Dovid HaMelech writes in Tehillim (19:1), “The Heavens speak of Hashem’s glory.” Every day as astronomers peer further and deeper into the universe, the heavenly proclamation of Hashem’s might accelerates into an encyclopedia of ever vaster intricacy. Let us view a tiny sampling through the lens of Chazal.
Discussing the verse (Tehillim 148:3), “Halleluhu kol kochvei ohr,” “Praise Him, all shining stars,” the Gemara at the beginning of Pesachim (2a) intervenes with an objection, “Do only stars that shine have to praise while stars that do not shine not have to praise?”
The question has been raised – what does the Gemara mean by “stars that do not shine?” Does this imply that there are stars out in space that do not shine? There are a number of possible answers to this question.
The first and simplest answer is that the Gemara is referring to meteorites, planets or even stars that are too small or too distant to be sighted from earth without the aid of binoculars or telescopes. After all, doesn’t the Gemara (Berachos 32b) itself state that there are about a billion, billion stars that exist even though the most hawkeyed person would probably spot less than 5,000 of them on the clearest night?
A second, more sophisticated explanation could be that the invisible stars include black holes or neutron stars. First postulated during the eighteenth century, black holes were also predicted by Einstein’s Theory of General Relativity in 5676/1916. The idea is that when massive stars collapse under their own weight, their particles become so tightly packed that one teaspoonful of their matter can reach several tons. This gigantic, dense mass exerts such a crushing force of gravity that nothing can escape its python like grip, not even light. As a result, stars are not only invisible to us here on Earth but also invisible to someone passing right next to them.
Of course, to pass that close would be a dangerous experiment as anything or anyone passing too near would risk entering the black hole’s point of no return. To make things worse, any object entering the black hole’s powerful gravitational field will theoretically experience a brief, unpleasant process known as “spaghettification.” What is spaghettification? Exactly what it sounds like. The powerful gravity pulls things into spindly spaghetti shapes.
Astrophysicists theorize that a giant black hole, containing millions or billions the mass of our sun, presently lurks like a spider in the middle of the Milky Way galaxy we call home. A third, even more exotic category of invisible star could be a newly discovered substance which fits neatly into our worldview of kedusha and light waging an unending battle against tumah and darkness. This comparison is even suggested in the title of a recent book on the subject of this substance – Dark Side of the Universe.
This mysterious matter was first postulated by Franz Zwicky. Back in 5693/1933, he suggested the existence of a substance which, while totally invisible, manifests its existence by “lensing.” “Lensing” is based on another idea of Einstein – that gravity distorts space. Because distorted space warps the light traveling through it, we can detect these invisible objects when they bend the light of stars like a giant lens and jolt the stars from their correct place on the celestial plane.
Although dark matter and dark energy may comprise up to 96% of the universe, no one quite knows what they are and whether they are large or small. Scientists have debated for years whether dark matter consists of WIMPs (Weakly Interacting Massive subatomic sized Particles) such as the photino, the zino and the higgsino, or MACHOs (Massive Compact Halo Objects), which would include objects as large as stars and planets.
The MACHO project, launched in 5751/1991, detected the presence of so many MACHO objects that they are suspected to comprise half the Milky Way. Could these MACHOs be the nonshining stars the Gemara mentions?
A fourth explanation of the Gemara is, perhaps, the simplest of all. Examine Rashi (d”h Ha kemashma lan) at the end of the sugya and see what he says.
R. YEHOSHUA’S COMET
The Gemara (Horayos 10a) relates: “There was an incident that R. Gamliel and R. Yehoshua were traveling in a ship on the high seas. R. Gamliel brought only bread while R. Yehoshua brought bread and fl our. When the bread of R. Gamliel was depleted, he relied on the fl our of R. Yehoshua. [R. Gamliel] asked him, ‘How did you know we would be so delayed that you took care to take extra flour?’ [R. Yehoshua] replied to him, ‘There is a certain star which rises every seventy years and confuses the sailors and I was concerned that it might rise now and confuse us.’”
