3096: Check Engine

2026-06-24T03:11:09Z

27.32.26.6: /* Explanation */ i just thought it'd be funny and made sense.

{{comic
| number = 3096
| date = May 30, 2025
| title = Check Engine
| image = check_engine_2x.png
| imagesize = 331x383px
| noexpand = true
| titletext = They say it's probably safe to keep orbiting for a while, but if it stays on or starts flashing we might have to call someone.
}}

==Explanation==
{{w|Sunspot}}s are temporary, relatively small, darker and colder regions on the surface of Earth's sun, and almost certainly other stars. The number of sunspots that can be observed varies over an approximately 11-year cycle. The current cycle is {{w|Solar_cycle_25|the 25th since reckoning began in 1755}}. Solar Cycle 25, which began in December 2019 and is expected to peak around mid-2025, has been more active than anticipated, raising some concerns about the impacts of recent solar flares and associated space weather events.

The joke in this comic is that the sunspot array shown has taken the form of a {{w|Check engine light|"Check engine" light}}, found on the instrument panel of most automobiles. The illumination of this light means that the automobile's onboard computer has detected an engine malfunction, which should be checked out by an experienced mechanic. For such a signal to appear among the nuclear fires and plasma of the Sun would most certainly be of concern to astronomers, and likely also theologians.

Many drivers will barely notice a Check Engine light, and may hope that they ''never'' have cause to see it appear except maybe briefly during the turning of the ignition key as one of the bulb-checks. If it lights persistently before or during driving, it could mean a costly problem, or at least the inconvenience of paying someone to investigate the problem. Frequently, such investigations reveal no identifiable issue with the engine itself, resulting rather from some kind of sensor fault. In this case, the advice may be that it's probably OK to keep driving unless the behaviour of the light changes, and fixing the sensor issue may cause more expense than the small risk of a genuine engine issue arising would warrant.

As we don't appear to be cycling the Sun's ignition process (i.e., it hasn't recently stalled, which would be a worry in itself) the showing of the light/dark-patch would probably be very concerning, and hopefully someone at least has the owner's manual in order to run through any initial troubleshooting, before perhaps a more extensive check is made at the local solar-repair shop to clear the error. Given the rotating nature of the star and Earth's orbit, one might also wonder how long this, or any other warnings, might be shown before becoming visible to {{w|Solar viewer|suitably equipped}} viewers of the Sun.

The title text says that "they" (presumably the astronomers) advise that it's probably safe for Earth to continue to orbit the Sun unless and until there is a change in the nature of the "check engine light" sunspot array. Such a change, on an instrument panel, signals that the matter needs immediate attention, lest something dramatic and expensive occur, such as an [https://www.reddit.com/r/explainlikeimfive/comments/l8j0ip/eli5_what_is_a_seized_engine/ engine seizure], which can be spectacular and is irreparable. The solar equivalent of an engine seizure would be a {{w|Nova|nova}}, which would definitely be of concern to astronomers (and [[1895 | everyone else]]), and for which the prospect of "calling [[673: The Sun | someone]]" that can do anything useful (a cosmic tow truck to pull Earth to a safe distance?) seems remote.

==Transcript==
:[In a black panel a large orange Sun-type sun is shown, depicted as it might look when viewed through solar eclipse glasses. A pattern in the form of a "check engine" light (as displayed on a car's instrument panel) is shown on the surface of the Sun, in the bottom right quarter. The pattern has a pictogram of a motor on the top with text below it, both in orange inside a black square, matching the orange shading of the rest of the Sun.]
:Check Engine

:[Caption below the panel:]
:This new sunspot cluster has raised concern among astronomers

{{comic discussion}}<noinclude>

[[Category:Comics with color]]
[[Category:Astronomy]]

explain xkcd - User contributions [en]

3096: Check Engine