We keep finding the raw material of DNA in asteroids—what's it telling us?

Asteroids repeatedly yield the chemical building blocks of DNA, strengthening the case that life's ingredients are cosmic. Recent analyses of samples from asteroid Bennu found all five nucleotide bases—adenine, guanine, cytosine, thymine, and uracil—at concentrations exceeding 10 parts per billion. The pattern now spans multiple asteroids and comets, suggesting that extraterrestrial delivery of organic compounds is not rare but routine. Each detection adds weight to the hypothesis that Earth's first genetic material may have arrived from space.