We live in the Milky Way Galaxy, which is a collection of stars, gas, dust, and a supermassive black hole at it’s very center. Our Galaxy is a spiral galaxy, which are rotating structures that are flat (disk-like) like a DVD when looked upon edge-on. There is also a bulge in the middle that consists of mostly old stars. When you look at a spiral galaxy face-on, you can see beautiful spiral arms where stars are being born. Our solar system is in the Orion arm, and we are about 25000 light years (2.5 × 10¹⁷ miles) from the very center of the Galaxy.

Schematic of the milky way credit: oglethorpe university.

New observations of young stellar object Elias 2–27 confirm gravitational instabilities and planet-forming disk mass as key to formation of giant planets.

A team of scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) to study the young star Elias 2–27 have confirmed that gravitational instabilities play a key role in planet formation, and have for the first time directly measured the mass of protoplanetary disks using gas velocity data, potentially unlocking one of the mysteries of planet formation. The results of the research are published today (June 17, 2021) in two papers in The Astrophysical Journal.

Protoplanetary disks — planet-forming disks made of gas and dust that surround newly formed young stars — are known to scientists as the birthplace of planets. The exact process of planet formation, however, has remained a mystery. The new research, led by Teresa Paneque-Carreño — a recent graduate of the Universidad de Chile and PhD student at the University of Leiden and the European Southern Observatory, and the primary author on the first of the two papers — focuses on unlocking the mystery of planet formation.

A team of astronomers might have discovered a “Giant Arc” of galaxies in deep space that would challenge our understanding of cosmology.

Dark matter may self-interact through a continuum of low-mass states. This happens if dark matter couples to a strongly-coupled nearly-conformal hidden sector. This type of theory is holographically described by brane-localized dark matter interacting with bulk fields in a slice of 5D anti-de Sitter space. The long-range potential in this scenario depends on a non-integer power of the spatial separation, in contrast to the Yukawa potential generated by the exchange of a single 4D mediator. The resulting self-interaction cross section scales like a non-integer power of velocity. We identify the Born, classical and resonant regimes and investigate them using state-of-the-art numerical methods. We demonstrate the viability of our continuum-mediated framework to address the astrophysical small-scale structure anomalies. Investigating the continuum-mediated Sommerfeld enhancement, we demonstrate that a pattern of resonances can occur depending on the non-integer power. We conclude that continuum mediators introduce novel power-law scalings which open new possibilities for dark matter self-interaction phenomenology.

A preprint version of the article is available at ArXiv.