Archive · 4 Oct 2025
Astronomers Find New Evidence of a Hidden Planet
Imagine our solar system has a secret!
Scientists have found clues that there might be a hidden planet far, far away.
They saw that some icy rocks, called Kuiper Belt objects, are tilted in a strange way.
They think this tilt could be because a planet, they call Planet Y, is tugging on them.
Planet Y would be smaller than Earth but bigger than Mercury, and orbiting way out there.
Scientists haven't seen it yet, but they are excited because a powerful new telescope might be able to spot it soon!
Astronomers have new evidence suggesting the existence of an unseen planet called Planet Y.
Planet Y's existence is inferred from the unusual tilt of distant Kuiper Belt objects.
Planet Y is hypothesized to be smaller than Earth but bigger than Mercury.
The hypothetical planet could be orbiting 100 to 200 times the Earth-Sun distance.
The Vera C. Rubin Observatory may provide evidence of Planet Y's existence.
- Who
- Astronomers, including Amir Siraj
- What
- Found evidence suggesting a hidden planet, Planet Y, in the solar system.
- When
- Study published recently; Vera C. Rubin Observatory survey this fall
- Where
- Outer reaches of our solar system
- Why
- To explain the unusual tilt of distant Kuiper Belt objects.
- Planet Name
- Planet Y
- Discovery Context
- Unusual tilt of Kuiper Belt objects
- Planet Size (Estimated)
- Smaller than Earth, larger than Mercury
- Orbital Distance (Estimated)
- 100-200 times Earth-Sun distance
- Orbital Tilt (Minimum)
- 10 degrees
- Planet Nine
- Also proposed as a possible planet
- Next Steps
- Vera C. Rubin Observatory survey