Question: Which direction does the aurora typically extend?
About the article "Aurora", section "Forms and magnetism".

Candidate passages:
Typically the aurora appears either as a diffuse glow or as "curtains" that approximately extend in the east-west direction.
At some times, they form "quiet arcs"; at others ("active aurora"), they evolve and change constantly.
Each curtain consists of many parallel rays, each lined up with the local direction of the magnetic field lines, suggesting that auroras are shaped by Earth's magnetic field.
Indeed, satellites show that electrons are guided by magnetic field lines, spiraling around them while moving toward Earth.
The similarity to curtains is often enhanced by folds called "striations".
When the field line guiding a bright auroral patch leads to a point directly above the observer, the aurora may appear as a "corona" of diverging rays, an effect of perspective.
Although it was first mentioned by Ancient Greek explorer/geographer Pytheas, Hiorter and Celsius first described in 1741 evidence for magnetic control, namely, large magnetic fluctuations occurred whenever the aurora was observed overhead.
This indicates (it was later realized) that large electric currents were associated with the aurora, flowing in the region where auroral light originated.
Kristian Birkeland (1908) deduced that the currents flowed in the east-west directions along the auroral arc, and such currents, flowing from the dayside toward (approximately) midnight were later named "auroral electrojets" (see also Birkeland currents).
Still more evidence for a magnetic connection are the statistics of auroral observations.
Elias Loomis (1860) and later in more detail Hermann Fritz (1881) and S. Tromholt (1882) established that the aurora appeared mainly in the "auroral zone", a ring-shaped region with a radius of approximately 2500 km around Earth's magnetic pole.
It was hardly ever seen near the geographic pole, which is about 2000 km away from the magnetic pole.
The instantaneous distribution of auroras ("auroral oval") is slightly different, centered about 3–5 degrees nightward of the magnetic pole, so that auroral arcs reach furthest toward the equator about an hour before midnight.
The aurora can be seen best at this time, called magnetic midnight, which occurs when an observer, the magnetic pole in question and the Sun are in alignment.
In the 1970s, astrophysicist Joan Feynman deduced that auroras are a product of the interaction between the Earth's magnetosphere and the magnetic field of the solar wind.
Her work resulted from data collected by the Explorer 33 spacecraft.
On 26 February 2008, THEMIS probes were able to determine, for the first time, the triggering event for the onset of magnetospheric substorms.
Two of the five probes, positioned approximately one third the distance to the moon, measured events suggesting a magnetic reconnection event 96 seconds prior to auroral intensification.
Dr. Vassilis Angelopoulos of the University of California, Los Angeles, the principal investigator for the THEMIS mission, claimed, "Our data show clearly and for the first time that magnetic reconnection is the trigger."
The Aurora Airlines fleet does not include any aircraft (as of 3 March 2010). 
Aurora B is responsible for phosphorylation of histone-H3 on serine 10 during mitosis.
This modification is conserved from yeast (where the kinase is known as Ipl1) to man.
Notably, histone-H3 phosphorylation by Aurora B seems not to be responsible for chromatin condensation.
Though Aurora B is enriched at centromeres, it localizes diffusely to all chromatin.
In Drosophila cells, Aurora B depletion disrupts chromosome structure and compaction.
In these cells, the condensin complex does not localize appropriately to the chromosomes.
Similarly, in C. elegans, condensin activity is dependent on Aurora B in metaphase.
However, in Xenopus cell extracts, condensin binding and chromosome condensation are independent of Aurora B.
Likewise, after treating cells with an Aurora B enzyme inhibitor (Aurora B localization is not affected), the condensin complex localizes normally.
Aurora B localizes to the paired arms of homologous chromosomes in metaphase I of C. elegans meiosis.and perturbs microtubule dynamics in mitosis.
Release of this cohesion, which is dependent on Aurora B, is required for progression to anaphase I and segregation of homologous chromosomes.
In mitotic vertebrate B lymphocytes, the proper centromeric localization of a number of Aurora B binding partners requires cohesin. 
New York State Route 78 (NY 78) is a state highway in western New York in the United States.
While it is signed north–south, the southern portion runs in an east–west direction across Wyoming and Erie counties, from its beginning at a junction with NY 19 north of the village of Gainesville to the village of East Aurora.
The part of the route north of East Aurora follows a generally north–south alignment to an intersection with NY 18 in the Niagara County town of Newfane (at the hamlet of Olcott), just south of the Lake Ontario shoreline.
The route is most closely identified in the region with Transit Road, a major north–south trunk road through the center of Erie and Niagara counties; however, NY 78 does not follow Transit Road for its entire length, nor does Transit Road comprise more than half its length.
The highway joins Transit Road north of East Aurora and stays with the road to its end in the city of Lockport.
The section of NY 78 between NY 5 in the town of Amherst and the Lake Ontario shoreline in Newfane was originally designated New York State Route 32 in the mid-1920s.
In the 1930 renumbering of state highways in New York, NY 32 was absorbed into NY 78, which ran from Gainesville to Newfane upon assignment.
From East Aurora to Depew, NY 78 originally used a slightly more easterly alignment along several local streets and a section of NY 422.
Two realignments in the 1930s moved the route onto its modern alignment, and NY 78's original routing between East Aurora and Depew was briefly designated NY 78A during the mid-1930s. 
The Illinois General Assembly chartered the Aurora Branch Railroad on February 12, 1849 to build a branch of the Galena and Chicago Union Railroad to Aurora, which it opened on September 2, 1850.
The company was renamed Chicago and Aurora Railroad on June 22, 1852, and given expanded powers to extend from Aurora to a point north of LaSalle; this extension, to Mendota, was completed on October 20, 1853.
Another amendment, passed February 28, 1854, authorized the company to build east from Aurora to Chicago via Naperville, and changed its name to Chicago and Southwestern Railroad.
The latter provision was never acted upon, and was repealed by an act of February 14, 1855, which instead changed the name to Chicago, Burlington and Quincy Railroad (CB&Q).
The Aurora-Chicago line was opened on May 20, 1864, by which time the CB&Q had, through acquisitions, acquired a main line from Chicago to Galesburg, where it split into branches for Burlington and Quincy.
The portion of the Chicago and Aurora between Aurora and Mendota remains a main line of CB&Q successor BNSF Railway, which calls it the Mendota Subdivision.
The original West Chicago-Aurora branch line is now an industrial track of the Chicago Subdivision.
It hosts about _ freight trains a day, and Amtrak Southwest Chief #3 and 4, California Zephyr #5 and 6,Illinois Zephyr #383 and 380, and Carl Sandburg #381 and 382.
It currently runs through Aurora, Montgomery, Bristol, Plano, Sandwich, Leland, Earlville, Meriden, Mendota, Clarion, Arlington, Zearing, Malden, Princeton, Wyanet, Buda, Neponset, Kewanee, Galva, Altona, Oneida, Wataga, and Galesburg.
It interchanges with the Illinois Railroad La Salle Line in Zearing, the Union Pacific Troy Grove Sub in Earlville, and the Illinois Railroad Ottawa Line in Montgomery, all in Illinois.