Free Astronomy Magazine May-June 2022

34 MAY-JUNE 2022 ASTRO PUBLISHING C ontinuum image of the Galactic Plane in ICRS Coordinates as viewed by the MWA at 155 MHz. ICRS (International Celestial Reference System) is the current standard ce- lestial reference system adopted by the International Astronomical Union. [Pawsey Supercomputing Centre] T his video sequence zooms into the Hubble Space Telescope view of the galactic core. Hubble’s in- frared vision pierced the dusty heart of our Milky Way to reveal more than half a million stars at its core. Ex- cept for a few blue foreground stars, the stars are part of the Milky Way’s nuclear star cluster, the most mas- sive and densest stellar cluster in our galaxy. Located about 27,000 light-years away, this region is so packed with stars that it is equivalent to having a million suns crammed into the volume of space between us and our closest stellar neighbor, Alpha Centauri, 4.3 light- years away. At the very hub of our galaxy, this star cluster surrounds the Milky Way’s central supermas- sive black hole, which is about 4 million times the mass of our Sun. [NASA, ESA, and G. Bacon (STScI)] parts of our galaxy, even within 1 kpc (1 kiloparsec = 3,260 light years) of Sagittarius A*, the number of planets potentially capable of host- ing complex life should be greater than anywhere else. Similar scenar- ios also emerged from more recent studies, which see the high density of the galactic center as a strong point in the search for technosigna- tures. In the field framed by MWA, there were over 3 million stars and 144 known planetary systems; how- ever, the instrument recorded only silence, excluding the inevitable human radio interference. Maybe this environment is not as hospitable as someone assumed? Tremblay her- self points out that there are also negative aspects in making observa- tions in the direction of the galactic center: “The high density of stars within the galactic center means that cataclysmic events such as stel- lar supernovae and magnetar flares are more likely to impact exoplan- ets, potentially destroying any life on their surface. With so many stars supposes a continuous transmission of signals by aliens. In contrast to these research weak- nesses, Tremblay and colleagues bring some arguments supporting their choice to aim into the heap in the direction of the galactic center. For example, theoretical studies con- ducted in 2011 and 2015 by Michael Gowanlock (Northern Arizona Uni- versity) and other researchers indi- cated that towards the innermost been recorded so far, we do not know which net is more suitable. Even the radio frequency chosen for the search was completely arbitrary, and if it is true that it offers a good angular resolution (75 arc seconds), it is also true that it is decidedly ex- clusive. In addition, the radio tele- scope remained “listening” for just two nights, producing 7 hours of data in total. This is an almost in- significant time coverage and pre-