Dear Urban Astronomer
I am pregnant, and am worried that all these Blood Moons are harming my baby. I have asked around in my community, but everybody has their own scary story about what will happen to my baby if I go outdoors during the blood moon. Please let me know what precautions I must take.
Okay so nobody actually mailed this question to me. But at the time of writing, my wife is pregnant and spends a lot of time online in pregnancy forums and facebook groups and she sees people asking it all the time, which seems odd since neither my wife nor I had ever heard of such fears. Now I thought everybody knew there was nothing to fear, so what is all this about?
First off, let’s recap about “Blood Moons”. A short while ago, some pastors published their “Blood Moon Prophecy”, in which they described a coming Tetrad of blood red moons. The timing of these blood moons had religious significance, and was a sign of coming troubles. It’s interesting to me for how they’ve used scary language to describe a perfectly ordinary phenomenon that happens every single year and I’ve written about it before, but the short version is this: A blood moon is nothing more or less than a lunar eclipse. There are between three and five of these every single year, although they are usually not all visible from the same location. At the deepest point of the eclipse, light refracting through the Earth’s atmosphere into the shadow lights the Moon dimly in various shades of orange and red, although as somebody who has actually seen both blood, and a lunar eclipse, I can categorically state that the Moon never becomes blood red. Still, “blood moon” captures the imagination and the name seems to be sticking.
So when I first heard about the warnings to pregnant women to avoid blood moons, I assumed it must just be part of the current minor hysteria over yet another doomsday prophecy. But then I did a bit of homework, and it turns out that this belief goes back to ancient times. It seems that the Aztecs believed that if a pregnant woman was exposed to the sight of a lunar eclipse, various terrible things would happen to her unborn baby. The list of deformities includes birth marks, hair lips, club feet, bad teeth, and even “being ugly”. These beliefs persist today in Mexico, and seem to be common among hispanic-american people, and the standard advice given in these communities seems to be that pregnant women should wear red, stick safety-pins in their clothing, avoid sharp objects, touch metal, avoid magnets, lie face-down without moving on their beds for the duration of the eclipse, and probably countless other variations on those basic themes. Surprisingly similar beliefs are found in India, with even medical professionals advising women to avoid the eclipse.
In fact, countries around the world have their own superstitions about the moon and lunar eclipses. With the exception of muslim states (who treat the lunar eclipse as a time for worship, forgiveness, and prayer), these events have traditionally always been seen as bad omens, portenting wars, famines, the deaths of kings, and so on. It’s always been the way with astrology: changes in the heavenly order like eclipses, comets, novae, all bad omens are bad, and nothing is ever good. Fortunately, astronomers know better, that there is nothing special about the alignment of the Moon, Sun, and Earth that has any effect at all on people living on Earth. To see why the effects predicted by these superstitions make no sense, we’ll examine the situation a bit.
An eclipse (Lunar or Solar) happens when Earth, the Moon and the Sun are all lined up accurately enough for one of these bodies to fall into the shadow of another. The geometry of the situation means that when this alignment happens, the Moon is either full (giving us a lunar eclipse), or new (giving a solar eclipse). Because the Earth’s shadow is so much bigger than the Moon’s, it’s far easier for the Moon to drift into the Earth’s shadow than for the Earth to intercept the Moon’s shadow, and so lunar eclipses happen every few months while solar eclipses are quite a bit rarer. Some people will point out the alignment as being unusual, bringing various forces to bear on the surface of the Earth. But if that were the case, we’d notice strange things happening every full and new moon. I’ve heard it claimed that the “Moon works with magnetism”, and that all these magnets line up during the eclipse, but that’s plain false – the Moon’s magnetic field is so weak that it can’t even protect itself from the Sun’s radiation. Meanwhile, the Earth’s quite powerful magnetic field is on 100% of the time and doesn’t seem to hurt us at all. Other people talk about the amplified gravitational effects, but this makes even less sense. We feel those gravitational effects twice a day, in the form of tides. Like the magnetic fields, the tides don’t seem to have any effect on our health or fortunes at all.
It just doesn’t make any sense that the strong forces that we’re all familiar with don’t do anything to us, yet the fainter and rarer ones do. So if anybody tells you to be frightened of the Moon, don’t be. It’s a lump of dead rock. It’s almost 400,000 kilometers away. It cannot hurt you or your baby. Not even if you forget to pin red ribbons to your underwear.
Footnote: As I researched the beliefs mentioned in this article, I found many comments from women explaining that they believed in the superstitions because of miscarriages and birth defects that had affected them or family members after a lunar eclipse. Now rationally, we expect this to happen because there are lots of lunar eclipses, and millions of babies are born every week. A small percentage of all children are born with some sort of deformity, and a significant number of pregnancies end with miscarriage, so it’s not surprising that sometimes it happens at the same time as a lunar eclipse. But I wasn’t going to be the one to say that to those women who had just lost their babies. Basic human compassion beats out the fight against ignorance any day of the week.