From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp12.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id mHtXCMbA12OMLwEAbAwnHQ (envelope-from ) for ; Mon, 30 Jan 2023 14:06:14 +0100 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp12.migadu.com with LMTPS id CN0hCMbA12O1pQAAauVa8A (envelope-from ) for ; Mon, 30 Jan 2023 14:06:14 +0100 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id E55EB16668 for ; Mon, 30 Jan 2023 14:06:13 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pMTqt-0004xW-Vr; Mon, 30 Jan 2023 08:05:40 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pMTqp-0004x7-OS for emacs-orgmode@gnu.org; Mon, 30 Jan 2023 08:05:36 -0500 Received: from mout02.posteo.de ([185.67.36.66]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pMTqn-0002lY-1U for emacs-orgmode@gnu.org; Mon, 30 Jan 2023 08:05:35 -0500 Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id C95A12401AB for ; Mon, 30 Jan 2023 14:05:29 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1675083929; bh=S5zTWFexDaXvqP00JzNCXnE/+CgC/iERqCD0nF6w85U=; h=From:To:Cc:Subject:Date:From; b=ocYJOHaBVe9WF58klHqjqCzvu4kpK8Bx0YwB5jt41V6ItKdUHY8Qk9dVosoV56GSh Q42GmONCiDyP7y2zeGmam4FMJcf5mzRdrBckXxL74Q3KSr3E/tTWFsHFDo3e1mz7PN q7DYIPjA2uxsyXZuXqQRTmkF1hj82ztPs/sakGT1brkJcSW6m2w1lLR2FO6V64ktO2 r7is9ShhlDO/bVh6xnpl2btn4BjlljZaTYeCOjxEzV8r52YxaqP0m8WcwBPzPIu7lA TRFYiK5hjNv0LPqtFJRbJe2BLgRYjQNVRkNlQiYZN/EbU9zqkL2IEQMOxU82RKLGrx u8aSatAFpkRNg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4P57hS5DmTz6tmF; Mon, 30 Jan 2023 14:05:28 +0100 (CET) From: Ihor Radchenko To: Tom Gillespie Cc: Org-mode , Carsten Dominik Subject: Re: Org mode timestamps on the Moon ;] (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda) In-Reply-To: References: <87bkmluxnq.fsf@localhost> Date: Mon, 30 Jan 2023 13:05:57 +0000 Message-ID: <871qnc5g0a.fsf@localhost> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=185.67.36.66; envelope-from=yantar92@posteo.net; helo=mout02.posteo.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-orgmode@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "General discussions about Org-mode." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-orgmode-bounces+larch=yhetil.org@gnu.org Sender: emacs-orgmode-bounces+larch=yhetil.org@gnu.org X-Migadu-Country: US X-Migadu-Flow: FLOW_IN ARC-Seal: i=1; s=key1; d=yhetil.org; t=1675083973; a=rsa-sha256; cv=none; b=QtZ90IPQFac9pzFVshacODCrzNylywHJyVuV3L8R+Iqm4y/ygSS3VninvRlBO0c3mzHeyO FQeZ13x+LN3u7DvrgJJSj2d3jq0jYetaz14X6i5hMz862rdQDURv84FK4aEC8GuNINt1b0 +w3y8yRNj/4OBj18PtKz1MXZ1oWRl2yFSkfVobRvzJK2LhWYvD3/S53hzU2P2ljB3lS1y4 OGEx0P/jNx0xfQsjMUlhPTroZ7NplUpz65ER8Nl5i5pcYbS99VyeBdfbPjxH35kidUumzt zB9LHqueXVY/H9T9ecip3NIotHTY6DuhkyHs5DuPwo1YjnT+hGG/sEJ6+TCjvA== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=ocYJOHaB; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=pass (policy=none) header.from=posteo.net ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1675083973; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post:dkim-signature; bh=vGcErMyo+D1a6QDSg3+bSC9l83MBFJiB5UtBPLIVLNc=; b=do04+bn08Y+qa90OQO8GBmmSQz1EetLTBpFSePY/AbPiHqp5o0hIVd8lTg2wI44riL6gAG 7e0mC/3bMO08+LF7F+bsyxEPWz0DhU/9IeMhImJgTArDedThGYNC+SRos4Se93dU/gpXl0 LY9vUrGKd+/yiLuUREA6+XvlZkd81xDdy1Vx7+0H8mMvCUYZCeXnuOFe5YXMszlkUEUVbN VFoSYC92B2ZsXGtMQ/z1LR8vU8aLxxv/C2BoMM1LhRYqr1hLeVrHhY/K4r1G7Y5s/ncB1t Ln4PYSRn9W42LJ4TLGt4w75IYtuYHTP0z87myQWLR2jP8QiOmibrLNosY0jL8g== Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=ocYJOHaB; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=pass (policy=none) header.from=posteo.net X-Migadu-Scanner: scn1.migadu.com X-Migadu-Spam-Score: -4.54 X-Spam-Score: -4.54 X-Migadu-Queue-Id: E55EB16668 X-TUID: lXKx8q6df9Cn Tom Gillespie writes: > Oh boy. In short, I think we can only hope they come up with > LTC and we already have a syntactic space to say whether > our reference seconds are TAI/UTC/LTC/MTC/JTC etc. And > being the privileged squats that we are if the time system is > left out then it means UTC. The friendly thing to do would be > to always include the time system code in our timestamps, > but I don't think those have standard reference codes yet? I cannot see anything in https://en.wikipedia.org/wiki/List_of_tz_database_time_zones So, just UTC. If we want to support more, it will have to be done manually. > I don't think we want to force users to start embedding their gps > coordinates, their current acceleration, etc. along with their > timestamp. But it turns out that the unix epoch is only standard > at 9.8m/s^2. So ... minutes should be ok right? > Joking aside. Clocks run faster on the moon, slower on the ISS, > so either clocks are synchronized back to earth seconds, or > they use some alternate standard reference time. I am afraid that calculating "real" time inside a given reference system is impossible now. Time from epoch in Greenwich when you are looking from inside Greenwich and time from epoch in Greenwich when you are looking from inside ISS are two different time intervals. And what about time from epoch in ISS when looking from Greenwich? And then we also synchronize time with UTC now. But time since epoch in UTC when looking from UTC and time from epoch in UTC when looking from different elevation are different times :) Further, what does it mean to have a meeting scheduled for <2023-01-30 Mon 14:00 @Europe/Berlin>--<2023-01-30 Mon 20:00 @Asia/Singapore> What is the reference frame? Europe/Berlin gravitation well? Asia/Singapore well? Local well? -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . 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