Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/17/84; site mhuxm.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!mhuxv!mhuxh!mhuxi!mhuxm!abeles From: abeles@mhuxm.UUCP (abeles) Newsgroups: net.religion.jewish Subject: When is the Sabbath? --or-- the TOTAL prayer experience: CONSTANTLY! Message-ID: <310@mhuxm.UUCP> Date: Fri, 8-Feb-85 16:17:24 EST Article-I.D.: mhuxm.310 Posted: Fri Feb 8 16:17:24 1985 Date-Received: Sat, 9-Feb-85 07:25:24 EST Organization: Bell Communications Research, Murray Hill, NJ Lines: 50 > > I never knew that time was variable, except maybe according to > Einstein. The fact that an Israeli keeps seven days is not a good analogy. > He does not keep it according to Israel time, but rather, local time. So > too in space. > > Eliyahu Teitz. If a person were to keep local time in space, a day (where the term day means the period of time from one sunrise or sunset to another) could be shorter than 3 minutes. This would arise because in a low orbit where the pull of gravity is strong a manned satellite would have to go at a speed of about 200 meters/sec to counteract the pull of gravity. (The acceleration of gravity is about 10 meters/sec/sec at the earth's surface. Centrifugal acceleration is the square of the velocity [200 * 200 = 40000 meters^2/sec^2] divided by the radius which is about the radius of the earth [4000 meters], or again about 10 meters/sec/sec. This 10 meters/sec/sec balances the pull of gravity and allows the orbit to exist.) If this spaceship goes at a speed of about 200 meters/sec, it would take only about 125 seconds (or under three minutes) to go around the world. This must be adjusted slightly to allow the orbit to take place above most of the atmosphere, but it will still be only a few minutes at such heights. The point is that in such a situation, Eliyahu Teitz would have an orthodox Jew daven shachris, mincha, and maariv in well under 5 minutes. What happens to kavannah (intention to pray; i.e., concentration) under these circumstances? Seriously, the result of this is that a Jewish human being would have to avoid such orbits since it would result in obligating him to pray continuously! No sleep! No eating! No going to the bathroom! Nothing but prayer! By taking off in a north-south orbit (which passes the north and south poles instead of circling the equator) such as is possible from Vandenburg Air Force Base in California (but not possible from Kennedy Space Flight Center in Florida), the observant Jew would be able to avoid these problems. So it would appear that we have discovered a new ramification of halacha! Or maybe halacha (only according to the Teitz point of view, of course) actually forbids space travel for Jews altogether! It already virtually restricts any travel to most places in the world--since kosher food isn't widely available in Borneo, Upper Volta, Czechoslovakia, Nigeria, Brazil, Japan, etc., etc., etc. So maybe it also restricts travel to any place outside the world. Eliyahu, we're waiting for your reply. A Good Shabbos to all, --J. Abeles