Amazing Webcast of the Aurora Borealis
The Aurora from Terje Sorgjerd on Vimeo.
Norwegian landscape photographer Terje Sorgjerd spent a week capturing one of the biggest aurora borealis shows in recent years. He shot the video in and around Kirkenes and Pas National Park bordering Russia at temperatures around -25 Celsius.
Aurora are caused by the collision of charged particles and the Earth’s magnetic field. Aurora Borealis is Latin for northern lights. An aurora is usually observed at night and typically occurs in the ionosphere. The lights 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 result from emissions of photons in the Earth’s upper atmosphere, above 80 km (50 miles), from ionized nitrogen atoms regaining an electron, and oxygen and nitrogen atoms returning from an excited state to ground state. They are ionized or excited by the collision of solar wind particles being funneled down and accelerated along the Earth’s magnetic field lines; excitation energy is lost by the emission of a photon of light, or by collision with another atom or molecule. Oxygen emissions give off a green or reddish hue, depending on the amount of energy. Nitrogen emissions give off a blue (if the atom regains and electron after it has been ionized) or red hue (if returning to the ground state from an excited state).
Auroras are associated with the solar wind, a flow of ions continuously flowing outward from the Sun. The Earth’s magnetic field traps these particles, many of which travel toward the poles where they are accelerated toward Earth. Collisions between these ions and atmospheric atoms and molecules cause energy releases in the form of auroras appearing in large circles around the poles. Auroras are more frequent and brighter during the intense phase of the solar cycle when coronal mass ejections increase the intensity of the solar wind.
Related: Magnetic Movie – Solar Eruption – Magnetic Portals Connect Sun and Earth – The Mystery of Empty Space – Looking for Signs of Dark Matter Over Antarctica
Giant Star Fish and More in Antarctica
Photo by John Mitchell, New Zealand’s National Institute of Water and Atmospheric Research. Read a great deal about the New Zealand Census of Antarctic Marine Life project: 26 scientists and 18 crew took a 50-day voyage aboard RV Tangaroa in February-March 2008.
Benthic invertebrates in Antarctica are well known for their large size. This feature, known as “gigantism” is common amongst certain groups including sea spiders, sponges, isopods, starfish, and amphipods. The phenomenon is a subject of intense scientific investigation, but there are many contributing factors.
Slow growth rates, late reproductive maturation, prolonged periods of embryonic development, and low predation rates that are typical of Antarctic waters contribute to long life-spans for many species and can also result in large size animals. Animal physiology is thought to play a role as well, as those groups that require large amounts of calcium should not, in theory, grow well in Antarctic waters. This is because the calcium carbonate (needed for growth of shells, or starfish ‘tests’) has low solubility in very cold seawater. Yet starfish, which have a calcareous exoskeleton or ‘test’ which needs lots of calcium, can reach much larger sizes than found in New Zealand waters, as seen in [photo].
Another crucial part of the story is that the low sea temperatures allow more oxygen to be dissolved in the sea water than in warmer latitudes. Sea spiders for example are not only larger, but reach more than 1000 times the weight of most temperate species. Amphipod crustaceans in the Southern Ocean are also large; more than five times as long as the largest temperate species.
Related: Ocean Life – Arctic Sharks – Antarctic Fish “Hibernate” in Winter – Lake Under 2 Miles of Ice