Auroras
by Rachel Lense
science.nasa.gov/sun/auroras/

Also known as the northern lights (aurora borealis) or southern lights (aurora australis), auroras are colorful, dynamic, and often visually delicate displays of an intricate dance of particles and magnetism between the Sun and Earth called space weather.

When energetic particles from space collide with atoms and molecules in the atmosphere, they can cause the colorful glow that we call auroras.

Aurora is the Latin word for "dawn" and is also the name of the Roman goddess of the dawn. Europeans living far from the Arctic Circle usually experienced auroras as a faint red glow to the north, resembling the reddish glow in the east at dawn. Aurora borealis translates to “northern dawn.”

Why Are Auroras Colorful?

An aurora can appear in a variety of colors, from an eerie green to blue and purple to pink and red. When particles from space bombard gases in the atmosphere, they can give the atoms and molecules of the gases extra energy that’s released as tiny specks of light.
The color of an aurora depends on the type of gas that is hit and where that gas is located in the atmosphere.
Oxygen excited to different energy levels can produce green and red. Green occurs roughly between 60 to 120 miles (100-200 km) altitude, and red occurs above 120 miles (200 km).
Excited nitrogen gas from about 60 to 120 miles (100-200 km) glows blue. Depending on the type and energy of the particle it is interacting with, nitrogen can give off both pink and blue light. If it is below about 60 miles (100 km), it gives the lower edge of the aurora a reddish-purple to pink glow.
Sometimes, the light emitted by these gases can appear to mix, making the auroras seem purple, pink, or even white.

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education

2024 June 12

Aurora over Karkonosze Mountains
* Image Credit & Copyright: Daniel Koszela
instagram.com/danielkoszelapho…

Explanation:
It was the first time ever. At least, the first time this photographer had ever seen aurora from his home mountains. And what a spectacular aurora it was. The Karkonosze Mountains in Poland are usually too far south to see any auroras. But on the amazing night of May 10 - 11, purple and green colors lit up much of the night sky, a surprising spectacle that also appeared over many mid-latitude locations around the Earth. The featured image is a composite of six vertical exposures taken during the auroral peak. The futuristic buildings on the right are part of a meteorological observatory located on the highest peak of the Karkonosze Mountains. The purple color is primarily due to Sun-triggered, high-energy electrons impacting nitrogen molecules in Earth's atmosphere. Our Sun is reaching its maximum surface activity over the next two years, and although many more auroras are predicted, most will occur over regions closer to the Earth's poles.
theconversation.com/are-the-no…
nasa.gov/news-release/solar-cy…

apod.nasa.gov/apod/ap240612.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #nature #education

2024 May 22

Green Aurora over Sweden
* Image Credit & Copyright: Göran Strand
astrofotografen.se/

Explanation:
It was bright and green and stretched across the sky. This striking aurora display was captured in 2016 just outside of Östersund, Sweden. Six photographic fields were merged to create the featured panorama spanning almost 180 degrees. Particularly striking aspects of this aurora include its sweeping arc-like shape and its stark definition. Lake Storsjön is seen in the foreground, while several familiar constellations and the star Polaris are visible through the aurora, far in the background. Coincidently, the aurora appears to avoid the Moon visible on the lower left. The aurora appeared a day after a large hole opened in the Sun's corona, allowing particularly energetic particles to flow out into the Solar System. The green color of the aurora is caused by oxygen atoms recombining with ambient electrons high in the Earth's atmosphere.
webexhibits.org/causesofcolor/…
nasa.gov/image-article/earths-…

apod.nasa.gov/apod/ap240522.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #nature

"These wonderful surprising moments in places where we do not expect those views are most likely caused by the following powerful phenomenon: "

Geomagnetic Substorms

While the huge auroral displays caused by geomagnetic storms are fun to see, they’re relatively rare since the Sun’s and Earth’s magnetic fields need to align just right for them to occur. Auroras that stay near the Arctic and Antarctic circles are much more frequent. They’re created by geomagnetic substorms, magnetic disturbances affecting portions of the magnetosphere. Geomagnetic storms, in contrast, are large-scale disturbances that distort the whole geomagnetic system. The everyday flow of charged particles within Earth’s magnetosphere can create small regions of magnetic imbalance that cause geomagnetic substorms.
en.wikipedia.org/wiki/Substorm
heliophysics.ucar.edu/sites/de…

