Infrared surveys may have captured our solar system’s missing giant
An object bigger than Neptune. 700 times farther than Earth. Seen once in 1983, then again in 2006. And now, astronomers believe it might be real.
The long-speculated Planet Nine—a theoretical ice giant lurking in the outer solar system—may have finally shown its face. And it didn’t happen in real-time. Instead, the evidence comes from two deep-sky infrared surveys, conducted 23 years apart, that captured a faint, slow-moving dot in two slightly shifted locations across the sky.
If this candidate object is confirmed, it would be the first direct detection of the elusive Planet Nine: a world that could dwarf Earth, outmass Neptune, and orbit between 280 and 1,120 astronomical units (AU) from the Sun.
What Did They Find?
A research team led by Dr. Terry Long Phan of National Tsing Hua University in Taiwan analyzed legacy data from:
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IRAS (Infrared Astronomical Satellite) — active in 1983
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AKARI (JAXA infrared observatory) — operated between 2006–2011
Using sophisticated motion-tracking techniques, Phan’s team searched for faint objects that shifted position between the two surveys. They corrected for Earth’s parallax (the apparent wobble of distant stars caused by our planet’s orbit) and filtered out fast-moving objects like asteroids.
One object stood out: a tiny infrared dot that appeared to have moved 47.4 arcminutes over 23 years—consistent with the slow orbital path of a distant planetary body at ~700 AU.
Could This Really Be Planet Nine?
This isn’t the first time Planet Nine’s existence has been proposed. The theory gained traction in 2016, when astronomers Michael Brown and Konstantin Batygin suggested that gravitational tugs on Trans-Neptunian Objects (TNOs)—like Sedna—could be explained by an undiscovered massive planet.
Planet Nine, as they envisioned it:
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5–10 times Earth’s mass
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A highly eccentric orbit far beyond Pluto
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Too cold and dim for optical telescopes—but potentially visible in mid- to far-infrared light
Phan’s discovery checks those boxes. The object’s brightness profile in both IRAS and AKARI data suggests it’s at least Neptune-sized, but without a precise orbital arc, astronomers can’t confirm its identity—yet.
Why It Was Missed Until Now
NASA’s WISE mission previously ruled out any Jupiter-sized planets out to 256,000 AU—but Neptune- or Uranus-class planets could easily go undetected. Why?
Because they’re cold, slow-moving, and fade below the detection thresholds of most sky surveys.
Even Phan’s team failed to locate a WISE counterpart to their object. Why? It moved. The object has likely shifted since AKARI’s 2006 image, and without a full orbital path, there’s no way to triangulate its current location precisely.
But now that we know where it was, a renewed optical search is underway using tools like:
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The Dark Energy Camera in Chile (3° field of view)
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The upcoming Vera C. Rubin Observatory
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NASA’s Nancy Grace Roman Space Telescope
Implications for Planetary Science
At a possible distance of 65 to 105 billion kilometers, this object—if confirmed—would redraw the map of the solar system. It also opens wild possibilities:
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Captured rogue planet? Maybe it didn’t form here. Planet Nine could be a wayward exoplanet captured by our Sun during the solar system’s chaotic youth.
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Scattered by giants? Alternatively, it may have formed among the known gas giants and been flung outward during gravitational instability.
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Comet shepherd? Some researchers speculate such a planet could help direct icy bodies from the Kuiper Belt or Oort Cloud into the inner solar system, possibly influencing impact events on Earth.
What Happens Next?
The candidate object must now be located in modern surveys. Phan’s team is preparing coordinates for deep imaging efforts—most likely with wide-field optical telescopes that can cover the vast search area.
His full results have been accepted for publication in the Publications of the Astronomical Society of Australia.
As Dr. Phan told reporters:
“Once we know the position of the candidate, a longer exposure with today’s large telescopes can detect it.”
And if it’s there, this time, Planet Nine won’t slip past us again.
Key Data at a Glance
| Feature | Estimate |
|---|---|
| Possible Object Mass | Larger than Neptune |
| Distance from Sun | ~700 AU (65 billion miles) |
| Angular Motion | 47.4 arcminutes (1983–2006) |
| Detection Instruments | IRAS (1983), AKARI (2006) |
| Follow-up Tools | DECam, Vera Rubin Observatory, Roman Space Telescope |
Is This Planet Nine?
The evidence is strong, but not conclusive. A moving infrared signature between two sky surveys, separated by decades, is a powerful lead—but until astronomers locate this object again, it remains a candidate.
Still, this is the strongest evidence yet that a Neptune-class planet may be hiding in the far reaches of our solar system—its long, dark orbit finally betraying its path across the stars.
Related Searches:
“Is Planet Nine real 2025” • “AKARI Planet 9 discovery” • “object at 700 AU” • “infrared detection of outer solar system planet” • “IRAS 1983 Planet Nine” • “Dr. Terry Long Phan discovery” • “Planet Nine motion arcminutes”
