“Invisible Light” Parashat Bo 5777

One of the things I like doing is finding scientific explanations for the 10 plagues. Some people engage is this sort of thing in order to show that the 10 plagues, while seemingly miraculous, were really not such a big deal and can be explained away. These explanations typically result in a rebuttal from the religious crowd to the tune of “Yeah, it might not have broken any rules of physics, but how did it happen precisely when Hashem said it would happen?” And so on. I’m not playing this sort of game. Whatever happened in Egypt happened 3,500 years ago and so unless we build a time machine, we will never really know for sure.

So what is so fascinating about the physics of the 10 plagues? They are interesting because if we can understand the underlying physical mechanism of a plague, perhaps we can understand the message that the plague is trying to convey. Recall that the 10 plagues were inflicted upon the Egyptians not only to punish them but to prepare Am Yisrael for their exodus. Each plague taught Am Yisrael another facet of Hashem’s dominion and each plague taught them something about themselves that as slaves they did not yet understand. Thirty-five hundred years later these messages are equally relevant to us and so it behoves us to understand each plague as much as possible.

This week we’re going to zoom in on the next-to-last plague, the plague of darkness. The Torah describes the plague in three short verses [Shemot 10:21-23]: “Hashem said to Moshe, ‘Stretch forth your hand toward the heavens and there will be darkness over the land of Egypt, and the darkness will become darker.’ Moshe stretched forth his hand toward the heavens and there was thick darkness over the entire land of Egypt for three days. They did not see each other and no one rose from his place for three days, but for all the Children of Israel there was light in their dwellings”. Since the dawn of time, philosophers and scientists have asked: What is “darkness”? Is it the absence of light? Is it the opposite of light? The above verses can give us a clue. In previous plagues, when Hashem would differentiate between the Egyptians and Am Yisrael the Torah would say something like [Shemot 9:26] “Only in the Land of Goshen where the Children of Israel lived was there no hail.” While the Egyptians felt the full force of a plague, the plague would “pass over” Am Yisrael. In the plague of darkness, however, we are told that “the Children of Israel had light”. Not that they “didn’t have darkness,” but, rather, they “[did] have light”[1]. This leads us to the conclusion that the plague of darkness was not the absence of light, but, rather, the opposite of light.

Based on this understanding, the medieval commentators offer similar explanations as to the essence of the darkness. Rashi, the Ramban, and the Ibn Ezra[2] assert that the darkness was a cloud of fog. The fog was thick and suffocating and it made movement impossible. Not only did the darkness not let any light pass through, it was so thick that it rendered any attempts at creating light irrelevant. Just as soon as a match was lit it was extinguished by the fog. Using this explanation, the words “v’yamesh choshech”, translated above as “the darkness will become darker”, can also be translated as “the darkness will be palpable”, meaning that it will have substance (mamashut).

The only problem that I have with this explanation is how Am Yisrael managed to have light while the Egyptians did not. Either there was fog or there wasn’t. The easiest answer would be that the fog of darkness did not enter the Land of Goshen, where Am Yisrael lived. This explanation, however, does not mesh with the language of the Torah. Looking back at the plague of hail, the Torah tells us that the hail did not fall in the “Land of Goshen where the Children of Israel lived”. Compare this with the plague of darkness, in which Am Yisrael had light “in their dwellings” – apparently wherever they happened to be. The Midrash teaches that Am Yisrael used the cover of darkness to enter the homes of the Egyptians and to locate their valuables for future use. This means that a Jew and an Egyptian could be standing in the very same location and yet the Jew could see while the Egyptian could not. How does this happen? If the fog affects the Egyptian, it should equally affect the Jew.

