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

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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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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.


Archive - Glacial Evidence in Central Park

April 09, 2022

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Every weekend we present a notable item from our archives.

This EPOD was originally published on September 25, 2014.

Photographer: Bruce Gervais
Summary Authors: Bruce Gervais; Jackie Phillips

There's ample evidence of New York City’s glacial history
throughout Central Park. The top photo shows two glacial
erratics. These large boulders were transported by moving ice at the
height of the Wisconsin glaciation, around 20,000 years ago. During
this time the Laurentide ice sheet covered what is now New York
City to a depth of about 1,000 ft (300 m). As the ice sheet flowed over
the landscape it smoothed the bedrock through abrasion and
plucked fragments of rock from the ground. These plucked fragments were
incorporated into the base of the moving ice and transported by it.
After the ice sheet melted, some 12,000 years ago, many fragments were
scattered throughout the landscape.

Nycglacialrock2

The lower photo shows an elongated asymmetrical landform called a
roche moutonnee. The axis of roches moutonnees indicates the
direction of ice flow. In this photo, the ice flowed from left to
right. These landforms are ubiquitous in the park and were cleverly
incorporated into its design. Photo taken on July 22, 2014.

Photo details: Top - Camera Maker: Panasonic; Camera Model: DMC-TS3;
Focal Length: 4.9mm (35mm equivalent: 28mm); Aperture: f/3.3; Exposure
Time: 0.0063 s (1/160); ISO equiv: 100. Bottom - same except: Focal
Length: 8 mm; Aperture: f/4.5; Exposure Time: 1/80 s; ISO equiv: 160.
Photo stitch program: Microsoft ICE.
* Glacial Erratic, Central Park Coordinates: 40.769358, -73.975933

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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 5 weeks, 5 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.


Sun Pillar Reflection on the Holtsós Lagoon

May 09, 2022

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Photographer: Gianluca Lombardi

Summary Authors: Gianluca Lombardi; Cadan Cummings

The photo above taken on the Holtsós Lagoon in Southern Iceland
highlights the calm wind moving across the water and a sun pillar
on the horizon. Due to the calm waters, a reflection of the sun pillar
is clearly visible on the lagoon along with the silhouette of the
Vestmannaeyjar (Western Islands). A sun pillar is a form of optical
phenomenon caused when hexagonal shaped ice crystals suspended in
the atmosphere are oriented horizontally and reflect incoming sunlight
toward an observer. Pillar hue can vary based on environmental
conditions, such as cloud cover and Sun color. The silence and
calm made everything very surreal.
* Holtsós Lagoon, Iceland Coordinates: 63.5370, -19.7494

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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 10 weeks, 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.


Rainbow Flashes

June 09, 2022

Rainbow Flahes on Dschubba and Mars

Photographer: Dario Giannobile

Summary Author: Dario Giannobile

This photo compilation features an optical effect called Green
Flash for the planet Mars and star Dschubba. Green ray is a
phenomenon caused by the refraction of incoming light as it passes
through thick layers of the atmosphere. Shorter wavelengths refract
more strongly than longer red wavelengths, and color separation gives a
green hue to the last visible ray of our luminous object. Green ray
evidence is extremely common on the solar disk but much rarer on the
Moon and planets. Even more peculiar is a separation of the light
that can lead to the observation of a blue-tinted flash. A
telescope or telephoto lens and camera can help capture this
tantalizing result of atmospheric refraction when celestial bodies are
close to the horizon. This one-of-a-kind image shows for the first time
the phenomenon in its entirety during the rising of the star Dschubba
of the constellation Scorpius (delta Scorpii). Various flashes
have been created around the star that have taken on the tints of the
rainbow, shifting from red (in the lower edge of the star) to blue /
purple in the upper edge. The same phenomenon happened shortly after
during the rising of Mars which presented different flashes and colors
mainly of red and green.
* Sampieri, Sicily Coordinates: 36.7219, 14.7370

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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 14 weeks, 3 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.


Ancient Fossil Assemblage Discovered in Utah

August 09, 2022

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JoeB_1 (18)

Photographer: Joe Bauman

Summary Author: Joe Bauman

While hunting trilobites in 1994, my son, Sky, and I came upon a
Cambrian site in Utah that at first seemed unpromising. But decades
later, when I resumed studying rocks picked up there, it became obvious
that this is one of the world’s most remarkable Lagerstätten
(extraordinary fossil assemblages) formations, with exceptional
preservation, including soft tissue of ancient lifeforms. Because of
the presence of the sponge-like archaeocyathids, I’m able to date
it to sometime during the Early Cambrian Period, about 540 million
or 530 million years ago. All of the fossils I found at this site are
small, the largest just a few centimeters long; most are far tinier, in
the range of millimeters or less.

Among the remains are leaflike forms, possible holdovers from the
Ediacaran Period of the Precambrian; echinoderms, particularly
carpoids and Gogia, and arthropods. The most astonishing of the
last are fossils preserved within globules of crystal (probably
calcite) or sheathed within it (bottom photo). Remains thus preserved
often show soft material such as legs and internal structures. Note
that insects preserved in amber are at least 200 million years younger.

To protect the site from collectors, it’s important to keep the
location secret from the public. But I’m hopeful that academic
paleontologists will want to know the location and to borrow specimens,
with which I’ll gladly comply. Eventually, many of the specimens I
found will be donated to the Utah Museum of Natural History in Salt
Lake City. Scientists interested in learning more may contact me
at josephmbauman@yahoo.com.

For a fuller description, see my blog at The Early Cambrian: A New
Utah Lagerstätte (the-nightly-news.com)



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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 23 weeks, 1 day, 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
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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
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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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More...

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
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