Aurora

Product Information

Red: At its highest altitudes, excited atomic oxygen emits at 630nm (red); low concentration of atoms and lower sensitivity of eyes at this wavelength make this color visible only under more intense solar activity. The low number of oxygen atoms and their gradually diminishing concentration is responsible for the faint appearance of the top parts of the "curtains". Scarlet, crimson, and carmine are the most often-seen hues of red for the auroras.

Freya and the other "starfarers" have trouble adjusting to life on Earth, especially with many Terrans hostile to them for a perceived sense of ingratitude and cowardice. At a space colonization conference, a speaker says humanity will continue to send ships into interstellar space no matter how many fail and die, and Freya assaults him. Eventually she joins a group of terraformers who are attempting to restore the Earth's beaches after their loss during previous centuries' sea level rise. While swimming and surfing, she begins to come to terms with life on Earth. Armstrong, J. C.; Zmuda, A. J. (1973). "Triaxial magnetic measurements of field-aligned currents at 800 kilometers in the auroral region: Initial results". Journal of Geophysical Research. 78 (28): 6802–6807. Bibcode: 1973JGR....78.6802A. doi: 10.1029/JA078i028p06802. In Japanese folklore, pheasants were considered messengers from heaven. However, researchers from Japan's Graduate University for Advanced Studies and National Institute of Polar Research claimed in March 2020 that red pheasant tails witnessed across the night sky over Japan in 620 A.D., might be a red aurora produced during a magnetic storm. [81] The Aboriginal Australians associated auroras (which are mainly low on the horizon and predominantly red) with fire. Brekke (1994) also described some auroras as "curtains". [21] The similarity to curtains is often enhanced by folds within the arcs. Arcs can fragment or break up into separate, at times rapidly changing, often rayed features that may fill the whole sky. These are also known as discrete auroras, which are at times bright enough to read a newspaper by at night. [22]Loomis, Elias (February 1860). "The great auroral exhibition of August 28 to September 4, 1859—3rd article". The American Journal of Science. 2nd series. 29: 249–266. An aurora was detected on Mars, on 14 August 2004, by the SPICAM instrument aboard Mars Express. The aurora was located at Terra Cimmeria, in the region of 177° east, 52° south. The total size of the emission region was about 30km across, and possibly about 8km high. By analyzing a map of crustal magnetic anomalies compiled with data from Mars Global Surveyor, scientists observed that the region of the emissions corresponded to an area where the strongest magnetic field is localized. This correlation indicated that the origin of the light emission was a flux of electrons moving along the crust magnetic lines and exciting the upper atmosphere of Mars. [95] [97] So far, so conventional. Indeed, Robinson foregrounds the bare facts of this voyage by giving most of his narration over to the ship’s central computer as it painstakingly works towards a de facto Turing test pass. This artificial mind is happy to provide great scads of data about every aspect of the ship. In the hands of another author it might amount to tedious specifying and dry-as-interstellar-dust worldbuilding, but Robinson makes it come thrillingly, grippingly alive. In the early 1900s, the Norwegian scientist Kristian Birkeland laid the foundation [ colloquialism] for current understanding of geomagnetism and polar auroras. a b Feldstein, Y. I. (2011). "A Quarter Century with the Auroral Oval". EOS. 67 (40): 761. Bibcode: 1986EOSTr..67..761F. doi: 10.1029/EO067i040p00761-02.

Gurnett, D.A. (1974). "The Earth as a radio source". Journal of Geophysical Research. 79 (28): 4227. Bibcode: 1974JGR....79.4227G. doi: 10.1029/JA079i028p04227.Procter, Henry Richardson (1878). "Aurora Polaris". Encyclopædia Britannica. Vol.III (9thed.). pp.90–99. Blue: At yet lower altitudes, atomic oxygen is uncommon, and molecular nitrogen and ionized molecular nitrogen take over in producing visible light emission, radiating at a large number of wavelengths in both red and blue parts of the spectrum, with 428nm (blue) being dominant. Blue and purple emissions, typically at the lower edges of the "curtains", show up at the highest levels of solar activity. [24] The molecular nitrogen transitions are much faster than the atomic oxygen ones. Oxygen is unusual in terms of its return to ground state: it can take 0.7 seconds to emit the 557.7nm green light and up to two minutes for the red 630.0nm emission. Collisions with other atoms or molecules absorb the excitation energy and prevent emission, this process is called collisional quenching. Because the highest parts of the atmosphere contain a higher percentage of oxygen and lower particle densities, such collisions are rare enough to allow time for oxygen to emit red light. Collisions become more frequent progressing down into the atmosphere due to increasing density, so that red emissions do not have time to happen, and eventually, even green light emissions are prevented. Bruzek, A.; Durrant, C. J. (2012). Illustrated Glossary for Solar and Solar-Terrestrial Physics. Springer Science & Business Media. p.190. ISBN 978-94-010-1245-4. Clarke, J. (1910), Physical Science in the time of Nero, pp. 39–41, London: Macmillan, accessed 1 January 2017.

