Dancing Lights on Sky

Auroras

australia

now, I'm very addicted to Aurora. a magnificient and breathtaking

phenomenon on ploar circle. this phenomenon so beautiful. But, we can see this phenomenon only on south and north polar circle. I'll share a litlle bout this beauty light.

tromso, norway

An aurora (plural: auroras or aurorae) is a natural light display in the sky, particularly in the polar regions, caused by the collision of charged particles directed by the Earth'smagnetic field. An aurora is usually observed at night and typically occurs in theionosphere. It is also referred to as a polar aurora or, collectively, as polar lights. These phenomena are commonly visible between 60 and 72 degrees north and south latitudes, which place them in a ring just within the Arctic and Antarctic polar circles.Auroras do occur deeper inside the polar regions, but these are infrequent and often invisible to the naked eye.

In northern latitudes, the effect is known as the aurora borealis (or the northern lights), named after the Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas, by Pierre Gassendi in 1621. The chance of visibility of the aurora borealis increases with proximity to the North Magnetic Pole. Auroras seen near the magnetic pole may be high overhead, but from farther away, they illuminate the northern horizon as a greenish glow or sometimes a faint red, as if the Sun were rising from an unusual direction. The aurora borealis most often occurs near the equinoxes. The northern lights have had a number of names throughout history. TheCree call this phenomenon the "Dance of the Spirits". In Europe, in the Middle Ages, the auroras were commonly believed a sign from God (see Wilfried Schröder, Das Phänomen des Polarlichts, Darmstadt 1984).

Its southern counterpart, the aurora australis (or the southern lights), has similar properties, but is only visible from high southern latitudes in Antarctica, South America, or Australasia. Australis is the Latin word for "of the South".

Auroras can be spotted throughout the world and on other planets. They are most visible closer to the poles due to the longer periods of darkness and the magnetic field.

Modern style guides recommend that the names of meteorological phenomena, such as aurora borealis, be uncapitalized.

source: http://en.wikipedia.org/wiki/Aurora_(astronomy) and others

Aurorae

Pada mitologi Romawi kuno, Aurora adalah Dewi Fajar yang muncul setiap hari dan terbang melintasi langit untuk menyambut terbitnya matahari

mungkin Dewi Fajar itulah yang mengilhami nama Aurora. Aurora adalah hal yang sangat indah dan menawan, banyak teori yang diajukan beberapa ilmuwan untuk menjelaskan mengapa fenomena ini dapat terjadi, salah satunya teori dari Benjamin Franklin. Dia berteori bahwa "Misteri Cahaya Utara" itu disebabkan oleh konsentrasi muatan listrik di daerah kutub yang didukung oleh salju dan uap air.

Dan menurut penelitian modern dapat dikemukakan bahwa fenomena ini terjadi pada lapisan ionosfer bumi akibat medan magnetik, dan partikel yang dipancarkan matahari. Sumber energi utama dari aurora adalah angin matahari yang mengalir melewati Bumi. Magnetosfer dan angin matahari terdiri dari gas terionisasi yang menghantarkan listrik.

Teori lainnya mengatakan aurora berhubungan erat dengan percikan matahari, yaitu saat bola percikan matahari ini mencapai bumi, maka akan terjadi aurora.Aurora ini terbentuk akibat panas dari bongkahan benda langit dari matahari ditolak oleh bagian kutub magnit bumi. Aurora ini memancar berwarna warni membentuk gambar tiga dimensi yang sangat indah

Aurora Borealis (Aurora Kutub utara) sering terjadi antara bulan Maret-April dan Agustus-September-Oktober. Pada saat Aurora Borealis terjadi, seakan-akan matahari akan terbit dari sebelah utara. Aurora Borealis bisa dilihat di Norwegia, Finlandia, swedia, Kanada Utara, Alaska, dll.

menurut catatan sejarah, mungkin aurora yang terjadi tanggal 28 Agustus dan 2 September 1859 mungkin adalah yang paling spektakuler sepanjang sejarah. Aurora di Boston tanggal 2 September 1859 juga dimuat oleh New York Times. Padahal Boston adalah daerah dimana Aurora sangat jarang dan hampir tidak pernah terjadi.
Tidak disangkan juga, ternyata aurora juga terjadi pada Planet lain d