Credits:
NASA/Goddard Space Flight Center/UNH/J. Raeder

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education

"And sometimes you don't even have to travel that far north, especially in the last year 2024, some of us suddenly and unexpectedly had such a light show on our doorstep"

2024 August 14

Meteors and Aurora over Germany
* Image Credit & Copyright: Chantal Anders
instagram.com/wetter_eule/

Explanation:
This was an unusual night. For one thing, the night sky of August 11 and 12, earlier this week, occurred near the peak of the annual Perseid Meteor Shower. Therefore, meteors streaked across the dark night as small bits cast off from Comet Swift-Tuttle came crashing into the Earth's atmosphere. Even more unusually, for central Germany at least, the night sky glowed purple. The red-blue hue was due to aurora caused by an explosion of particles from the Sun a few days before. This auroral storm was so intense that it was seen as far south as Texas and Italy, in Earth's northern hemisphere. The featured image composite was built from 7 exposures taken over 26 minutes from Ense, Germany. The Perseids occur predictably every August, but auroras visible this far south are more unusual and less predictable.
swpc.noaa.gov/news/severe-g4-g…
science.nasa.gov/solar-system/…

apod.nasa.gov/apod/ap240814.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #nature

"And now finally (thank you p
@p for your generous p atience) we come to the point of magnetic reconnection. I'll spare you as linking to Youtube and Google with this simulation generously provided by the Goddard Space Flight Center. "

Magnetic Reconnection

As we’ve seen, the solar wind emanating from the Sun flows around Earth’s magnetosphere like a river rushing around a rock. This onrush of charged particles stretches Earth’s magnetosphere away from the Sun, creating a long wake known as the magnetotail.

The magnetic shields of the Sun and Earth are polarized, like refrigerators and the magnets that adhere to them. The polarity of Earth’s magnetic shield is mostly stable, but the Sun’s can vary due to its more dynamic nature.

Sometimes, the magnetic polarity of the solar wind is opposite that of Earth’s magnetosphere. When the solar wind buffets the magnetosphere under these conditions, the field lines of the Sun and Earth snap together, similar to when an everyday magnet connects to a fridge. This is called magnetic reconnection.

The continuously blowing solar wind then pushes these newly connected Sun-Earth field lines, wrapping them around the magnetosphere and stretching them out toward the magnetotail. Eventually, these field lines stretch to their limit and snap like a rubber band. This severs the direct Sun-Earth magnetic connection, releasing energy back along the field lines and reinstating the original magnetic configuration in the process.
en.wikipedia.org/wiki/Magnetic…
energy.gov/science/articles/so…
heliophysics.ucar.edu/sites/de…

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education

"A special box seat for the phenomenal earthly light shows belongs to the members of Expedition 71 and such wonderful views are part of the reward for the hard work. How nice that they share these beautiful pictures with us who stayed at home! We'll treat ourselves to a short film about it later .."

2024 September 13

Aurora Australis and the International Space Station
* Image Credit: NASA, ISS Expedition 71
nasa.gov/mission/expedition-71…

Explanation:
This snapshot from the International Space Station was taken on August 11 while orbiting about 430 kilometers above the Indian Ocean, Southern Hemisphere, planet Earth. The spectacular view looks south and east, down toward the planet's horizon and through red and green curtains of aurora australis. The auroral glow is caused by emission from excited oxygen atoms in the extremely rarefied upper atmosphere still present at the level of the orbiting outpost. Green emission from atomic oxygen dominates this scene at altitudes of 100 to 250 kilometers, while red emission from atomic oxygen can extend as high as 500 kilometers altitude. Beyond the glow of these southern lights, this view from low Earth orbit reveals the starry sky from a southern hemisphere perspective. Stars in Orion's belt and the Orion Nebula are near the Earth's limb just left of center. Sirius, alpha star of Canis Major and brightest star in planet Earth's night is above center along the right edge of the southern orbital skyscape.
earthobservatory.nasa.gov/imag…
science.nasa.gov/earth/earth-a…
apod.nasa.gov/apod/ap240913.ht…

apod.nasa.gov/apod/ap240913.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #nature #education

