Is Planet 9 more than just theory? A new infrared data match suggests it might be the Solar System’s most elusive giant.
After decades of speculation, a potential Neptune-sized planet beyond Neptune has finally left a fingerprint—one that infrared telescopes spotted 23 years apart. This isn’t just another orbital anomaly. This is a candidate sighting backed by measurable movement across the sky. The search for Planet 9 just turned from theory to hard data.
Researchers from Taiwan, Japan, and Australia analyzed full-sky infrared surveys from IRAS (1983) and AKARI (2006). These space telescopes scanned the sky in infrared, the only spectrum where a distant cold planet might glow faintly.
Key findings:
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13 possible moving objects were flagged
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After cross-validation, only one candidate remained
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It moved 47.5 arcminutes in 23 years — about 1.5x the width of the full Moon
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Movement speed and thermal signature match predictions for a ~Neptune-mass planet at 300+ AU
Infrared telescopes bypass the optical trap. A planet 10x farther than Neptune reflects almost no sunlight — it appears 10,000x dimmer. But in thermal IR, it’s only ~100x dimmer, and the heat doesn’t need to bounce back from the Sun.
This new object aligns with both:
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Expected thermal profile of a cold gas giant
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Predicted orbital motion from gravitational modeling of trans-Neptunian object (TNO) clusters
Telescope time. Fast.
Two sky coordinates 23 years apart don’t confirm an orbit. But they give a trajectory. The team will likely push for follow-up observations with DECam in Chile. With its deep sensitivity and wide field, DECam can nail the third data point required to calculate an orbit.
If confirmed, this object would:
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Redefine Solar System boundaries
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Support models that predict outer Solar System mass anomalies
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Potentially open a new category of planetary migration theories
You’re not just reading another speculative “Planet 9” headline. This one has:
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Archival data
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Matched movement
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Infrared signal integrity
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Real peer-reviewed analysis (Phan et al., 2025)
If you care about space, this is the signal you were waiting for. No hype—just data finally doing what theory has teased for decades.
Sources:
Phan et al. (2025), “A Search for Planet Nine with IRAS and AKARI Data” [arxiv.org/abs/2504.17288]
NASA/JPL-Caltech, DECam specifications, IRAS & AKARI mission logs
