Gas might keep the dwarf planet's subsurface ocean from freezing.
The Event Horizon Telescope peered into the Messier 87 galaxy.
Even in space, bureaucracy exists.
It could be something even cooler.
MU69 is far from your run-of-the-mill solar system object.
It's the farthest object we've ever spotted in our neighborhood.
We're under a time crunch.
Short answer: Because we changed the definition of the word “planet” to better fit its meaning.
And it could help prove the existence of Planet Nine.
Here are some highlights from its journey
Is there a planet—or even planets—waiting to be discovered out there?
But we won't know until we get there.
Something's got the Kuiper belt's rocks off, and there's a scramble to find it.
Submarines and rovers will go for a dive on the moons of Jupiter and Saturn
Like, can we even do that?
New Horizons will soon find out what's up with MU69.
It has to do with a surprisingly hazy atmosphere.
Another day, another hypothetical object on the outskirts of the solar system.
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
Based on NASA's best photos, anyway
The heavy heart may have tipped the world over
The moon won't be this close again for another 18 years
Imagine the space-scuba diving potential
Charon's polar cap once belonged to Pluto
Bubble, bubble, toil and trouble
Where can I find a planet like that?
This summer, the mission may get funding to travel to a mysterious rock at the edge of the solar system
Emails among scientists suggest it's possible
And it's still not Pluto
Massive chasms on the dwarf planet's largest moon explained
Here's the whole collection
Like icebergs in the Arctic Ocean
Planet 2MASS J2126-8140 orbits a trillion kilometers out from its sun
How skeptical should we be, and how will we find out if this mystery planet is really out there?
Scientists are hot on the trail of our solar system's 9th planet
With 'Star Trek' and Pluto stamps, its time to start mailing things again
The Dawn spacecraft has just moved in for a closer look at the dwarf planet
The Dawn mission may finally have an answer
Lookin' pretty sharp, for a dwarf planet
Pluto's favorite sister, mapped
Cathy Olkin talks about what New Horizons has seen and where it's going next
Could icy slush be driving the dwarf planet's geological activity?
Space sailors' delight?
Charon is the real #SuperBloodMoon in latest New Horizons pics
Latest New Horizons images show an alien landscape, and highest-resolution color map yet
The ocean-filled moon might hold the life we've long searched for in space. And scientists have one shot to reach it.
The dwarf planet may have a hydrological cycle, but it's not like ours
Here's what New Horizons saw as it zoomed past the former planet
Short answer: It depends who you ask
Just in case you get lost in the Asteroid Belt
A total eclipse of the heart
It just keeps getting better
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
Pluto is just the beginning
The New Horizons flyby is over, but now the real fun begins
Stranger worlds to come
So. Many. Things.
New false color images reveal surprising geologic details
Can you feel the love?
NASA releases a breathtaking close-up right before New Horizons flyby
Popular Science goes way back
Fasten your seatbelts
New Horizons spacecraft reveals the dwarf planet is slightly larger, has polar ice cap, and more
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
Just 3.5 million miles to go!
It's been 50 years since we got the first images of Mars. Now we're about to get the first images of Pluto.
The first color movies from New Horizons show Pluto and Charon in a weird waltz
And he thinks the upcoming flyby will prove it
I spy with my little eye some variations in tone
Plus, is that a polar ice cap we see?
An interview with Keri Bean, NASA engineer and R2D2's best friend
Who knows what might be lurking on this weird, tiny space rock
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
The spacecraft closes in on Ceres in March
A tour of places in our solar system where life could persevere
The little white dot is only going to get bigger
Hello, dwarf planet
As you battle the blizzard, just be happy you don't live on Pluto
The Dawn spacecraft arrives at Ceres this March, and it could be the most surprising space mission in decades
From 283,000 miles out, the spacecraft is already making discoveries
What will we find when we reach Pluto and Ceres? We don't know, but it's going to be wild.
What's on the horizon for the New Horizons spacecraft
Humankind's greatest adventure lies beyond the sun
Pulled by dual gravity, the egg-shaped satellites tumble like eerie dice
Erupting slush instead of lava
We just can't get enough
To everything, turn, turn, turn
Welcome to Ceres
The former planet is frosted in the stuff
Our best view yet of the dwarf planet's mysterious bright splotches
A good week for space photography