Shabbat 107b ~ Can the Leopard Change Its Spots?

In a discussion about the permanence of wounds and their ability to heal comes this:

בעא מיניה לוי מרבי מנין לחבורה שאינה חוזרת דכתיב היהפוך כושי עורו ונמר חברברתיו מאי חברברתיו אילימא דקאי ריקמי ריקמי האי ונמר חברברתיו נמר גווניו מבעי ליה אלא ככושי מה עורו דכושי אינה חוזרת אף חבורה אינה חוזרת 

Levi raised a dilemma before Rabbi Yehuda HaNasi: From where is it derived that a wound is defined as something irreversible? He answered him that it is derived as it is written: “Can a Cushite change his skin, or a leopard its spots [chavarburotav]?” (Jeremiah 13:23). The Gemara explains: What does chavarburotav mean? If you say that they are spotted marks on the leopard’s skin, that phrase: Or a leopard its spots, should have been: Or a leopard its colors. Rather, chavarburotav means wounds, and they are similar to the skin of a Cushite: Just like the skin of a Cushite will not change its color to white, so too a wound is something that does not reverse.

“Can a leopard change its spots?” It is a famous question from the Book of Jeremiah, asked rhetorically. The presumptive answer is “why no, a leopard cannot change its spots!” And with this in mind, God tells Jeremiah that because the Jewish people don’t change their wicked ways, He will punish them. And so in the next verse God announces that he will scatter the Jewish people “like straw that flies before the desert wind.”

The leopard and its spots is a great analogy, but it turns out to be rather more complicated than perhaps the great prophet first understood.

the origins of camouflage in Big Cats

In 2010 William Allen and colleagues published a review of the camouflage patterns in thirty-five different species of wild cats, including lions, panthers, and our leopards. After controlling for the effects of shared ancestry, they found that “the likelihood of patterning and pattern attributes, such as complexity and irregularity, were related to felids’ habitats, arboreality and nocturnality.” In other words, the markings on a wild cat are related to where it lives, how it hunts, and when it sleeps. Because the primary hunting strategy of all cats is to stalk prey until they are close enough to capture them with a pounce or quick rush, the hunts are more successful when an attack is initiated from shorter distances. So the cat must remain undetected for as long as possible and its camouflage helps achieve this. Allen concluded that evolution has generally paired plain cats with relatively uniformly colored, textured and illuminated environments, and patterned cats with environments that Rudyard Kipling described as “full of trees and bushes and stripy, speckly, patchy-blatchy shadows.”

Cats such as leopards – which live in dense habitats, among trees and are active at low light levels – are the most likely to be patterned, especially with irregular or complex shapes. Species that live in open grassland, such as lions, tend to have plainer coats. Allen’s research also explains why black leopards are common but black cheetahs unknown. Unlike cheetahs, leopards live in a wide range of habitats and have varied behavioural patterns. 

Leopards without any spots

In fact there are completely black leopards, which are more commonly called black panthers. (One was even kept in the Tower of London in the late eighteenth century.) This feature is called melanism, and according to a 2017 international survey of leopards, it occurs in about 11% of the species. That’s a lot of leopards without any spots.

A leopard that changed its spots. It happens in about 11% of the species. Don’t tell Jeremiah.

But Can People Change?

Despite the rather technical talmudic re-reading of Jeremiah’s verse, there is no doubt as to its original meaning. It was divine despair, as God gave up, as it were, on the ability of the Jewish people to ever meaningfully change its national character. Here, for example is the commentary of the Malbim, Rabbi Meir Leibush Wisser (1809-1879):

,הלא א"א שהנמר יהפך חברברותיו, שצבע עורו הוא טבע כולל בכל המין וכל הנמרים, כן אי אפשר שתוכלו להיטיבאתם למודי הרע שכבר נעשה הרע טבעי לך, ולכן ואפיצם כקש עובר