2024 October 16

Colorful Aurora over New Zealand
* Image Credit & Copyright: Tristian McDonald
cre8tivestr3k.com/info-contact

Explanation:
Sometimes the night sky is full of surprises. Take the sky over Lindis Pass, South Island, New Zealand one-night last week. Instead of a typically calm night sky filled with constant stars, a busy and dynamic night sky appeared. Suddenly visible were pervasive red aurora, green picket-fence aurora, a red SAR arc, a STEVE, a meteor, and the Moon. These outshone the center of our Milky Way Galaxy and both of its two satellite galaxies: the LMC and SMC. All of these were captured together on 28 exposures in five minutes, from which this panorama was composed. Auroras lit up many skies last week, as a Coronal Mass Ejection from the Sun unleashed a burst of particles toward our Earth that created colorful skies over latitudes usually too far from the Earth's poles to see them. More generally, night skies this month have other surprises, showing not only auroras -- but comets.

apod.nasa.gov/apod/ap241016.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #nature #education

This animation shows all L3 WISPR full-field observations from the twenty-first PSP Mission Encounter (2024-09-25 - 2024-10-05). We have superimposed a grid showing helioprojective longitude and latitude, and a scale representation of the size and location of the Sun in the observations using the SDO/HMI Carrington map for this time period. The velocity and distance metrics displayed on the movies correspond respectively to the spacecraft's heliocentric velocity in kilometers per second, and its distance from the Sun's center in units of solar radii (where 1 solar radius = 695,700km). The "FOV Range" label provides the plane-of-sky distance limits of the inner and outermost edges of the fields of view, in units of solar radii. The horizontal blue line indicates the orbital plane of PSP. The timespan of this composite movie covers only the nominal science window when the spacecraft was within 0.25 au; a limited amount of data outside of this range may be available at the below links.
You can download this movie directly as an 101MB mp4 file. This sequence is also available as data processed via the LW Algorithm developed by Dr. Guillermo Stenborg (JHUAPL) and detailed in Appendix A of Howard et al. 2022 (ApJ, 936, id.43. DOI 10.3847/1538-4357/ac7ff5). Please contact the team for access to this data, which will be posted here one year after the acquisition of those observations. Team contact information can be found in Section 1.2 of the WISPR User's Guide
wispr.nrl.navy.mil/sites/wispr… [PDF link].

[Credit: NASA/NRL/JHUAPL. Movie processed/compiled by Guillermo Stenborg (JHUAPL) and Karl Battams (NRL). SDO inset courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.]

/*grobi: for a better resolution go to:
wispr.nrl.navy.mil/encounter21… but that's a huge file !😁

#space #solarsystem #sun #parker #astrophotography #photography #science #astronomie #nature #NASA

" @p but before that, we have to talk about Coronal Mass Ejections: "

Coronal Mass Ejections

Occasionally, magnetic storms on the Sun eject large amounts of solar material into the solar atmosphere. These huge, flying blobs of Sun-stuff are called coronal mass ejections, or CMEs.

If directed at Earth, fast-moving CMEs can reach our planet in as little as 15 hours. (The Sun is approximately 93 million miles away from Earth. A CME arriving here in 15 hours means that it’s traveling around 6.2 million miles per hour, or about 0.9% the speed of light. At those speeds, you could fly from San Francisco to Washington, D.C. in ~1.5 seconds!)

As they billow away from the Sun, fast CMEs can overtake slower-moving charged particles ahead of them in the solar wind. These particles are accelerated as they’re swept into the careening solar ejecta, increasing the risk and intensity of a radiation storm when they reach Earth.

