Galactic current — the drift is nanometres per second
Ampère reading of the named Milky Way disk · travel of kilometres in 12,000 years · no ledger row · no promote
CPT Framework — Book C / FT-PERATT / GAL-PLASMA-FRAC Date: 2026-10-07 Status: RECORD · public page/cosmology/galactic-current · this file charters no §0bn row
Parents: a_geom_ft_peratt_homology_spec.md · a_geom_ft_peratt_homology_results.md · a_geom_galactic_plasma_mass_fraction_consideration.md · a_geom_bulk_current_join_design.md · §0bn967 · §0bn964 · §0bn660
Tags: [E algebra] of the frozen inputs · [E honesty] on what stays free
0. One-line
The net galactic current, spread through the warm ionized disk at the frozen inputs, is a drift of \(8.94\times 10^{-9}\,\mathrm{m\,s^{-1}}\). A carrier moves \(0.282\,\mathrm{m}\) in a year, \(3.39\,\mathrm{km}\) in \(12{,}000\) years, and \(4.00\times 10^{9}\,\mathrm{m}\) in one Hubble time at \(H_0=68.973\). A \(12{,}000\)-year sheet crossing is not this motion.
1. Frozen inputs
From the Peratt spec, catalogue values, not a fit:
| Input | Value | |-------|--------| | \(B\) | \(5\,\mu\mathrm{G}\) | | \(n_e\) | \(0.03\,\mathrm{cm^{-3}}\) | | \(T\) | \(8000\,\mathrm{K}\) | | \(R\) | \(8.5\,\mathrm{kpc}\) | | \(h\) | \(0.3\,\mathrm{kpc}\) | | Warm ionized mass | \(\sim 2\times 10^{9}\,M_\odot\) |
\[ I=\frac{BR}{\mu_0}=1.044\times 10^{17}\,\mathrm{A}. \]
The current crossing a radial cut of height \(h\) has mean density \(J=B/(\mu_0 h)\). Quasi-neutrality gives one relative drift,
\[ v_d=\frac{B}{\mu_0 n_e e h}=8.94\times 10^{-9}\,\mathrm{m\,s^{-1}}. \]
That is \(8.94\,\mathrm{nm}\) in one second, and \(2.57\times 10^{-14}\) of the electron thermal speed at \(8000\,\mathrm{K}\) (\(3.48\times 10^{5}\,\mathrm{m\,s^{-1}}\)). A full reversal of the same field doubles the surface current and doubles the drift.
2. How far a carrier travels
| Clock | Distance at \(8.94\times 10^{-9}\,\mathrm{m\,s^{-1}}\) | |-------|----------------------------------------------------------| | One second | \(8.94\,\mathrm{nm}\) | | One year | \(0.282\,\mathrm{m}\) | | Eighty years | \(22.6\,\mathrm{m}\) | | \(12{,}000\) years | \(3.39\,\mathrm{km}\) | | One Hubble time, \(H_0=68.973\,\mathrm{km\,s^{-1}\,Mpc^{-1}}\) | \(4.00\times 10^{9}\,\mathrm{m}\) (\(4{,}000\,\mathrm{km}\)) |
The same fluid in a Harris sheet of half-thickness \(70\,\mathrm{pc}\) has a peak drift \(3.83\times 10^{-8}\,\mathrm{m\,s^{-1}}\) and travels \(14.5\,\mathrm{km}\) in \(12{,}000\) years. At \(160\,\mathrm{pc}\) the peak drift is \(1.68\times 10^{-8}\,\mathrm{m\,s^{-1}}\) and the travel is \(6.35\,\mathrm{km}\).
Drift kinetic energy is \(1.1\times 10^{-29}\) of the magnetic energy for electrons and \(2.0\times 10^{-26}\) for protons. Magnetic energy is \(0.621\,\mathrm{eV\,cm^{-3}}\). The banked plasma \(\beta\) is \(0.033\). The energy does not choose which sign slips. Proton gyroradius is \(170\,\mathrm{km}\). Electron gyroradius is \(4.0\,\mathrm{km}\).
\(B\), \(n_e\), and \(h\) are catalogue orders. A factor of a few in any one of them moves \(v_d\) by that factor. The travel in \(12{,}000\) years stays a few kilometres.
3. What this motion is
The mass in the circuit is the warm ionized medium, about \(2\times 10^{9}\,M_\odot\). The banked disk split puts the stars near \(5\times 10^{10}\,M_\odot\) and the neutral gas near \(10^{10}\,M_\odot\). The plasma is quasi-neutral hydrogen: equal numbers of protons and electrons, mass in the protons, net charge at the scored leftover. The current is the slip \(v_i-v_e\).
A \(12{,}000\)-year crossing of a galactic sheet is a different claim. At \(7\,\mathrm{km\,s^{-1}}\) the Sun travels \(0.086\,\mathrm{pc}\) in \(12{,}000\) years. The published local magnetic reversal is a tilted plane \(0.25\)–\(0.55\,\mathrm{kpc}\) from the Sun (Booth et al. 2026, ApJ 997, 304). The Radcliffe Wave oscillates on a timescale of tens of millions of years (Konietzka et al. 2024, Nature 628, 62). The heliospheric current sheet turns over with the solar rotation and the 11-year cycle. None of those clocks is this drift.
The halo stays the open leftover of Book G. This record does not retire it.
4. Integrity
| Gate | Verdict | |------|---------| | Drift at the frozen inputs | Direct calculation · \(8.94\times 10^{-9}\,\mathrm{m\,s^{-1}}\) | | Travel in \(12{,}000\) years | \(3.39\,\mathrm{km}\) on the disk mean | | \(12{,}000\)-year sheet crossing as this current | Not this motion | | Which sign slips, and any faster canceling legs | Free | | Halo | Stays open | | Ledger row / chip / promote | No |
Exit: record only. Public text is/cosmology/galactic-current.