It is not possible for a leopard to change its spots, (for the color of its skin is its natural state in all of the leopard species,) so it is not possible to incline your natural inclination for the good, for evil has become natural to you. That is why I will scatter you as straw in the wind…

Can we change our characters to a meaningful degree? That is the question we ask each year on Yom Kippur, and the answer we are always given by our spiritual leaders is this: we can change, if we put in the effort that is required. Maimonides also believed that it is possible to change (Laws of Repentence 2:2):

וּמַה הִיא הַתְּשׁוּבָה. הוּא שֶׁיַּעֲזֹב הַחוֹטֵא חֶטְאוֹ וִיסִירוֹ מִמַּחֲשַׁבְתּוֹ וְיִגְמֹר בְּלִבּוֹ שֶׁלֹּא יַעֲשֵׂהוּ עוֹד

What is repentance? The sinner shall cease sinning, and remove sin from his thoughts, and wholeheartedly conclude not to revert back to it…

But are there limits to this belief in the religious ability to repent? Here is perhaps one of the most challenging questions ever seen asked in this context. What happens when a Nazi repents of his beliefs and actions, and asks to convert to Judaism? Must he be accepted, or are there limits, even when we believe that true repentance is possible? This question is found in a 1991 work about the laws of conversion, Chukkat Hager, by Rabbi Moshe Steinberg (1909-1993) who was the Chief Rabbi of the town of Kiryat Yam in Israel:

Regarding a gentile who was once a member of the Nazi Party, and it is likely that he himself took part in war crimes, and who now has repented and wishes to become Jewish, should we accept him?

What do you think? Assuming the former Nazi was indeed repentant, would you approve of his conversion to Judaism? If not, why not? Is it because a leopard cannot change its spots?

[If you want to read how Rabbi Steinberg ruled on the question, click here, but first formulate your own opinion…]

Shabbat 81 ~ A History of Toilet Paper

Toilet paper has been in short supply recently. But it was non-existent in talmudic times. People used stones instead. Today’s page of Talmud gets into the details of personal hygiene, and discusses how the stones used to clean oneself after defecation may be prepared and used on Shabbat:

שבת פא,א

זוּנִין עַל לְבֵי מִדְרְשָׁא, אֲמַר לְהוּ: רַבּוֹתַי, אֲבָנִים שֶׁל בֵּית הַכִּסֵּא שִׁיעוּרָן בְּכַמָּה? אָמְרוּ לוֹ: כְּזַיִת כֶּאֱגוֹז וּכְבֵיצָה. אֲמַר לְהוּ: וְכִי טוּרְטָנֵי יַכְנִיס? נִמְנוּ וְגָמְרוּ מְלֹא הַיָּד. תַּנְיָא, רַבִּי יוֹסֵי אוֹמֵר: כְּזַיִת כֶּאֱגוֹז וּכְבֵיצָה. רַבִּי שִׁמְעוֹן בְּרַבִּי יוֹסֵי אוֹמֵר מִשּׁוּם אָבִיו: מְלֹא הַיָּד

Examples of terracotta pessoi found in Roman latrines dating from the 2nd century AD. The one on the left comes from Utica (Sicily). The one the right was found in Crete. From Charlier, P. Brun L. Prêtre C. Huynh-Charler I. Toilet Hygiene in the Classical era. British Medical Journal. 2012; 345; e8287.

The Gemara relates: Zunin entered the study hall and said to the Sages: My teachers, with regard to stones that may be moved on Shabbat for wiping in the bathroom, how much is their measure? They said to him: Stones of only three sizes may be moved for that purpose: An olive-bulk, a nut-bulk, and an egg-bulk. He said to them: And will he take scales [turtani] into the bathroom to weigh each stone? They were counted and the Sages concluded that one need not measure the stones. He simply takes a handful of stones. It was taught in a baraita: Rabbi Yosei says the measure of bathroom stones is an olive-bulk, a nut-bulk, and an egg-bulk. Rabbi Shimon, son of Rabbi Yosei, says in the name of his father: One need not measure the stones. He simply takes a handful of stones.

