Starship Asterisk*

geckzilla wrote:Let's take it a step further and ebonicise it. We gots some aurizzles in this hizzle.

Chris Peterson wrote:

lewcook wrote:
I wish we could get back to the old form of the plural: aurorae.

Why? Latin plurals are inconsistent with the English language. Good riddance to them. Language regularization is a good thing!

Some evening when I'm out looking at nebulas through my telescope, and enjoying the auroras, I hope to see a supernova with my eyes. So far, the only supernovas I've seen have been telescopic.

lewcook wrote:I wish we could get back to the old form of the plural: aurorae.

http://en.wikipedia.org/wiki/Geomagnetic_pole wrote:

[b][color=#0000FF]Illustration of the difference between geomagnetic poles (Nm and Sm) and geographical poles (Ng and Sg).[/color][/b]

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<<The geomagnetic poles are antipodal points where the axis of a theoretical dipole intersects the Earth's surface. This dipole is equivalent to a powerful bar magnet at the center of the Earth, and it is the dipole that comes closest to accounting for the magnetic field observed at the Earth's surface. Owing to motion of fluid in the Earth's outer core, the poles are constantly moving. However, over thousands of years their direction averages to the Earth's rotation axis. Over millions of years, the poles reverse (north changes place with south).

As a first-order approximation, the Earth's magnetic field can be modelled as a simple dipole (like a bar magnet), tilted about 11° with respect to the Earth's rotation axis (which defines the Geographic North and Geographic South Poles) and centered at the Earth's center. The North and South Geomagnetic Poles are the antipodal points where the axis of this theoretical dipole intersects the Earth's surface. If the Earth's magnetic field were a perfect dipole then the field lines would be vertical at the Geomagnetic Poles, and they would coincide with the North and South magnetic poles. However, the approximation is imperfect, and so the Magnetic and Geomagnetic Poles lie some distance apart.

Like the North Magnetic Pole, the North Geomagnetic Pole attracts the north pole of a bar magnet and so is in a physical sense actually a south magnetic pole. It is the centre of the region of the magnetosphere in which the Aurora Borealis can be seen. As of 2005 it was located at approximately 79.74°N 71.78°W, off the northwest coast of Greenland, and is drifting away from North America toward Siberia.

The locations of geomagnetic poles are predicted by the International Geomagnetic Reference Field, a statistical fit to measurements of the Earth's field by satellites and in geomagnetic observatories. If the Earth's field were exactly dipolar, the north pole of a magnetic compass needle would point directly at the North Geomagnetic Pole. In practice it does not because the geomagnetic field that originates in the core has a more complex non-dipolar part, and magnetic anomalies in the Earth's crust also contribute to the local field.

The geomagnetic poles move over time because the geomagnetic field is produced by motion of the molten iron alloys in the Earth's outer core. Over the past 150 years the poles have moved westward at a rate of 0.05° to 0.1° per year, with little net north or south motion.

Over several thousand years, the average location of the geomagnetic poles coincides with the geographical poles. Paleomagnetists have long relied on the Geocentric axial dipole (GAD) hypothesis, which states that, aside from during geomagnetic reversals, the time-averaged position of the geomagnetic poles has always coincided with the geographic poles. There is considerable paleomagnetic evidence supporting this hypothesis.

Over the life of the Earth, the orientation of Earth's magnetic field has reversed several times, with geomagnetic north becoming geomagnetic south and vice versa – an event known as a geomagnetic reversal. Evidence of geomagnetic reversals can be seen at mid-ocean ridges where tectonic plates move apart. As magma seeps out of the mantle and solidifies to become new ocean floor, the magnetic minerals in it are magnetized in the direction of the magnetic field. Thus, starting at the most recently formed ocean floor, one can read out the direction of the magnetic field in previous times as one moves further away to older ocean floor.>>

http://www.universetoday.com/91561/earths-magnetic-pole-reversal-dont-flip-out/#more-91561 wrote:
Earth’s Magnetic Pole Reversal – Don’t “Flip Out”!
by Tammy Plotner on December 5, 2011

[b][color=#0000FF]Schematic illustration of Earth's magnetic field. Credit: Peter Reid[/color][/b]

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<<Have you heard or read stories about how Earth will some day reverse its magnetic poles? If you have, then chances are very good you’ve also heard this perfectly normal function of our planet could spell disaster. Before you buy into another “end of the world as we know it” scenario, let’s take a look at the facts.

