EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Fascinating Ice Patterns

February 05, 2021

IM2_17297_pe_mid

Photographer: Wayne Robinson
Summary Authors: Wayne Robinson; Jim Foster

On a winter’s, morning walk along the Washington, Baltimore and
Annapolis spur trail, I saw these fascinating patterns in the ice
at the edge of a nearby pond. The low temperature overnight had dropped
to about 27 F (-3 C), and the icy surface looked so unworldly that it
might be mistaken for the surface of one of Jupiter’s moons.
Explaining just how such patterns occur is always challenging. It
seems, though, that in shallow water when air temperatures fall just
below the freezing point, ice crystals form thin sheets that grow
at similar rates but often at different angles. Slight differences in
stress on the ice, from above and below the surface, can lead to an odd
quilt-work of patterns that may please the eye but also baffles the
mind. Note that the entire image width here covers approximately 2 feet
(0.6 m). Photo taken on December 30, 2020.
Photo Details: Canon 80D DSLR camera; Canon f/5.6 70-300 mm lens; f/11;
244 mm fl; 1/100 sec. exposure; ISO 400
* Bowie, Maryland Coordinates: 39.0068, -76.7791

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Fascinating Ice Patterns Angle of Repose for Graupel
Methane Bubbles Frozen in an Alaskan Marsh Dark Spots and
Patterns on Lake Ice Surface Hoar Formation Not all Snow
Crystals are Perfectly Symmetrical
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Cryosphere Links

* Guide to Frost
* What is the Cryosphere?
* Bentley Snow Crystals
* Glaciers of the World
* Ice, Snow, and Glaciers: The Water Cycle
* The National Snow and Ice Data Center Google Earth Images
* Snow and Ice Crystals

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 7 weeks, 2 days, 21 hours, 27 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)

EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Setting Crescent Moon over California

March 05, 2021

Stephe b crescent moon

Photographer: Stephanie Becker
Summary Author: Stephanie Becker

Seen above is the setting waxing crescent Moon as observed over San
Francisco Bay, California. The passing clouds were beautifully
illuminated as the Moon disappeared beyond the hillside. Additionally,
on this midwinter’s eve, earthshine was particularly noticeable.
Photo taken January 15, 2021.

Photo Details: Canon EOS 70D, 0.3s, f6.3, ISO12800
* San Francisco Bay, California Coordinates: 37.86246, -122.38697

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Setting Crescent Moon over California Orion, Geminid Meteors
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Above Pieve di Cadore, Italy The Quadrantids Mars and Moon
Conjunction of October 28, 2020
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Night Sky Links

* Space Weather Live
* Space Weather Live Forum
* About the Moon
* American Meteor Society
* Arbeitskreises Meteore e.V.
* Global City Lights
* Heavens Above Home Page
* The International Meteor Organization
* Lunar and Planetary Institute
* MoonConnection
* NASA Eclipse Web Page
* Understanding The Moon Phases

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 11 weeks, 2 days, 21 hours, 27 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)

EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Einstein's Eclipse, Colorized

April 05, 2021

1919_05_29_TSE_Eddington_Soft_SCAN_light_det_FINAL_1500px
Image Creator: ESO/Landessternwarte Heidelberg-Königstuhl/F. W. Dyson,
A. S. Eddington, & C. Davidson, P. Horálek/Institute of Physics in
Opava, M. Druckmüller
Summary Author: Petr Horálek

The total solar eclipse shown above was observed on May 29,
1919, from Sobral, Brazil. Using a digital scan of this eclipse from
one copy of a photographic plate, part of the Heidelberg Digitized
Astronomical Plates (HDAP) project funded by the Klaus Tschira
Foundation, it was possible to reconstruct the solar corona and
also structures of the huge prominence of this scientifically
important eclipse that helped confirm Einstein’s General
relativity. In order to so, however, we needed to separate real details
from scratches and dust on the scan and focus on sub-threshold
information hidden in a high dynamic range of the original photograph.
Since the eclipse was photographed on a classical photographic
plate and the scan was saved in high quality, it was possible to apply
basic postprocessing methods, which are nowadays used for digital
photography, and also apply special Noise Adaptive Fuzzy
Equalization software developed by Professor Miloslav Druckmüller.
Despite very inhomogeneous exposure of the plate and non-perfect
removal of artifacts, fine details in the solar corona of the 1919
eclipse have been preserved and revealed.
The most notable feature is the huge prominence located close to
the equatorial area of the Sun -- the largest prominence ever
captured during a total solar eclipse. Also of note are structures
typical of the uneven solar magnetic field. When such structures
became more obvious, by defining the basic colors of known phenomena in
the image (prominence, solar corona), it was then possible to colorize
the final result and thus for the first time show this famous eclipse
in a way never seen before.
* Sobral, Brazil Coordinates: -3.6895, -40.3486

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Sun Links

* NASA Solar Dynamics Observatory
* NASA Solar Eclipse Page
* NOAA Solar Calculator
* The Sun-Earth Connection: Heliophysics
* The Sunspot Cycle
* Solar System Exploration: The Sun
* The Sun Now
* This Week’s Sky

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 1 week, 3 days, 22 hours, 10 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)

EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


The Colorado Plateau and a Small Model of Subduction Compression

June 04, 2021


TomMc_EPOD.CottonwoodCanyonRoadUtah copy (005)

TomMc_EPOD.DuctileAndBrittleFoldsPhylliteCT.WallRockB (005)

Photographer: Thomas McGuire
Summary Author: Thomas McGuire

The cause of the uplift and the compressional features on the
Colorado Plateau during the Laramide Orogeny (mountain building
roughly 60 million years ago) were not understood until it was proposed
that the Farallon Tectonic Plate is subducting at a low angle
beneath the North American Plate. This is what raised the whole
plateau. Additionally, compressional folding, including dozens
of asymmetric folds ( Cockscomb, San Rafael Swell, Comb Ridge,
Raplee Anticline, Waterpocket Fold, and many others) was caused by
frictional drag with the remains of the subducting Farallon plate. Many
of the folds are also related to sub-surface compressional
faulting.