Roman Toilet HygiEne

Museum of Fine Arts Boston. Drinking Cup (kylix) c. 500 BCE. From Orvieto Greece. A gift of Edward Perry Warren to MFA; accessioned 1910. Accession # RES.08.31b

In a helpful paper titled Toilet hygiene in the classical era, the authors explain that in the Roman world there was no toilet paper. After defecation, the Roman rear end would be cleaned with a natural sponge attached to a stick called a tersorium. This sponge was then rinsed off in water or vinegar and thoughtfully left for the next person to use. They also used small stones or ceramic fragments called pessoi in place of a sponge, much like those described in today’s page of Talmud. These pessoi have been uncovered in ancient latrines all around the Mediterranean.

The next time you have a chance to visit the Museum of Fine Arts in Boston, have a look at their Greek drinking cup or kylix dated around 500 BCE (accession number RES.08.31b.) It demonstrates (as if you needed an explanation) how these pessoi were used. A man is shown semi-squatting with his clothing raised. While he maintains his balance with a cane in his right hand he is clearly wiping his buttocks using a pessos with his left hand. So now you know.

Early Toilet Paper

I remember waxed toilet paper, rather like baking paper (yes, it was once a thing) from my grandparents homes in north London in the 1960s and 70s. Rather inexplicably, the British once liked their paper to be hard and impervious to absorbing anything, and had to be persuaded to try a softer approach.

Toilet paper was used in China as early as the sixth century CE. In fact the scholar Ten Chih-Thui (531-91 CE) wrote that “paper on which there are quotations or commentaries from Five Classics or the names of sages, I dare not use for toilet purposes.” All this was a bit much for an Arab traveller through China in 851. He was horrified at the practice of using toilet paper: “They are not careful about cleanliness, and they do not wash themselves with water when they have done their necessities; but they only wipe themselves with paper.” One can only wonder what the traveller would have thought of the English and their waxed shiny toilet paper.

Toilet Paper and Human Dignity

Later in today’s page of Talmud, Rav Chisdah was asked if it would be permitted to carry the pessoi up to a rooftop latrine on Shabbat. The concern here is that this would involve additional exertion, which is forbidden. Rav Chisdah ruled that it was certainly permissible, because “human dignity is so important that it suspends a prohibition of the Torah” (גָּדוֹל כְּבוֹד הַבְּרִיּוֹת שֶׁדּוֹחֶה אֶת ״לֹא תַעֲשֶׂה״ שֶׁבַּתּוֹרָה).

This lofty principal has many disparate applications; it has been cited in modern responsa literature as the driving force behind allowing the deaf to wear hearing aids on Shabbat, or allowing women to be called to read from the Torah. But from today’s page of Talmud we are reminded that, for the rabbis of the Talmud, the principal of human dignity operates in our most private and intimate spaces.

Shabbat 77b ~ On the Healing Power of Honey

In today’s page of Talmud we learn that aside from being delicious, honey was once used as a salve to heal a wound:

שבת עז,ב

דְּבַשׁ כְּדֵי לִיתֵּן עַל הַכָּתִית. תָּנָא: כְּדֵי לִיתֵּן עַל פִּי כָתִית. בָּעֵי רַב אָשֵׁי: ״עַל כָּתִית״ — אַפּוּמָּא דְּכוּלַּהּ כָּתִית, אוֹ דִילְמָא אַמּוּרְשָׁא קַמָּא דְּכָתִית, לְאַפּוֹקֵי הוּדְרָנָא דְּלָא — תֵּיקוּ

We learned in the mishna: The measure that determines liability for carrying out honey is equivalent to that which is used to place on a sore caused by chafing. A tanna taught in a Tosefta: The precise measure is equivalent to that which is placed on the opening of a sore, i.e., on the wound itself. Rav Ashi raised a dilemma: Does the term on a sore mean the measure of honey spread on the opening of the entire sore; or, perhaps it means the measure spread on the primary protuberance of the sore, to the exclusion of the surrounding area upon which he does not spread honey? No resolution was found for this dilemma either. Therefore, let it stand unresolved.

