Blood Moon Bullshit

There's a total lunar eclipse early Tuesday morning that will be visible across the United States.  Unfortunately, for those of us in the EDT time zone, totality won't occur until about 3:00 am (and I have an 8:40 am class that morning).  Also, and this is depressingly predictable for the Hudson Valley during interesting astronomical events, the weather forecast currently says "Showers likely" for Monday night and a 90% chance of showers for Tuesday.  Probably won't even set my alarm.

The NASA Eclipse web site has useful information if, against all odds, it happens to be clear where you are located in the Hudson Valley.

This is where the Moon will be around 3:30 am Tuesday morning in the Mid-Hudson Valley.  The red "star" to the right of the Moon will be the planet Mars.

One of the neat things about an eclipsed Moon is that it turns a beautiful reddish color.

Why is that?  Well let's first look at what causes lunar eclipses.  As shown in the diagram below (not in any way to scale), we see that an eclipse occurs when the Moon moves into the Earth's shadow - the umbra (there are penumbral eclipses, but they're too dim for most people to notice).  When the Moon is in this position, on the opposite side of the Earth from the Sun, it's at its full moon phase (the side of the Moon facing us is normally fully lit by the Sun).

So, why don't we have total lunar eclipses every month when the Moon is in that position?  To answer that, let's first look at the true scale of the Earth and the Moon (size and distance).

Now consider that the Moon does not orbit the Earth is the same plane as the ecliptic (the plane in which the Earth orbits the Sun).  The Moon's orbit is tilted by just over 5° from the ecliptic.  About half the time the Moon is below the ecliptic (and can't pass into the Earth's umbral shadow) and about half the time the Moon is above the ecliptic (and also can't pass into the Earth's umbral shadow).  Only when the Moon is passing through the ecliptic (points called the ascending or descending nodes) at the same time it happens to be a full moon, can we have a total lunar eclipse (you can also have partial and penumbral eclipses if things are quite exactly lined up).

For the 100 years from 2000 through 2099, there will be 85 total lunar eclipses (and 87 penumbral and 58 partial).

OK, back to the red Moon during an eclipse.  If the Earth had no atmosphere, the eclipsed Moon would be dark.  But because the Earth has an atmosphere and the gases in our atmosphere (78% nitrogen and 21% oxygen) scatter the shorter wavelength light at the blue end of the color spectrum, the longer wavelength reddish light makes it through.  This is why the sky looks blue on a sunny day (the blue light being scattered about) and why sunsets and sunrises look red (the longer wavelengths making it through the thick atmosphere on the horizon to our eyes).  As the reddish light passes through our atmosphere, it's also refracted (bent) and this allows it to faintly illuminate the Moon during a total eclipse.

This is called science, boys and girls.  Basic knowledge of eclipses goes back thousands of years to the ancient Babylonians and since then we've learned quite a bit about how it all works.  Using celestial mechanics, we can predict, with virtual 100% certainty, that there will be a total lunar eclipse on September 14, 2099 at 16:57:52 UTC visible in North America (mark your calendars).

OK, now here's where I'm going to piss some people off (and where the title of the post comes from).  Crazy Texas televangelist John Hagee from Cornerstone Church in San Antonio is preaching that this month's eclipse is the first of a series of four "blood moon" eclipses heralding the end of the world (the ever-popular apocalypse).

So, what is a blood moon?  According to CBN News (Pat Robertson's organization):

"A blood moon is when the Earth comes between the sun and the moon," Hagee explained. "And the sun is shining through the atmosphere of the Earth and casts up on the moon a red shadow. And so the moon appears to be red."

Um, OK, but that's what happens with virtually all total lunar eclipses.  Now all of a sudden the dumb ass lazy journalists writing for all these media outlets are calling the eclipse a "blood moon" (just Google the phrase to see)!  What the fuck?  There's nothing special at all about this particular eclipse.

But wait, Steve, you might say, Hagee is arguing that this is a special sequence of four eclipses.  Again, according to CBN News:

"Blood moons are set to appear in April 2014, on Passover, and then again in September 2014 during the Feast of Tabernacles, or Sukkot.

The timing is the same for 2015 -- a total of four blood moons, all appearing on Jewish feast days.

"The sun and the moon and the Earth are controlled by God almighty," Hagee said. "He is the one that is getting them in a direct alignment on a certain day at a certain time -- but each time, it's a Passover or Sukkot."

Well, if God's controlling the Sun and Moon, he's doing it in such a way that it's completely indistinguishable from perfectly natural physical processes (e.g. gravity).  Go to the NASA Eclipse page to view a 5,000 year calendar of lunar eclipses to see how perfectly predictable it all is.

Yes, there are total lunar eclipses on Passover and Sukkot in 2014 and 2015 (October 8, 2014, not September as the news article incorrectly states, but oh well).  Is there something special about this?  Well, think about the following.  Total lunar eclipses can only occur on the full moon.  The Jewish holidays of Passover and Sukkot are tied to the Jewish lunar calendar.  Passover starts on the night of the full moon after the vernal equinox and Sukkot also starts on a full moon six lunar months later.

Since these Jewish holidays start on the full moon, and lunar eclipses are on a full moon, it's certainly inevitable that they should line up sometimes.  Lunar eclipses also occur in cycles and tetrads (a group of 4 eclipses such as this) are not all that unusual.

As the following table from Universe Today shows, there are 8 of these tetrad eclipses in the 21st century:

Eclipse #1	Eclipse #2	Eclipse #3	Eclipse #4
May 16th, 2003	November 9th, 2003	May 4th , 2004	October 28th, 2004
April 15th, 2014*+	October 8th, 2014	April  4th, 2015*+	September 28th, 2015
April 25th, 2032	October 18th, 2032	April 14th, 2033*+	October 8th, 2033
March 25th, 2043*	September 19th, 2043	March 13th, 2044	September 7th, 2044
May 6th, 2050	October 30th, 2050	April 26th, 2051	October 19th, 2051
April  4th, 2061*+	September 29th, 2061	March 25th, 2062*	September  18th, 2062
March 4th, 2072	August 28th, 2072	February 22nd, 2073	August 17th, 2073
March 15th, 2090	September 8th, 2090	March 5th, 2091	August 29th, 2091
*Paschal Full Moon
+Eclipse coincides with Passover

No big deal.  If anyone's convinced that the end of the world is nigh because of these lunar eclipses, I'd be happy to take any extra money off your hand - won't need it after you're raptured anyway, right?

One final rant.  Science works!  Religion has never successfully predicted or explained a damn thing in the real world.  Yes, I'm cranky today.  Rant off.