Small scale rocks often reflect larger regional features. The top image
is The Cockscomb monocline along Cottonwood Canyon Road in Arizona.
The second image is a rock from Connecticut. What is now western New
England was an area of subduction in the closing of the Ordovician
Pre-Atlantic Iapetus Ocean (about 400 million years ago), which
created the Pangea land mass. This rock is a smaller-scale model of
the Colorado Plateau’s asymmetric compressional folds, like The
Cockscomb. My drawing on the image shows how this smaller rock
represents The Cockscomb (a penny is used for scale).


Cottonwood Canyon Road, Arizona Coordinates: 37.306608, -111.886410


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Geology Links

* Earthquakes
* Geologic Time
* Geomagnetism
* General Dictionary of Geology
* Mineral and Locality Database
* Mohs Scale of Mineral Hardness
* This Dynamic Earth
* USGS
* USGS Ask a Geologist
* USGS/NPS Geologic Glossary
* USGS Volcano Hazards Program

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 4 weeks, 1 day, 12 hours, 15 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)

EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Rainbows Over the Italian Shoreline

July 05, 2021

KSEO9220rinforz

Photographer: Kevin Saragozza

Summary Author: Marco Meniero, Cadan Cummings

Rainbows are undoubtedly one of the atmospheric events that most
strikes the human imagination. This photo of a double rainbow rising
out of the sea was taken in the Province of Syracuse in Italy. The
optics of rainbows was first studied by the mathematician René
Descartes in 1637. From his work in physics, he understood the
mechanism of light passing through water and mathematically determined
the angular position of the primary rainbow (about 42 degrees from the
center point of the rainbow or the antisolar point). The physicist
Isaac Newton further advanced the science thirty years later when
he observed light is reflected at various angles based on the different
wavelengths of the electromagnetic spectrum: red at 42 degrees
and violet at 40 degrees from the center of the arc. Advancing our
understanding of optics and the Earth’s atmosphere, we now
understand that rainbows consist of an arc with the colors of the
visible spectrum from red to violet. These colorful arcs occur 39 to 43
degrees from the antisolar point and are exactly opposite the position
of the sun with regard to the viewer.

A product of both reflectance and refraction, rainbows are formed
when sunlight passes through a water droplet and the light is
refracted, reflected, and then refracted again- like a prism. If two
reflections occur in the water droplet, a second symmetrical
rainbow is formed with a radius varying from 50 to 57 degrees from the
antisolar point.

Both the primary and secondary rainbow are clearly seen in this image.
The image is very poetic and seems to recall the vision of navigators
who went to sea following the atmospheric events without having the
right scientific interpretation. Photo taken April 20, 2021.

Photo data: Canon EOS R, 1/30 second exposure, 16mm, f/8, ISO 800
* Augusta, Province of Syracuse, Italy Coordinates: 37.250000,
15.216667

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Atmospheric Effects Links

* Atmospheric Optics
* Color and Light in Nature
* The Colors of Twillight and Sunset
* Refraction Index
* Image Gallery: Atmospheric Effects
* What is a Rainbow?

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 8 weeks, 3 days, 12 hours, 15 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)

EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Fireflies and Star Trails in Italy

August 05, 2021

StarStaX_IMG_6412-IMG_6613_lighten(2)

Photographer: Elena Paschetto

Summary Author: Elena Paschetto; Cadan Cummings

This composite image consisting of 197 long-exposure photos features
star trails and fireflies taken on a summer night in
Sanfront, Italy. Fireflies emit light in the 510-610 nm portion of
the visible spectrum. This bioluminescent light is used by
fireflies, or lightning bugs, to attract mates. Bioluminescence is
produced when calcium, oxygen, adenosine triphosphate (ATP), and a
chemical luciferin combine in the presence of the enzyme
luciferase. The resulting chemical reaction creates an excited energy
state that emits light and slowly dims as the reaction uses up its
available ATP and oxygen. There are approximately 2,000 firefly species
in the family Lampyridae worldwide. Some types of fireflies are
crepuscular and prefer to only come out at dusk / dawn to limit the
chance of being eaten by nocturnal predators, while others choose to
fly around later at night in complete darkness. As a result, fireflies
pair well with night sky viewing since you can watch in wonderment the
blinking light of the fireflies and the counterclockwise motion of the
stars across the sky. Photos taken on June 12, 2021.

Photo data: Canon EOS 80D; Wide-angle Lens, 14mm, ISO 800, f/3.5, 10
second exposure, 197 photos processed using StarStaX
* Sanfront, Italy Coordinates: 44.647, 7.320

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Animal Links

* Animal Diversity Web
* ARKive
* BirdLife International
* Bug Guide
* Discover Life
* Integrated Taxonomic Information System
* Microbial Life Resources
Earth Science Picture of the Day is a service of the
-
Universities Space Research Association.

https://epod.usra.edu

--- up 12 weeks, 6 days, 12 hours, 15 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)