But elsewhere in the Talmud, honey was considered to be bad for a wound:

בבא קמא פה,א 

כדתניא הרי שעבר על דברי רופא ואכל דבש או כל מיני מתיקה מפני שדבש וכל מיני מתיקה קשין למכה והעלה מכתו גרגותני יכול יהא חייב לרפאותו ת"ל רק

It was taught in a Braisa: If the victim of an assault disobeyed the advice of his doctor and ate honey or all types of sweets - and this violated his doctor's instructions because honey and all types of sweets are harmful for a wound - it could be thought that the assailant is still obligated to heal the victim. Therefore the Torah uses the word רק (only) to teach otherwise...(Bava Kamma 85a)

Secretions of the honey bee. From Israili, Z. Antimicrobial Properties of Honey. American Journal of Therapeutics 2014. 21; 304–323.

But certainly in today’s page of Talmud, honey was considered to be beneficial. In fact honey has been used as a medicine for at least the last 3,000 years.  And as we will see, honey has some quite amazing therapeutic uses.

FROM WHERE DOES HONEY COME?

The honeybee is the only insect that produces food eaten by humans. Here is what happens: The female honeybees use their proboscis (a tube-like tongue) to up suck flower nectar and mix it with their saliva and enzymes. Then they store it in a honey sack. Back at the hive, the mixture is regurgitated into cells, dried to about 16% moisture, and stored as a primary food source. As you might expect, the content of the honey depends on a number of factors including the species of bee, the kind of flowers on which they fed, and the conditions in which the honey was stored.

Honey as an Antibiotic

In a recent review article that focuses on the antimicrobial properties of honey, Zafar Israili from the Emory School of Medicine noted that a large number of laboratory and clinical studies have confirmed the broad-spectrum antimicrobial properties of honey.  These include antibacterial, antifungal, antiviral, and antimycobacterial.  “Honey,” wrote Israili, “was found to be an effective topical treatment for ringworms, athlete’s foot, jock itch, nail fungus, and yeast infections and reported to be comparable to many over-the-counter antifungal preparations.” These properties are likely due to the honey’s acidity, osmotic effect, high sugar concentration, and the presence of chemicals like hydrogen peroxide, antioxidants, and lysozymes.  

Honey contains more than 600 compounds (you can see a list of them here), and the wound healing properties of honey are probably its oldest and best studied medicinal property.  It has been shown to aid wound healing in conditions such as chronic pressure sores, traumatic and diabetic wounds, diabetic foot ulcers, boils, burns, fistulas, necrotizing fasciitis, and a very nasty condition called Fournier’s gangrene. (That's necrosis of the scrotum. Yes, quite gross.) So in contrast to the advice of the talmudic doctors that "honey is bad for an injury", honey turns out to be rather good for wounds, especially when applied directly to them.  But honey isn't just good for wounds...

“There is a large body of evidence to support the use of honey as a wound dressing for a wide range of types of wounds. Its antibacterial activity rapidly clears infection and protects wounds from becoming infected, and thus it provides a moist healing environment without the risk of bacterial growth occurring. It also rapidly debrides wounds and removes malodor.”

— Molan, PC. The Evidence supporting the use of honey as a wound dressing. Lower Extremity Wounds 2006. 5 (1); 52.

