(Correction: An earlier version of this story misstated how far Pluto is from the sun. The correct number is 3.7 billion miles.) What was discovered in Flagstaff, Arizona, and killed off in Prague? If ...

Pluto hasn't been a planet for almost 20 years. In the early 2000s, scientists discovered several objects of a similar size to Pluto. So, during the summer of 2006, members of the International ...

The space probe began making discoveries even before today's flyby. — -- Three billion miles and nearly ten years of travel led up to the moment NASA's New Horizons probe zoomed past Pluto today, ...

Visual observation of Pluto using amateur telescopes is challenging due to its faint magnitude (currently 14.4), requiring instruments larger than 8 inches in aperture for a reasonable chance of ...

Rather than a vast ocean, Pluto’s heart might be hiding a huge, heavy treasure. Computer simulations suggest that an object about 730 kilometers wide, slightly larger than the asteroid Vesta, could ...

What was discovered in Flagstaff, Arizona, and killed off in Prague? If you answered "Pluto's planethood," your grasp of the astronomical is excellent. Feb. 18 marks the 95th anniversary of the ...