Betacoronavirus the Latin “corona” meaning crown or halo, referring to their image under electron microscopy of crown-like spikes on their surface similar to the solar corona. This morphology is created by the viral spike (S) peplomers, which are proteins that populate the surface of the virus and determine host tropism. The order Nidovirales is named for the Latin nidus, which means nest. It refers to this order’s production of a 3' co-terminal nested set of subgenomic mRNA's during infection. Betacoronavirus Betacoronaviruses are one of four genera of coronaviruses of the subfamily "Coronavirinae" in the family "Coronaviridae", of the order "Nidovirales". They
Galactic halo Galactic halo A galactic halo is an extended, roughly spherical component of a galaxy which extends beyond the main, visible component. Several distinct components of galaxies comprise the halo: The distinction between the halo and the main body of the galaxy is clearest in spiral galaxies, where the spherical shape of the halo contrasts with the flat disc. In an elliptical galaxy, there is no sharp transition between the other components of the galaxy and the halo. The stellar halo is a nearly spherical population of field stars and globular clusters. It surrounds most disk galaxies as well as some