Your Mother was correct

A 2012 study from physicians at the Sackler School of Medicine in Tel Aviv tested the effects of honey on nocturnal cough and sleep quality.  They enrolled 150 children age 1-5 years (and presumably, their tired and exasperated parents) and half an hour before bedtime, gave half of them “a single dose of 10g of eucalyptus honey, citrus honey, or labiatae honey,” and the other half a placebo. (In case you were wondering, as was I, as to what the placebo was, here’s the answer: date extract, “because its structure, brown color, and taste are similar to that of honey.” True enough.) What they found might change the way you treat your own cough this winter. Each of the three honey groups had a better response compared with the date extract, and no significant differences were found among the different types of honey. The authors concluded that honey may be preferable to cough and cold medications for childhood respiratory infections. 

The effect of different types of honey and date extract on cough frequency (I), cough severity (II), cough bothersome to child (III), the child’s sleep (IV), parent’s sleep (V), and combined symptoms score (VI). P <0.05 for the comparisons between group D and the other groups. A, eucalyptus honey; B, citrus honey; C, labiatae honey; D, silan date extract. From Cohen, AH. et al. Effect of Honey on Nocturnal Cough and Sleep Quality: A Double-blind, Randomized, Placebo-Controlled Study. Pediatrics 2012. 130 (3); 465-471.

Honey as a Medicine for Pretty much everything

There are dozens of other medical conditions for which honey may be used. Here is what the review from Israili has to say:

Honey has been reported to be of benefit in a large number of human pathologies including allergy, asthma, bronchitis, common cold, flu, hay fever, nasal congestion, rhinitis, sinusitis, upper respiratory infections, sore throat, cough, fatigue, anxiety, migraine (stress related), cuts, lacerations, burns, wounds (venous, arterial, diabetic, malignant), pressure ulcers, malignant ulcers, perianal and gluteofemoral fistulas, bed sores, adult and neonatal postoperative infections, necrotizing fasciitis, pilonidal sinus, insect bites, infections (bacterial including antibiotic-resistant strains and fungal), septicemia, conjunctivitis and other eye diseases, endophthalmitis, acne, chronic seborrheic dermatitis, dandruff, eczema, psoriasis, inflammation, gingivitis, stomach ache, stomach ulcers, digestive disorders, constipation, vomiting, diarrhea, colitis, dehydration, diabetes, osteoporosis, insomnia, chronic fatigue syndrome, anemia, hypertension, immune disorders, multiple sclerosis, cardiovascular disease, hepatitis, tumors, cancer, and radiation/chemotherapy-induced oral mucositis.

You'd have to check the references and decide if the evidence supports claims like this. But in any event, this list supports the observation in today’s page Talmud that honey was used to heal wounds. If only it helped heal the present pandemic.

Shabbat 75a ~ Some Jewish Astronomers

שבת עה,א

 אָמַר רַבִּי שְׁמוּאֵל בַּר נַחְמָנִי אָמַר רַבִּי יוֹחָנָן: מִנַּיִן שֶׁמִּצְוָה עַל הָאָדָם לְחַשֵּׁב תְּקוּפוֹת וּמַזָּלוֹת — שֶׁנֶּאֱמַר: ״וּשְׁמַרְתֶּם וַעֲשִׂיתֶם כִּי הִיא חׇכְמַתְכֶם וּבִינַתְכֶם לְעֵינֵי הָעַמִּים״, אֵיזוֹ חָכְמָה וּבִינָה שֶׁהִיא לְעֵינֵי הָעַמִּים — הֱוֵי אוֹמֵר: זֶה חִישּׁוּב תְּקוּפוֹת וּמַזָּלוֹת

And Rabbi Shmuel bar Nahmani said that Rabbi Yochanan said: From where is it derived that there is a mitzva incumbent upon a person to calculate astronomical seasons and the movement of constellations? As it was stated: “And you shall guard and perform, for it is your wisdom and understanding in the eyes of the nations”(Deuteronomy 4:6). What wisdom and understanding is there in the Torah that is in the eyes of the nations, i.e., appreciated and recognized by all?  It is the calculation of astronomical seasons and the movement of constellations, as the calculation of experts is witnessed by all.

