During the meal at the second seder, the topic of discussion turned to astronomy. When the subject of the planets came up (specifically regarding the decision to "demote" Pluto), my fourteen year old niece, who tends toward the fundamentalist side, announced that the Torah says that there are only seven planets. When I mentioned to her that there were, in fact, more than seven planets, she simply repeated her assertion with a "that's-what-the-Torah-says-and-that's-that" tone.
I didn't press the point any further that evening, but as I thought about it the next day, I realized that my niece was both right and wrong. The problem, very simply, is that she and I were not using the same definition of the word "planet."
Allow me to give some historical background.
When the ancients studied the skies at night, they made some observations about the positions of the stars. They noticed that as the sky rotates overhead during the night (remember, they didn't know that it was the earth that was rotating), the stars in the sky moved, but kept their positions relative to each other. In addition, they kept their positions during the year as well -- a particular star could be counted on to disappear below the horizon at a certain time of the year and reappear at the same position (relative to the other stars) at a later point during the year.
However, there were seven heavenly bodies, they noted, that did not keep their positions. These planets "wandered" among the other stars -- sometimes moving forward against the other stars, sometimes regressing backwards (and sometimes displaying both behaviors at different times). These seven wanderers became the "planets," from the Greek word for wanderer. The seven bodies that displayed these properties were the Moon, Mercury, Venus, the Sun, Mars, Jupiter and Saturn.
Of course, as time went on, we gained a better understanding of the heavens than the ancients had. Copernicus showed that most of the "planets" actually revolved around the sun, not around the Earth. The sun was eventually identified as a star, one of the billions of stars in our galaxy. The word "planet" now no longer referred to the wanderers of the heavens, but to heavenly bodies (of significant size) that orbit the sun. In addition, with better optics than the ancients had at their disposal, we even discovered that most of the planets in our solar system had moons of their own. Better telescopes and observations have allowed us to find Uranus, Neptune, Pluto, Sedna and other minor ("dwarf") planets. And, of course, within the last fifteen years, we've gained the ability to detect planets orbiting other stars and have, to date, discovered 442 of them.
So, what is the true believer to do? If one believes that the Torah says that there are seven planets, and one wants to remain "Torah true," how does one reconcile the astronomy of the last few hundred years with the words of Chazal? Does one say that astronomy is a sham and that the data is faked? Does one say that the pictures NASA released from the Pioneer and Voyager missions are fakes? Does one say that the astronomers know the truth, but are simply faking it to suppress God's truth?
Well, you could take that approach -- although I think it's really very silly. The simple answer is also the best answer -- that when Chazal (or the Rishonim) talk about planets, they are referring to points of light that "wander" against the background sky. Using that definition, they are correct -- there are only seven* planets. But one has to recognize that the definition of the word "planet" has changed over the years and that when we discuss planets today, we are using a different definition of the term. As a result, it is also correct to say that there are well more than seven planets.
I often wonder how many Torah/science arguments could be avoided if we simply recognize that the meanings of words, including planet, species, bird, animal, star and even science among many others have had their definitions change over the years. Of course, not all Torah/science arguments would end -- but a fair number of them could be put to rest.
* Yes, I know Uranus is sometimes visible with the naked eye which would make eight planets -- but it's so infrequent and it's orbital period so long that it was probably just not noticed by the ancients. And, of course, this also excludes comets.
I also got into the Torah/Science מח' over yuntiff with my essay on zugos.
I'll agree that the definition of planet is different now than it was in very ancient times. But doesn't so much of the controversy that erupts over science versus Torah hinge on a different word altogether--discovery.
We are nowhere near having discovered everything that God created in our world. Seemingly every day someone discovers something that is new, that is first coming to light now. And as mankind invents new tools to help more is able to be discovered. This does not controvert the Torah in any way but does point out that all knowledge of everything possible did not reside in our ancient wise men. Discovery comes in stages over thousands of years, and I'm quite certain that we have in no way discovered all there is yet. And as new things are uncovered and discovered there is bound to be brought out that things we thought were one way are, in fact, another way altogether. This does not cast our ancients in a bad light but we need to see their pronouncements placed in the context of the times they lived in and what was available to them to procure knowledge. Man, not having God's qualities the way He has them, plods on slowly, and it is only over a long period of time, a time that is not yet finished, that man will be able to see all that God created.
"(remember, they didn't know that it was the earth that was rotating)"
Actually, Albert Einstein in General Relativity (the latter portion of the Theory of Relativity) scientifically demonstrated it is no more correct to state that the earth revolves around the sun than to state the sun revolves around the earth. It is all "relative" to ones position.
I'm fairly certain that you're wrong. But I'll also admit that I don't know the science well enough to back up my statement. I think I'll allow some of my regular commentators, who do have the science background to properly explain it, to do so.
