Editor’s note: This letter is the first of two letters in response to a man who questioned the Rebbe’s position that the sun revolves around the earth and not vice-versa. For the Rebbe’s second letter, see here. For the man’s original letter, see here.

By the Grace of G‑d
Rosh Chodesh Kislev, 5736
[November 5, 1975]
Brooklyn, N.Y.

Greeting and Blessing:

This is in reply to your inquiry on the question of the rotation of the sun and the earth in relation to each other, namely, whether the sun revolves around the earth, or the earth around the sun, and which view is to be accepted, etc.

I presume you have in mind the scientific view, i.e., what science has to say on this question, and I will address myself to this aspect.

It is well known that this was a controversial issue in ancient and medieval science. However, since about half a century ago, with the introduction of the theory of relativity, the latter has been universally accepted as the basis of modern science. To be sure, in the beginning there were scientists working under the Soviet regime who opposed the relativity theory—for various reasons which need not be reviewed here—but even this opposition fell by the wayside later, so that now all scientists generally accept the theory of relativity as the latest and most plausible scientific system.

One of the conclusions of the theory of relativity is that when there are two systems, or planets, in motion relative to each other—such as the sun and earth in our case—either view, namely, the sun rotating around the earth, or the earth rotating around the sun, has equal validity. Thus, if there are phenomena that cannot be adequately explained on the basis of one of these views, such difficulties have their counterpart also if the opposite view is accepted.

Secondly, the scientific conclusion that both views have equal validity is the result not of any inadequacy of available scientific data, or of technological development (measuring instruments, etc.), in which case it could be expected that further scientific and technological advancement might clear up the matter eventually and decide in favor of one or the other view. On the contrary, the conclusion of contemporary science is that regardless of any future scientific advancement, the question as to which is our planetary center, the sun or the earth, must forever remain unresolved, since both views will always have the same scientific validity, as stated.

Thirdly, it follows that anyone declaring that a person who chooses to accept one of these systems in preference to the other is a fool, while one who accepts the other is a wise man—such a judgment shows that the person making it is ignorant of the conclusions of modern science, or that he has not advanced beyond the science of Ptolemy and Copernicus. Obviously, a person not versed in the development of science in the course of the past half-century or so is not qualified to make any judgment pertaining to science.

A further point may be added, though perhaps not directly pertinent to our discussion. It is that every person, including modern scientists, actually has three options to choose from in this matter: (a) that A revolves around B, (b) that B revolves around A, (c) that A and B revolve around each other. But such a choice cannot be dictated by science; it would be one’s personal choice and belief.

What has been said above is—to repeat—the deduction of the theory of relativity, as it is expounded in various scientific texts, and it can be checked with any scientist who is thoroughly familiar with the said theory. Of course, on the elementary and high school level, science in general, and the so-called Solar System in particular, is taught from relatively simple textbooks, and the change in the scientific attitude towards the subject under discussion is not emphasized. But, as stated, it would be quite simple to verify it with any scientist who knows this particular field.

With esteem and blessing,