Occurrence [ edit ] Earth's atmosphere as it appears from space, as bands of different colours at the horizon. From the bottom, afterglow illuminates the troposphere in orange with silhouettes of clouds, and the stratosphere in white and blue. Next the mesosphere (pink area) extends to just below the edge of space at one hundred kilometers and the pink line of airglow of the lower thermosphere (dark), which hosts green and red aurorae over several hundred kilometers.Loomis, Elias (July 1862). "On electrical currents circulating near the earth's surface and their connection with the phenomena of the aurora polaris—9th article". The American Journal of Science. 2nd series. 34: 34–45. Alongside the book, Aurora is also releasing a special edition vinyl version of The Gods We Can Touch. Inspired by Greek mythology, described as “remarkable” by MOJO and “heavenly” by NME, the album landed at No.8 in the Official UK Album Chart and was the third most streamed new album in the world on Spotify the weekend of its release. The oldest known written record of the aurora was in a Chinese legend written around 2600 BC. On an autumn around 2000 BC, [80] according to a legend, a young woman named Fubao was sitting alone in the wilderness by a bay, when suddenly a "magical band of light" appeared like "moving clouds and flowing water", turning into a bright halo around the Big Dipper, which cascaded a pale silver brilliance, illuminating the earth and making shapes and shadows seem alive. Moved by this sight, Fubao became pregnant and gave birth to a son, the Emperor Xuanyuan, known legendarily as the initiator of Chinese culture and the ancestor of all Chinese people. [ citation needed] In the Shanhaijing, a creature named Shilong is described to be like a red dragon shining in the night sky with a body a thousand miles long. In ancient times, the Chinese did not have a fixed word for the aurora, so it was named according to the different shapes of the aurora, such as "Sky Dog" ( 天狗), "Sword/Knife Star" ( 刀星), "Chiyou banner" ( 蚩尤旗), "Sky's Open Eyes" ( 天开眼), and "Stars like Rain" ( 星陨如雨). [ citation needed] In northern latitudes, the effect is known as the aurora borealis or the northern lights. The former term was coined by Galileo in 1619, from the Roman goddess of the dawn and the Greek name for the north wind. [11] [12] The southern counterpart, the aurora australis or the southern lights, has features almost identical to the aurora borealis and changes simultaneously with changes in the northern auroral zone. [13] The aurora australis is visible from high southern latitudes in Antarctica, Chile, Argentina, South Africa, New Zealand and Australia. The aurora borealis is visible from areas around the Arctic such as Alaska, the Canadian Territories, Iceland, Greenland, Norway, Sweden, Finland, Scotland, and Siberia. On rare occasions the aurora borealis can be seen as far south as the Mediterranean and the southern states of the US. Like the neolithic humans of Robinson’s last novel, Shaman, the characters in Aurora learn what it means to go chronically hungry. As in his kaleidoscopic 2312, terraforming new worlds proves much harder than fixing the environmental problems of our own beautiful planet – although we seem to be finding it difficult to do even that simple thing. Robinson is wise on the whys of this. As he puts it in Galileo’s Dream: “Fights over ideas are the most vicious of all. If it were merely food, or water, or shelter, we would work something out. But in the realm of ideas one can become idealistic.” Ideas simplify and metaphors distort. Reality is otherwise. Aurora’s ship’s computer notes: “Life is complex and entropy is real.” The novel dramatises these two great truths stunningly well.

