Cosmological Implications of the First Measurement of the Local ISM Abundance of [TSUP]3[/TSUP]He

Deuterium plays a crucial role in testing big bang nucleosynthesis. However, its chemical evolution is intertwined with that of 3 He. Gloeckler & Geiss's new measurement of the 3 He abundance and the Hubble Space Telescope measurement of D, both in the local ISM today, can be compared to the presolar nebula abundances of D and 3 He. Within the uncertainties, the sum of D 3 He relative to hydrogen is unchanged. This indicates that over the past 4.5 Gyr there has been at most modest stellar production of 3 He, in contradiction with stellar modeling, or modest stellar destruction of 3 He, in contradiction with efficient "solar spoons." The constancy of D 3 He alleviates some of the cosmic tension between the big bang 4 He abundance and those of D and 3 He.