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.


Exact Time of Sunrise and Sunset

February 03, 2021

Capture

Photographer: Dario Giannobile
Summary Author: Dario Giannobile; Marcella Giulia Pace

The beautiful sunset shown above was photographed without using
special filters or lenses to enhance its majesty. It was taken near the
Capo Granitola Light House in Sicily, on August 21, 2020.

Near the horizon, the Sun passes through a dense layer of
atmosphere that attenuates its brightness and makes it appear
red/orange. But this dense layer also generates an apparent slowdown in
the advancement of the solar disk towards the horizon, causing the time
of sunset to be different from that reported in the almanacs that don’t
take into account atmospheric refraction. The amount of time of the
slowing down of a sunset, as well as the anticipation of sunrise, is
different everywhere in the world. Of course, it also depends on the
latitude where you live. At my latitude, the Sun delays its setting by
about two minutes.

Defining this gap in time between the actual and apparent sunrise and
sunset is essential for navigation purposes. Sailors who use
celestial navigation know the importance of this definition. It’s
as important as a GPS signal or the beam of light from a
lighthouse.

Photo Details: Camera: Canon EOS 6D; Software: Adobe Photoshop 21.1
(Windows); Exposure Time: 0.0040s (1/250); Aperture: ƒ/8.0; ISO
equivalent: 400; Focal Length: 283.0mm
* Capo Granitola Light House, Italy Coordinates: 37.56595,
12.66208

Related EPODs

Exact Time of Sunrise and Sunset Total Solar Eclipse of
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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 7 weeks, 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.


Overshooting Storm Top

March 03, 2021

Pablo_PSX_20210116_215520

Photographer: Pablo Barrios
Summary Authors: Pablo Barrios Jim Foster

In most cases when storms ascend through the troposphere, upon
reaching the tropopause, the storm’s top will flatten out, giving
it an anvil shape. However, on occasion, a particularly vigorous
thunderstorm will develop vertically at such a rate that it actually
passes through the tropopause into the lower levels of the
stratosphere, resulting in a noticeable prominence. This is
referred to as an overshooting top.

The tropopause is turbulent and well mixed compared to the more
stratified, and therefore stable stratosphere, where the temperature
increases with altitude. Only the most powerful and fastest developing
storms can protrude into this more stable portion of our Earth’s
atmosphere. The level where the tropopause occurs varies from about 5
to 10 miles (8 to 16 km) but is typically lower as latitude increases.
Additionally, it’s generally lower during the winter season than in
summer. Photo taken from La Carolina, San Luis, not long after
nightfall on January 15, 2021.

Photo Details: Canon T6i camera; 24 mm; f/5,6; 30 sec exposure; ISO
400.
* La Carolina, Argentina Coordinates: -32.80062, -66.09831

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Thunderstorm on the Mediterranean Sea Red Sprites and GHOST
Archive - Southern California Wildfires Archive - Eye Wall of
Katrina
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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 11 weeks, 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.


Volcano Villarrica, the Southern Cross and the Carina Nebula

May 03, 2021

VolcanoAndCrossSMALLer

Photographer: Tomas Slovinsky
Summary Authors: Tomas Slovinsky; Jim Foster
Shown above is my favorite image from a recent visit to Chile; the snow
covered flanks of the Villarrica Volcano (9,380 ft or 2,860 m) and
above it the Southern Cross, just to the left of Villarrici’s
summit. The Southern Cross is an asterism of the constellation of
Crux. Within the striking Cross and directly above the summit, the
dark area called the Coalsack, a massive cloud of light absorbing
dust and gas, is clearly visible to the unaided eye. It’s referred to
as the “shadow of the cross.”

In the upper left corner is another celestial gem of the southern sky,
the red-colored Carina Nebula. This grand nebula is even brighter
that the well known Orion Nebula. Again, it can easily be detected
with the naked eye, but with even minimal magnification, and or
increased exposure, details such as texture and intensity become more
obvious. Image taken on December 16, 2020.


Villarrica Volcano, Pucoón, Chile Coordinates: -39.4203, -71.9396

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Geography Links

* Atlapedia Online
* CountryReports
* GPS Visualizer
* Holt Rinehart Winston World Atlas
* Mapping Our World
* Perry-Castañeda Library Map Collection
* Types of Land
* World Mapper

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

https://epod.usra.edu

--- up 2 weeks, 5 days, 22 hours, 42 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.


Sunrise and Sunset Skies

June 03, 2021

2021 March 12 - Pismo Beach Sunrise after Storm

Teresa_iridiscent cloud

Photographers: Cindy Todd; Teresa Molinaro

Summary Author: Cindy Todd

While hiking on the Ontario Ridge Trail in Pismo Beach,
California, I observed the beautiful sunrise featured above. It had
been stormy for two days before I snapped this picture, but since the
rain had stopped overnight, I decided to take a little hike and was
glad I did as I was rewarded with a stirring sunup. Photo taken on
March 12,2021.

