If you turn on the 'Stars' in that, you'll see that its currently in the interesting direction of the sky - 'twards the center of the Milky Way where we've got other telescopes looking. I wonder if we would have detected it if it was 180° further in its orbit.

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combobyte a day ago | parent [-]

> Another factor that kept ED138 hidden is that it is on the same plane as our galaxy. “For the last 20 years, the object has kind of been looping its way across the Milky Way, from our point of view,” Holman explained. “People don’t typically search for things in the Milky Way, because there’s so many stars that it’s really hard to find moving objects.” [1]

This thing was actually found despite its location, not because of it. If it had been in the opposite part of the sky we almost certainly would have spotted it sooner, given that it's one of the brightest TNOs we've discovered.

We're finding it now because Vera Rubin (the instrument that found it) just came online and is exceptionally good at finding these kinds of objects specifically, even when they're hiding amidst a dense population of stationary background stars.

[1] https://edition.cnn.com/2026/10/28/science/ed138-dwarf-plane...

	▲	shagie a day ago \| parent [-]
		https://www.washington.edu/news/2026/10/27/rubin-observatory... > ED138 joins the rapidly growing sample of solar system objects discovered by Rubin since it began collecting early data in preparation for the Legacy Survey of Space and Time (LSST), which began in June 2026. In April, before LSST formally began, the Rubin solar system team announced observations of over 11,000 new asteroids, which included roughly 380 new TNOs. At the time, the team called this large submission “the tip of the iceberg” and expressed their excitement for the discoveries to come once LSST began. With the discovery of ED138, those hopes are coming to fruition. My point was that the LSST survey was looking in those areas as part of its "mapping the Milky Way" https://rubinobservatory.org/explore/how-rubin-works/lsst Another recent discovery from Rubin - https://www.washington.edu/news/2026/11/05/rubin-observatory... You can see that it is looking in those dense starfield areas. https://rubinobservatory.org/gallery/collections/news-images... is where Rubin detected 12,700 new asteroids... and ED138 is in that part of the sky where Rubin was looking. Pluto has a 248 year orbit... which is close to the 282 years for ED138. 100 years ago, maybe Tombaugh would have found ED138 that if he was looking in that part of the sky. https://dahlend.github.io/ketev/#t=1930-02-18.717&sel=2026%2... In 1925, ED138 was crossing Pluto's orbit (and closer to Earth than Pluto was).