1644: "Stargazing"

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1644: "Stargazing"

Postby NotAllThere » Wed Feb 17, 2016 5:28 am UTC

Image

Title Text: Some of you may be thinking, 'But wait, isn't the brightest star in our sky the Sun?' I think that';s a great question and you should totally ask it. On the infinite tree of possible conversations spread out before us, I think that's definitely the most promising branch.

Is Randall angry about something? I think I may be missing the point.
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Re: 1644: "Stargazing"

Postby rhomboidal » Wed Feb 17, 2016 6:03 am UTC

I think the correct term here is "ass-tronomer."

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Re: 1644: "Stargazing"

Postby flicky1991 » Wed Feb 17, 2016 6:40 am UTC

"Me"? Is she Ashildr from Doctor Who? :lol:
any pronouns
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Re: 1644: "Stargazing"

Postby StormAngel » Wed Feb 17, 2016 8:37 am UTC

making XKCD slightly Spaaaaaaaaaaaace!
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I'm not sure if this is better or worse?
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Re: 1644: "Stargazing"

Postby Eshru » Wed Feb 17, 2016 9:31 am UTC

rhomboidal wrote:I think the correct term here is "ass-tronomer."

I thought it was skientest

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Re: 1644: "Stargazing"

Postby Echo244 » Wed Feb 17, 2016 10:05 am UTC

I can totally hear the dominant voice from this strip in the voice of Dara O'Briain. A bit unfair, but it's quite reminiscent of the amateur astronomy enthusiasm displayed on Stargazing Live.

(Which is actually a good programme, taking the threads of enthusiasm and weaving them in to some of the more advanced science, getting people on from ESA and NASA and other places to talk knowledgeably about their field, crowdsourcing image examination to pore through masses of data and find interesting science, then involving people and pointing big telescopes at things to make better studies of things that were found... it's much more engaging than the classic Sky At Night).
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Re: 1644: "Stargazing"

Postby sfmans » Wed Feb 17, 2016 10:06 am UTC

NotAllThere wrote:Is Randall angry about something? I think I may be missing the point.


I think Randall has seen some episodes of the UK BBC series Stargazing Live, which is a bizarre mixture of
60% hard science and
40% exactly the sort of inane comment that Megan is providing in the strip.

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Re: 1644: "Stargazing"

Postby sfmans » Wed Feb 17, 2016 10:06 am UTC

Oops, ninja'd!

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Re: 1644: "Stargazing"

Postby Echo244 » Wed Feb 17, 2016 10:12 am UTC

sfmans wrote:
NotAllThere wrote:Is Randall angry about something? I think I may be missing the point.


I think Randall has seen some episodes of the UK BBC series Stargazing Live, which is a bizarre mixture of
60% hard science and
40% exactly the sort of inane comment that Megan is providing in the strip.


I think that sums up the earlier series, though I think they've tidied things up somewhat since they decided to interrupt an interesting discussion on the history of the universe for a recorded question from K9, the robot dog from Doctor Who.

Mind you, I struggled a bit with the latest series which was focussed around "There's a British chap in SPAAAAAACE!". Hopefully future series will be a bit more linking-enthusiasm-in-to-hard-science-in-an-engaging-yet-educational-manner.
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Re: 1644: "Stargazing"

Postby Jaruzel » Wed Feb 17, 2016 10:36 am UTC

40% exactly the sort of inane comment that Megan is providing in the strip.


Is that Megan? Looks like Dr Brian Cox to me... even talks like him :)

-Jar

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Re: 1644: "Stargazing"

Postby sonar1313 » Wed Feb 17, 2016 11:52 am UTC

Wait a minute, I think that branch of the conversation tree is more interesting than all that. What actually is the brightest star in the sky? It's neither the Sun nor Sirius, probably; they just happen to be the ones that are brightest from Earth. But if you could make all else equal, which star really would be the brightest?

