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.


Double Rainbow Over LaJolla, California

January 20, 2020

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Photographer: Jim Grant
Summary Authors: Jim Grant; Jim Foster

This surf shack in La Jolla, California, on Windansea Beach, is
splashed with color from a beautiful double rainbow I observed on
Christmas Day. I had been trying to frame such a rainbow for at
least 10-years and finally, everything fell into place early in the
morning on December 25, 2019. It’s worth mentioning that this shaggy
shack is considered a historic landmark in La Jolla.

Double rainbows are frequently observed but not often are both the
primary and secondary bows so showy from horizon to horizon.
Note the supernumerary bows beneath the primary bow, just above the
top of the shack. At upper right, brown pelicans cruise over the
shoreline.
* Windansea Beach, California Coordinates: 32.8312, -117.2811

Related EPODs

Double Rainbow Over LaJolla, California Encore - Green Flash
Turning Blue Paraselene and Pooch Alpenglow and Moonrise
Anticrepuscular Rays Observed Over Miami Beach, Florida Sunrise
Sequence Observed from Sicily
More...

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 7 weeks, 2 days, 14 hours, 54 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.


Cattle Point, Oak Bay, British Columbia

February 20, 2020

222

Photographer: Stu Witmer
Summary Author: Stu Witmer

Named for being the delivery place for barges of livestock to the local
farms in years past, Cattle Point is now a popular park and
boat-launching site on Haro Strait between the San Juan Islands
of Washington state (seen in the distance) and the Saanich
Peninsula of Vancouver Island, British Columbia.
Characteristic of the Victoria area and recognizable by its
alternating bands of light ( quartz and plagioclase feldspar)
and dark ( hornblende) layers the rock here is metamorphosed
sedimentary and volcanic rock of the Colquitz gneiss.
Glacial erosion processes, including abrasion, frost
wedging and plucking, have produced a landscape known as roche
moutonnée (sheep-like rock). Also in the area are erratic boulders
of granodiorite which were carried here by glaciers of the
Fraser Glaciation 25,000 to 10,000 years ago.
Apparently, this is also a popular area to feed the birds. Note the
crows in the foreground waiting for me to toss them some more
almonds. Photo taken January 7, 2020.
Photo Details: Camera: Samsung SM-G960U; Exposure Time: 0.0003s
(1/3585); Aperture: ƒ/2.4; ISO equivalent: 50; Focal Length (35mm): 26.
* Cattle Point, British Columbia Coordinates: 48.4383, -123.2946

Related EPODs

Cattle Point, Oak Bay, British Columbia Encore - Tufa
Formations at Winnemucca Dry Lake, Nevada Archive - Sulfur
Sandstone Towers Landmannalaugar, Iceland Archive - Soft
Sandstone on the Oregon Coast
More...

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, 15 hours, 25 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.


Differential Erosion on Ice

March 20, 2020

Sawyer Glacier bergie bit_sm
Photographer: James J. Van Gundy
Summary Author: James J. Van Gundy

This approximately 30 foot (9 m) diameter chunk of ice was calved from
the active front of South Sawyer Glacier, a tidewater glacier
that sits at the head of the Tracy Arm fjord in southeastern
Alaska. A house-sized chunk of calved ice such as this is often
referred to as a bergie bit in distinction to smaller, piano-sized
chunks called growlers and even smaller sized fragments that are
referred to in the aggregate as brash ice.

This particular piece of ice has been rotated approximately 90 degrees
from right to left from its original orientation on the face of the
glacier. Ice from mountain glaciers is typically stratified with
layers of dense clear blue ice alternating with thin layers of
sediment and layers of white ice filled with air bubbles. These
different layers absorb, transmit, and scatter sunlight to
different degrees. For example, the blue-colored ice absorbs nearly
all of the long wavelengths of visible light (red, orange, yellow).

