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Vera Rubin Observatory

|< < Prev #3278 (July 29, 2026)

Title text: 'Spurious signals from the kitchen' is harder for an optical telescope than a radio one, but with enough determination and creativity, I believe it's possible.

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Explanation

This shows a bingo card of various items discovered or potentially discoverable using the Vera Rubin Observatory. This is an astronomical observatory located in Chile, featuring the largest (as of 2026) digital astronomical camera; it began gathering scientific data shortly before the publication of this comic. Some of the listed possibilities are highly likely, some are quite improbable, and some are entirely ridiculous. The observatory has released a genuine bingo card game, featuring more likely objects, intended for educational purposes.

A table of the items on the comic's bingo card is shown below:

#	Item	Explanation
1	Black hole tidally disrupting a star	A few days before this comic, a paper describing the detection of a tidal disruption event was published. However, it was detected by the Palomar Observatory, not Rubin.
2	Planet nine	This is a hypothetical planet in the distant reaches of the Solar System whose gravitational effects could explain the orbits of some extreme trans-Neptunian objects (see further entries below). Before it was redesignated as a dwarf planet, Pluto was considered the ninth planet.
3	Remnants of a former Milky Way companion galaxy
4	10,000 new trans-Neptunian objects	The Vera Rubin Observatory is predicted to discover over 37,000 trans-Neptunian objects by the mid-2030s. For comparison, only about 5,000 trans-Neptunian objects had been discovered as of December 2024. Vera Rubin Observatory began observing in June 2025 and discovered 380 trans-Neptunian objects by April 2026.
5	Object on interstellar trajectory	Interstellar objects are celestial bodies travelling through interstellar space, not gravitationally bound to any star, including our Sun. While most interstellar objects we see are many light years away, some may occasionally come close enough to Earth for us to study in detail. These close-passing interstellar objects are most likely found as small asteroids or comets. Only three such objects have been discovered to date: 1I/ʻOumuamua, 2I/Borisov, and 3I/ATLAS. One of Vera Rubin Observatory's goals is to efficiently detect interstellar objects thanks to its wide field of view, which will help astronomers figure out the abundance and properties of the interstellar object population. Vera Rubin Observatory actually detected 3I/ATLAS several days before its discovery, which highlights the observatory's potential to discover new interstellar objects, if there are any more to be found.
6	Star being eclipsed by weird object	The Vera Rubin Observatory will routinely measure the brightnesses of stars over time, producing a light curve. Many stars change brightness over time, though by different amounts and speeds. Stars generally dim because of starspots rotating in and out of view, stellar pulsation of their temperature and radius, clouds of dust passing in front of them, or even orbiting planets and stars. In rare cases, a star may dim so much that it ends up disappearing—but only temporarily, ranging from a few hours to a few years. Such events are believed to be caused by large objects (radius spanning millions of kilometers) eclipsing the star—such large objects may be a dense dust cloud (such as the one responsible for the 2019-2020 dimming of Betelgeuse) or a protoplanetary disk surrounding a dim planet, brown dwarf, or star. These dimming events may either repeat once every few years (if the eclipsing object is orbiting the star, like in Epsilon Aurigae), never repeat (if the eclipsing object is not orbiting the star, like J1407b), or may occur irregularly. For the last case, a famous example is Boyajian's Star (aka Tabby's Star), which is thought to have large amounts of thick dust and a giant planet orbiting in front of it (or perhaps a Dyson Swarm if you wanna be extravagant).
7	Secret military satellite	During the development of the Vera Rubin Observatory, an unspecified United States agency raised concerns that the observatory would detect spy satellites, posing a risk to national security. These concerns were addressed after a 2023 meeting with the observatory's director Željko Ivezić. The observatory now has an automated system that checks for any spy satellites in images, and deliberately delays their access to astronomers for 3 days if any were found.[1][2] The VRO alert system also does not publish objects moving across the sky faster than 10 degrees per day to avoid spurious notifications of low-orbiting satellites (and in particular secret military satellites).