For the record, we know that Earth’s magnetic field has changed its polarity more than once in its lifetime. For example, if you could step back in time some 800,000 years ago with a compass in your hand, you’d see the needle pointed to south – instead of north. Why? Because a compass works on magnetic fields, its needle directs you to the magnetic pole, measured as either positive or negative. The markings on the modern compass dial would be incorrect if the polarity of Earth’s magnetic fields were reversed! Like a witch hunt, many would-be prophets say natural occurrences like this might signal doom… But could their theories be correct? Unfortunately for hyperbole, the geologic and fossil records from past reversals show the answer is “No.” We’ll still be around.

Just like the Sun reversing its magnetic poles, Earthly switches are just a part of our planet’s schedule. During about the last 20 million years of our formation, Earth has settled into a pattern of switching magnetic poles about every 200,00 to 300,000 years… with a period of twice that long since our last reversal. And, it’s not a thing that happens rapidly. Magnetic pole reversal takes up to hundreds of thousands of years to complete. The fields blend together and magnetic poles pop up at odd latitudes as it happens. It’s not that scary! Scientists say that Earth has reversed its magnetic field hundreds of times over the last three billion years and have sped up slightly with time.

How do we know about the impacts of magnetic pole reversal? We take a look at the deep evidence – sediment cores taken from the ocean floor. These samples are perfect fossil records which show us what direction the magnetic field was pointed in as the underwater lava emerged. These ancient flows were magnetized in the field’s direction at the time of their creation and exist on either side of the Mid-Atlantic Rift where the North American and European continental plates are moving away from each other.

[b][color=#FF00FF]The movement of Earth's north magnetic pole across the Canadian arctic, 1831–2001.[/color][/b]

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The last time that Earth’s poles flipped in a major reversal was about 780,000 years ago, in what scientists call the Brunhes-Matuyama reversal. The fossil record shows no drastic changes in plant or animal life.” says NASA’s Patrick Lynch. “Deep ocean sediment cores from this period also indicate no changes in glacial activity, based on the amount of oxygen isotopes in the cores. This is also proof that a polarity reversal would not affect the rotation axis of Earth, as the planet’s rotation axis tilt has a significant effect on climate and glaciation and any change would be evident in the glacial record.”

Unlike a hard-wired magnet, Earth’s polarity isn’t constant – it moves around a bit. The reason we have a magnetic field is our solid iron core surrounding by hot, fluid metal. According to computer modeling, this flow creates electric currents which spawn the magnetic fields. While it’s not possible at this point in time to measure the outer core of our planet directly, we can guess at its movement by the changes in the magnetic field. One such change has occurred for almost 200 years now… Our northern pole has been shifting even more northward. Since it was first located, the pole has shifted its place by more than 600 miles (1,100 km)! What’s more, it’s speeding up. It would seem that it’s moving almost 40 miles per year now, instead of the 10 miles per year as recorded in the early 20th century.

Don’t be fooled by those saying a magnetic pole reversal would leave us temporarily without a magnetic field, either. This is simply isn’t going to happen and we’re not going to be exposed to harmful solar activity. While our magnetic field goes through weaker and stronger phases, there is simply no evidence to be found anywhere that it has ever disappeared completely. Even if it were weakened, our atmosphere would protect us against incoming particles and we’d have more auroral displays at lower latitudes!

