14 July 2010

7 amazing auroras seen on Earth ... and beyond

The world's biggest light show


The world's biggest light show

The flickering lights over our northern- and southern-most skies at times seem like a mystical offering. Good ole northern lights (aurora borealis) and southern lights (aurora australis) — visible 65 to 72 degrees north and south latitudes respectively — are actually just natural light shows that exist in our ionosphere.
Scientists say auroras are created when a solar wind of charged particles from the sun crashes into the Earth's upper atmosphere over the polar regions. As a result, auroras are generally spotted closer to the north or south poles. You can see them here.

Bear Lake, Alaska

Bear Lake, Alaska

This photo was taken by a U.S. Air Force airman who was stationed nearby. NASA explains that auroras occur most often when the sun is in the most intense phase of an 11-year sunspot cycle. Sunspots increase in number due to violent solar flare eruptions. This means more electrons and protons are added to the solar particles sent into the Earth’s atmosphere. Consequently, this brightens up the northern and southern lights considerably.

Kulusuk, Greenland

Kulusuk, Greenland

This photo of aurora borealis was taken on Kulusuk, a small island on the east coast of Greenland. In Greenland, the northern lights are most visible on a dark, clear night from September to the beginning of April. They are present all year but cannot be seen during the summer months because of the shining midnight sun. Inuit legend says that when the northern lights “dance in the night sky, it means that the dead are playing football with a walrus skull.”

A red aurora seen from Kangaroo Island in south Australia

Kangaroo Island, Australia

Red auroras are considered among the rarest sights on Earth. People living in south Australia are often treated to aurora australis during strong geomagnetic events. The southern lights are most visible during Australia’s autumn and winter months. Experts say the best way to see aurora australis or aurora borealis is to wait for a dark, clear, moonless night. Viewers should head into rural areas to avoid light pollution from neighboring cities.

Lapland, Finland

Lapland, Finland

Lapland is home to some spectacular views of the northern lights. Lapland is a geographic region in northernmost Sweden and Finland, though Sweden has no administrative powers. The photographer says this is a shot of the boreal dawn, which occurs 200 days per year. It is never visible when the summer midnight sun is shining.

An aurora is seen in the Arctic

The Arctic

Auroras have had many names throughout the centuries. The name comes from the Roman goddess of dawn, and the Cree call them the "Dance of the Spirits." In the Middle Ages, auroras were simply called a sign from God. NASA refers to them as “the world’s greatest light show.”

Aurora over Canada as seen from the International Space Station

Canada from space

This picture was taken from the International Space Station (ISS). NASA says the ISS orbits at the same height as many auroras. "Therefore, sometimes it flies over them, but also sometimes it flies right through. The auroral electron and proton streams are too thin to be a danger to the ISS, just as clouds pose little danger to airplane.” This image shows auroras borealis over northern Canada. NASA reports that changing auroras look like “crawling giant green amoebas” from space.

A blue aurora on Jupiter

Jupiter

Auroras can also be spotted on other planets. This sharp blue aurora glows half a billion miles away on Jupiter. This photo is a result of a NASA Hubble Space Telescope close-up. One of the many details that make this aurora different from those seen on Earth are the “satellite footprints” within them. As NASA writes, “Auroral footprints can be seen in this image from Io (along the lefthand limb), Ganymede (near the center), and Europa (just below and to the right of Ganymede's auroral footprint).” These emissions, produced by electric currents generated by the satellites, bounce in and out of the upper atmosphere.

3 comments:

  1. no word can describe it..! So.. Beautiful..

    ReplyDelete
  2. wow! i knew bout aurora but duno its this beautiful.

    ReplyDelete

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