The star R. Yehoshua mentions may have been Halley’s Comet that appeared in 3826/66 CE, four years before the Churban, because R. Yehoshua and R. Gamliel passed away not so long afterwards in 3877/117 CE and 3875/115 CE, respectively. Although the Chinese sighted Halley’s Comet centuries earlier in 3521/240 BCE, and it was sighted many times since in China, Japan, Persia and Babylon, no one except R. Yehoshua realized that it was the same comet returning each and every time.
More recently, Edmund Halley confidently predicted that this comet would return in 5527/1757 after realizing that it had previously appeared three times, at intervals of 76 years. This is the time it takes this nine mile long comet to hurtle to the edge of the solar system and back. Because of this prediction, Halley’s Comet was named after him when it was spotted in 5528/1758, fourteen years after his death.
Since then, a handful of Jews have claimed that this is grave injustice – after all, was it not R. Yehoshua who first realized the periodic (regularly returning) nature of “Halley’s” Comet and, if so, should it not be called R. Yehoshua’s Comet? Although R. Yehoshua is indeed the first person to describe the cyclical nature of comets, it is by no means certain which comet he was describing. First, R. Yehoshua said that his star was due every seventy years and not every seventy-six years!
Although one can claim that he was only giving an approximate figure, this argument weakens accrediting R. Yehoshua with the discovery.
Furthermore, Halley’s Comet is usually very large and distinctive. How could experienced sea-dogs, familiar with the stars after endless years of navigation, confuse this giant-tailed comet with the regular stars they knew like the back of their hands? How could the distinctive Halley’s Comet lead them astray off familiar shipping routes?
Because of these two problems, perhaps another candidate comet can be suggested in its place. This is the 12P Pons/Brooks Comet, discovered in 5643/1883, by the most famous comet hunter of the last century, William Roberts King. Its cyclic route of 70.9 years is closer to R. Yehoshua’s 70- year figure. Also, as this comet is less spectacular than Halley’s Comet, it is more likely to be confused with other stars. Perhaps clinching the matter is the quick calculation that the 12P Pons/Brooks Comet was due to pass overhead in about 3871/111 CE, a few years before R. Yehoshua’s passing.
The Gemara (Taanis 9b) discusses the source of rain.
“It was taught in a Baraisa – R. Eliezer says, ‘The whole world drinks from the waters of the ocean, as it says (Bereishis 2:6), ‘And a mist rose from the land and watered all the face of the earth,’ etc. R. Yehoshua says, ‘The whole world drinks from the upper waters since it says (Devorim 11:11), “From the rain of the heavens, you will drink water,” etc.’”
Some years ago, a University of Iowa space physicist, Frank Louis, asserted the claim that many meteorites are made of ice and dissolve into water as they plow into Earth’s atmosphere. This seemed to offer a new understanding of R. Yehoshua’s statement regarding the source of rain. Perhaps the upper waters he mentions are molten meteorites.
However, there are serious objections to this suggestion. The Ramban on Chumash warns that the “waters above the ‘rakia’” mentioned in Bereishis is a reference to deep Kabbalistic concepts and the same might apply to this sugya. Also, the Baraisa includes R. Yehoshua’s description of how rain reaches Earth and the process is a totally different mechanism than melting meteorites.
Also, the numbers do not crunch. Every year, our planet sweeps up 35,000 to 100,000 tons of space debris as it circles the sun. This consists of a wide variety of flotsam, including dust, meteorites and icy meteorites. Is this enough to make a significant contribution to earth’s rainfall? It is not! 6.6 billion tons of rain fall every year in the United States alone, and the total amount of rain, snow and ice pelting down annually worldwide equals 505,000 billion tons! Accordingly, even if one argues that 35,000 tons of icy meteorites blast through the atmosphere on an annual basis, this would contribute far less than a billionth of the world’s annual water supply – literally a drop in the ocean.
Perhaps we can say the same for our knowledge of what is really going on above our heads – a drop in the ocean!