On eve of New Horizons flyby, Ultima Thule still holding onto its mysteries
A day before NASA’s New Horizons spacecraft closes in on a frozen outpost nicknamed Ultima Thule 4.1 billion miles from Earth, basic facts about the city-sized object continued to elude scientists Sunday as the ground team braced for a deluge of data and imagery that should unmask the unexplored world at the frontier of the solar system.