In any event, it's really a side point. The main point of the post isn't about what revolving around what but about changing definitions.
I do know enough about science to address Volvie's question. And I will do so briefly below. However, it really doesn't get to the heart of the issue, which turns on something raised by Prof K. The real issue is precisely the notion that one can discover something that was not revealed at Har Sinai. It runs counter to the more extreme notions of Da'as Torah that have become more prevalent in certain sectors of the frum community over the last 30 or 40 years ago. It is that, rather than any argument about this or that piece of science that is at issue. I cannot imagine anyone who has both more than the slightest knowledge of science and a good knowledge the Torah literature taking this position seriously for a moment.
As to Volvie's point, it is true that Einstein showed that one can equally validly express the equations in any frame one likes. In that sense, yes, one can work in a frame in which the Earth is at rest. But not all frames lead to equal understanding. The dominant effect driving solar system dynamics is the Sun, not the Earth. In general relativity terms, the curvature of space time induced by the Sun's stress-energy tensor determines the dynamics of the solar system, to very good first approximation. Or if you prefer Newtonian vocabulary, it is the gravitational field of the Sun that keeps the solar system together and determines the planetary orbits. Jupiter and Saturn come next. In the sense in which the words are used casually, no one world say the Sun moves around the Earth. You can also say that your broom is sitting still while you and the whole universe make a sweeping motion back and forth, but no one is his right mind would talk that way.
Where does the Torah say that there are only 7 planets?
Btw, we also ended up speaking about Pluto getting demoted... can't remember how or why, though.
Torah vs. science arguments can be avoided by acknowledging the obvious: the Torah is not a scientific textbook, and chazal operated according to the science of their time. This is a simple, straightforward, torah-true tradition with a pedigree going back centuries. It does not denigrate chazal in any way, unless you ascribe magical powers to them that they themselves never claimed. This was the general outlook of my yeshiva upbringing 20+ years ago, and I'm at a loss to explain when the yeshiva world decided to switch over to the anti-science side.
I don't know where the Torah states that there are only 7 planets. I don't know that there's any such statement in tanach. A quick Google search turned up some midrashic references, but that's as far as I've gotten, and taking too many midrashim literally will really get you into trouble quickly.
ProfK: I have no problem with saying our ancients were somewhat ignorant, and knew a lot less than we do nowadays. But how do you reconcile this notion of Chazal's fallibility with the tenet of faith that the entire Torah was GIVEN to Moses. Even if you don't think Torah she'baal peh is divine, at least the Pentateuch would have to be divine, to an Orthodox person. So how can one not believe in the absolute truth of the Torah while also calling themselves Orthodox?
Or: Some facts about our world are so hidden in the Torah that we on our level don't make the connection until we find out about them through observation, deduction, etc.
Off the Derech,
I fail to see where any of my statements impugned the truth of the Torah. They dealt with the abilities, or lack thereof, of humans to make "perfect" sense of what they read in the Torah. As humans grow older, individually and as the generations move on, they possibly see things differently than when they were younger, or different from how earlier generations saw and interpreted things, due to increased knowledge of the world. The Torah didn't change--the people did.
To segue back to Einstein, would you attempt to teach a two year old about E=MC2? No, because a two year old would not have the "tools" to be able to understand any of what it refers to. But let's say you taught a 9-year old the idea. And let's say you found some basic words that might give some basic understanding of the concept to someone of that age and experience. Would that understanding be the same as the understanding of a 27-year old with an advanced degree in Physics? Hardly. The analogy can be made and will hold up that the ancients were akin to that 9-year-old as far as their "real" knowledge of science.
Fine, but that renders the Torah so meaningless as to be extremely irrelevant. If there are ways of interpreting it, and no sure way of knowing the correct one, how is it useful in any way other than some nice poetry? If there's no way of knowing the truth, why even bother with religion altogether?
Maybe our increased knowledge of the world tells us the world didn't need a higher power to create it. Can I interpret the Torah to say that even atheists are now Orthodox? You have two major questions to resolve: who is allowed to "interpret" the Torah, and what are the boundaries of interpretation (is Slifkin okay? How about atheists? etc.)
Off the Derech,
Far from c"v rendering the Torah meaningless or irrelevant, the growth of knowledge of human beings across the ages shows and links to the centrality of Torah to our lives. It is what we measure ourselves against--how much more are we sure that we know and understand of it, how much closer are we coming to what is truer than what we knew before. Attaining knowledge of what is written in the Torah is the quest of each generation, built on what was learned by previous generations but not carved in stone when new knowledge comes to the forefront.