According to the great Rabbi Yochanan (or more likely Rabbi Yonatan, since he was Rabbi Shmuel’s teacher) it is a mitzvah for every person to calculate for herself the positions of the planets and constellations. This is also the position of the important work Sefer Mitzvot Gagdol (#47) complied by Moses ben Jacob of Coucy and completed in 1247. Moses gave two reasons for this mitzvah. The first is that by understanding astronomy, farmers will gain insight into the planting cycle. And secondly, a knowledge of astronomy and the passage of the seasons will help determine when additional months must be intercalated into the calendar so as to allow Pesach to be celebrated in the Spring. But Rabbi Yochanan’s prooftext “for it is your wisdom and understanding in the eyes of the nations” suggests that it is not just about an understanding of astronomy. That knowledge must be demonstrated to those outside of Judaism. And there is, in fact, a long tradition of Jews being astronomers, and sharing their knowledge far beyond the Jewish community. It started with the very first Jew: Abraham.

THE THREE Abraham the Astronomers

According to David Gans, Abraham, the first Jew, was also the first Jewish astronomer. Gans, who wrote his compendium on astronomy around 1612, believed that Abraham had obtained his own knowledge of the stars from none other than the primordial human, Adam.

Adam was an outstanding astronomer . . . and Josephus has written that when Abraham went down to Egypt because of the famine he taught them astronomy and mathematics and was praised by the Egyptians for his outstanding wisdom in these two disciplines....Abraham passed this knowledge to his son Isaac and grandson Jacob.

And so began our long tradition of taking a special interest in astronomy. It would be hard to call the early medieval practitioners astronomers in the modern sense of the word, since almost none actually sat around and looked at the motions of the heavens. Instead they translated works of astronomy into Hebrew, or drew up tables and charts of where the planets could be located, called ephemerides. One of the earliest was Sahl ibn Bishr al-Israili (c. 786–c. 845), also known as Haya al-Yahudi (Haya the Jew) who is believed to have been the first person to translate Ptolemy’s Almagest into Arabic, though not everyone believes that he was actually Jewish.

There is no doubt though that the famous exegete, grammarian and poet Abraham ibn Ezra (d.1167) was Jewish. And he was also a bit of an astronomer too. Actually what he did was mostly astrology, but hey, that’s what everyone did in the twelfth century. He was, according to Bernard Goldstein, “one of the foremost transmitters of Arabic scientific knowledge to the West,” and since Ibn Ezra was one of the first scholars to write on scientific subjects in Hebrew, he had to invent or adapt many Hebrew terms to represent the technical terminology of Arabic. Sadly, some of his translations and original works are no longer extant, but among his most famous works are Sefer Ha’Ibbur (The Book of Intercalation), about the calendar, and Sefer HaMeorot, on medical astrology.

A third “Abraham the Astronomer” was the Spanish Abraham bar Hiyya (d. 1136) who was also an important mathematician. This Abraham wrote Tzurat Ha’aretz (The Form of the Earth) on the formation of the heavens and the earth, as well as Cheshbon Mahalach HaKochavim (Calculation of the Course of the Stars).

Levi ben Gershon

Measuring the height of a star with a Jacob's Staff. From John Sellers' Practical Navigation (1672).

Levi ben Gershon (d.1344) -the “Ralbag” - lived a century later and made an enormous contribution to astronomy. He is well known as a Jewish philosopher and the author of Sefer Milhamot Ha-Shem, (The Wars of the Lord), which took some twelve years to write. He also wrote Ma’aseh Choshev, a work on mathematics. It was not widely read outside of Jewish circles since it was never translated from the Hebrew, though it contains a number of very important theorems. But Levi was also an astronomer in the sense of the word used today. According to the late Yuval Ne’eman, “he personally remeasured everything, basing his models on his own observations only. In that, he is rather unique for that period. Levi writes "no argument can nullify the reality that is perceived by the senses, for true opinion must follow reality, but reality need not conform to opinion" - certainly not the usual position in the Middle Ages.” The Ralbag is also generally credited with the invention of an astronomical device called Jacob’s Staff. It measured the angles between heavenly bodies, and was also used by European sailors for navigation. Levi’s contributions to astronomy are recognized today; there is a crater on the moon named after him.

