# Glaring astronomy mistakes in a movie or video **URL:** \ **Category:** Cafe Society\ **Tags:** movies\ **Created:** [September 5, 2026, 8:39pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849 "2026-09-05T20:39:34Z")\ **Posts on this page:** 20\ **Page:** 9
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 9, 2026, 9:49pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/161 "2026-09-09T21:49:04Z")
According to Google’s AI assistant, the naked eye star with the brightest intrinsic (absolute) magnitude is Mu Cephei, a relatively dim star as seen from Earth. However I’m not sure I trust this answer. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 9, 2026, 10:04pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/162 "2026-09-09T22:04:11Z")
Per [Wikipedia’s list of stars by absolute magnitude](https://en.wikipedia.org/wiki/List_of_most_luminous_stars), it looks like the intrinsically-brightest star visible to the naked eye is either eta Carina (if you count that as a star), absolute magnitude -11.77, or zeta Scorpii if you don’t count it, absolute magnitude -10.88 (eta Carina is a really weird object). mu Cephei is only -7.6. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [September 9, 2026, 10:12pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/163 "2026-09-09T22:12:48Z")
Wikipedia has mu Cephi’s absolute magnitude as -7.63. It also reports S Doradus’s abs mag (which is variable) from -7.6 to -10.0. Mu Cephi is also variable, but there’s only one value for its abs mag. Another star with a very high abs mag is eta Carinae, but Wikipedia doesn’t give an value for it. Eta Car is extremely variable, but also shrouded in a lot of gas and dust given off by the star. It’s actually at least two stars, but may be more. The gas and dust make observing it very difficult. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 9, 2026, 10:22pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/164 "2026-09-09T22:22:36Z")
Even Zeta Scorpii may be two stars, so if we allow that one, we should allow Eta Carina. Compared to these giants, Sirius is feeble. ---
**Author:** ![Xocomil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xocomil/32/14927_2.png) [@Xocomil](https://boards.straightdope.com/u/Xocomil)\ **Post date:** [September 10, 2026, 3:26am UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/165 "2026-09-10T03:26:46Z")
> [@Just\_Asking\_Questions](#): > > Yet he had no trouble with humans in 32 degree water having meaningful conversations? Damn it, **JAQ** , he’s an astrophysicist not a doctor. But seriously, his problem with the sky was that it was such a lazy, careless mistake in a movie that expended so much money and effort on _Historical Accuracy_, IIRC, even down to the fuckin tableware. Jack being capable of sustaining a conversation with Rose isn’t realistic but it serves a dramatic purpose. What’s the dramatic purpose of having some random starry sky instead of the actual one? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 11, 2026, 2:03am UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/166 "2026-09-11T02:03:59Z")
Last time I went to an American Astronomical Society meeting (mumblety-mumble years ago), there were five objects that got their own category for presentations and talks: The Earth, the Sun, the Milky Way, the Universe, and eta Carina. That kind of gives an idea of how weird eta Carina is. ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [September 11, 2026, 2:15am UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/167 "2026-09-11T02:15:17Z")
> [@DrDeth](#): > > > [@eschereal](#): > > > > _Every_ freakin sequence (pick your movie/TV episode) that involves flying into a field of asteroids or other objects (e.g., the mines in _Galaxy Quest_). > > Yes, if your spaceship flew through our asteroid belt, you _might_ see one or two as points of light. Maybe there is more “dust” there, perhaps. But you will not have to dodge asteroids- at least not more than once. Space is BIG. Yep. Based on the observation from Neil Degrasse Tyson, the average distance between the 1mill+ (and counting) known objects in the asteroid belt is 600,000 miles. [The average distance between asteroids 🤯 w Neil deGrasse Tyson #science #space #astronomy | Theoretical Tales | Facebook](https://www.facebook.com/61550289884308/videos/the-average-distance-between-asteroids-w-neil-degrasse-tyson-science-space-astro/2183748199247102/) ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [September 11, 2026, 1:49pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/168 "2026-09-11T13:49:39Z")
The density of debris in an “asteroid” field looks more like what you’d find in Saturn’s rings. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [September 13, 2026, 8:47pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/169 "2026-09-13T20:47:36Z")
_“My Hovercraft is full of Eels!”_ ---
