cover EN.qxp_l'astrofilo 28/10/2020 17:55 Page 1 THE FREE MULTIMEDIA MAGAZINE THAT KEEPS YOU UPDATED ON WHAT IS HAPPENING IN SPACE Bi-monthly magazine of scientific and technical information ✶ November-December 2020 Small molecules, big questions–the detection of Venusian phosphine • A planet-forming disc torn apart by its three central stars • Hubble maps a giant halo around the Andromeda galaxy • A spectacular supernova time-lapse • Hubble captures crisp new image of Jupiter and Europa The Anthropocene as an interstellar messenger Good morning Earth. This is ET radio! www.astropublishing.com ✶✶www.facebook.com/astropublishing [email protected] colophon EN_l'astrofilo 29/10/2020 11:43 Page 2 ESO Calendar 2021 Now Available https://www.eso.org/public/usa/shop/product/calendar_2021/ The 2021 edition of one of our most popular products, the ESO Calendar, is now available and can be purchased from the online ESOshop and in the ESO Supernova Planetarium & Visitor Centre. The calendar’s cover features a spectacular starscape around the relatively unknown central object, Gum 15, a nebula in which stars are being born. The image also features one of the closest supernova remnants to Earth, which exploded between 11,000 and 12,300 years ago and is located 800 light-years away from our cosmic home. For the month of March, the bright band of the Milky Way arcs above the ALMA antennas on the Chajnantor plateau. One of the closest stellar nurseries to Earth, the Orion Nebula, is the chosen image for July and the massive 3-tonne blank for the Extremely Large Telescope’s (ELT) secondary mirror is the star of September. Finally, in December the viewer will feel they are speeding towards the centre of our galaxy, thanks to a clever photographic technique used on an observation of the Milky Way. These are just a few highlights, we invite you to view the individual pages of the ESO Calendar 2021 here. The calendar has a total of 14 pages, and is available for 9.50 EUR in the ESOshop — but stock is limited so don’t delay! colophon EN_l'astrofilo 29/10/2020 11:43 Page 3 S U M M A R Y BI-MONTHLY MAGAZINE OF SCIENTIFIC AND TECHNICAL INFORMATION Small molecules, big questions – the detection of Venusian phosphine FREELY AVAILABLE THROUGH On the local morning of September 14th, the Royal Astronomical Society tweeted an announcement for THE INTERNET an afternoon press briefing about a significant discovery. Within hours, “phosphine” and “Venus” were being proposed by some on social media as the discussion topic. In combination with shared links to the... November-December 2020 4 A planet-forming disc torn apart by its three central stars A team of astronomers have identified the first direct evidence that groups of stars can tear apart their planet-forming disc, leaving it warped and with tilted rings. This new research suggests exotic planets, 16 not unlike Tatooine in Star Wars, may form in inclined rings in bent discs around multiple stars. The... Hubble maps a giant halo around the Andromeda galaxy In a landmark study, scientists using NASA’s Hubble Space Telescope have mapped the immense enve- lope of gas, called a halo, surrounding the Andromeda galaxy, our nearest large galactic neighbor. Scien- 20 tists were surprised to find that this tenuous, nearly invisible halo of diffuse plasma extends 1.3 million... The Anthropocene as an interstellar messenger It seems incredible, but in an age when humans communicated remotely using horseback couriers, car- rier pigeons, fires and mirrors, the first signals were already being transmitted into space. The Roman, 24 Chinese and Spanish empires unwittingly added traces of their existence to the light reflected from the... English edition of the magazine lA’ STROFILO Hubble captures crisp new image of Jupiter and Europa This latest image of Jupiter, taken by the NASA/ESA Hubble Space Telescope on 25 August 2020, was cap- Editor in chief tured when the planet was 653 million kilometres from Earth. Hubble’s sharp view is giving researchers Michele Ferrara 34 an updated weather report on the monster planet’s turbulent atmosphere, including a remarkable new... Scientific advisor Prof. Enrico Maria Corsini Good morning Earth. This is ET radio! Publisher Astro Publishing di Pirlo L. The patchy search for alien civilizations in the Milky Way continues tirelessly. Nearly all surveys are fo- Via Bonomelli, 106 cused on radio waves, and will continue to be in the future, thanks largely to the planning of gigantic 25049 Iseo - BS - ITALY networks of radio telescopes, such as the Square Kilometer Array, soon to be built in Australia and... email [email protected] 38 Internet Service Provider Aruba S.p.A. A spectacular supernova time-lapse Via San Clemente, 53 24036 