NOVA

For decades, scientists have tried to unlock the secrets of ancient DNA. But life's genetic blueprint is incredibly fragile, and researchers have struggled to find DNA in fossils that could survive millions of years. Then, one maverick scientist had the controversial idea to look for DNA not in fossils or frozen ancient tissue – but in dirt. Join the hunt as scientists decipher the oldest DNA ever found, and reveal for the first time the genes of long-extinct creatures that once thrived in a warm, lush Arctic.

Can we harness the power of artificial intelligence to solve the world's most challenging problems without creating an uncontrollable force that ultimately destroys us? ChatGPT and other new A.I. tools can now answer complex questions, write essays, and generate realistic-looking images in a matter of seconds. They can even pass a lawyer's bar exam. Should we celebrate? Or worry? Or both? Correspondent Miles O'Brien investigates how researchers are trying to transform the world using A.I., hunting for big solutions in fields from medicine to climate change.

Explore the spectacular cosmic phenomenon of a total solar eclipse. In April 2024, the Moon's shadow is sweeping from Texas to Maine, as the U.S. witnesses its last total solar eclipse until 2044. This extraordinary astronomical event is plunging locations in the path of totality into darkness for more than four minutes – nearly twice as long as the last American eclipse in 2017. Learn how to watch an eclipse safely and follow scientists as they work to unlock secrets of our Sun – from why its atmosphere is hundreds of times hotter than its surface, to what causes solar storms and how we might one day predict them.