The ACME Collaboration has measured the electric dipole moment (EDM) of the electron using a polar molecule, thorium monoxide (ThO), achieving an upper limit of |d_e| < 8.7 × 10⁻²⁹ e cm with 90% confidence, an order of magnitude improvement over previous limits. This result constrains time-reversal (T) violating physics at the TeV energy scale. The EDM is an asymmetric charge distribution along the spin, and its measurement relies on the high internal effective electric field of ThO molecules, which is up to a million times larger than any static laboratory field. The measurement involves spin precession of ThO molecules in parallel electric and magnetic fields, with the precession angle proportional to the EDM. The experiment used a cryogenic buffer gas beam source and a laser to prepare and read out the spin state. The EDM was determined from the phase shift in the spin precession, which was measured using a readout laser and fluorescence detection. Systematic errors were minimized by varying experimental conditions and applying corrections based on the measured phase shifts. The result is consistent with previous measurements and provides a more precise limit on the EDM, which has implications for theories of T violation and dark matter. The EDM measurement is sensitive to new physics beyond the Standard Model, and the result constrains CP violation at energy scales up to 3 TeV. The experiment involved a detailed analysis of systematic errors, including those from laser polarization gradients, AC Stark shifts, and magnetic field gradients. The final EDM limit is 12 times smaller than the previous best limit, demonstrating the power of using ThO molecules and cryogenic sources for EDM measurements.The ACME Collaboration has measured the electric dipole moment (EDM) of the electron using a polar molecule, thorium monoxide (ThO), achieving an upper limit of |d_e| < 8.7 × 10⁻²⁹ e cm with 90% confidence, an order of magnitude improvement over previous limits. This result constrains time-reversal (T) violating physics at the TeV energy scale. The EDM is an asymmetric charge distribution along the spin, and its measurement relies on the high internal effective electric field of ThO molecules, which is up to a million times larger than any static laboratory field. The measurement involves spin precession of ThO molecules in parallel electric and magnetic fields, with the precession angle proportional to the EDM. The experiment used a cryogenic buffer gas beam source and a laser to prepare and read out the spin state. The EDM was determined from the phase shift in the spin precession, which was measured using a readout laser and fluorescence detection. Systematic errors were minimized by varying experimental conditions and applying corrections based on the measured phase shifts. The result is consistent with previous measurements and provides a more precise limit on the EDM, which has implications for theories of T violation and dark matter. The EDM measurement is sensitive to new physics beyond the Standard Model, and the result constrains CP violation at energy scales up to 3 TeV. The experiment involved a detailed analysis of systematic errors, including those from laser polarization gradients, AC Stark shifts, and magnetic field gradients. The final EDM limit is 12 times smaller than the previous best limit, demonstrating the power of using ThO molecules and cryogenic sources for EDM measurements.