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.


Auroral Dunes Observed Over Norway

August 20, 2021

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Photographer: Geir T. Birkeland Oye

Summary Author: Geir T. Birkeland Oye; Cadan Cummings

The astounding photos above show a unique and newly named atmospheric
phenomenon called auroral dunes. Named after their visual
similarity to sand dunes, these wavy, green sheets of aurora
occur between 65-80 degrees latitude and 50 - 75 miles (80-120 km)
in altitude in the auroral mesosphere-lower thermosphere-ionosphere
(MLTI). Mesospheric studies are difficult to conduct because the
altitude is too high for balloons and below the altitude satellites
orbit, thus causing this region of the atmosphere to be nicknamed the
ignorosphere. For years, viewers in the Arctic have observed these
colorful dune-like auroras without the ability to fully explain them.
In 2018, new insights into what causes this type of aurora were
unveiled when several teams of citizen scientists across Finland and
Sweden worked together to photograph and triangulate their
location. Their research findings suggested that auroral dunes are
likely a type of atmospheric gravity wave- called a mesospheric
bore- that gets trapped in the mesosphere at approximately 60 miles
(100 km) in altitude and illuminates when interacted with solar
wind particles. Although mesospheric bores would likely be extremely
difficult to observe in the Arctic due to interference from airglow
and nightglow events, the proposed mechanism for auroral dunes is
supported by their approximately 45 km wavelength and high incidence in
this very thin layer of the atmosphere. Photos taken January 22,
2012.

Photo Details: Sigma 15mm fisheye lens, Canon EOS 500D, ISO: 1600,
various exposure times.
* Ørsta, Norway Coordinates: 62.1981, 6.1276

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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 15 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.


Altair

October 20, 2021


Altair_4minMod6DDSLR_ChumackHRweb (004)

Photographer: John Chumack

Summary Author: John Chumack; Jim Foster

Altair, one of the brightest stars visible during summer (in the
Northern Hemisphere), gets relatively little attention compared to
stars such as Vega and Antares. Nonetheless, it has a stunning
background star field. Also designated α Aquilae (Alpha Aquilae), it’s
the brightest star in the constellation of Aquila (The Eagle) and
the twelfth brightest star in the night sky. Altair is relatively close
by our solar system --16.7 light-years ( 5.13 parsecs) away. It’s
approximately 1.8 times the mass of the Sun and 11 times as
luminous.

The southernmost star of the vertices that form the “ Summer
Triangle” asterism, Altair is visible nearly all summer and well into
autumn. Look for it now in the western sky, just after sunset. Photo
taken on August 2, 2020.
Photo details: TPO 12-inch F4 Newtonian reflector telescope; Modified
Canon 6D DSLR camera; Baader Coma Corrector; Bisque ME mount; ISO 800;
4-minute exposure.
* Dayton, Ohio Coordinates: 39.7589, -84.1916

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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 6 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 - Bountiful Autumn

November 20, 2021

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Every weekend we present a notable item from our archives.

This EPOD was originally published November 28, 2013.

Photographer: Jeanette Stafford
Summary Author: Jeanette Stafford
Folklore suggests that a bountiful crop of hawthorn berries
( haws) in the autumn predicts a severe winter ahead. However, this
year’s glut of berries and soft fruits is the result of unusually
cold weather in the first half of the year. Thus, spring arrived
several weeks late. Temperatures in the UK during March 2013 were about
6 F (3.3 C) below average, making it colder than the preceding three
winter months and the coldest March in 50 years. The unusually cold air
inhibited plant growth and delayed blossoming by around six weeks for
some trees and plants, such as hawthorns ( Crataegus monogyna).
Hawthorne Hawthorn or “ may” usually flowers during the month of
May, at least here in Scotland (at left). This year the hawthorn didn’t
bloom until June, the latest I’ve ever observed. Once the risk of
frost damage passed, blossoms were quite abundant. Now that the
leaves have dropped, hawthorn trees are laden with crimson berries, a
plentiful harvest for birds and other wildlife.
Unusually cold spells in the British Isles often occur when a
climatic pattern called the North Atlantic Oscillation (NAO)
experiences an extreme negative phase. March 2013 as well as the cold
winters of 2009/2010 and 2010/2011 all had acutely negative NAOs. Time
will tell if cold conditions prevail during the coming winter. Should
this in fact happen, those who espouse folklore may well feel
vindicated. Top photo taken on October 14, 2013.

Photo details: Top - Camera Model: PENTAX K-5; Focal Length: 42.5mm
(35mm equivalent: 64mm); Aperture: f/4.5; Exposure Time: 0.0080 s
(1/125); ISO equiv: 100. Inset - same except: Aperture: f/8.0; Exposure
Time: 0.0016 s (1/640); ISO equiv: 200.
* Mugdock Country Park, Scotland Coordinates: 55.973306, -4.330566

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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

--- up 1 week, 1 day, 16 hours, 24 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.


Meteor Panorama and Zodiacal Light From Greece

December 20, 2021

SandToDustSMALLER

Photographer: Tomas Slovinsky, Petr Horalek, Josef Kujal

Summary Author: Tomas Slovinsky

This photo showcases the Perseid meteor shower from a beach near
Crete, Greece. During this past August, I along with my friends
Petr Horalek and Josef Kujal captured five days of meteors.
Although people typically like spending time near lagoons and
beaches while on vacation, observing a meteor shower from these
beautiful destinations makes them even more epic. Up to 232 meteors
were captured during five clear nights of viewing around the event
maximum. I registered the meteors into the panoramic background image
above from the same beach. In addition to the meteors, zodiacal
light is also visible across the sky as well as gegenschein between
Jupiter and Saturn. Both of these atmospheric phenomena are a
consequence of interplanetary dust reflecting sunlight. It is
interesting to consider how many splendid and magical views can be
produced by these particles of dust. Photos taken August 9 to 14,
2021.

Photo details: Canon 6D mod, Sigma Art 28mm for panorama; Canon 6D,
Samyang 12mm (x3) for meteors; Tracked HaRGB Panorama, Registered
meteors
* Crete, Greece Coordinates: 35.240, 24.809

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