8	Kuiper Belt object that's a surprising color	Kuiper belt objects (KBOs) are icy celestial bodies found in the Solar System's Kuiper belt, the home of Pluto beyond the orbit of Neptune. KBOs are generally found with optical colors ranging from "blue"/"neutral" to "red" to "very red". (Note that to the human eye, these colors would actually range from gray to brown.) The Vera Rubin Observatory can distinguish the optical colors of astronomical objects by measuring their brightness through multiple visible-light filters. These colors translate to a specific surface composition, with gray colors indicating abundant water ice and red colors indicating abundant organic compounds ("tholins"). Certain colors and compositions may be found more frequently than others in different parts of the Kuiper belt (e.g. KBOs with low-inclination circular orbits tend to be very red), which gives astronomers hints to how the Kuiper belt evolved in the Solar System's early history. If a KBO has a color and composition not matching any of this, it might suggest a different origin from the typical KBOs, which would be exciting! For example, the KBO (120216) 2004 EW95 has a dark gray, carbon-rock-rich surface more like that of asteroids than icy KBOs, which makes astronomers think that it might be an ejected asteroid. In addition, some KBOs may have unusually "blue" (gray) surfaces with very high albedos (making their surfaces highly reflective like white ice)—such objects would be considered members of the Haumea family, which are believed to be fragments flung off from the dwarf planet Haumea after a catastrophic collision billions of years ago.
9	Mars-sized TNO	Trans-Neptunian objects (TNOs) are celestial bodies orbiting the Sun beyond Neptune. The largest one (by volume) found to date is Pluto, which is substantially smaller than Mars. If there is an undiscovered Mars-sized TNO, then it must be dim (apparent magnitude >24) and extremely far away (over 500 to 1,000 AU from the Sun) in order to remain undetected by sky surveys before Vera Rubin Observatory. According to a 2020 study, thousands of Pluto- to Mars-sized planets may have once existed in the early Solar System, but ended up ejected by larger planets, leaving less than 10 remaining in the outer Solar System.
10	Local group supernova	The observation of a supernova in the Local Group (the group of galaxies that contains our own Milky Way) by modern telescopes would provide an unprecedented wealth of information about their dynamics. Astronomers have been waiting for such an event for decades (as referenced in 3208: SNEWS). The only two Local Group supernovae observed since the invention of telescopes were SN 1885A in Andromeda and SN 1987A in the Large Magellanic Cloud.
11	Spurious signal from observatory kitchen	This is an allusion to an incident at the Parkes Observatory where their radio telescope detected signals that turned out to be radiation from a microwave oven. This was previously referenced in 2886: Fast Radio Bursts. It could also be in reference to 3275: Calibration Nobel, although calibration would probably not help here as much as microwave-turning-off skills. The title text points out that the Rubin observatory, housing an optical telescope rather than radio, would be unlikely to detect signals like this, but Randall thinks some clever technique could be used to get it to observe them. There is no obvious reason why anyone would want to create such artefacts, beyond filling in this bingo card.
12	Glitch in alert system spams all astronomers	The VRO alert stream offers near-real time notification about brightness or position changes in images taken by the telescope. Astronomers can subscribe to downstream 'alert brokers' to filter the subset of alerts that are of interest to them or their automated processing pipelines. As approximately seven million alerts are generated every night, a glitch that sent an alert (or multiple alerts) to all astronomers (including ones who did not sign up) is likely to be massively annoying and disruptive.
13	Space (free)	The center square of a 5x5 bingo card is typically marked as a "free space", meaning it automatically counts toward the goal (typically 5-in-row). This square makes a pun by labeling the center square with the requirement "space"; since the telescope is virtually guaranteed to find space, the square is essentially "free". Free space in this context may mean space in which the telescope observes no objects.
14	Earth-sized TNO	See 'Mars-sized TNO' above. Since Earth is significantly larger than Mars, and discovery of this type would be even more exciting. Some astronomers have hypothesized the existence of an Earth-sized TNO in place of Planet Nine, as in 2023 this study by Lykawka & Ito.
15	Defunct spacecraft	A reference to space pollution, the phenomenon of manmade objects in space (such as spacecraft) that are defunct, but have not disintegrated into atmospheric matter (for instance, by burning up on reentry) remaining in space. A specific form of space pollution, Kessler syndrome, has been referenced in xkcd before. In addition to these, survey telescopes like Pan-STARRS and Vera Rubin can misidentify spacecraft—defunct or not—as near-Earth objects, especially if their trajectories are not well-documented. An example of such an incident is 2020 SO, a piece of a 1966 rocket that was mistakenly identified as a near-Earth object by Pan-STARRS in September 2020. A subset of space trash consists of pieces of foil or insulation in high orbits that are light and easily perturbed by solar radiation pressure; such 'high area-to-mass ratio objects' (HAMOs) or 'empty trash bag objects' (ETBOs), are regularly reported as spurious new asteroids, due to not being recorded in existing satellite catalogues such as those from the United States Space Force. These could conceivably be moving slowly enough at apogee to generate alerts from Rubin.