So, go ahead… Sleep at night. Earthly magnetic pole reversal is a normal function of our planet and when it does happen its affects will be spread out over hundreds of thousands of years – not flipped like a pancake.>>

http://en.wikipedia.org/wiki/Magnetic_North_Pole wrote:

[img3="Part of the Carta Marina of 1539 by Olaus Magnus, depicting the location of magnetic north vaguely conceived as "Insula Magnetu[m]" (Latin for "Island of Magnets") off modern day Murmansk. The man holding the rune staffs is the Norse hero Starkad."]http://upload.wikimedia.org/wikipedia/e ... tarkad.jpg[/img3]

[b][color=#0000FF]William Gilbert, also known as Gilberd, (24 May 1544 – 30 November 1603)[/color][/b]

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<<The Earth's North Magnetic Pole is the point on the surface of the Northern Hemisphere at which the Earth's magnetic field points vertically downwards (i.e., the "dip" is 90°). Though geographically in the north, it is, by the direction of the magnetic field lines, physically the south pole of the Earth's magnetic field. The North Magnetic Pole should not be confused with the Geographic North Pole, nor with the lesser known North Geomagnetic Pole described later in this article.

The North Magnetic Pole moves slowly over time due to magnetic changes in the Earth's core. In 2001, it was determined by the Geological Survey of Canada to lie near Ellesmere Island in northern Canada at 81.3°N 110.8°W. It was estimated to be at 82.7°N 114.4°W in 2005. In 2009, it was moving toward Russia at between 34 and 37 mi (55-60 km) per year. Its southern hemisphere counterpart is the South Magnetic Pole. Because the Earth's magnetic field is not exactly symmetrical, the North and South Magnetic Poles are not antipodal: a line drawn from one to the other does not pass through the geometric centre of the Earth.

In early times European navigators believed that compass needles were attracted either to a "magnetic mountain" or "magnetic island" somewhere in the far north, or to the Pole Star. The idea that the Earth itself acts as a giant magnet was first proposed in 1600 by the English physician and natural philosopher William Gilbert. He was also the first to define the North Magnetic Pole as the point where the Earth's magnetic field points vertically downwards. This is the definition used nowadays, though it would be several hundred years before the nature of the Earth's magnetic field was understood properly.

The first expedition to reach the North Magnetic Pole was led by James Clark Ross, who found it at Cape Adelaide on the Boothia Peninsula on June 1, 1831. Roald Amundsen found the North Magnetic Pole in a slightly different location in 1903. The third observation was by Canadian government scientists Paul Serson and Jack Clark, of the Dominion Astrophysical Observatory, who found the pole at Allen Lake on Prince of Wales Island in 1947.

The Canadian government has made several measurements since, which show that the North Magnetic Pole is moving continually northwestward. In 1996 an expedition certified its location by magnetometer and theodolite at 78°35.7′N 104°11.9′W. Its estimated 2005 position was 82.7°N 114.4°W, to the west of Ellesmere Island in Canada. During the 20th century it moved 1100 km, and since 1970 its rate of motion has accelerated from 9 km/year to approximately 41 km/year, or 1.3 mm/sec (2001–2003 average; see also Polar drift). If it maintained its present speed and direction it would reach Siberia in about 50 years, but it is expected to veer from its present course and slow its rate of motion. This general movement is in addition to a daily or diurnal variation in which the North Magnetic Pole describes a rough ellipse, with a maximum deviation of 80 km from its mean position. This effect is due to disturbances of the geomagnetic field by charged particles from the Sun.

The first team of novices to reach the Magnetic North Pole did so in 1996, led by David Hempleman-Adams. It included the first British woman and first Swedish woman to reach the Pole. The team also successfully tracked the location of the Magnetic North Pole on behalf of the University of Ottawa. The biennial Polar Race takes place between Resolute Bay in northern Canada and the 1996-certified location of the North Magnetic Pole at 78°35.7′N 104°11.9′W. On 25 July 2007, the Top Gear Polar Challenge Special was broadcast on BBC Two in the United Kingdom, in which Jeremy Clarkson and James May became the first people in history to reach this location in a car.>>

Beyond wrote:I think i have a purr-fect count of 89 stars, at the too numerous to count link.

Hunter wrote:Any chance of getting a FB "share" button?

neufer wrote:On the down side:

Playgrounds in Tromsø consist of these small depressing looking little buildings resembling WWII bunkers
where the children can play in the wintertime with both light and warmth.

nstahl wrote:
What an experience that would be! Wow.