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Recent Astronomy Articles at Cosmic Pursuits

Mammatus Clouds After Thunderstorms

July 7, 2019 by Brian Ventrudo Filed Under: Atmospheric Sightings

Mammatus clouds passing over Calgary, Canada on July 6, 2019.

The summer ‘monsoons’ have obliterated the stars for the past couple of weeks and at least for one week more. But a good stargazer still needs to look up from time to time, which is how I found a formation of mammatus clouds passing overhead after an afternoon and evening of heavy thunderstorms near Calgary, Canada.

These ominous and distinctively shaped clouds are usually formed on the underside of anvil-shaped cumulonimbus clouds that cause severe thunderstorms. These sagging pouches are mostly made of ice crystals. An individual “pouch” can range anywhere from one to three kilometers in diameter, and a mammatus cloud field can stretch for dozens of kilometers across the sky.

Their formation is still poorly understood, but they may form from cold, dense air sinks toward the earth from higher up. This sinking air pokes through the bottom of the anvil resulting in the pouch-like appearance. So they may be a rare occurrence of cloud formation caused by sinking air rather than rising air. The cloud droplets and ice crystals eventually evaporate and the mammatus clouds dissipate. These clouds were passing quickly and moved over the horizon before they faded away.

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Filed Under: Atmospheric Sightings

The Great ‘South American Eclipse’ of 2019

July 2, 2019 by Brian Ventrudo Filed Under: Celestial Events


Observers in a narrow band across the southern Pacific Ocean and north-central Chile and Argentina enjoyed a rare spectacle today: a total solar eclipse. The lovely seaside towns of La Serena and Coquimbo, Chile, enjoyed two minutes and thirteen seconds of totality, and observers at some of the world’s great astronomical observatories got in on the fun. This is the first total solar eclipse visible anywhere since the ‘Great American Eclipse‘ of August 21, 2017. The next total solar eclipse occurs on December 14, 2020, once again across the South Pacific, Chile, and Argentina.

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Filed Under: Celestial Events

Hopping Galaxies in the Bear’s Den

June 20, 2019 by Joe Bergeron Filed Under: Deep Sky

The galaxies M82 (lower left) and M81 in the constellation Ursa Major. Image credit: Joe Bergeron.

So many galaxies, so little time! A good place to begin an evening of galaxy hopping on a northern spring or summer night is with the Messier galaxies M81 and M82 in the constellation Ursa Major (see above). Conveniently located by drawing a line through the Big Dipper stars Phecda and Dubhe and extending it an equal distance beyond the Big Dipper asterism, this is probably the finest galaxy pair in the sky. Separated by just 38 arc-minutes, both fit into the low power field of a small telescope. With a 22mm Panoptic eyepiece in my 8″ EdgeHD telescope, I had 93x and a field of view of 45 arc minutes, so I had to slew the mount a little from one to the other to see them both well [Read more…] about Hopping Galaxies in the Bear’s Den

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Filed Under: Deep Sky

The Poet Laureate of Stargazing

May 31, 2019 by Brian Ventrudo Filed Under: Stargazing


Today marks the 200th anniversary of the birth of the great and good American poet, essayist, and humanist Walt Whitman. Sometimes called the ‘father of free verse’, Whitman was often beheld as the key to understanding America as it was in the promising days of late 19th century, after the Civil War. He was also, in my view, the poet laureate of stargazers everywhere, especially on account of two of his poems ‘When I Heard the Learn’d Astronomer’ and ‘A Clear Midnight’, reproduced below for your reading pleasure.

“A Clear Midnight”
This is thy hour O Soul, thy free flight into the wordless,
Away from books, away from art, the day erased, the lesson done,
Thee fully forth emerging, silent, gazing, pondering the themes
thou lovest best,
Night, sleep, death and the stars.

“When I Heard the Learn’d Astronomer”
When I heard the learn’d astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts and diagrams, to add, divide, and measure them,
When I sitting heard the astronomer where he lectured with much applause in the lecture-room,
How soon unaccountable I became tired and sick,
Till rising and gliding out I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.

Or enjoy the latter poem in the video format below (which is likely the only time you will ever see a video from ‘Breaking Bad’ on this website):

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Filed Under: Stargazing

Emergent Crystals

May 9, 2019 by Brian Ventrudo Filed Under: Science

We normally cover really big things in these pages, things like planets, stars and galaxies. But the cosmos is ultimately built from very small bits and pieces that organize themselves on a tiny scale that are at least as beautiful as anything to be seen in the night sky. This video, created by Beauty of Science, shows at an accelerated pace the formation of six kinds of crystals out of solution. Whereas many astronomical objects coalesce because of gravity, these crystals are made from a beautiful interplay of electric forces, geometry, and quantum mechanics. Quite a beautiful sight!

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Filed Under: Science

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