There are four types of solar eclipses:
A total eclipse occurs when the Sun is completely obscured by the Moon. The intensely bright disk of the Sun is replaced by the dark silhouette of the Moon, and the much fainter corona is visible. During any one eclipse, totality is visible only from at most a narrow track on the surface of the Earth.
An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon.
A hybrid eclipse is intermediate between a total and annular eclipse. At some points on the surface of the Earth it is visible as a total eclipse, whereas at others it is annular. Hybrid eclipses are rather rare.
A partial eclipse occurs when the Sun and Moon are not exactly in line, and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of the Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as a partial eclipse, because the umbra never intersects the Earth's surface.
The match between the apparent sizes of the Sun and Moon during a total eclipse is a coincidence. The Sun's distance from the Earth is about 400 times the Moon's distance, and the Sun's diameter is about 400 times the Moon's diameter. Because these ratios are approximately the same, the sizes of the Sun and the Moon as seen from Earth appear to be approximately the same: about 0.5 degree of arc in angular measure.
Because the Moon's orbit around the Earth is an ellipse, as is the Earth's orbit around the Sun, the apparent sizes of the Sun and Moon vary. The magnitude of an eclipse is the ratio of the apparent size of the Moon to the apparent size of the Sun during an eclipse. An eclipse when the Moon is near its closest distance from the Earth (i.e., near its perigee) can be a total eclipse because the Moon will appear to be large enough to cover completely the Sun's bright disk, or photosphere; a total eclipse has a magnitude greater than 1. Conversely, an eclipse when the Moon is near its farthest distance from the Earth (i.e., near its apogee) can only be an annular eclipse because the Moon will appear to be slightly smaller than the Sun; the magnitude of an annular eclipse is less than 1. Slightly more solar eclipses are annular than total because, on average, the Moon lies too far from Earth to cover the Sun completely. A hybrid eclipse occurs when the magnitude of an eclipse is very close to 1: the eclipse will appear to be total at some locations on Earth and annular at other locations.
The Earth's orbit around the Sun is also elliptical, so the Earth's distance from the Sun varies throughout the year. This also affects the apparent sizes of the Sun and Moon, but not so much as the Moon's varying distance from the Earth. When the Earth approaches its farthest distance from the Sun (the aphelion) in July, this tends to favor a total eclipse. As the Earth approaches its closest distance from the Sun (the perihelion) in January, this tends to favor an annular eclipse.
Wednesday, July 22, 2009
MARC FABER NEWS
Dr. Doom? Marc Faber Sees Stock Buying Opportunity
The dean of doom, Marc Faber, told CNBC on Tuesday that a variety of asset classes—including equities—may be worth buying for short-term gains. In the midst of market volatility on concerns over Federal Reserve tapering, he said, "Treasury bonds ...
Marc Faber aka Dr. Doom: S&P 500 Index Could Fall 20% To 30% Easily
Dr Doom warns stocks are oversold but S&P readies for another drop
Marc Faber Forecasts 30% Stock Market Crash, Says Buy Gold
The Market Oracle
The Fed's 'tapering' comments have ramped up market volatilaty and Faber gives some advice for short and long-term strategies. For example: ""The best course of action is to actually not buy anything, but rather to reduce positions on a rebound," Faber ...
Marc Faber: Bull in the short term, bear in the long term
... so perhaps it's best left to someone who has historically said “sell.” Marc Faber, author of the ”The Gloom, Boom & Doom Report,” and often called “Dr. Doom” because of his bearish sentiment, says there are buying opportunities — at least in the ...
Marc Faber: Gold a possible canary in the deflation coalmine
Here's what Marc Faber, editor of Gloom Boom Doom report told MarketWatch in an email. “Maybe gold is signaling a deflationary collapse of all asset prices. If this were indeed the case I suppose I would rather own gold than government bonds, high ...
MARC FABER: The Way Things Are Going, Bernanke Will Have To Give Us 96 ...
"Incredibly Bad Sentiment" Makes Gold & Bonds a Buy Says Marc Faber, as All ...
“Sentiment on Gold and Bonds Incredibly Negative” – Marc Faber Predicts ...
Marc Faber Sees Further Downside
China's factory output weakened to a 9-month low today, and financials saw a huge sell-off today, with the FM traders; and The Gloom, Boom and Doom Report's Marc Faber, shares his economic outlook. There's plenty of room for the stock market to decline ...
Marc Faber: More S&P downside, commodities 'horrible'…except gold
Marc Faber says 'thanks' to Bernanke
[An earlier version of this blog mistakenly attributed the comments to Marc Faber's blog. The original comments were made in an interview with Barron's on June 1. The comments were picked up Tuesday in a tracking blog that aggregates Faber's public ...
Dr. Doom Marc Faber: Don't Bet on New Market Highs
Faber said large cap stocks like McDonald's, Coca-Cola, Procter & Gamble and Wal-Mart "have most likely peaked." However, he thinks there are still stocks that show strength that could continue to appreciate "because all the money flows into fewer and ...
Marc Faber Is Glad He Owned Stocks, Even As He Warned Everyone Of Stock ...
"People with assets are all doomed, because prices are grossly inflated globally for stocks, bonds, and collectibles," says the investment advisor in a new interview published in this week's Barron's. But Faber is the first to admit that at least the ...
Marc Faber notes liquidity squeeze depressing stocks but still buying gold
Famously contrarian in his approach, Dr. Faber is usually out of step with Wall Street but has an excellent reputation for calling the major market turns. He does not say he is shorting equities, though he notes emerging market equities and currencies ...