Timestamp proof

Status

Anchored in Bitcoin

Bitcoin block

#969,239

Block time

2026-09-30 02:33 UTC

Recorded

2026-09-30 01:04 UTC

SHA-256

d25a0adb90f5d1d9931d51dbff6c878235b2bbb8a2d9b5e6113602a8f6b84b0b

Verify it

1. Here, in one click

Checks the stored proof against the Bitcoin blockchain and confirms it covers the payload below. To check files you downloaded, use Verify a timestamp.

2. On opentimestamps.org (independent of PubPhys)

1. Download the payload (.json) and the proof (.ots) above.
2. Open opentimestamps.org and drop pubphys-problem-47-stamp-15.json.ots onto Drop here a file to stamp or an .ots proof file to verify in the Stamp & Verify section.
3. Then drop pubphys-problem-47-stamp-15.json onto Drop here the stamped file.
4. The site reports the Bitcoin block that attests the file — here block #969,239. Your file never leaves the browser; only its hash is compared.

3. From the command line

With both files in one folder, run the reference Python client (pip install opentimestamps-client) or the Ruby gem (gem install opentimestamps, 0.4 or newer):

ots verify pubphys-problem-47-stamp-15.json.ots

The Ruby gem checks the block against a public block explorer. The Python client checks it only against your own Bitcoin Core node; without one, run ots --no-bitcoin verify pubphys-problem-47-stamp-15.json.ots and compare the merkle root it prints with the block's merkle root on any explorer (e.g. block 969239).

Until the calendars anchor the proof in a Bitcoin block (usually a few hours), every check reports it as pending. Once PubPhys shows a block number, download the proof again, or complete your copy with ots upgrade pubphys-problem-47-stamp-15.json.ots.

Hashed payload

{
  "author": "grigori_p",
  "field": "statistical_mechanics",
  "id": 47,
  "published_at": "2026-07-28T05:48:51Z",
  "recorded_at": "2026-09-30T01:04:42Z",
  "references": null,
  "schema": "physicdb.problem/1",
  "site": "physicdb.yet.bz",
  "slug": "the-arrow-of-time-and-the-low-entropy-past",
  "statement": "The microscopic laws are (nearly) time-symmetric, yet entropy increases,\n$$\\frac{dS}{dt} \\geq 0.$$\nThis macroscopic arrow is usually traced to an extraordinarily low-entropy initial state of the universe (the \"Past Hypothesis\").\n\nWhy did the early universe have such low entropy, and can the thermodynamic arrow be derived without simply postulating it?\n",
  "title": "The Arrow of Time and the Low-Entropy Past"
}

Shown pretty-printed; the digest covers the compact bytes in the downloadable file.