**Author:** ![Xocomil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xocomil/32/14927_2.png) [@Xocomil](https://boards.straightdope.com/u/Xocomil)\ **Post date:** [September 14, 2026, 4:18am UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/170 "2026-09-14T04:18:39Z")
> [@Toxgoddess](#): > > Did Rafferty never wander outside at night and look up??? I do on occasion wander out for a peek and tonight I was rewarded with the lovely sight of an absurdly bright Venus near a waxing crescent Moon, which reminded me of this thread. > [@Toxgoddess](#): > > The North Star is around magnitude 1.98, dim to middling. Not to nitpick, but I’m going to nitpick. I live under the tragically light polluted skies of a giant urban agglomeration. Polaris is one of the few dozen stars visible. In my book, if I can see it from my backyard, it’s a bright star. More than that, I think Polaris is a bright star by any reasonable definition. It’s one of the fifty brightest stars out of at least several hundred that are visible in not particularly dark skies. It deserves at least a little love. It bears mentioning that Rafferty didn’t invent the idea that the North Star is the brightest. It is or at least was a common belief. I hasten to add that I’m neither defending nor excusing his perpetuation of that misconception. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [September 14, 2026, 4:27am UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/171 "2026-09-14T04:27:48Z")
> [@Xocomil](#): > > More than that, I think Polaris is a bright star by any reasonable definition. It’s one of the fifty brightest stars out of at least several hundred that are visible in not particularly dark skies. It is the 20th brightest star in the Northern hemisphere. > **[List of brightest stars](https://en.wikipedia.org/wiki/List_of_brightest_stars)** > > This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a V-band filter in the UBV photometric system. Stars in binary systems (or other multiples) are listed by their total or combined brightness if they appear as a single star to the naked eye, or listed separately if they do not. As with all magnitude systems in astronomy, the scale is logarithmic and inverted, ... And one of the easiest to find. So yeah, I agree. But of course that song does not qualify in the OP. ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [September 14, 2026, 5:44am UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/172 "2026-09-14T05:44:00Z")
Yes, Venus is LIT tonight. Took the grandkids out to see the moon/ Venus pairing. Unusually clear in Hawaii tonight. ---
**Author:** ![JWT\_Kottekoe](https://avatars.discourse-cdn.com/v4/letter/j/3ec8ea/32.png) [@JWT\_Kottekoe](https://boards.straightdope.com/u/JWT_Kottekoe)\ **Post date:** [September 14, 2026, 3:45pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/173 "2026-09-14T15:45:44Z")
> [@DrDeth](#): > > But of course that song does not qualify in the OP. I welcome bad astronomy examples from songs. In fact, one that I will definitely include is Katie Melua’s “correction” to the lyrics of her song “9 Million Bicycles in Beijing”, [as recounted by Michael Shermer in a Ted talk.](https://www.youtube.com/watch?v=r8AgJ5Y8unU) I highly recommend clicking the link and watching the 2.5 minute video. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 14, 2026, 4:14pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/174 "2026-09-14T16:14:31Z")
_13.7 billion light years to the edge_ is only one of several different values of the distance from Sol to the edge of the visible universe. 13.7 billion light years is the Light Travel Time, the distance measured by estimating the time that light has taken to reach us from the observable edge, i.e. the Big Bang. 46 billion light years is the co-moving distance, the distance to which the edge of the universe has now moved over those 13.7 billion years. 42 _million_ light years is the proper distance, which is the distance that the edge of the universe was at when the light was actually emitted. All these figures are estimates and will probably change as we get better figures. And don’t forget the Hubble Tension, whatever that is. ---
**Author:** ![terentii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terentii/32/212_2.png) [@terentii](https://boards.straightdope.com/u/terentii)\ **Post date:** [September 14, 2026, 4:41pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/175 "2026-09-14T16:41:46Z")
> [@eburacum45](#): > > _13.7 billion light years to the edge_ is only one of several different values of the distance from Sol to the edge of the visible universe. So that’s the radius of the cosmic sphere? ---
