The Disappearing Planet That Wobbles Like a Top
Astronomers have discovered the first known "disappearing planet" — a world about 1,000 light-years away that was crossing in front of its star, and then, over seven years of watching, simply stopped. The planet has not vanished. Instead, as a team led by UCLA reports in Astrophysical Journal Letters on 9 November 2026, gravity from a neighbouring planet is tilting its orbit, like a spinning top slowly leaning over.
The planet is called TOI-2535 b. It is a "hot Jupiter" — a gas giant about the size of Jupiter, orbiting extremely close to its star. It whips around its star in only 8.25 days, roughly ten times faster than Mercury, the fastest planet in our Solar System, takes to orbit the Sun (88 days).
How a planet disappears without moving
NASA's TESS space telescope finds planets by watching for transits: the tiny dip in a star's brightness when a planet passes in front of it. A transit only happens if the star, the planet and our telescopes line up exactly. TOI-2535 b was spotted in TESS images taken between April 2019 and March 2026 — but its transits did not keep a regular schedule. They ran early or late by up to six hours, and they grew shorter and shallower over the years, until in 2026 they failed to appear at all.
The explanation is a hidden neighbour. The astronomers' calculations show that an unseen planet, on an orbit tilted relative to TOI-2535 b, is pulling on it gravitationally. The two planets make each other's orbits wobble like a top, and the wobble has now tilted TOI-2535 b's orbit out of alignment with our line of sight. It will next cross its star sometime in 30 to 50 years — although its hidden neighbour may come into view sooner.
"This is the most extreme example we've seen because the two planets are interacting so strongly. The planet's orbit is tilting so quickly that its transit disappeared while we were watching," said Samuel Yee, a postdoctoral fellow at UCLA and the paper's corresponding author.
The same trick as an eclipse
The phenomenon is the same one that makes eclipses on Earth rare. "If the moon's orbit around the Earth was perfectly aligned with the Earth's orbit around the sun, we would see an eclipse every month," said UCLA astrophysicist Erik Petigura, a co-author. "But because the moon's orbit is tilted, eclipses are less common."
The discovery also tells astronomers something about how hot Jupiters form. These giant planets sit far too close to their stars to have formed there — models say they need ice to form, which only exists further out — so they must have migrated inwards. One idea is a violent flinging-in; the other is a slow spiral inwards with the disc of gas and dust around the young star. The wobble of TOI-2535 b suggests its system was tilted by interactions over time, and Yee thinks it probably migrated by slowly spiralling in — "a formation channel that doesn't happen very often but is very interesting."
For students, this is gravity and orbits doing something no textbook diagram quite captures: two planets, invisible to each other in the dark, pulling each other's paths out of shape over years. It is also a reminder that in science, a missing result — a transit that stops happening — can be the discovery itself.
If your child looks up at the night sky and wonders how planets are found, or how gravity shapes whole solar systems, a first lesson in physics or astronomy can start with this vanishing world. Book your first lesson
Sources:
- UCLA via phys.org, "First known 'disappearing planet' has a neighbor that makes it wobble like a top", 9 November 2026: https://phys.org/news/2026-11-planet-neighbor.html
- Samuel W. Yee et al., "A TESS Disappearing Act: The Vanishing Transits of TOI-2535 b", The Astrophysical Journal Letters (2026). DOI: 10.3847/2041-8213/aeb4a4
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