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.


Grebes Courtship Display

July 27, 2021

Grebes1

Photographer: Mila Zinkova

Summary Author: Mila Zinkova

Western and Clark's Grebes both have a very elaborate courtship
display. It culminates with the male and female rushing over the water,
rising up on the water’s surface onto their feet, side by side
“ with wings held up and back, necks curved, pattering with their
powerful feet in what looks like a perfect bird ballet." Click here
to see a video of this amazing display.

A 2015 study explained the mechanisms that permit the grebes to
“run” as they do: "First, rushing grebes use exceptionally high stride
rates. Second, grebe foot size and high-water impact speed allow grebes
to generate up to 30-55% of the required weight support through water
slap alone. Finally, flattened foot bones reduce downward drag,
permitting grebes to retract each foot from the water laterally."
Running grebes can thus make between 14 and 20 steps per second.



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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 11 weeks, 4 days, 12 hours, 15 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.


Transit of the Sun by the International Space Station and Cicadas

August 27, 2021


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Photographer: Wayne Robinson
Summary Author: Wayne Robinson

The photo above shows a 5-second composite of a transit of the
International Space Station (ISS) passing over the Sun as observed
from my location in Bowie, Maryland. About 8 minutes before I activated
the shutter, among the trillions and trillions of photons emitted
by the Sun (about 1.5x10^43 photons), a very select number - about 4.5
tera photons (4.5x10^12) - made it to my camera's detector. At the
time, the Sun's disk was uniformly bright except for a sunspot
about half-way out from the center -- at the 6:30 position. This spot,
as with all sunspots, is dark due to a relative cooling of the Sun's
surface caused by a local disturbance in its magnetic field.
The ISS took only about 3.4 seconds to cross the solar disk. Note that
at this time it was approximately 870 miles (1,400 km) from the camera.
Just one second before the ISS transit occurred, a pair of winged
creatures, likely periodical cicadas from Brood X, flew past
the solar disk, taking perhaps ½ second to do so, giving the Sun's face
on this exposure a number of curious "eyes." Photo taken June 8, 2021,
at 7:30 p.m. (local time).
Photo details: Canon 80D camera; Canon 400 mm telephoto lens; 2 x and
1.4 x teleconverter.
* Bowie, Maryland Coordinates: 39.0068, -76.7791

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Einstein's Eclipse, Colorized
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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 16 weeks, 12 hours, 15 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.


Armored Mud Balls and Mud Cracks in Southern Utah

September 27, 2021

EPOD.MudballsWirePass

Photographer: Tom McGuire

Summary Author: Tom McGuire; Cadan Cummings

The picture above features armored mud balls and soil cracking taken
near the trailhead of the Wire Pass in Kane County, Utah.
Armored mud balls are spherical soil formations composed of a
mixture of silt, clay, sand, and gravel that form in stream beds or
previously flooded areas. The diameter of mud balls usually ranges
between 2 to 4 inches (5 to 10 cm), but it largely depends on the
soil particles and gravel present. The size of the particles in a
stream bed is directly related to the speed of the water. This
means that when stream water slows down, larger particles like gravel
and sand are deposited first, while smaller soil particles such as silt
and clay can stay suspended in the water until the water is mostly
stagnant. Sediments can be mud where flood water becomes stagnant, or
pebbles deposited in a moderate current. As mud dries, it hardens and
forms tessellated chunks caused by shrinking during
desiccation.

Cracked pieces of soil may be dislodged by wind or water, while the mud
is still wet below the surface. The pieces become round as they are
pushed along the surface. Rolling balls of sticky mud can pick up
pebbles that “armor” them. These armored mud balls were found below the
Buckskin Wash trailhead on the Utah-Arizona border. Mud balls can
also be geologically preserved given the correct environmental
conditions. Such examples include fossilized Triassic mud balls
collected by Professor Richard Little, which are displayed in the
Greenfield Community College Rock Park north of Amherst, Massachusetts.

Photo Details: Olympus E-510: 42 mm, f/9, 1/250 second exposure,
ISO-100
* Kane County, Utah Coordinates: 37.019, -112.025

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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 3 weeks, 3 days, 21 hours, 55 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.


Beautiful Mountain Shadow in Western Italy

October 27, 2021

DAN_0027

Photographer: Daniele Cipollina

Summary Author: Daniele Cipollina; Cadan Cummings

This photo of a beautiful mountain shadow was taken in
Valdieri, Italy near the entrance to the Valasco Refuge. A
product of atmospheric optics and impeccable timing, landscape
shadows appear most prominently in the morning and evening when the Sun
is low in the sky. Note the triangular shape of the shadow projected
from the top of the mountain. Due to perspective, mountain shadows
can appear triangular regardless of the shape of the mountaintop. This
image was taken at 7:41 am local time on August 17, 2021.

Photo data: Nikon Z50 + Nikkor 16/50; focal length 16 mm; ISO 100;
1/320 sec; f: 6.3
* Valdeier, Italy Coordinates: 44.278, 7.395

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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 7 weeks, 5 days, 21 hours, 55 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 - Water Drops and Inverted Images

November 27, 2021

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Every weekend we present a notable item from our archives.

This EPOD was originally published December 24, 2011.

Photographer: Bertrand Kulik
Summary Authors: Bertrand Kulik; Jim Foster
Within these decorative water drops is the inverted image of
the flowers in my garden and my house in Paris, France. A liquid drop
acts as a simple lens, like a camera lens, so the refracted
image is upside-down when viewed through the drop. Note that these
drops have more or less spherical shapes because surface tension
minimizes the surface area of a drop of water or even a falling
raindrop. Photo taken in early September 2011.

Photo Details: Canon EOS 7D camera; 100mm macro lens with macro rings.
* Paris, France Coordinates: 48.856667, 2.350833

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

https://epod.usra.edu

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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.


Moonflower

December 27, 2021

DaleH_moonflower2

Photographer: Dale Hugo

Summary Authors: Dale Hugo

My neighbor couldn’t wait to show me this beautiful moonflower as
she has waited several seasons for the vines to come to maturity and
produce flowers. This was the first one she’d seen — and it was worth
the effort and waiting. But keep them under control as they can spread!

The flower is about 7 inches (~18 cm) across and has a unique,
5-pointed star shape. The fragrance is to me reminiscent of
gardenias. As their name implies, they bloom at night and fold up
at dawn. The moonflower vine, botanically Ipomoea alba, is often
mistaken for its cousins, the morning glory and sweet potato
plant. Moonflowers contains several compounds poisonous to the human
body, including atropine and scopolamine, both of which
interfere with the nervous system.

When I was a teenager, I made money ‘ walking the beans’ — soybeans.
Farmers would hire us to chop out weeds, second growth corn, pumpkin
vines, and morning glories. These vines could grow through a row of
soybeans for a long way, intertwining with the beans and making their
removal very difficult. One had to chop them out with a corn knife — a
machete we field workers carried. Leaving the vining plants would
invariably jam the bean combine. It was like trying to harvest rope!
* Arlington Heights, Illinois Coordinates: 42.0884, -87.9806

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Plant Links

* Discover Life
* Tree Encyclopedia
* What are Phytoplankton?
* Encyclopedia of Life - What is a Plant?
* USDA Plants Database
* University of Texas Native Plant Database
* Plants in Motion
* What Tree is It?

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

https://epod.usra.edu

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