**Author:** ![JWT\_Kottekoe](https://avatars.discourse-cdn.com/v4/letter/j/3ec8ea/32.png) [@JWT\_Kottekoe](https://boards.straightdope.com/u/JWT_Kottekoe)\ **Post date:** [September 14, 2026, 4:50pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/176 "2026-09-14T16:50:22Z")
> [@terentii](#): > > So that’s the radius of the cosmic sphere? There is no known limit to the size of the universe. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [September 14, 2026, 4:51pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/177 "2026-09-14T16:51:39Z")
> [@terentii](#): > > In _ **TOS** _’s “Tomorrow Was Yesterday,” it takes the _Enterprise_ several minutes to reach lightspeed in the 93 million miles between the Sun and Earth. They must have been spiraling instead of following a straight course. Well, some time travel stuff was going on there, which might explain it. My real problem with that scene is that while traveling at high warp speed to go back in time they had time to beam Captain Christopher back into his jet at exactly the right moment. The updated version seems to have them orbiting the sun to go back in time, not just heading to it, which might help a bit. Maybe. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 14, 2026, 5:12pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/178 "2026-09-14T17:12:36Z")
> [@terentii](#): > > So that’s the radius of the cosmic sphere? If you mean the radius of the observable universe, then I listed three different values for this. Another possible value for this radius would be the furthest distance a spaceship (or a photon) could travel at the speed of light before it reaches the edge of the universe, which is infinite (according to current theories). Of course, even at the speed of light it would take an eternity to get there. Unless you use the frame of reference of the photon, which would be instantaneous. Distances are hard. ---
**Author:** ![terentii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terentii/32/212_2.png) [@terentii](https://boards.straightdope.com/u/terentii)\ **Post date:** [September 14, 2026, 5:18pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/179 "2026-09-14T17:18:17Z")
> [@JWT\_Kottekoe](#): > > There is no known limit to the size of the universe. I know _that_. 13.7 billion ly is only an estimate according to our current level of knowledge. I’m saying that distance (whatever it is) must be omnidirectional, and thus the radius of a sphere. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [September 14, 2026, 9:53pm UTC](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849/180 "2026-09-14T21:53:03Z")
> [@Toxgoddess](#): > > Someone upthread mentioned a song. I have another one; it has grated on me for decades. The song _Right Down the Line_ by Gerry Rafferty contains the following terrible line: > > “You’ve been as constant as the Northern Star - the brightest star that shines.” > > I do not need to tell this group that the North Start (not the Northern Star 🙄 ) is nowhere close to the “brightest star that shines”. While the discussion of stellar magnitudes has been very interesting, I think this is based on a fundamental misinterpretation of the lyric. ISTM that the singer is telling his woman about **multiple** things he loves her for: only she “can see the changes” he’s been through, she “believed in” him, she’s “as constant as the northern star”, she’s “the brightest light [**not “star”**] that shines”. I don’t think that needs to be interpreted as claiming that the North Star itself actually **is** literally the brightest star in the sky; the singer just switched the figure of speech partway through the line. Anyway, sci-fi schmi-fi, I think the most annoying astronomy mistakes happen in ordinary “realistic” fiction where the author/filmmaker doesn’t seem to quite grasp that periodic night-sky events are fairly tightly limited by basic spherical-astronomy constraints. A lot of people seem to think that they just happen more or less at random, like weather. A 2022 thriller by an otherwise perfectly competent and even somewhat nature-aware writer (names suppressed to protect the guilty) has the main character staking out a site somewhere in Texas in the summer, beginning about _“a half hour after sunset”_ with _“no moon”_ visible. Two hours afterward, _“a narrow crescent new moon poked over the eastern horizon; two hours after that, the Milky Way was rising overhead”_. Some time later, _"the sliver of moon was straight overhead_". **NO! NO! NO! BAD AUTHOR!! That is NOT how crescent moons work!! It’s a narrow crescent in form because _its position in the sky is close to that of the SUN,_ so you see it shortly before sunrise or shortly after sunset!! It is not wandering around on its lonesome near the zenith in the middle of a dark night! Stop that kind of silly talk!!!** [Previous page](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849.md?page=8) [Next page](https://boards.straightdope.com/t/glaring-astronomy-mistakes-in-a-movie-or-video/1032849.md?page=10)