Under certain conditions, CMEs can supercharge the magnetosphere as they blow past, creating powerful geomagnetic storms in response.
science.nasa.gov/sun/solar-sto…

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education

"Other planets in our solar system also have the aurora phenomenon. You can also enjoy a solar light show there. In my simple mind, I think of a drive-in cinema with planets instead of cars and the sun as a projector. But there is probably a different movie on each planet..?"

2024 December 8

Aurora around Saturn's North Pole
* Image Credit: NASA, ESA, Hubble, OPAL Program, J. DePasquale (STScI), L. Lamy (Obs. Paris)

Explanation:
Are Saturn's auroras like Earth's? To help answer this question, the Hubble Space Telescope and the Cassini spacecraft monitored Saturn's North Pole simultaneously during Cassini's final orbits around the gas giant in September 2017. During this time, Saturn's tilt caused its North Pole to be clearly visible from Earth. The featured image is a composite of ultraviolet images of auroras and optical images of Saturn's clouds and rings, all taken by Hubble. Like on Earth, Saturn's northern auroras can make total or partial rings around the pole. Unlike on Earth, however, Saturn's auroras are frequently spirals -- and more likely to peak in brightness just before midnight and dawn. In contrast to Jupiter's auroras, Saturn's auroras appear better related to connecting Saturn's internal magnetic field to the nearby, variable, solar wind. Saturn's southern auroras were similarly imaged back in 2004 when the planet's South Pole was clearly visible to Earth.
en.wikipedia.org/wiki/Solar_wi…
apod.nasa.gov/apod/ap050219.ht…

apod.nasa.gov/apod/ap241208.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education

The Heliosphere and Solar Wind

Just as planets with churning cores like Earth produce magnetic shields, the Sun’s dense, ever-roiling interior also produces a magnetic shield — on a much larger scale. The Sun’s magnetic shield is called the heliosphere, and it fills the solar system.

As the Sun seethes, it radiates its energy throughout the heliosphere. Planets and other objects in the solar system experience much of this radiation as a continuous stream of charged particles and magnetic fields blowing by. This stream of fields and particles is called the solar wind.

When the solar wind blows past Earth, it buffets Earth’s magnetosphere like a strong breeze flapping a flag.
science.nasa.gov/sun/what-is-t…

Credits:
NASA/Goddard Space Flight Center/Conceptual Image Lab/Jonathan North

** --> Uploading animated files in ".gif" format is a bit of a trick, because the originals are usually too big. The free software imagemagick does a great job here when it comes to resizing your file! You can try it yourself with the following command:

$convert(or "magick" depending on your version) in.gif -coalesce -resize (desired size eg:"256")x -deconstruct out-deconstruct.gif

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education

"Yes, I know, from the Christian holidays we are already at Pentecost! But I still hope that you can enjoy this aurora as well .. "

2024 December 23

Christmas Tree Aurora
* Image Credit & Copyright: Jingyi Zhang

Explanation:
It was December and the sky lit up like a Christmas tree. Shimmering, the vivid green, blue, and purple auroral colors that formed the tree-like apparition were caused by high atmospheric oxygen and nitrogen reacting to a burst of incoming electrons. Collisions caused the orbital electrons of atoms and molecules to jump into excited energy states and emit visible light when returning to their normal state. The featured image was captured in Djúpivogur, Iceland during the last month of 2023. Our Sun is currently in its most energetic phase of its 11-year cycle, with its high number of active regions and sunspots likely to last into next year. Of course, the Sun has been near solar maximum during this entire year, with its outbursts sometimes resulting in spectacular Earthly auroras.
en.wikipedia.org/wiki/Solar_ma…
aps.org/apsnews/2000/10/discov…
periodic.lanl.gov/8.shtml
periodic.lanl.gov/7.shtml
youtube.com/shorts/m3C7Pv9u2l0
funkot.ru/wp-content/uploads/2…

apod.nasa.gov/apod/ap241223.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #nature #education