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Re: 1644: "Stargazing"

Postby sfmans » Wed Feb 17, 2016 12:02 pm UTC

Jaruzel wrote:
Is that Megan? Looks like Dr Brian Cox to me... even talks like him :)

-Jar


Harsh.


But accurate. "It's really am-ay-zzing ... "

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Re: 1644: "Stargazing"

Postby cellocgw » Wed Feb 17, 2016 12:37 pm UTC

sonar1313 wrote:Wait a minute, I think that branch of the conversation tree is more interesting than all that. What actually is the brightest star in the sky? It's neither the Sun nor Sirius, probably; they just happen to be the ones that are brightest from Earth. But if you could make all else equal, which star really would be the brightest?


Yes! Let's Get Down and Get Technical :twisted: . Onwards: here, "brightest" should be replaced with "surface radiance of greatest magnitude." And then we can branch out.
1) Total radiated power (watts/steradian) over the entire EM spectrum.
2) Total radiated luminance , which is quite different from number 1.

Then there's the question of peak outburst, whether we allow supernovas to qualify for this study, and so on.

Please submit all answers using the American Units Standards: furlongs/fortnight, Libraries of Congress, football-fields, or Olympic swimming pools (volume). Remember to include a car-analogy.
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Re: 1644: "Stargazing"

Postby Soupspoon » Wed Feb 17, 2016 3:00 pm UTC

Echo244 wrote:I can totally hear the dominant voice from this strip in the voice of Dara O'Briain. A bit unfair, but it's quite reminiscent of the amateur astronomy enthusiasm displayed on Stargazing Live.

(Which is actually a good programme, taking the threads of enthusiasm and weaving them in to some of the more advanced science, getting people on from ESA and NASA and other places to talk knowledgeably about their field, crowdsourcing image examination to pore through masses of data and find interesting science, then involving people and pointing big telescopes at things to make better studies of things that were found... it's much more engaging than the classic Sky At Night).


Stargazing Live doesn't tend to put celebrities on the show (in the latest shows, at least) just because they're celebrities. Generally there are celebrities-who-are-scientific, if not scientists-who-are-celebrities. (Brian Cox is a possibly funny case of this, given his previous celebrity life, but then we all know that Things Can Only Get Better.) The inclusion of John Bishop as 'guinea pig' for the (very abbreviated) astronaut training segment in the latest set of programmes seemed to be tuned more to his willingness to undergo physical hardships (oxygen deprivation, centrifuge training, etc), but he at least proclaimed an actual interest in the subject.

The radio (and podcasted) show "The Infinite Monkey Cage" is a bit more like this (for science). After 'Early Instalment Weirdness', it has settled down to the co-hosts (Brian Cox as the serious scientific one with a hint of comedy, and Robin Ince as the comedic one with a (heavily downplayed, his non-science degree driving his character) hint of science) doing the primary Holmes And Watson bits, but two or more genuine scientific (or philosophical) experts in the subject-of-the-week and a 'spare wheel' guest who is more known for something else but may actually be a stealth-expert (e.g. Paul Foot in the recent Mathematics-related show, although his comedic personality (as always) tended to shine out above his actual mathematics graduate status; presumably entirely intentionally).

(The 'problem' with TIMC seems to be that the unrestrained nature of the programme may allow interesting diversions, but often means that the half hour (radio broadcast cut) or 45 minutes (podcast-length) almost always seems to end with several discussion points left untouched. In a recent show it was said that they'd only got to the third 'question' on the prepared list. A certain amount of 'semi-scripted anarchism' is probably a large part of its appeal. Stargazing Live, meanwhile, seems to conform more to preplanned progressions across the intended subject, as is common for live TV, with much tighter scheduling and structuring for guest-spots and segments so that it's more educational, although not so much as The Sky At Night is (live 'cloudy skies', aside). Meanwhile if you want something on the radio that's designed to be more paced, try In Our Time with Melvin Bragg. Sometimes rushed, but obviously designed to be tighter, likely from a pre-show discussion and note-taking session and then the presenter fighting to keep the guest experts on the tracks he has assumed they wish to travel upon , for the duration of the broadcast.)

