Earth’s composition seemingly does not fit into planet formation theory. Ripping apart its building blocks by collisions during accretion might sound violent, but can be a way to go.
How to form clumps in the intermediate ranges of massive protoplanetary disks? Could these later be planets?
A model that needs fewest parameters to explain a scenario is favourable. The fact that mm-size dust grains (chondrules) are present in the entire solar system brings rise to the question, whether all bigger solid objects are a collection of chondrules.
Planets are ubiquitous in the Milky Way. Therefore, building them must be straightforward, right? Not at all!
Pulsars, or rapidly-spinning neutron stars, have been observed suddenly change how fast they spin. Typically, the pulsars we’ve seen do this are isolated—what happens if they have a stellar companion?
This paper reports the results of a cosmological simulation, and how smooth accretion and mergers affect three important aspects of galaxy formation: stellar mass growth, size increase, and morphology changes.