Mass Extinctions in the history of Life: Significance of NASA’s Artemis Moon and Planetary Defence DART Missions

Abstract

Evolution and extinction of new species have gone hand in hand since life began on Earth. However, there have been at least five episodes of large-scale extinctions of life-forms in the past 500 million years. In these episodes, more than three-quarters of the existing species got eliminated. These are referred to as global extinction or mass extinction. The Fifth Mass Extinction was the last such episode that occurred about 65 million years ago in Cretaceous period. This was caused due to asteroid impact. The resulting conditions led to the elimination of dinosaurs from the face of Earth. In the current Anthropocene period (i.e., the period of humanity), it is suspected that the Earth may already be in or on the verge of Sixth Mass Extinction, due to man-made environmental issues (such as climate change, pollution, deforestation, global warming, etc.). Further factors like nuclear, biological or other types of warfare/conflict, natural environmental disasters such as volcanic eruption or asteroid impact also have the potential to trigger mass extinction. Spreading out into space is one of the ways to deal with existential challenges posed. NASA’s Artemis Moon Mission is a beginning towards deep space human habitation by future colonisation of the Moon and Mars. Planetary defence by deflecting an asteroid away from the Earth is another strategy being considered. NASA’s DART Mission is the first such asteroid deflection test. This mission will try to deflect a near-Earth asteroid next month.