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).
...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.
Carl Sagan wrote that "If you wish to make an apple pie from scratch, you must first invent the universe.” We wish to know our home, so back we go, to the Big Bang, and step by step to today.
Are we alone or do we share our solar system and galaxy with other forms of life? And how widespread are advanced civilizations with whom we could communicate? Right now we don’t have answers to these profound questions. But scientists are in hot pursuit...
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.
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.
Andrew Taylor “Andy” Weir is an American novelist born on June 16, 1972 in Davis, California, USA. He is best known for his science fiction novel, The Martian, which was written and self-published in 2011. Three years later, Crown Publishing purchased the rights and re-released it.
Earth sits right in the Goldilocks zone. Venus, only a little closer to the sun, has a surface hot enough to melt lead, and Mars is cold enough to have dry ice -- C02 -- at its poles. What can the atmospheres of these three planets tell us about the future of our climate?
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).