For many years I worked in Air-to-Surface weapons, particularly in television (TV)-guided missiles. The missile is launched and it flies toward the target. As it approaches the target, target features gradually become more prominent and the aim point can be refined. Most modern TV-guided missiles can be slid into a particular window of a building, such as a room in which terrorist leaders are meeting. When a target is attacked at night, ordinary television guidance cannot be used because the operator can’t see the target. In these situations an Infra-Red (IR) seeker is used. IR seekers, also known as “thermal seekers”, can “see” wavelengths that are not visible to the naked eye. Most IR seekers operate in the 3-5 or 8-11 micron bandwidth. You’ve seen the Special Ops guys with their night-vision goggles that turn everything green. IR seekers work using the same principle. To an IR seeker, day and night are one and the same. In order to hide from a TV-guided weapon, the enemy will sometimes try to mask himself behind a smoke screen. Soldiers will use a smoke-grenade and a tank is usually equipped with a smoke-generator. A benefit of IR seekers is that they can see through smoke, fog, haze, and other atmospheric obscurants significantly better than an ordinary TV camera can. I’ve seen demonstrations of a guided missile with an IR seeker hitting a target that was covered by the thickest smoke I’d ever seen. You cannot hide from the law.[3]

The connection of the previous paragraph to the plague of darkness should be clear. Rav Baruch HaLevi Epstein, writing in the “Torah Temima,” basing himself on the idea that the darkness was tangible, suggested that the Egyptians grew cataracts over their eyes. I’d like to propose something similar: perhaps Am Yisrael “had light in [all] their dwellings” because they were given the temporary ability to see infra-red wavelengths. They could see through the smoke as if it wasn’t even there. This explanation is appealing because of the message that it teaches: One of the purposes of the 10 plagues was to “show-off” Hashem’s might to both the Egyptians and to Am Yisrael. After more than two hundred years of slavery and exile, Am Yisrael had forgotten that there existed an omnipotent G-d and the plagues were reminders of His omnipotence. The plague of darkness showed them that Hashem’s omnipotence existed even when it couldn’t be seen. Through the years, Am Yisrael have suffered through periods of “Hastarat Panim,” when Hashem hides His face, as it were, and lets nature take its course. The plague of darkness was to prepare us for these periods. It was meant to permanently burn into our national DNA the belief – nay, the knowledge – that even though Hashem’s presence may be cloaked, He is always still there. We just need the proper spiritual equipment and training to see Him.

This explanation can also give us a new way to interpret the words “v’yamesh choshech”. Notice that the word “v’yamesh” has the same root as the word “Moshe”. As the tenth plague is essentially a knock-out punch, it can be posited that the process of preparation for the exodus concludes with the plague of darkness, meaning that it both begins and ends with the word “Moshe”. Referring back to an earlier shiur[4], we met a Midrash that taught that the word “Moshe” comes from the word “Moshech” – “to pull [towards a goal]”. The purpose of the plague of darkness was to give one last and final tug, to pull Am Yisrael toward their goal of redemption and to their coalescence from a band of slaves into a “Kingdom of Priests and a Holy Nation”.

Ari Sacher, Moreshet, 5777

Please daven for a Refu’a Shelema for Moshe Dov ben Malka and Yechiel ben Shprintza.

[1] Rav Levi Yitzchak of Berdichev notes this in his “Kedushat Levi” and he offers a beautiful Kabalistic explanation that goes waaaaaay beyond the scope of this shiur.

[2] The Ibn Ezra tells of fogs that he has seen while at sea that fit this description.

[3] IR seekers are not omnipotent. They have trouble seeing the target during thermal inversions, when a layer of warm air settles over a layer of cooler air that lies near the ground.

[4] Shemot 5777

About the Author
Ari Sacher is a Rocket Scientist, and has worked in the design and development of missiles for over twenty-five years. He has briefed hundreds of US Congressmen on Israeli Missile Defense, including three briefings on Capitol Hill at the invitation of House Majority Leader. Ari is a highly requested speaker, enabling even the layman to understand the "rocket science", and his speaking events are regularly sold-out. Ari has also been a scholar in residence in numerous synagogues in the USA and Canada. He is a riveting speaker, using his experience in the defense industry to explain the Torah in a way that is simultaneously enlightening and entertaining. Ari came on aliya from the USA in 1982. He studied at Yeshivat Kerem B’Yavneh, and then spent seven years studying at the Technion. Since 2001 he has published a weekly parasha shiur that is read around the world. Ari lives in Moreshet in the Western Galil along with his wife and eight children.
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