Solar Eclipse of March 20th 2015

Friday 20th March is Important. It is the Equinox, but We Also Have the Rarest Solar Eclipse of the Last 334 Years.

What is the Equinox?

It is the day that the Sun's rays are directly over the Equator. The Sun is moving from being directly over one Hemisphere to being directly over another and this is the day it crosses the line or the most central part. This is best described by one of my poor hand drawings!

At the Equinox, the tilt of the Earth is `side on` to the Sun and therefore the rays are falling directly over the Equator. Put that another way, at midday on the Equinox the Sun is directly over-head on the Equator. As you can see from the drawing, at the June Solstice, the rays are over head the Northern Hemisphere.

If you live in the Northern Hemisphere, you won’t think this that big a deal because not much is happening in terms of the weather. We are still eagerly awaiting the Summer. But, the Earth knows what is happening all right, because the Sun's gravity is pulling as its navel.

New Moons and Eclipses on the Day of the Equinox

It takes 19 years for the Moon's orbit to re-coincide with the calendar set by the Sun, so it follows that an unusual event combining the two then takes another 19 years to happen again. This is one of the reasons that the huge stone circles or observatories of monolithic times had to be set up. So that observation and measurement would predict the next 19-year occasion.

And so the coming unusual event of a New Moon happening on the day of the Equinox, which occurs this Friday, won't happen again for another 19 years and it last happened 19 years ago.

BUT… there is more…. for the angle of the Sun, Moon and Earth can be slightly different during each of these times that there is a New Moon on the Equinox. If the Moon gets exactly in the way, it can result in an eclipse, but if it doesn't get exactly in the way, it won't – the exact alignment doesn't happen every 19 years. So actually, the Equinox that sees an eclipse is rare. These special eclipses comes in bundles of 4 or 5 and they occur one after another, every 19 years, for a century or so and then they disappear again for 334 years.

So just to recap… there is a New Moon on the Equinox every 19 years for definite. But it only eclipses the Sun if we are in one of those centuries where there is a bundle of Equinoctial eclipses. And it so happens that such a bundle starts on Friday. Cool huh?

The last time that we saw such a thing was in the 17th century, 334 years ago, and there hasn't been one since. We have 3 more in this century - all 19 years apart - and then nothing again until the 24th century.

You can see where I'm going with this…. VERY RARE event about to happen!

There is another interesting but weird mathematical fact about 2015 and 2387 – both years in which a new bundle of eclipse's on the Equinox begins. We have three Friday the 13th's this year. February 13th, March 13th and November 13th. And the next time that happens is at the start of the next bundle – 2387. I have no idea why!

Okay we understand the rarity now, but what does it mean?

Well the Earth is undergoing major stress, because the bulge of the Earth is actually a significant part. It is where the Earth is at its widest and where it is spinning fastest. If you stand at the North Pole, you aren't spinning at all, but if you stand at the Equator, you are travelling at a cool 1,000 miles per hour. (Well not `cool` perhaps, but you know what I mean!) Structurally the middle has importance. The `weather` starts there - as in winds - and Earth's geomagnetic field is `centred` around it.

But I think the gravitational effects will be the most significant. The Moon is at its closest, so the combined gravity of the Sun and Moon will be great.

The effect is likely to be disturbing. The huge tidal waves of air and sea that crash around our planet are disturbed and so too are the geomagnetic field lines and channels for ionised plasma. Expect your hair to stand on end!