"If there's no way of knowing the truth, why even bother with religion altogether?" Who says we don't know the truth? Truth is relative as a definition based on the evidence and details and facts able to be gathered at any given time. What was true 400 years ago was indeed the truth, given what was known then. It fit the facts available. All actions taken were based on this truth, both in our religion and in the world in general. 400 years later more facts and details have arisen and we have a different truth, based on that expanded knowledge. That doesn't make the previous "truth" a lie--it was the truth as that time period could see it.
Centuries ago people believed that ill or evil humors caused disease. Based on the evidence available to them the idea of an evil humor was perfectly rational. Were they crazy people? No. They were working with the knowledge they had and the tools they had. And what they believed was true for them. That truth has changed as we have become more knowledgeable about illness. What has not changed is the human body being studied. The human body we inhabit would be recognizable by others down through the centuries. What we now know about that body is what has changed.
As to "If there's no way of knowing the truth, why even bother with religion altogether," substitute the word "science" for religion and you may see the absurdity of the statement. Throughout time human beings have striven to know the truth and have not always been successful in attaining what they believed to be the truth, the whole truth, and nothing but the truth. Should they have given up the quest for that truth just because it alluded them or was hard? There have always been those who have said "fine, this is what we know, but what if it isn't everything there is to know? What if there is more? What if what we know contains an error? It is the quest for knowledge, the quest for the truth that pushes mankind onward and upward, in every field and in every endeavor. Religion is not excepted.
Yes, but there is the very important point of how we know what we know. In science it's called epistemology and what can observe we can know. Things that are unobeervablw by the human mind tend to be off limits. In religion, how do we know what we know? If we concede that are our books may be beyond our comprehension, what good are they, practically speaking? If there is no official interpretation we can believe in, how is it relevant to our lives? I don't mean to harp on this, but it's a major issue. If there is no foolproof way of determining the truth, religion becomes a completely subjective endeavor. For all I know, the Torah really meant to advocate Hinduism. It's not much different than a bunch of gibberish scribbled by a three year old. Sure, I can read whatever I want into it--BUT WHAT'S THE POINT?
Actually Volvie GR does not say that.
Newton's laws of gravity says that both rotate around a common center of mass, but since the sun is MUCH more massive than the Earth (I'm going from memory here but its about 300,000x) the center of mass might as well be at the center of the sun.
What GR says is that Newtonian gravity breaks down in the presence of very large mass. So for example you can not compute the details of the orbit of the planet mercury without GR. However the difference between GR and Newtonian mechanics is only 43 arc seconds per century. (The orbit of Mercury precesses around the sun, and this is the part of that that Newtonian physics can't explain).
In terms of how much GR affects Mercury it should be noted that the relivent term of the metric is R(shwartzchild)/ R(orbit). The SemiMajor Axis of the orbit of Mercury is 5.8 x 10^7 KM, where the shwartzchild radius of the sun is 3km. So the metric is VERY small. (~10^-7). And smaller for the other planets. For the Earth the difference between GR and Newtonian physics is about 1 part in a billion.
GR does not really show MAJOR effects until you get into very high gravity, for example a white dwarf of a black hole.
Relativity is rather misquoted, a LOT.
In terms of if the earth is rotating on its axis or not there are several obvious tests that you can do here.
1) First of all the nearby stars show definite parallax which would not happen from a stationary earth. (Its a very small effect that was not observed until about 1830 by Bessel, of the start 51 Cygni)
2) There is the Coriolis effect. This would not happen on a fixed Earth as it depends on the fact that angular momentum must be changing from the equator to the poll. But without this you would not get cyclonic storms.
What is happening here is that as an object moves from the equator the earth is turning more slowly as it has to complete a smaller circle, so there is less angular momentum, which causes an apparent force.
(yes I did major in physics)
Actually Comets were thought to be an atmospheric phenomenon until the time
of Tycho Bryhe. He was able to see a comet and show that it was in orbit around the sun and was past the moon via parallax.
Wolf, the problem is that people can't change their definitions because if they do, its admitting chazal were NOT infallable. Apparently, to YWN that's apikorsus.
If you want to know more about the history of astronomy and modern thinking on it here are some references, all are audio which can be downloaded for free from the net. All are in the form of Audio podcasts and are aimed at a college level audience.
Prof Richard Pogge from Ohio State has 3 semesters worth of lectures on his web site. Most germane here
would be lectures numbers 12- 21 of Astronomy 161 and lectures 31 -33 of Astronomy 162. Both can be found via iTunes or at his web site (http://www.astronomy.ohio-state.edu/~pogge/) I very much recomend listening to all 3 of the courses if you have time. Prof Pogge gives a great lecture. (And he will respond to emails)
Professor Charles Bailyn of Yale also has some course ware up online, both in Audio and video format, you can find it here
http://oyc.yale.edu/, the lectures to look at are 9 - 13. You can get the audio via iTunes U, or the video. I go for the audio as I tend to listen to these on the bus home from work.
