The article reports the discovery of a Type Ia supernova (SN 1997ap) at a redshift of \( z = 0.83 \), making it the most distant spectroscopically confirmed supernova to date. The Supernova Cosmology Project, involving multiple institutions and telescopes, conducted extensive observations of SN 1997ap, including photometry with the Hubble Space Telescope and ground-based telescopes. The spectrum and photometry of SN 1997ap were analyzed to determine its properties and compare it with nearby supernovae. The results suggest that SN 1997ap is a "normal" Type Ia supernova, with a stretch factor of \( s = 1.03 \pm 0.05 \). The peak magnitudes of SN 1997ap are \( I = 23.20 \pm 0.07 \) and \( R = 24.10 \pm 0.09 \). The study also discusses the significance of SN 1997ap in cosmological measurements, showing that it can help distinguish between different models of the universe, particularly in distinguishing the effects of mass density \( \Omega_M \) and cosmological constant \( \Lambda \). The combined analysis of SN 1997ap with previous lower-redshift supernovae provides evidence for a low-mass-density universe, with \( \Omega_M = 0.6 \pm 0.2 \) in a flat universe or \( \Omega_M = 0.2 \pm 0.4 \) in a \( \Lambda = 0 \) universe. The article also mentions the discovery of additional high-redshift supernovae, which will further improve the cosmological measurements.The article reports the discovery of a Type Ia supernova (SN 1997ap) at a redshift of \( z = 0.83 \), making it the most distant spectroscopically confirmed supernova to date. The Supernova Cosmology Project, involving multiple institutions and telescopes, conducted extensive observations of SN 1997ap, including photometry with the Hubble Space Telescope and ground-based telescopes. The spectrum and photometry of SN 1997ap were analyzed to determine its properties and compare it with nearby supernovae. The results suggest that SN 1997ap is a "normal" Type Ia supernova, with a stretch factor of \( s = 1.03 \pm 0.05 \). The peak magnitudes of SN 1997ap are \( I = 23.20 \pm 0.07 \) and \( R = 24.10 \pm 0.09 \). The study also discusses the significance of SN 1997ap in cosmological measurements, showing that it can help distinguish between different models of the universe, particularly in distinguishing the effects of mass density \( \Omega_M \) and cosmological constant \( \Lambda \). The combined analysis of SN 1997ap with previous lower-redshift supernovae provides evidence for a low-mass-density universe, with \( \Omega_M = 0.6 \pm 0.2 \) in a flat universe or \( \Omega_M = 0.2 \pm 0.4 \) in a \( \Lambda = 0 \) universe. The article also mentions the discovery of additional high-redshift supernovae, which will further improve the cosmological measurements.