Ponte San Pietro - BG - ITALY The NASA/ESA’s Hubble Space Telescope has tracked the fading light of a supernova in the spiral galaxy NGC 2525, located 70 million light-years away. Supernovae like this one can be used as cosmic tape mea- Copyright sures, allowing astronomers to calculate the distance to their galaxies. Hubble captured these images... All material in this magazine is, unless 48 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 copy- right law. A single copy of the materi- als available through this course may be made, solely for personal, noncom- mercial use. Users may not distribute such copies to others, whether or not in electronic form, whether or not for a charge or other consideration, with- out prior written consent of the copy- right holder of the materials. The publisher makes available itself with having rights for possible not charac- terized iconographic sources. Advertising - Administration Astro Publishing di Pirlo L. Via Bonomelli, 106 25049 Iseo - BS - ITALY email [email protected] phosphine EN_l'Astrofilo 28/10/2020 17:57 Page 4 4 ASTROCHEMISTRY Small molecules,bi detection of Venus by Damian G. Allis NASA Solar System Ambassador On the local morning of September 14 th, the Royal Astronomical Society tweeted an announcement for an afternoon press briefing about a significant discovery. Within hours, “phosphine” and “Venus” were being proposed by some on social media as the discussion topic. In combination with shared links to the January 2020 Astrobiology article “Phosphine as a Biosignature Gas in Exoplanet Atmospheres,” some were already anticipating a most remarkable event. NOVEMBER-DECEMBER 2020 phosphine EN_l'Astrofilo 28/10/2020 17:57 Page 5 ASTROCHEMISTRY 5 big questions–the usian phosphine usian phosphine n artist’s vi- n international team from the UK, ing and multi-disciplinary discovery to A sion of elec- USA, and Japan, led by Prof. Jane fruition was obvious to all in attendance. trical discharges A Greaves of Cardiff University, re- No topic in science generates more specu- in the hot sky of leased their open access article “Phosphine lation than extraterrestrial life, and the Venus. Lightning gas in the cloud decks of Venus” in Nature discoverers will go down in history for and volcanism Astronomy as the press briefing was tak- that achievement − this would clearly be a could be the ori- gin of the re- ing place. The cautious excitement of milestone as the names “Gagarin” and cently discovered Greaves, Dr. Anita Richards (Jodrell Bank “Armstrong/Aldrin/Collins” conjure. One phosphine in the Centre for Astrophysics), and Dr. William assumes the most benevolent intentions planet’s atmos- Bains and Prof. Sara Seager (MIT) over of such a briefing, especially with the pre- phere. [J. Peter] bringing such a potentially groundbreak- senters stating that their work is of a mo- NOVEMBER-DECEMBER 2020 phosphine EN_l'Astrofilo 28/10/2020 17:57 Page 6 6 ASTROCHEMISTRY lecular detection and an interpretation in duced by lightning and volcanism, both eft, a false- the absence of any known non-biological common on Venus. That said, the atmos- Lcolor enhance- explanations. That said, one can only imag- pheric and geochemical routes to phos- ment of an origi- ine the instinct to be the first to make such phine could only account for a fraction of nal photograph a discovery, however preliminary, known to the amount detected based on our current of the opaque Venus cloud the world as soon as possible. understanding of both phenomena. The cover taken by What has followed is a story of measure- possible explanation put forth by the au- Mariner 10 during ment, interpretation, reserved speculation, thors applies the predominant method of its gravity-assist and controversy − not over the discovery of phosphine production on Earth – biochem- maneuver en phosphine, but over its indication as a pos- ical processes in low-oxygen conditions. route to Mercury sible biological marker, which has driven As is obvious from the many design fea- in February, 1974. discussion beyond just the astronomical tures of the few successful Venera and Pio- [NASA/JPL] community. What is most Right, the surface clear is how little we still of Venus as cap- know about our own tured by the solar system, as a simple Magellan space- molecule can lead to craft. [Magellan Project/NASA/JPL] heated debate because On the side, an of our incomplete under- artistic enlarge- standing of the chemistry ment of a tiny and geology of our near- region of the est planetary neighbors. Venusian atmos- What we know and do phere, showing not yet know about the the geometry of production of phosphine, the phosphine molecule. [ESO] PH3 , on Venus are central to the past few weeks of speculation.