Planetary sciences and exploration: An Indian perspective JNGOSWAMI∗ andSVSMURTY Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, India. ∗e-mail:
[email protected] Studies of cosmic ray records in meteorites and lunar samples in the nineteen sixties mark the beginning of research in planetary sciences in India. These studies led to very significant results that include discovery of ancient solar flare records in meteorites and constancy of solar and galactic cosmic ray fluxes over long (million year) time scales. Several research groups in India studied fossil records of nuclear track, noble gas, nitrogen, trace element and radioactivity in returned Apollo and Luna samples to understand both the nature of long-term solar wind, solar energetic particle and galactic cosmic ray fluxes as well as chemistry of lunar rocks and soils and their evolution on the lunar surface. The identification of meteorites of martian origin has also led to studies of such meteorites to understand the evolution of martian atmosphere over time. Analysis of diagnostic trace elements in samples of Cretaceous-Tertiary (K/T) boundary and chronology of Deccan volcanism supported asteroid impact as the cause of extinction of life ∼65 million years ago. Studies of impact craters records in the Indian shield have also been pursued and led to the identification of new impact structures. The realization that some primitive meteorites host refractory oxides and silicates that are some of the first solids to form in the solar system has opened a new window to study the events and time scales leading to the origin and early evolution of the solar system.