Service Provider Aruba S.p.A. Loc. Palazzetto, 4 52011 Bibbiena - AR - ITALY Copyright All material in this magazine is, unless otherwise stated, property of Astro Publishing di Pirlo L. or included with permission of its author. Reproduction or retransmission of the materials, in whole or in part, in any manner, with- out the prior written consent of the copyright holder, is a violation of copyright law. A single copy of the materials available through this course may be made, solely for personal, non- commercial use. Users may not distrib- ute such copies to others, whether or not in electronic form, whether or not for a charge or other consideration, without prior written consent of the copyright holder of the materials. The publisher makes available itself with having rights for possible not characterized iconographic sources. Advertising - Administration Astro Publishing di Pirlo L. Via Bonomelli, 106 25049 Iseo - BS - ITALY email admin@astropublishing.com ASTROFILO l’ March-April 2016 BI-MONTHLY MAGAZINE OF SCIENTIFIC AND TECHNICAL INFORMATION FREELY AVAILABLE THROUGH THE INTERNET English edition of the magazine S U M M A R Y Rivelate le onde gravitazionali Per la prima volta gli scienziati hanno osservato quelle increspature nella struttura dello spazio-tempo chiamate onde gravitazionali, in arrivo sulla Terra a seguito di un evento cataclismico nel lontano uni- verso. Ciò conferma una delle principali previsioni della teoria della relatività generale di Albert Einstein... 4 Planet Nine is more probable than ever! Once again, we talk about the existence of a large planet in the remotest depths of our solar system. This time, though, such presence seems all the more concrete. The thrilling challenge in the field of higher math that 170 years ago led to the discovery of Neptune looks set to be repeated today... 8 First light for future black hole probe The GRAVITY instrument combines the light from multiple telescopes to form a virtual telescope up to 200 metres across, using a technique called interferometry. This enables the astronomers to detect much finer detail in astronomical objects than is possible with a single telescope. Since the summer of 2015... 20 Svelata l'età di due dischi nucleari Nelle regioni più centrali di molte galassie esistono delle piccole e compatte strutture a forma di disco che possono essere usate come cronometri per misurare il tempo trascorso dall'ultima fusione con altre galassie. Per la prima volta, due team di ricercatori sono riusciti a leggere “l'ora” segnata da quelle... 24 NASA's observatories weigh massive young galaxy cluster Astronomers have used data from three of NASA's Great Observatories to make the most detailed study yet of an extremely massive young galaxy cluster. This rare galaxy cluster, which is located 10 billion light-years from Earth, is almost as massive as 500 trillion suns. This object has important implications... 32 Eta Carinae is not unique: 5 Eta twins discovered For the first time a group of astronomers have found in neighbouring galaxies 5 objects whose pro- perties are very similar to those of Eta Carinae, an amazing star system that seems to have no equiva- lent in the Milky Way and which it is difficult to study in detail precisely because of its uniqueness. 36 ALMA finds cold grains in planet-forming disc An international team led by Stéphane Guilloteau, at the Laboratoire d'Astrophysique de Bordeaux, France, measured the temperature of large dust grains around the young star 2MASS J16281370- 2431391 in the spectacular Rho Ophiuchi star formation region, about 400 light-years from Earth. 44 Monstrous cloud boomerangs back to our galaxy Hubble Space Telescope astronomers are finding that the old adage "what goes up must come down" even applies to an immense cloud of hydrogen gas outside our Milky Way galaxy. The invisible cloud is plummeting toward our galaxy at nearly 700,000 miles per hour. Though hundreds of enormous... 46 Ceresian craters collection This view from NASA's Dawn spacecraft captures a portion of the southern hemisphere of Ceres. The image of this unnamed crater is centered at approximately 46 degrees south latitude, 101 degrees east longitude. Dawn captured the scene on Dec. 20, 2015 from its low-altitude mapping orbit (LAMO), at... 50 The turbulent birth of a quasar Quasars are distant galaxies with very active supermassive black holes at their centres that spew out powerful jets of particles and radiation. Most quasars shine brightly, but a tiny fraction of these energetic objects are of an unusual type known as Hot DOGs, or Hot, Dust-Obscured Galaxies (only one of every 16