Ridges and valleys have been eroded into the surface of this ice
mass from differential melting by sunlight. Some layers absorb more
solar energy than others and therefore melt faster. The resulting
surface looks rather like a satellite view of the ridge and valley
section of the central Appalachian Mountains, a landscape dominated by
elongate ridges of resistant rocks and parallel valleys eroded into
softer rocks. Although the two landscapes are very different in terms
of spatial scale, time scale, materials involved, and erosive
agents, the basic process of different rates of erosion on
materials of differing erodibility remains the same. Photo taken on
August 16, 2018.
* South Sawyer Glacier, Alaska Coordinates: 57.848227,
-133.113857

Related EPODs

Differential Erosion on Ice Path of the Sun on the Days of the
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Archive - Sheep Mountain Anticline Mulaku Atoll, Maldives
More...

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, 2 days, 14 hours, 5 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.


Encore - Position of the Setting Sun

June 20, 2020
Sun1 copy
Sun2 copy
Sun3 copy

August 2014 Viewer's Choice Today and every Saturday Earth Science
Picture of the Day invites you to rediscover favorites from the past.
Saturday posts feature an EPOD that was chosen by viewers like you in
our monthly Viewers' Choice polls. Join us as we look back at these
intriguing and captivating images.

Photographer: Randall Scholten
Summary Author: Randall Scholten
This series of photos shows the progression of the point of sunset as
it occurs on the western horizon at Port Orford, Oregon. The
photos were taken on three consecutive nights (August 7-9, 2014)
looking out across the Pacific Ocean toward the islands and rocks of
the Orford Reef. These islands are 5 mi (8 km) from shore. The
island on the right is Arch Rock.

At this time of year and from this location, the Sun sets at
approximately 293 degrees, and 0.4 degrees farther south every day and
1 minute and 20 seconds sooner. This change will increase as the
autumnal equinox gets closer (September 23). Then the point at
which the Sun sets (270 degrees) will change by .53 degrees, and will
be 1 minute and 47 seconds earlier.

During the solstices, when the direction of movement of the
sunset’s location reverses, there's very little movement of that
point and very little change in the length of day. The inclination of
the Earth's rotation axis causes the position of sunset and sunrise
to change every day. The maximum angular distance between two sunsets
is the angle between two solstices. This angle changes with the
latitude of the location. It's minimum at the equator (where
it's equal to twice the ecliptic obliquity). After that the angle
increases according to the absolute value of the latitude until it
causes the midnight Sun in polar areas.

Photo Details: Nikon D810 camera; 1/125 sec. exposure; f/6.3; ISO 200;
sigma 50-500 mm - f/4.0-6.3 zoom lens at 500 mm. Source of azimuth,
sunset times: SunEarthTools.com.
* Port Orford, Oregon Coordinates: 42.751337, -124.5084847

Related EPODs

Encore - Position of the Setting Sun Mount Ararat at Sunset
Acatenango and Fuego Sapphire Cove and Approaching Storm
Southern Andes of Santa Cruz, Argentina Artist’s Palette in
Death Valley
More...

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 21 weeks, 3 days, 16 hours, 4 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.


Comet Neowise Seen from Arches National Park

July 20, 2020

Comet Neowise

Photographer: Terrence Cook
Summary Author: Terrence Cook

Shown above is Comet Neowise framed by one of the arches at
Arches National Park near Moab, Utah. This was a fun challenge. To
find this faint comet I needed to leave Moab at 3:45 a.m. on the
morning of July 8, 2020, in order to be assured of arriving as the
comet was rising with the Sun. My goal was to align the comet
through one of the park’s famous windows. A band of clouds on the
horizon blocked my scouting opportunity so I decided to set up camp at
North Window in hopes that something might appear. A few minutes
later an obvious tail came into view.

Note that Neowise is now an evening apparition. When the Big
Dipper can be seen, look for Neowise close to the western horizon,
between where the Sun has just set and the Dipper. You'll likely need a
pair of binoculars to detect it. Neowise is the nickname for this
comet, discovered by the Near-Earth Object Wide-field Infrared
Survey Explorer.
* Arches National Park, Utah Coordinates: 38.68571, -109.53282

Related EPODs

Comet Neowise Seen from Arches National Park Big Dipper and the
Seasons The Carbon Star T-Lyrae M51 and Group Colorful
Sirius Lunar Libration Observed from Sicily, Italy
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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 4 days, 15 hours, 25 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.