Note that he tends to throw out quite a bit of math.
Mr. Kessin: Einstein changed sciences viewpoint and described GR in which all motion is relative. In GR you can use any frame of reference and they are all equally valid.
Yes, it is a bit harder to explain stellar parallax from the perspective of an Earth-fixed reference frame than from the perspective of a solar system barycentric reference frame. But it's not all that hard to explain stellar parallax from the perspective of an Earth-centered frame. The motion of the stars can be explained in terms of the "third body effect". People who model the behavior of satellites in Earth orbit vastly prefer to use an "Earth-centered inertial" reference frame (a non-rotating reference frame with origin at the center of the Earth) than a barycentric frame. From the perspective of such a reference frame, the Sun and Moon (and the planets) make the satellite's orbit not quite Keplerian. The perturbation is explained by a pseudo-force called the third body effect.
GR is not studied in detail by even most students of Relativity until advanced or doctoral studies are reached in depth. Thus GR is relatively little understood even by students of physics. Nevertheless it is integral to its thorough understanding. And what I've described here is a faithful rendition of Einstein's description of GR.
From the Earths perspective there are only seven "other" planets.
you are assuming that Einstein replaced newtonian physics, nothing could be farther from the truth, SR & GR both reduce to Newtonian dynamics if the speeds are small (vs the speed of light) or if Gravity is week. Both of these cases apply in all the cases we are talking about.
If you are going to claim that stellar Parallax is due to a 3rd body effect then where is the 3rd body, and how does it cause an osculation with a period of exactly 1 year in every case? When the orbit of Uranus was not acting as Kepler said it should it was possible to determine where the extra mass was and predict an 8th planet to with 1°.
Of course when working with satellites people use an Earth centric reference frame, they are going around the Earth. For an object in Low Earth Orbit the major force in the gravity of the Earth. Yes, the sun and moon and other planets can cause things to be perturbed from the keplerian ideal, but the effect is small and has nothing to do with GR, you can explain it with Newtonian gravity. There is no Pseudo-force, just gravity.
All motion is relative, but here is the point you are missing, the physics of a stationary body is *DIFFERENT* from that of a rotating one.
Example, if you were to go to an amusement park and get on the Merry-Go-Round could you tell if the thing was turning or not without observing the outside world? Actually yes you could, if you had a ball with you it would act differently if the platform was turning or standing still. If it was standing still the ball with stay in place, but if the platform was turning the ball would act as if a force was being applied and roll off the edge.
The other thing to understand about relativity is that while some things do change other values are kept invariant. So the distance between 2 events in space or in time can change depending on the observer, the distance in Space time does not change, specificly the metric [X^2+Y^2+Z^2- (iCT)^2] will be the same for all observers. Similar (but more complex) metrics apply to GR.
Volvie, I have to ask where do you get your background in physics, I have BA from Brandies in Physics (With Department Honors, class of '03).
BTW If you would like more clarification I would be happy to put you in touch with Rachel my classmate who works for JPL as a project scientist.
The best frame of reference is the one that most easily or simply addresses the immediate need, so expect the best frame to vary with the need.
In the context of Torah law, the need is often to facilitate timely, correct decisions by those who lack the appropriate (or even any) instrumentation. The Halacha has to recognize such situations.
GR is not studied in detail by even most students of Relativity until advanced or doctoral studies are reached in depth. Thus GR is relatively little understood even by students of physics.
Little understood by advanced students of physics, yet so well understood by High-school diploma bearing Joseph? Come on.
Just a note, Uranus and the Asteroid 4 Vesta are sometimes naked eye visible. However only just barley so, if you know exactly where to look you may be able to spot them, but noticing them at random without a good star chart would be very hard. The 5 classic planets are among the brightest things in the night sky and VERY obvious.
Also Uranus being quite far out moves very slowly.
Don't be so sure Josh, that the most advanced degree is a HS diploma, as you would be mistaken if you are. It is always foolish to assume your own limitations upon others.
Zach, Speaking of relativity, you might be interested in this:
Quasars don't show time dilation
(Don't know if it has much to do with what we're talking about, but it seems like it has the physicists in a tizzy.)
Zach, I don't see how you can purport to explain Einstein's GR, of all things, with simply a bachelor's in physics.
I don't claim to be an expert on GR. I know some basic stuff, what I have heard in lectures and read in various physics books I have read. At no point did I give a detailed explanation of GR, nor did I try to give original solutions.
You will notice that most of what I talk about is classical Newtonian Mechanics, and very small post Newtonian effects (all of which I looked up)
I also suspect that I have the most physics background of anyone here.
I had not seen that Quasar article. If I have time I may email an old professor of mine who works on quasars.
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