Pemberitaan tentang Aurora Borealis di Boston, 2 September 1859 di New York Times

alam tata surya, misalnya Planet Uranus dan Neptunus. Jupiter dan Saturnus memiliki medan magnet yang lebih kuat dari Bumi dan memiliki sabuk radiasi yang besar. Teleskop Huble digunakan untuk menangkap terjadinya Aurora di planet lain.
Tgl. 14 Agustus 2004, Pesawat Mars Express mendeteksi terjadinya Aurora di planet Mars, para Ilmuwan mempelajari dengan memasukkan data-data yang dihasilkan Mars Global Surveyor, dimana daerah emisi berhubungan dengan suatu daerah yang memiliki medan magnet paling kuat, dan menunjukkan bahwa asal-usul emisi cahaya adalah aliran elektron.

Pada sebuah fenomena Aurora, satelit menangkap gambar Aurora yang terlihat seperti “cincin api”. Aurora-aurora jenis lain juga diamati dari luar angkasa, misalnya "Poleward Busur", tapi tampaknya masih perlu penelitian lebih lanjut mengenai fenomena ini, mengingat fenomena ini sangat jarang akan terjadi.

Aurora Borealis pada polar circle nampak dari atas bumi

sources : http://id.shvoong.com/exact-sciences/astronomy/1974267-aurora-borealis/

and others

Spring? Time For Borealis!

Spring is aurora season! ask why? scientists don't really know too.

For reasons not fully understood by scientists, the weeks around the vernal equinox are prone to Northern Lights. When Canadians walking their dogs after dinner, Scandinavians popping out to the sauna, Alaskan Huskies on the Iditarod trail -- all they have to do is look up and behold, the green curtains of light dancing across the night sky. It's the Borealis!

This is a bit of a puzzle. Auroras are caused by solar activity, but the sun doesn't know what season it is on Earth. So how could one season yield more auroras than another?

"There's a great deal we don't understand about auroras," says UCLA space physicist Vassilis Angelopoulos. For instance, "Auroras sometimes erupt with little warning and surprising intensity. We call these events 'sub-storms,' and they are a big mystery." What triggers the eruptions? Where is sub-storm energy stored? (It has to gather somewhere waiting to power the outburst.)

And, of course, why springtime, why not on autumn or summertime?

To answer these questions and others, NASA has deployed a fleet of five spacecraft named THEMIS (short for "Time
History of Events and Macroscale Interactions during Substorms") specially instrumented to study auroras. Angelopoulos is the mission's principal investigator.

Auroras are much more than just pretty lights in the sky. Auroras has many mysteries to discover. Underlying each display is a potent geomagnetic storm with possible side-effects ranging from satellite malfunctions in orbit to power outages on terra firma. Telecommunications, air traffic, power grids and GPS systems are all vulnerable. In a society that relies increasingly on space technology, understanding these storms is vital.

THEMIS may have found the storm's power supply:

"The satellites have detected magnetic 'ropes' connecting Earth's upper atmosphere directly to the sun," says Dave Sibeck, project scientist for the mission at the Goddard Space Flight Center. "We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras." Sibeck likens them to ropes because the magnetic fields in question are organized much like the twisted hemp of a mariner's rope. Solar wind particles flow along the ropes in whirligig trajectories leading from the sun to Earth. That's so amazing, right? A magnetic ropes which made connection between the atmoshpere and sun. It means if we can learn and know the see the working way of this rope, we can predict when Auroras will appear on certain time.

Which brings us back to spring.

It turns out that magnetic connections between the sun and Earth are favored in springtime. It's a matter of geometry: As Earth goes around in its orbit, Earth's magnetic poles wobble back and forth. (The poles don't really wobble, but the combination of Earth's 23-degree polar tilt plus orbital motion makes the poles seem wobble from the solar point of view.) Around the time of the equinox, Earth's magnetic field is best oriented for "connecting-up" with the sun, opening the door for solar wind energy to flow in and spark Northern Lights.

But wait, there are two equinoxes, spring and fall, with similar magnetic geometry. Indeed, autumn is aurora season, too. Geomagnetic disturbances are almost twice as likely in spring-fall versus winter-summer, according to historical records.

One thing is certain, though. 'This the season for auroras -- and lots of data for THEMIS. Says Sibeck, "We welcome the spring!"