If an asteroid ever does come hurtling toward Earth, we might be ready now to handle it and save humanity. 

You can thank NASA scientists if it ever comes to that. We know the DART spacecraft smashed into a distant asteroid successfully. We didn't know right away whether it changed the big rock's trajectory. Now we do. It did. Back with us to explain is Terik Daly, DRACO deputy instrument scientist for the DART mission. He's also a planetary scientist at the Johns Hopkins Applied Physics Lab.