David Gans, Astronomer Extraordinaire

Another Jewish astronomer who actually did real astronomy was David Gans, who we mentioned above. Gans was born in 1541 in Germany though he spent most of his later life in Prague. While there, he frequented the observatory of Tycho Brahe and Johannes Kepler and learned his astronomy directly from what he saw. His description of the time he spent inside the observatory is perhaps the only one of its kind in rabbinic literature: It’s worth reading just for that:

I can recount how in the year 5360 (1600) our exalted lord Emperor Rudolf (may his glory be uplifted), a man of wisdom, full of general knowledge and expert in astronomy, who values and honors those who are learned, sent a mission to Denmark to invite the eminent scholar Tycho Brahe. He was a scientist and learned in astronomy, and a man who is a prince among his people. The Emperor installed him in a castle in Benatky (which is about five parsaot from the capital Prague), where he remained isolated. [Rudolf] gave him a yearly allowance of three thousand talars together with bread, wine and beer, not to mention other gifts. There he lived with twelve others, all of whom were experts in astrology [sic] and in the large instruments [for measuring,] the likes of which had never been seen. The Emperor Rudolf built thirteen consecutive rooms, and in each room were special instruments that enabled them to view the paths of the all the planets and most of the stars.

Throughout the year they would make and record daily observations of the Sun’s orbit, its latitude and longitude and its distance from the Earth. At night they would carefully do the same for each of the six planets and most of the stars, noting their latitude, longitude and distance from the Earth. I, your author, was there on three separate occasions, each lasting five consecutive days. I sat with them in their observatory, and I saw how they worked. They did amazing work, not just with the planets but also with the stars, recognizing each by its name. When each star would cross the meridian its position would be measured with three different instruments, each operated by two experts. This position would then immediately be transcribed into hours and minutes, for which purpose [Tycho] had an amazing clock. I can testify that none of our ancestors had ever seen or heard of such a device, and it has never been described in a book, whether written by a Jew or Gentile.

And a Famous Jewish Female Astronomer

There are dozens and dozens of other examples of famous medieval and modern astronomers that we cannot include because of space (though you can find a partial listing here). But let’s end with a Jewish astronomer who just had an observatory named in her honor - Vera Rubin (1928-2016). She was born to Jewish immigrants in Philadelphia, educated at Vassar, Cornell and Georgetown, and moved to the Carnegie Institution in Washington in the 1960s. She studied the rotation of galaxies, and discovered that something other than their matter must be holding them together. As her obituary in The New York Times noted, “her work helped usher in a Copernican-scale change in cosmic consciousness, namely the realization that what astronomers always saw and thought was the universe is just the visible tip of a lumbering iceberg of mystery.” Being a woman in a man’s field had tremendous challenges, and called for ingenuity:

…she still had to battle for access to a 200-inch telescope on Palomar Mountain in California jointly owned by Carnegie and Caltech. When she did get there, she found that there was no women’s restroom. …Dr. Rubin taped an outline of a woman’s skirt to the image of a man on a restroom door, making it a ladies’ room.

Vera Rubin was elected to the National Academy of Sciences, and last year the Large Synoptic Survey Telescope was renamed the National Science Foundation Vera C. Rubin Observatory in recognition of her contributions to the study of dark matter and her outspoken advocacy for the equal treatment and representation of women in science. Despite her achievements she remained humble. “I’m sorry I know so little. I’m sorry we all know so little” she once said."But that’s kind of the fun, isn’t it?” Yes. It is.