A year on these planets flies by, lasting between five and 10 Earth days.
"It was surprising, but you like to be surprised in science."
"The first thing that comes to my mind when I think back on it was just how loud it was, the roar of the eruption."
The spacecraft's target is more than four billion miles away from Earth.
Almost two-thirds of respondents thought climate and asteroid monitoring should be top priorities for the agency.
The collective gravity of lots of little objects might add up to a powerful force.
A lahar, which is essentially a mudflow filled with rock particles, can reach speeds as high as 120 miles per hour.
"It's so flat and white and boring in every direction but underneath you is a mountain range as big as the Pyrenees."
The scientists will study what's happening 3,000 feet below the ocean's surface, above what will one day become the newest island in the chain.
Last year's collision was the first in which scientists could actually see what was happening during and after the collision.
"It's like a paternity test, not between father and son but among peoples."
The extinct big cat resembled some species you might see in a zoo today, sharing some features with lithe African cheetahs and others with larger, more muscular cats like jaguars and leopards.
They are some of the last unexplored parts on Earth; the largest is more than 200 miles long.
Tiny fish remains were time capsules of climate change.
The drill malfunctioned in December 2016.
"It will truly be a historical mission to take our first step into interstellar space."
The original photos were taken over the course of half an hour and more than 30,000 miles of travel.
The 2015 BZ509 asteroid orbits the sun in the opposite direction to everything else in the solar system.