If we ever make contact with an alien civilization, how will we understand what they’re saying? That’s the question that preoccupies John Elliott of...
The formula for collisional excitation of the atoms responsible for auroral emission can explain why green auroras from excited oxygen atoms can occur at relatively low altitudes, but red auroras from these same atoms are constrained to higher altitudes of lower density. The same formula also suggests much lower electron velocities (~100 km/s) than are required to excite the oxygen atoms to the required metastable levels for subsequent emission (~1000 km/s).
Fast Radio Bursts are flashes of radio emission lasting for several milliseconds. The time of arrival of signals depends on the radio frequency, called the dispersion measure (DM), which depends on the environment through which the signals travel, specifically the number of free electrons in their path. Very few FRBs have matches with sources observed at other wavelengths (Wikipedia - Fast Radio Burst).
...What we have come to appreciate is the seminal role played by clustered star formation in driving the physical and chemical evolution of the galaxies that host these stellar nurseries. Such concentrated sites of newborn stars along with their nebular environs constitute what are known as galactic ecosystems. These energized realms represent vital “crucibles” for growing the chemical complexity that is necessary for biotic processes.
There has always been a lot of conflict and contention between religion and science, arguably since the beginning of human abstract thought. Everyone has an opinion on how the two interact, intermingle, or completely repel against each other. The Accidental Universe: The World You Thought You Knew is simply one man’s opinion written into a book.
We’ve all shown Saturn to someone, or perhaps have shared a clear view of a bright globular, say, M13, with someone who hasn’t seen such a thing before. In these and similar cases, the sheer beauty of the thing is the whole point; any impressive facts are secondary.
