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.


Red Jellyfish Sprite Over Mediterranean Sea

February 09, 2022

GrosJellycarre_compress98

Photographer: Arnaud Besançon

Summary Authors: Arnaud Besançon; Cadan Cummings

This breathtaking photo taken on the night of November 24, 2021,
captures red “jellyfish” sprites as seen from the Grand Ballon
mountain (4500 ft / 1400 m) in Eastern France. Grand Ballon translates
“great round-topped mountain” and it is the tallest elevation in the
Vosges. Sprites are electrical discharges that appear high in the
atmosphere and are prompted by severe thunderstorm activity. The
storm cells from which these sprites originated were located to our
south over the Mediterranean Sea. With the help of Serge Soula from
the Aerology Laboratory ( National Center for Scientific Research
and Paul Sabatier University), both the distance and power of these
sprites were able to be accurately determined. The event was generated
by four parent arcs that were respectively 352, 363, 384, and 381 miles
(567, 585, 618 and 614 km) away. Their power was also determined to
vary with each emitting 61, 153, 62 and 44 kiloamperes. This specific
storm cell was very intense, which likely explains why I had
previously never captured so many sprites in one night!
* Grand Ballon, Alsace, France Coordinates: 47.9010, 7.0982

Related EPODs

Red Jellyfish Sprite Over Mediterranean Sea Warning! Snow
Squall Slices Through Utah Shelf Mushroom on Cottonwood Tree
Ribbon Lightning Over the Czech Republic Desert Monsoon in
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Severe Weather Links

* World Severe Weather Information Center
* Enhanced Fujita Scale
* A Lightning Primer
* More About Thunderstorms
* Staying Safe Outdoors in Severe Weather
* NOAA Storm Prediction Center
* Patterns of Lightning Activity
* US National Weather Service

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

https://epod.usra.edu

--- up 9 weeks, 3 days, 20 hours, 43 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)

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.


Ice Blade in Bucket

March 09, 2022

IceSail_20220111_083516 (003)

Photographer: Pierre Renoult

Summary Authors: Pierre Renoult; Jim Foster

Imagine my surprise when one morning earlier this winter I found a
large piece of ice protruding from a bucket of water left out overnight
on the terrace of my home, in Aurillac, France. The day before it
rained most of the day, and then the sky cleared allowing overnight
temperatures to plummet below the freezing point. By the next morning,
I couldn’t open my mailbox as it was frozen. This protrusion had an
obvious slope and was about 16 inches (40 cm) in length.

Once the sky cleared, fast freezing or “ supercooling” of the water
in the bucket took place. When water is confined in small places, such
as a pool or a bucket, the water freezes first along the edges and so
water in the center is slightly raised with respect to the sides. As
ice expands beneath the surface it forces out the remaining liquid
through the hole at center. This is where the hollow ice blade emerged.
Different shapes can be observed, including spikes, sails and
needles. The size of the pool of water, just how it’s confined, and
differential freezing rates all play a role in determining if
protrusions will form and just what shape they'll take.

It’s worth noting that because ice expands in crystalline planes,
protrusions commonly occur at similar angles, typically about 60
degrees to the ice-covered surface. If you have a frost-free
freezer, maybe you've noticed that sharp spikes sometimes form on ice
cubes. Photo taken on January 11, 2022.
* Aurillac, France Coordinates: 44.9310, 2.4450

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Ice Blade in Bucket Archive - Heart-Shaped Opening of a
Michigan Ice Cave Archive - Rupturing of Perito Moreno Glacier
Bridge Plate Crystal with Simple Extensions Archive - Deep Blue
Abyss on Godwin's Glacier Archive - Frost Crystal Congregation
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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 1 week, 2 days, 20 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)

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.


Twilight Comparison at Curitiba, Brazil, Before and Post Eruption of
Hunga Tonga

September 09, 2022

Ep2016-07-07 e 2022-06-12 - Sol a -11 graus

Photographer: Fabiano Belisário Diniz
Summary Author: Fabiano Belisário Diniz

Shown above is a dramatic comparison between a normal twilight and a
volcanic twilight as observed from Curitiba, Brazil, on July 7,
2017 (top) and on June 12, 2022 (bottom). Ash from the Hunga
Tonga volcano played a major role in enhancing the dusk colors on
the 2022 photo. Note that both photos were taken when the sun was 11
degrees below the horizon in Curitiba. Many places in the southern
hemisphere, and elsewhere, have been experiencing particularly
colorful twilights since late January, some two weeks after the
eruption.

Photo details: Although both photos show the same stage of twilight
(sun at -11 degrees), the city lights appear fainter in the bottom
photo because I used a graduated filter with the dark portion facing
down.


Curitiba, Brazil Coordinates: -25.4372, -49.2700

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a Tower Atacama Desert and Volcanic Twilight
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Atmospheric Effects Links

* Atmospheric Optics
* Optic Picture of Day: Gruppo Astrofili Galileo Galilei
* 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 27 weeks, 4 days, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)

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.


Cloud Shadow Projection over Novi Ligure, Italy

November 09, 2022

Nuvola e ombra (2)

Photographer: Valter Luna

Summary Authors: Valter Luna; Jim Foster

The photo above showing an eye-catching cloud shadow was captured
from my home in Novi Ligure, Italy on July 30, 2022. Shadow projections
such as shown here are formed when a shadow is cast upon a layer of
thin dust or haze. The scattering angle of sunlight by the
aerosols within the layer plays a role in observing the projected
shadows. Typically, you’ll have more success seeing them if you’re
looking in the vicinity of the Sun – about 10 degrees away or about the
width of your fist when extended as arm’s length. Also, it seems that
they can be seen more often in cumulus congestus clouds than in
other cloud types.

Photo details: Nikon D100 camera; Sigma 18-250 lens; 50mm; 1/200 second
exposure; f / 16; ISO 200.


Novi Ligure, Italy Coordinates: 44.7620, 8.7859


Recent EPODs

wafer_thin_moon_and_pumpkin_sky
the_primeval_rocks_of_unicorn_point
paraselene_antares_and_supermoon
two_types_of_bewildering_sunset_mirages
lamiaceae_family_of_aromatic_flowering_plants
meteors_from_fragments_of_chang_zheng_2f_rocket_launch
-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 36 weeks, 2 days, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)

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.


Crystal Forms in Petrified Wood

December 09, 2022

TomMc_EPODImage2.WolverineLoopPetrifiedForest2022#2 (003)

TomMc_EPODImage1.PetrifiedWoodWolverineClose2022#1 (003)

Photographer: Thomas McGuire

Summary Author: Thomas McGuire


Grand Staircase National Monument is a spectacularly rich geologic
area in remote southern Utah. Within this monument, Wolverine
Petrified Forest, shown above at top, features silicified (petrified)
tree trunks and sections. The variety of colors is caused by iron
oxide and other oxide minerals.


In the bottom photo, the geometric forms at right are dark stained
quartz crystals that probably grew by groundwater deposition in
openings called “ vugs.” Quartz is extremely common, but visible
quartz crystals less so. When an igneous rock cools and
crystallizes, quartz is the last common mineral to harden, so it
usually fills in the irregular openings between previously formed
minerals including feldspar, mica, amphibole and pyroxene. What
surprised me was the texture on this expose surface. The radial forms
at the bottom of the photo are new to me, and I have yet to understand
how they formed. Photos taken in July 2022.



Grand Staircase National Monument, Utah Coordinates: 37.799633,
-111.214906


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at Wyoming’s Fossil Butte Wagon Tracks from the Old West?
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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
* MyShake - University of California, Berkeley
* 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 40 weeks, 4 days, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)