We're under a time crunch.
Short answer: Because we changed the definition of the word “planet” to better fit its meaning.
New Horizons will soon find out what's up with MU69.
There's still more to explore after Pluto.
A sky full of super-Earths
More exciting news about cold, dead rocks
Scientists aren't just jerking you around—this is about something more than your childhood nostalgia
Scientists are hot on the trail of our solar system's 9th planet
How much are we really paying to explore the universe?
Bringing snark to Mars
Choose wisely, because this is for real
Short answer: It depends who you ask
A total eclipse of the heart
The latest and greatest images from the New Horizons mission
Pics captured by New Horizons from just 48,000 miles away reveal the strange alien world
Popular Science goes way back
After nine years and three billion miles, here's what we're learning from it all
Even though I helped demote it
Witness history in the making
New Horizons scientist Leslie Young discusses what to expect from the flyby on Tuesday, and the 28-year wait leading up to it
And he thinks the upcoming flyby will prove it
This year's missions to the outer solar system are set to shake up the planetary family tree
That's three moons down, two to go