The heaviest natural elements on the periodic table such as gold, platinum, and uranium were forged during the mergers of binary neutron stars. Astronomers have previously estimated that tens of thousands of such binary neutron star mergers must have occurred throughout our Milky Way Galaxy during the past 10 billion years, sprinkling neutron-rich elements throughout the gas that eventually formed the next generation of stars and planets. By studying the composition of meteorites, astronomers now conclude that a single collision of neutron stars occurred shortly before and near to the formation of our solar system, producing a measurable fraction of the heavy elements here on Earth.
Cosmological simulations include dozens of prescriptions to describe the 13.8-billion-year evolution of the Universe, including numerical recipes for dark energy (so-called lambda), weakly interacting cold dark matter, gas accretion onto primordial galaxies, star formation and evolution, and feedback from quasars and supernovae. The outcome of these lambda cold dark matter simulations reproduce many of the observed features of the real universe. However, the models predict that dozens of small dwarf satellite galaxies should orbit medium-sized galaxies like our Milky Way and Andromeda in random orientations, but new research suggests most satellite galaxies orbit their host galaxies aligned along a single plane.
What would life be like on a planet orbiting a pulsar? Astronomers estimate that the Milky Way galaxy contains an estimated 1 billion neutron stars, of which about 200,000 are pulsars –neutron stars of only 10 to 30 kilometers in diameter with enormous magnetic fields, that accrete matter and regularly burst out large amounts of X-rays and other energetic particles. So far, 3000 pulsars have been studied and only 5 pulsar planets have been found. In 1992, the first exoplanets ever were discovered around pulsar PSR B1257+12.
“Beautiful as it is, our Universe is constantly evolving, often through violent events like the Milky Way’s forthcoming collision with the Large Magellanic Cloud,” said Carlos Frenk, Director of the Institute for Computational Cosmology at the University of Durham. “Barring any disasters, like a major disturbance to the Solar System, our descendants, if any, are in for a treat: a spectacular display of cosmic fireworks as the newly awakened supermassive black hole at the center of our galaxy, Sagittarius A*, reacts by emitting jets of extremely bright energetic radiation.”
Editor, Jackie Faherty, astrophysicist, Senior Scientist with AMNH. Jackie was formerly a NASA Hubble Fellow at the Carnegie Institution for Science. Aside from a love of scientific research, she is a passionate educator and can often be found giving public lectures in the Hayden Planetarium. Her research team has won multiple grants from NASA, NSF, and the Heising Simons foundation to support projects focused on characterising planet-like objects. She has also co-founded the popular citizen science project entitled Backyard Worlds: Planet 9 which invites the general public to help scan the solar neighbourhood for previously missed cold worlds. A Google Scholar, Faherty has over 100 peer reviewed articles in astrophysical journals and has been an invited speaker at universities and conferences across the globe. Jackie received the 2020 Vera Rubin Early Career Prize from the American Astronomical Society, an award that recognises scientists who have made an impact in the field of dynamical astronomy and the 2021 Robert H Goddard Award for science accomplishments.
This week’s “Heard in the Milky Way” episode, narrated by dailygalaxy.com founder, Val Landi, takes you on a journey with two stories that change our knowledge of Planet Earth, our Galaxy, and the vast cosmos beyond.