16	Surprising number of small galaxies
17	Neutron star merger	Neutron star mergers have been observed by gravitational wave detectors LIGO and Virgo, which are more suited for such an observation. Some afterglow photons could be observed by a telescope in the visual spectrum, since the photons arrive after the gravitational waves.
18	New supernova constraints on dark energy
19	New dwarf planet bigger than Pluto/Eris	Pluto is the largest known dwarf planet by radius and volume, whereas Eris is the largest known dwarf planet by mass. Both dwarf planets have pretty similar radii, although Eris is only a few kilometers smaller. If there is an undiscovered dwarf planet bigger than those two, than it must be quite dim (apparent magnitude >24) and extremely far away (over 500 to 1,000 AU from the Sun) in order to remain undetected by sky surveys before Vera Rubin Observatory.According to a 2020 study, thousands of Pluto- to Mars-sized planets may have once existed in the early Solar Solar System, but ended up ejected by larger planets, leaving less than 10 remaining in the outer Solar System.
20	Lost historical comet	Some comets were discovered several hundred years ago but were never seen again, either because they physically disintegrated, their orbits were too poorly known to make accurate predictions for their reappearances, or because their orbital periods are simply too long to observe within a human lifetime. Destroyed lost comets are labeled with a capital "D" (e.g. 3D/Biela), comets with unknown orbits are labeled with "X", and comets with long orbital periods are labeled with "C". In the majority of cases where lost comets end up being rediscovered, they are found as faint, unremarkable asteroids—dormant husks of their former selves. An example of this is asteroid (529668) 2010 JL33, which was identified as a likely fragment of Lexell's comet (D/1770 L1).
21	5 million asteroids and comets	The Vera Rubin Observatory is predicted to discover over 5 million asteroids (near Earth and in the main asteroid belt) by the mid-2030s. For comparison, only 1.5 million asteroids had been discovered as of July 2026. Vera Rubin Observatory began observing in June 2025 and discovered 11,000 asteroids by April 2026.
22	50,000 near-Earth asteroids	The Vera Rubin Observatory is predicted to discover over 127,000 near-Earth objects (majority of which would be near-Earth asteroids) by the mid-2030s. For comparison, about 42,000 near-Earth objects had been discovered as of July 2026. Vera Rubin Observatory began observing in June 2025 and discovered 33 near-Earth asteroids by April 2026.
23	Object likely to impact Earth	Sentry is a monitoring system maintained by NASA to identify asteroids which have a non-negligible likelihood to impact Earth. A previous such asteroid, the Chixculub asteroid, was responsible for a mass extinction event, killing 75% of all plant and animal species on Earth, most notably all non-avian species of dinosaur. Another such impact would prove catastrophic to humankind,[citation needed] meriting an early warning and response system. 2024 YR4 is an asteroid that previously held an impact rating of 3 on the Torino scale, defined as "A close encounter, meriting attention by astronomers."
24	Vera Rubin herself (faked death, stole spaceship)	Vera Rubin, the namesake of the observatory, died in 2016. This card proposes that she may have faked her death and flown out into space in secret, only to be found out and caught by the observatory named after her. This would be considered unlikely by astronomers.[citation needed]
25	Many very small dots	"Very small dots" is a pithy way to describe the objects in distant space visible from Earth. The primary purpose of an observatory is to study these 'small dots' in great detail, so in this case discovering "small dots" would be a free bingo space, unless it is observing space free of dots. Alternatively, this may be a reference to the Petrova Line in Project Hail Mary, which is described as "space dots", or maybe some variation on the little red dots discovered by the James Webb Space Telescope, previously referenced by the comic 3212: Little Red Dots.

Transcript

[Title:]

Vera Rubin Observatory discoveries

Bingo card

[A bingo card is shown, with 25 squares. They are as follows:]

Black hole tidally disrupting a star

Planet nine

Remnants of a former Milky Way companion

10,000 new trans-Newtonian objects

Object on interstellar trajectory

Star being eclipsed by weird object

Secret military satellite

Kuiper Belt object that's a surprising color

Mars-sized TNO

Local group supernova

Spurious signal from observatory kitchen

Glitch in alert system spams all astronomers

Space (free)

Earth-sized TNO

Defunct spacecraft

Surprising number of small galaxies

Neutron star merger

New supernova constraints on dark energy

New dwarf planet bigger than Pluto/Eris

Lost historical comet

5 million asteroids and comets

50,000 near-Earth asteroids

Object likely to impact Earth

Vera Rubin herself (faked death, stole spaceship)

Many very small dots

---

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