Bottom photo showing an i ridescent sunset was captured from the
terrace of my home in Bagheria, Italy, as mid-level clouds approached
the Sun. Photo taken on February 5, 2021.


Pismo Beach, California Coordinates: 35.1428, -120.6413

Bagheria, Sicily Italy Coordinates: 38.0789, 13.5124


Related EPODs

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Viterbo Airport, Italy
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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 3 weeks, 6 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.


Archive - Washington, D.C. from Space

July 03, 2021

6a0105371bb32c970b011570af88e2970c-600wi

Today's archive EPOD was selected because this weekend is Independence
Day (July 4th) in the United States. Every weekend we present a notable
item from our archives. This post was originally published July 3, 2009
and was updated to reflect the anniversary.

Landsat-7 Satellite Image
Summary Author: Jim Foster

The Landsat-7 satellite image above features the capital city of
the U.S., Washington, D.C. Tomorrow, the U.S celebrates the 245th
anniversary of its independence. From its inception, Washington,
which sits at the confluence of the Potomac River (lower left) and
Anacostia River (right center), was built to serve as the capital
of the fledgling nation. Pierre Charles L’Enfant originally designed
the layout of the city streets.

The U.S. Capitol can be discerned near the center of the image, the
Washington Monument and Lincoln Memorial are at left center – directly
to the left (west) of the Capitol. Just southwest of the Lincoln
Memorial, across the Potomac River in the state of Virginia, is the
Arlington Memorial Cemetery. The emerald green peninsula to the south
of the Capitol is East Potomac Park. At the top left of this image, the
dark green strip is Rock Creek Park, which noticeably contrasts with
the bright white of adjacent buildings and homes.
The donut-like structure to the right (east) of the Capitol is Robert
F. Kennedy Stadium. Portions of the state of Maryland can be seen at
upper left and also at lower right.

This is a natural-color image composed of several bands in the visible
portion of the electromagnetic spectrum. Image acquired May 9, 2005.
* Washington, District of Columbia Coordinates: 38.907, -77.037

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Geography Links

* Atlapedia Online
* CountryReports
* GPS Visualizer
* Holt Rinehart Winston World Atlas
* Mapping Our World
* Perry-Castañeda Library Map Collection
* Types of Land
* World Mapper

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

https://epod.usra.edu

--- up 8 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.


Volcanoes in New Mexico

August 03, 2021

Petroglyphnm_small

Photographer: Tom Wildoner

Summary Author: Tom Wildoner

Volcanoes in New Mexico? Indeed there are volcanoes, however,
they have been inactive for over 150,000 years. The volcano in the
image above is named the Black Volcano and it is located 5 miles (8
kilometers) outside Albuquerque, New Mexico. This inactive volcano
is part of the Petroglyph National Monument and is one of five
inactive fissure volcanoes in the region. The protected monument is
composed of a dark basalt rock, on which native populations have
scribed over 25,000 petroglyphs. These intricate rock carvings have
since become the namesake for the national monument and the surrounding
landmarks. In addition to Black Volcano, you can also see a smaller
volcano on either side of Black Volcano in my image, Vulcan and JA
Volcanoes.
* Albuquerque, NM Coordinates: 35.132448, -106.772687

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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 12 weeks, 4 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.


Archive - Gurgler Glacier

October 02, 2021
6a0105371bb32c970b01b7c85d7cfd970b

Every weekend we present a notable item from our archives.

This EPOD was originally published May 23, 2016.
Photographer: Klaus Sandforth
Summary Author: Klaus Sandforth

May 2016 Viewer's Choice Shown above are several ski
mountaineers entering the Gurgler Glacier in the Ötztaler Alpen
(Eastern Alps) of Austria. What looks at first sight like a classic
glacier snout is dead ice of the retreating Gurgler Glacier,
not far from Schalfkogel Peak, where the group is heading to climb.
Dead ice is forming in receding glacial environments, where
distinct ice bodies get separated from the main glacier. Note the
slightly stratified but mostly crystal clear ice here. The rippled
surface texture might be caused by differential melting and
sublimation due to warm air currents, particularly in spring and
summer. The surface of the ice is perfectly smooth and appears to
be polished. This structure is rather temporary and fragile as it
developed only a few years ago and will likely fade away just as
quickly. Our passage might seem dangerous, but during the winter season
when temperatures are generally below freezing level, it’s a pretty
safe place to stay.
Like many glaciers in the Alps, the Gurgler Glacier lost much of
its mass in the last 150 years and is now retreating on average a
few tens of meters every year. Climate change and glacier retreat
in the Alps has both ecological and economical impacts. Glaciers
attract tourists and also provide natural water reservoirs and
hydropower. Photo taken on March 17, 2015.
Photo Details: Apple iPhone 4S back camera; 35 mm focal length; ƒ/2.4
aperture; 1/1126 sec. exposure; ISO 50.
* Gurgler Glacier, Austria Coordinates: 46.8193, 10.9756

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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 4 weeks, 2 days, 21 hours, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)