a b Grandin, Maxime; Palmroth, Minna; Whipps, Graeme; Kalliokoski, Milla; Ferrier, Mark; Paxton, Larry J.; Mlynczak, Martin G.; Hilska, Jukka; Holmseth, Knut; Vinorum, Kjetil; Whenman, Barry (2021). "Large-Scale Dune Aurora Event Investigation Combining Citizen Scientists' Photographs and Spacecraft Observations". AGU Advances. 2 (2): EGU21-5986. Bibcode: 2021EGUGA..23.5986G. doi: 10.1029/2020AV000338. The effect of the Aurora on the electric telegraph is generally to increase or diminish the electric current generated in working the wires. Sometimes it entirely neutralizes them, so that, in effect, no fluid [current] is discoverable in them. The aurora borealis seems to be composed of a mass of electric matter, resembling in every respect, that generated by the electric galvanic battery. The currents from it change coming on the wires, and then disappear: the mass of the aurora rolls from the horizon to the zenith. [75] Historical views and folklore [ edit ] A mid 19th-century British source says auroras were a rare occurrence before the 18th century. [94] It quotes Halley as saying that before the aurora of 1716, no such phenomenon had been recorded for more than 80 years, and none of any consequence since 1574. It says no appearance is recorded in the Transactions of the French Academy of Sciences between 1666 and 1716; and that one aurora recorded in Berlin Miscellany for 1797 was called a very rare event. One observed in 1723 at Bologna was stated to be the first ever seen there. Celsius (1733) states the oldest residents of Uppsala thought the phenomenon a great rarity before 1716. The period between approximately 1645 and 1715 corresponds to the Maunder minimum in sunspot activity. Most auroras occur in a band known as the "auroral zone", [6] which is typically 3° to 6° (approximately 330–660 km) wide in latitude and between 10° and 20° from the geomagnetic poles at all local times (or longitudes), most clearly seen at night against a dark sky. A region that currently displays an aurora is called the "auroral oval", a band displaced by the solar wind towards the night side of Earth. [7] Early evidence for a geomagnetic connection comes from the statistics of auroral observations. Elias Loomis (1860), [8] and later Hermann Fritz (1881) [9] and Sophus Tromholt (1881) [10] in more detail, established that the aurora appeared mainly in the auroral zone. In the case of diffuse auroras, the electron pitch angles are altered by their interaction with various plasma waves. Each interaction is essentially wave-particle scattering; the electron energy after interacting with the wave is similar to its energy before interaction, but the direction of motion is altered. If the final direction of motion after scattering is close to the field line (specifically, if it falls within the loss cone) then the electron will hit the atmosphere. Diffuse auroras are caused by the collective effect of many such scattered electrons hitting the atmosphere. The process is mediated by the plasma waves, which become stronger during periods of high geomagnetic activity, leading to increased diffuse aurora at those times.The Gods We Can Touch is a highly intimate book, taking readers on a journey to the very heart of Aurora’s world, through her creative process and the inspiration for her acclaimed third studio album. This full-color reproduction of Aurora’s personal notebook also features all the song lyrics from the album, original album artwork and stunning photography. Video (02:43) (time-lapse) − Auroras – Ground-Level View from Tromsø, Norway, 24 November 2010 (video on YouTube) See also: Magnetosphere of Jupiter §Aurorae Jupiter aurora; the far left bright spot connects magnetically to Io; the spots at the bottom of the image lead to Ganymede and Europa. An aurora high above the northern part of Saturn; image taken by the Cassini spacecraft. A movie shows images from 81 hours of observations of Saturn's aurora. Geomagnetic storms that ignite auroras may occur more often during the months around the equinoxes. It is not well understood, but geomagnetic storms may vary with Earth's seasons. Two factors to consider are the tilt of both the solar and Earth's axis to the ecliptic plane. As Earth orbits throughout a year, it experiences an interplanetary magnetic field (IMF) from different latitudes of the Sun, which is tilted at 8 degrees. Similarly, the 23-degree tilt of Earth's axis about which the geomagnetic pole rotates with a diurnal variation changes the daily average angle that the geomagnetic field presents to the incident IMF throughout a year. These factors combined can lead to minor cyclical changes in the detailed way that the IMF links to the magnetosphere. In turn, this affects the average probability of opening a door [ colloquialism] through which energy from the solar wind can reach Earth's inner magnetosphere and thereby enhance auroras. Recent evidence in 2021 has shown that individual separate substorms may in fact be correlated networked communities. [64] Auroral particle acceleration [ edit ]