Aurora Australis Artwork
Northern Lights Art
sometimes referred to as polar lights, northern lights (aurora borealis), southern lights (aurora australis), is a natural light display in the Earth's sky, predominantly seen in the high-latitude regions (around the Arctic and Antarctic).
Auroras are the result of disturbances in the magnetosphere caused by the solar wind. These disturbances are regularly strong enough to alter the trajectories of charged particles in both solar wind and magnetospheric plasma. These particles, mainly electrons, and protons precipitate into the upper atmosphere (thermosphere/exosphere).
The resulting ionization and excitation of atmospheric constituents emit light of varying color and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from the atmosphere. Proton auroras are usually observed at lower latitudes.
Aurora Australis 2019
Most auroras occur in a band known as the "auroral zone", which is typically 3° to 6° 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 towards the night side of the Earth. Early evidence for a geomagnetic connection comes from the statistics of auroral observations. Elias Loomis (1860), and later Hermann Fritz (1881) and S. Tromholt (1882) in more detail, established that the aurora appeared mainly in the auroral zone. Day-to-day positions of the auroral ovals are posted on the Internet. 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. 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. The Aurora Australis is visible from high southern latitudes in Antarctica, Chile, Argentina, New Zealand, and Australia.
A geomagnetic storm causes the auroral ovals (north and south) to expand, and bring the aurora to lower latitudes. The instantaneous distribution of auroras ("auroral oval") is slightly different, being centered about 3–5° nightward of the magnetic pole, so that auroral arcs reach furthest toward the equator when the magnetic pole in question is in between the observer and the Sun. The aurora can be seen best at this time, which is called magnetic midnight. Auroras seen within the auroral oval may be directly overhead, but from farther away, they illuminate the poleward horizon as a greenish glow, or sometimes a faint red, as if the Sun were rising from an unusual direction. Auroras also occur poleward of the auroral zone as either diffuse patches or arcs, which can be subvisual.
Auroras are occasionally seen in latitudes below the auroral zone when a geomagnetic storm temporarily enlarges the auroral oval. Large geomagnetic storms are most common during the peak of the 11-year sunspot cycle or during the three years after the peak. An aurora may appear overhead as a "corona" of rays, radiating from a distant and apparent central location, which results from perspective. An electron spirals (gyrates) about a field line at an angle that is determined by its velocity vectors, parallel and perpendicular, respectively, to the local geomagnetic field vector B. This angle is known as the "pitch angle" of the particle. The distance, or radius, of the electron from the field line at any time is known as its Larmor radius. The pitch angle increases as the electron travel to a region of greater field strength nearer to the atmosphere. Thus, it is possible for some particles to return, or mirror, if the angle becomes 90° before entering the atmosphere to collide with the denser molecules there. Other particles that do not mirror enter the atmosphere and contribute to the auroral display over a range of altitudes. Other types of auroras have been observed from space, e.g."poleward arcs" stretching sunward across the polar cap, the related "theta aurora", and "dayside arcs" near noon. These are relatively infrequent and poorly understood. Other interesting effects occur such as flickering aurora, "black aurora" and subvisual red arcs. In addition to all these, a weak glow (often deep red) observed around the two polar cusps, the field lines separating the ones that close through the Earth from those that are swept into the tail and close remotely.
Aurora Australis Sydney
Your best chance at witnessing the Aurora Australis is to be as far south as possible. Tasmania is the obvious choice, and you’ll want to aim for places away from city lights. Mount Wellington, Bruny Island, Cradle Mountain-Lake St Clair National Park, the Huon Valley, the Central Highlands and Tasmania’s South Arm all offer great horizon views down south. But it’s not all bad news for mainland dwellers: Victoria, southern New South Wales and the southernmost parts of South Australia and Western Australia are occasionally treated to an eyeful of lights. In Victoria, we’d suggest Point Lonsdale, Cape Schanck, Flinders, the south side of Phillip Island, Tidal River at Wilsons Promontory, Aireys Inlet, Anglesea or wherever there’s an uninterrupted horizon view. Closer to the city you can try the coast near Werribee South, Point Cook and up to a hill in Meredith.
Aurora Australis Visual Forms
Auroras frequently appear either as a diffuse glow or as "curtains" that extend approximately in the east-west direction. At some times, they form "quiet arcs"; at others, they evolve and change constantly. These are called "active aurora". The most distinctive and brightest are the curtain-like auroral arcs. Each curtain consists of many parallel rays, each lined up with the local direction of the magnetic field, consistent with auroras being shaped by Earth's magnetic field. In situ, particle measurements confirm that auroral electrons are guided by the geomagnetic field, and spiral around them while moving toward Earth. The similarity of an auroral display 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 the discrete auroras, which are at times bright enough to read a newspaper by at night. and can display rapid subsecond variations in intensity. The diffuse aurora, though, is a relatively featureless glow sometimes close to the limit of visibility. It can be distinguished from moonlit clouds because stars can be seen undiminished through the glow. Diffuse auroras are often composed of patches whose brightness exhibits regular or near-regular pulsations. The pulsation period can be typically many seconds, so is not always obvious. Often there are black aurora i.e. narrow regions in diffuse aurora with reduced luminosity. A typical auroral display consists of these forms appearing in the above order throughout the night.
Museum quality work made for the home! Brighten up any space with our beautiful and professionally finished canvas prints.
Northern Lights Canvas Painting
• Breathing color canvas; 440gsm with a satin finish
• Firwood stretcher bars sourced from sustainable Canadian forests
• Printed by an Epson 9900 eleven color printer using Epson archival inks
• Inks are water-resistant, durable and provide vivid print results
• Canvases are hand stretched perfectly flat and stapled to the wood frame
• Each canvas is printed, stretched and stapled by hand in Montreal, Canada
• Will arrive ready to hang
Aurora Australis Canvas Painting For Sale