Episode 344 - Colliding galaxies, stellar foundires and the emptiness of space

We look at galactic events, where galaxies collide, stars form and emptiness of space. Space is so unfathomably huge, but its still possible for galaxies to collide. The Milky Way was formed through one of this violent collisions over 10 billion years ago. Space seems empty but there are sections of space that are emptier than others, the great Local Void around the Local group. Stars forming in galaxies rely on gas clouds, but what does it take to form a star? What do you need to really make a good nursery for stars? R. Brent Tully, Daniel Pomarède, Romain Graziani, Hélène M. Courtois, Yehuda Hoffman, Edward J. Shaya. Cosmicflows-3: Cosmography of the Local Void. The Astrophysical Journal, 2019; 880 (1): 24 DOI: 10.3847/1538-4357/ab2597 Kazufumi Torii, Shinji Fujita, Atsushi Nishimura, Kazuki Tokuda, Mikito Kohno, Kengo Tachihara, Shu-ichiro Inutsuka, Mitsuhiro Matsuo, Mika Kuriki, Yuya Tsuda, Tetsuhiro Minamidani, Tomofumi Umemoto, Nario Kuno, Yusuke Miyamoto. FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN). V. Dense gas mass fraction of molecular gas in the Galactic plane. Publications of the Astronomical Society of Japan, 2019; DOI: 10.1093/pasj/psz033 Carme Gallart, Edouard J. Bernard, Chris B. Brook, Tomás Ruiz-Lara, Santi Cassisi, Vanessa Hill, Matteo Monelli. Uncovering the birth of the Milky Way through accurate stellar ages with Gaia. Nature Astronomy, 2019; DOI: 10.1038/s41550-019-0829-5