Could key ingredients for life have arrived from space? Scientists say yes

A fresh examination of meteorites that landed in the United States, Canada and Australia is bolstering the notion that such objects may have delivered to Earth early in its history chemical ingredients vital for the advent of life.

Scientists previously had detected on these meteorites three of the five chemical components needed to form DNA, the molecule that carries genetic instructions in living organisms, and RNA, the molecule crucial for controlling the actions of genes. Researchers said on Tuesday they have now identified the final two after fine-tuning the way they analyzed the meteorites.

Unlike in previous work...