Noctilucent Clouds Observed from Paris, France

August 20, 2020

1a

3a

Photographer: Bertrand Kulik
Summary Authors: Bertrand Kulik; Jim Foster

The photos above showing noctilucent clouds were captured at 11:10
p.m. on July 5 (2020), from my home in Paris, France. These
night-shining clouds are composed of water ice that forms as water
vapor condenses around tiny particles in the upper atmosphere. They
can only be observed if the upper atmosphere ( mesosphere) is
sufficiently cold and if the Sun is at the proper angle to
illuminate them -- between 6 and 16 degrees below the horizon. Because
the mesosphere is counter-intuitively coldest (120 degrees C or about
150 kelvin). in late spring, noctilucent clouds are most frequently
reported at this time of year and also in early summer. The photo at
bottom is a close-up that shows some wavy characteristics of these
particular clouds.

Photo Details: Top - Camera Canon EOS 5D Mark III; Software Adobe
Photoshop 21.2 (Windows); Exposure Time 1.600s; Aperture ƒ/5.0; ISO
400; Focal Length 100.0mm. Bottom - same except: Exposure Time 5.000s;
Aperture ƒ/5.6; Focal Length 400.0mm.
* Paris, France Coordinates: 48.8583, 2.2945

Related EPODs

Noctilucent Clouds Observed from Paris, France Archive -
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More...

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 5 weeks, 15 hours, 25 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.


EPOD 20th - The Mysterious Moving Rocks

September 20, 2020

MYSTERIOUSMOVINGROCKS
We’re celebrating 20 years of Earth Science Picture of the Day during
the month of September! Today’s photo features a popular EPOD from the
past. Thanks to all of our followers (on the blog, Facebook, Instagram
and Twitter) for supporting us. Thanks also to all of you who’ve
submitted your photos. We’re most appreciative. This EPOD was
originally published March 5, 2002.

Provided by: Joe Orman
Summary author: Joe Orman

In a remote corner of California's Death Valley National Park, on the
floor of a dry lakebed called Racetrack Playa, can be seen the
geological oddity of the sliding stones. While the force of gravity
easily explains how dozens of rocks -- weighing up to 700 pounds --
could have fallen from the adjacent hillsides onto the margins of this
long-vanished ancient lake, it cannot explain how the rocks have moved
far out onto the perfectly flat surface.

No one has ever seen the rocks actually move, but the evidence is
indisputable: distinct tracks in the hard clay surface, some extending
for hundreds of feet. Some of the grooves are arrow-straight, while
others curve, take sharp turns, or even make complete loops.

For decades scientists have plotted the tracks, analyzed the soil, and
charted the weather in an attempt to solve the mystery. All of the
theories involve extremely strong winds, but they differ on the exact
physical process that allows the rocks to overcome friction. Is the
answer mud, water, ice -- or some combination of these? What is clear
is that the Racetrack is a unique opportunity for science to explain
what at first appearance seems to be completely inexplicable.

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

https://epod.usra.edu

--- up 3 weeks, 5 days, 20 hours, 20 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.


Iceberg Lagoon

October 20, 2020

Salvatore Cerruto B

Photographer: Salvatore Cerruto
Summary Authors: Salvatore Cerruto; Stu Witmer

Iceland is truly a geologically rich land. The Jökulsárlón
(Icelandic for glacial river lagoon) holds great charm for visitors.
This lagoon is populated by icebergs that originate from the
Breiðamerkurjökull glacier, an arm of the massive
Vatnajökull Ice Cap, the largest ice cap in Europe. In 1935
increasing amounts of silt began to build the lagoon which then
grew quickly. Today, erosion continues to increase the area of the
lagoon. Breiðamerkurjökull was formed during the Little Ice Age (c
1300 -1850). When I saw the iceberg pictured above, I was amazed by the
colors that stood out like a diamond on a gray day. Standing there
looking at it for a while I began to feel a very strong connection with
nature.
* Jökulsárlón, Iceland Coordinates: 64.070278, -16.211667

Related EPODs

Iceberg Lagoon EPOD 20th - Rideau River Pancake Ice EPOD
20th - Lake Michigan Ice Balls Recurrence EPOD 20th - Hair Ice
EPOD 20th - Snow Crystals In February Snowfalls EPOD 20th -
Microscopic View of Frost on Blade of Grass
More...

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 8 weeks, 20 hours, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)