  We propose that the X-ray emission detected by Chandra from the
100-kiloparsec-scale jet of PKS 0637-752 is produced through inverse Compton
scattering of the Cosmic Microwave Background (CMB). We analyze the physical
state of the jet and show that inverse Compton scattering from the CMB is
consistent with equipartition for a moderate beaming of the emission, with
Doppler factor delta~10. The power transported by the jet is then similar to
that of other powerful blazars, Lj~10^{48} erg/s and the jet has low radiative
efficiency. The radiative cooling times of the electrons are a few thousand
years, compatible with the size of the knot. The low-energy cutoff of the
electron distribution is constrained to be gamma_min~10, the first such
constraint from spectral considerations. A parallel analysis for the SSC model
yields far less reasonable physical conditions.