2011 September 23

September's Aurora
* Image Credit & Copyright: Yuichi Takasaka / TWAN / www.blue-moon.ca
twanight.org/profile/yuichi-ta…

Explanation:
September's equinox arrived that day at 0905 UT. As the Sun crosses the celestial equator heading south, spring begins in the southern hemisphere and autumn in the north. And though the seasonal connection is still puzzling, both spring and autumn bring an increase in geomagnetic storms. So as northern nights grow longer, the equinox also heralds the arrival of a good season for viewing aurora. Recorded earlier this month, these curtains of September's shimmering green light sprawl across a gorgeous night skyscape. In the foreground lies Hidden Lake Territorial Park near Yellowknife, Northwest Territories, Canada. Calm water reflects the aurora, with bright star trails peering through the mesmerizing sky glow. Of course, shining at altitudes of 100 kilometers or so, planet Earth's auroras are visible from space.

apod.nasa.gov/apod/ap110923.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education #4sAur

"Hey,
may i take you on a ride through the twilight into the night sky?? OK, buckle up and off we go .. scroll upwards if you dare to!"

2013 March 31

Flying Over the Earth at Night
* Video Credit: Gateway to Astronaut Photography, NASA
eol.jsc.nasa.gov/
nasa.gov/;
* Compilation: David Peterson youtube.com/user/Bitmeizer;
* Music: Freedom Fighters (Two Steps from Hell)
en.wikipedia.org/wiki/Two_Step…

Explanation:
Many wonders are visible when flying over the Earth at night. A compilation of such visual spectacles was captured recently from the International Space Station (ISS) and set to rousing music. Passing below are white clouds, orange city lights, lightning flashes in thunderstorms, and dark blue seas. On the horizon is the golden haze of Earth's thin atmosphere, frequently decorated by dancing auroras as the video progresses. The green parts of auroras typically remain below the space station, but the station flies right through the red and purple auroral peaks. Solar panels of the ISS are seen around the frame edges. The ominous wave of approaching brightness at the end of each sequence is just the dawn of the sunlit half of Earth, a dawn that occurs every 90 minutes.

apod.nasa.gov/apod/ap130331.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education #4sAur

2018 December 9

Aurora Shimmer, Meteor Flash
* Image Credit & Copyright: Bjørnar G. Hansen

Explanation:
Some night skies are serene and passive -- others shimmer and flash. The later, in the form of auroras and meteors, haunted skies over the island of Kvaløya, near Tromsø Norway on 2009 December 13. This 30 second long exposure records a shimmering auroral glow gently lighting the wintery coastal scene. A study in contrasts, the image also captures the sudden flash of a fireball meteor from the excellent Geminid meteor shower of 2009. Streaking past familiar stars in the handle of the Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both auroras and meteors occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, but aurora caused by energetic charged particles from the magnetosphere, while meteors are trails of cosmic dust. Nine years after this photograph was taken, toward the end of this week, the yearly 2018 Geminids meteor shower will peak again, although this time their flashes will compete with the din of a half-lit first-quarter moon during the first half of the night.

apod.nasa.gov/apod/ap181209.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education #4sAur

2018 September 22

Window Seat over Hudson Bay
* Image Credit & Copyright: Ralf Rohner
ralf-rohner.pixels.com/

Explanation:
On the August 18 night flight from San Francisco to Zurich, a window seat offered this tantalizing view when curtains of light draped a colorful glow across the sky over Hudson Bay. Constructed by digitally stacking six short exposures made with a hand held camera, the scene records the shimmering aurora borealis or northern lights just as the approaching high altitude sunrise illuminated the northeastern horizon. It also caught the flash of a Perseid meteor streaking beneath the handle stars of the Big Dipper of the north. A few days past the meteor shower's peak, its trail still points across the sky toward Perseus. Beautiful aurorae and shower meteors both occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, far above commercial airline flights. The aurora are caused by energetic charged particles from the magnetosphere, while meteors are trails of comet dust.

apod.nasa.gov/apod/ap180922.ht…

#space #earth #aurora #astrophotography #photography #NASA #science #physics #nature #education #4sAur