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.
Per Wikipedia’s list of stars by absolute magnitude, 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.
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.
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.
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?
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.
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.
w Neil deGrasse Tyson #science #space #astronomy | Theoretical Tales | FacebookThe density of debris in an “asteroid” field looks more like what you’d find in Saturn’s rings.
“My Hovercraft is full of Eels!”
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.
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.
It is the 20th brightest star in the Northern hemisphere.
And one of the easiest to find.
So yeah, I agree. But of course that song does not qualify in the OP.
Yes, Venus is LIT tonight. Took the grandkids out to see the moon/ Venus pairing. Unusually clear in Hawaii tonight.
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. I highly recommend clicking the link and watching the 2.5 minute video.
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.
So that’s the radius of the cosmic sphere?
There is no known limit to the size of the universe.
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.
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.
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.
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!!!