Kerberos
The Dark Surprise
Expected to be bright, but turned out to be surprisingly dark and coal-black
🌙 Mind-Blowing Fact
Scientists predicted Kerberos would be bright based on its visibility, but New Horizons revealed it's actually dark as charcoal - a complete surprise!
What is Time on Kerberos?
What is Time on Kerberos?
Kerberos (discovered in 2011) is famous for being the exact opposite of what scientists expected - dark instead of bright!
The 32-Day Orbit
- One orbit = 32.17 Earth days - About 4.5 weeks
- Estimated rotation: ~5.3 Earth days (chaotic)
- Very dark surface - Reflects only ~4% of light
- Double-lobed shape - Like a contact binary
The Dark Mystery
Kerberos was a surprise:
- From Earth, seemed relatively bright
- Expected to be large and reflective
- New Horizons revealed: small and VERY dark!
- Dark as coal or asphalt
- Why? Unknown!
The Contact Binary
Kerberos appears to be two objects stuck together:
- Two lobes connected by narrow neck
- Size: ~19 km × 10 km × 9 km
- Probably formed from two smaller objects merging
- Common for small irregular moons
A Day in the Life
The Dark Deception
From Earth, astronomers predicted Kerberos would be large and bright. New Horizons proved them spectacularly wrong.
You land on Kerberos's dark surface. It's coal-black, absorbing 96% of light.
"Why is it so dark?" you ask.
"Radiation processing," your geologist explains. "Billions of years of cosmic rays breaking down the ice, creating complex carbon compounds. Or maybe it's just ancient material that never got refreshed. Either way, Kerberos is one of the darkest objects we've ever studied."
You look at the contact binary shape - two lobes joined by a narrow neck. "It looks like two moons merged."
"Probably. A low-velocity collision billions of years ago. They stuck together instead of shattering. Now they tumble through space as one dark, deceptive world."
Thought Experiments
Why was Kerberos so surprising to scientists?
From Earth, Kerberos was visible despite being small, so scientists assumed it must be very reflective (bright). But New Horizons revealed it's actually very dark - meaning it's just barely big enough to be visible despite absorbing most light. It's like expecting to see a white car from far away, but when you get close you realize it's actually a dark car that's just larger than you thought!
The Science of Time on Kerberos
Kerberos: The Expectation Breaker
Discovered in 2011 by Hubble, Kerberos (named after the three-headed dog guarding the underworld) defied predictions.
Expected: Large (40+ km), bright surface
Reality: Small (~19 km), very dark surface (albedo ~0.04)
The puzzle: If Kerberos is so dark, why was it visible from Earth at all? Answer: It's just barely large enough and close enough to reflect enough light despite being very dark.
Composition theories:
- Carbon-rich surface from radiation processing
- Ancient surface never refreshed
- Different formation history than Nix/Hydra