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).
Each year, the American Astronomical Society (AAS) hosts two big meetings in January and June that span all of astronomy and its subfields of cosmology, helioastronomy, and planetary science. The COVID-19 pandemic took its toll, beginning in June 2020, when the meeting format pivoted to online presentations. The January 2022 meeting was canceled outright, but by June 2022, the society pivoted again, offering a hybrid mix of in-person and online formats. These two meetings underscored the unquenchable thirst for astronomical questing among our veteran and rising scientists. Here are a few highlights from these meetings.
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).
In this essay, I argue in support of teaching the Earth & space sciences together, so that students can attain a more holistic understanding of their planetary environment, how it came to be, and where it is headed. Such teaching (and teachers) should receive the same priority as in the teaching of physics, chemistry, and biology.
Galaxies comprise the largest self-gravitating systems of luminous matter in the universe, swirling masses of matter and energy just looking for trouble. Over the past few decades, astronomers have come to appreciate how fervently active galaxies can be. Besides hosting roiling clouds of intense starburst activity, they often also sport supermassive black holes in their centers that can pack a powerful punch. These myriad histrionics can affect the host galaxy's subsequent evolution and even the destinies of neighboring galaxies.