daf bit: Shabbat 8

[cellio]

Just as the previous traactate, B'rachot, jumped into the discussion by starting with a detail (what time to say the evening Sh'ma), so too does Tractate Shabbat begin with a discussion of one of the 39 categories of work forbidden on Shabbat. (The full list will come page 70, IIRC.) The talmud here discusses carrying items between the public domain and a private domain (in either direction). It is because of this prohibition that a city (or neighborhood) might have an eiruv, a boundary that makes the space it surrounds into a single domain. (It's more complicated than that. Way more complicated. It has its own tractate, actually.)

On today's daf the rabbis discuss throwing things (which counts as carrying). Suppose there is a tree on private ground with a branch overhanging public ground, and you throw something and it lands on the branch? Rabbi says the branch is as the trunk, so if you throw it from the public space you have transgressed by moving the object to a private domain. The sages, however, dispute this, saying we do not cast the branch after the trunk. (8a)

Usually "the sages" have the last word, though I'm not sure if that's always true and the g'mara here doesn't say. If any of my readers need to throw things on Shabbat outside of an eiruv, you should consult better sources than me.

Comments

[cellio]

Interesting question. The case probably hasn't come up, since the timing would be tricky on earth, but it piques my curiosity.

We're talking about throwing in the last instant of Shabbat so that when it lands moments later it's no longer Shabbat. That's possible in theory and I don't know what the answer would be; I could argue that where it is after Shabbat is over doesn't matter (so as long as it doesn't cross the boundary before, you're ok), and I could also argue that you set in motion a chain of events that couldn't help but be a Shabbat violation, so you lose.

The reason I said this would be hard to have come up "on earth" is that we're not actually certain when Shabbat is; we start before sundown on Friday and end after nightfall on Saturday because we don't know exactly when "evening" (in "there was evening and morning") is -- sunset-ish, sure, but: when the bottom edge crosses the horizon? When the center crosses? The top? At sea level, or your elevation? When the last rays of light are completely gone? To really bring your case into play we'd need the thing being thrown to stay airborne for about an hour. That's hard to do without the aid of combustion and mechanics, unless we get help from very low gravity and maybe atmospheric friction. I only bring this up to say that I doubt there's literature on this problem yet, not to discount the question. :-)

[ralphmelton.livejournal.com]

Hm. If I felt a great need to do this, I'd try throwing a paper airplane across the International Date Line. So you could throw it on Saturday and have it land on Sunday.
Though it might be hard to have an eiruv whose border was near the International Date Line.

[ralphmelton.livejournal.com]

Another way to do this: release a helium balloon.
With a sufficiently long delay, you could also have the question of building a boundary while the object is airborne.