{
  "export": {
    "source": "https://urth.darkrealm.vip/thread/urth/1732",
    "note": "Exported from an unofficial mirror of a public mailing list. Copyright in each message remains with the person who wrote it.  Email addresses are obscured as `user at host`, the form the original archive published. This file was rebuilt from parsed fields rather than retained headers, so it is faithful in content but not byte-exact.",
    "addresses": "obscured as 'user at host'"
  },
  "archive": "urth",
  "thread": {
    "id": 1732,
    "subject": "Fliers of Urth, or \"Tiger in the tank\"",
    "messages": 1,
    "voices": 1,
    "first": "1999-08-02T16:39:44+00:00",
    "last": "1999-08-02T16:39:44+00:00"
  },
  "messages": [
    {
      "message_id": "<urth-v0028-0036@digest.urth.net>",
      "from": {
        "name": "Michael Andre-Driussi",
        "address": "mantis at sirius.com"
      },
      "date": "1999-08-02T16:39:44+00:00",
      "subject": "(urth) re: Fliers of Urth, or \"Tiger in the tank\"",
      "in_reply_to": null,
      "reply_link": null,
      "blocks": [
        {
          "kind": "quote",
          "depth": 1,
          "text": "Mitchell A. Bailey wrote:\nNow let me get this straight: the cherry-leaf fliers the Autarch and a\nfew privileged characters of the Commonwealth (including Vodalus)\npossess supposedly get their lift from the supposed repulsion of\nantimatter to a gravitational field of pro-matter (i.e. that of Urth) ?\nI.e. antimatter generates antigravity?\n\nThis looks like a definite case of \"hard-physics-this-ain't\". General\nrelativity definitely says that antimatter would behave\nindistinguishibly from promatter, gravitywise. Supposedly there are some\nexotic field theories out there that predict _maybe_ differently, but\nthey aren't any of them widely accepted."
        },
        {
          "kind": "text",
          "depth": 0,
          "text": "Well of course it could very well be the blunder you make it out to be.\n\nThen again, people have been tripped up by various \"science\" issues in the\nUrth Cycle, for example: \"solar\" sails (they seem more \"cosmic\" than\n\"photonic\"); \"dying\" sun (a huge pile of complaints here--timescales; inner\nplanets reduced to cinders . . .); etc.\n\nFWIW, and I know that ain't much, my sense of it was that the mysterious\nsubstance was not \"antimatter\" so much as it was \"anti-lodestone\"; that is,\nit is =not= what we skiffy types call \"antigravity\" but what we call\n\"magnetic monopole.\"\n\nThat is to say: the lift is provided by magnetic repulsion as the monopole\nreacts to Urth's magnetic field.  Now, a normal magnet forced into this\n\"repulsive\" mode will tend to (seek to?) flip over onto its other pole and\naccelerate in its \"attractive\" mode (assisted by gravity) toward the\nplanetary body.  However, a magnetic monopole, by definition, lacks the\n\"other pole.\"  That is, it can't flip over.\n\nHmmm.\n\nYou don't like that one?\n\nOkay, well then brace yourself, because Science speculation has outstriped\nyou and everything you know is wrong! <g>\n\nRobert L. Forward, in INDISTINGUISHABLE FROM MAGIC:\n\n     \"All the matter that we know of is the type called regular (positive)\nmatter.  Yet both the Newton and the Einstein Theories of Gravity allow the\nexistence of an opposite form of matter, called negative matter.  According\nto the  theories of gravity and mechanics, an atom of negative matter would\nrepel all other matter (including other atoms of negative matter).\n\n     \"Now, the first thing you should realize is that negative matter is\n_not_ `antimatter.'  Antimatter is different from regular matter in its\nquantum mechanical properties, not its gravitational properties.  Although\nit has yet to be proven experimentally, we are fairly sure that antimatter\nattracts other forms of matter, just like normal matter.  Negative matter,\nhowever, would repel other forms of matter.\"\n\n     \"We do not know how to make negative matter.  But when we do, we will\ndiscover that it will not cost us any energy to make that negative matter.\nBecause the rest mass energy of a particle is proportional to its mass\n(E=mc^2), the rest mass energy of a negative mass particle is negative!\"\n(p. 173-174 in my paperback edition).\n\nWith this model, the lift is provided by the negative matter trying to\nleave the proximity of the planet--a kind of antigravity effect.\n\n=mantis="
        }
      ]
    }
  ]
}