Nondweni dacite, and 4.3 $\pm$ 1.0 x 10$^{22}$ A m$^{2}$ for the Barberton dacite. Thus a strong magnetic field was present during a time for which we have the oldest microfossil evidence for life [@Wacey2011]. However, what were the details of the shielding environment? Having these magnetic dipole moment constraints, the next step in our quest to calculate magnetopause standoff is to constrain solar wind pressure in the past, as discussed below.\

Solar Wind and magnetopause at 3.45 Ga
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The property of the Archean to Hadean Sun that has most captured the attention of the geological community is its luminosity. The Sun began the main sequence phase of its life at a luminosity $\sim$30% lower than the present-day value [@Gough1981]. Because of the conversion of H to He in the Sun’s core, density and temperature increase, and luminosity rises. The “Faint Young Sun Paradox" highlights the expectation that this reduced luminosity should have resulted in a snowball Earth [@Sagan1972], but sediments (including those from the Barberton Greenstone belt) indicate deposition in shallow warm seas.

The solution to the paradox is generally posed in the form of some greenhouse gas concentration in the early Earth’s atmosphere. We will briefly revisit 