does the Earth have a ring system? does it affect weather?
In 1980, John O’Keefe suggested that an Earth ring could have caused the onset and breakup of an Ice Age (Nature 285, 309-311) The idea is difficult to test observationally. Yet it becomes more intriguing and perhaps likely as time goes by, as more and more planetary rings are discovered. And it is a physically beautiful thing to consider.
How can we test the idea, short of flying a special purpose satellite toward the Sun where it could look backward to see the illuminated ring? Well, here’s an idea. Let’s see if we can forecast the weather accurately, months ahead, by hypothesizing that a ring system exists and working out what the consequences should be.
Here is the first effort:
Very first ring-based weather guess.
Today is December 31, 2010. From the second week of January 2011 forward, winter in the Northern Hemisphere will undergo a deep chill compared to today and compared to average Januaries (and Februaries, and Marches). The cold anomaly will lighten somewhat on or about March 21, 2011, but the weather will still remain unusually cold until June 10 approx.
While the Northern Hemisphere is cold, however, the Southern Hemisphere will be having a relatively hot summer up to March 21. The Southern Hemisphere will not rise to new levels of high temperature on any single day, but it will have many hot days. Autumn in the Southern Hemisphere will suddenly cool, though, on or about the first week of June.
Here is the reasoning. (i) A ring in the equatorial plane (most common orientation, so let’s assume Earth has one of these) would shade the northern hemisphere from the Sun from September 21 to March 21.
(ii) A second ring orientation is also possible, a ring in the plane of the lunar orbit. Saturn has one so we hypothesize that we have one too. Such a ring would shade the Sun every year from the day of the Sun’s passage downward across the Moon’s orbit until the Sun’s passage upward across the Moon’s orbit (I think there is a name in Hindu for these two moving points on the ecliptic, “Rahu” and “Ketu”). This year, the shaded period in the Northern Hemisphere would be approx December 11, 2010 to approx June 10, 2011. The Southern Hemisphere, meantime, is shaded exactly when the North is not.
(iii) Last year’s winter was harsh, at about the time frame that would be accounted for by the lunar-plane ring, so we hypothesize that the lunar-plane ring must be particularly dense. We further suppose that it is dense because of the quiet sun. Solar activity can knock satellites out of their orbits so we can reasonably suppose that it tends to erode a ring too, by knocking material out of the marginally stable orbits. OK, so the ring is dense, and it will stay dense until something perturbs the orbits.
(iv) The Southern Hemisphere is un-shaded when the Northern Hemisphere is shaded, so when NOrthern Hemisphere shade is diminished on March 21, the Southern Hemisphere receives that shade. And when Northern Hemisphere shade from the lunar-plane ring is withdrawn entirely in June, then just then the Southern Hemisphere falls into shade.
(v) The reason weather may become more harsh in the second week of January than it is now (December 31) would be that, as O’Keefe noted in 1980 and as geometry readily confirms, the shading of the Sun by a ring in the equatorial plane should become less as the winter solstice nears. The Sun is behind less and less material. At tropical latitudes, the Sun probably fully emerges below the shade of the ring. But at all latitudes, the shade is reduced as the solstice nears. After the solstice, the Sun begins to rise upward toward the equator, and doing so, it slips again behind the shade of the equatorial-plane ring. The cold therefore will return as the Sun is now making its way upward toward the equator.