sfmans wrote:I think Randall has seen some episodes of the UK BBC series Stargazing Live, which is a bizarre mixture of
60% hard science and 40% exactly the sort of inane comment that Megan is providing in the strip.
Not so much the latter, IMO, at least these days. Occasionally an Audience/Viewer's Question is something like that, but gets a decent treatment by the presenters (unlike a typical TIMC/Bryan Cox rant against one branch of pseudo-science or another, which is probably still a deliberate bit of 'prepartee').

The thing about Stargazing is that it's also intended for kids (who need more 'low aimed' questions and answers to be covered) rather than the older and nerdier audience of TIMC or the kind of person who would already go out of their way to watch The Sky At Night. It's necessarily a lot more 'round-cornered' than certain types of 'hard-science' educational programmes.

Echo244 wrote:Mind you, I struggled a bit with the latest series which was focussed around "There's a British chap in SPAAAAAACE!". Hopefully future series will be a bit more linking-enthusiasm-in-to-hard-science-in-an-engaging-yet-educational-manner.
The previous series(/season) was centred upon "There's a Solar Eclipse!", and wasn't in the traditional January-based slot so that it coincided with the event, and I think that the programme taking a topical space-related event and using that as a hook for a focussed look on that subject isn't a bad thing.

I wonder, is there any possible astronomical event happening next January or slightly before (like the December 2015 'Blast Off' prequel bits to the January 2016 set) or that after that might indicate what major subject for the 2017(/late-2016) grouping might be? The production team is probably on the look out (or keeping their ears to the ground) for such things, if they don't know already what they're doing.

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Re: 1644: "Stargazing"

Postby HES » Wed Feb 17, 2016 3:58 pm UTC

+1 for the Infinite Monkey Cage. There a plenty of people here who would enjoy it.
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Re: 1644: "Stargazing"

Postby BrandonH66 » Wed Feb 17, 2016 4:30 pm UTC

Some of the dialogue and attitude remind me of April Ludgate from Parks & Recreation.

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Re: 1644: "Stargazing"

Postby magnum_opus » Wed Feb 17, 2016 7:16 pm UTC

For the record I helped run starparties for 4-5 years, with both amateur and professional astronomers. As in people who actually got paid to do nothing but astronomy professionals not just a physics professor who dabbled.

This is EXACTLY how they go.

Also a lot of people looking in telescopes, oohing, then you check and realize that the Orion Nebula has been out of sight for at least 5 minutes.

Saturn, it must be said is completely unmistakable. You may think to your self "oh those photos are always false colored and photoshoped to be more dramatic, yes but, Saturn is very obviously Saturn. Ask me how many times a night I got asked what they were looking at. I got the Moon more often than you would think possible too.

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Re: 1644: "Stargazing"

Postby Rombobjörn » Wed Feb 17, 2016 7:44 pm UTC

That woman can't be Sirius.

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Re: 1644: "Stargazing"

Postby orthogon » Wed Feb 17, 2016 9:34 pm UTC

Rombobjörn wrote:That woman can't be Sirius.

Shirley?
xtifr wrote:... and orthogon merely sounds undecided.

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Re: 1644: "Stargazing"

Postby rmsgrey » Thu Feb 18, 2016 3:32 am UTC

Wait, Beret Guy's a woman?

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Re: 1644: "Stargazing"

Postby Flumble » Thu Feb 18, 2016 3:43 am UTC

rmsgrey wrote:Wait, Beret Guy's a woman?

Beret guy doesn't do negativity like in the second and last panels.

This is probably his sister. :P

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Re: 1644: "Stargazing"

Postby ps.02 » Thu Feb 18, 2016 5:13 am UTC

sonar1313 wrote:What actually is the brightest star in the sky?

"In the sky"? I guess you mean the one outputting the most lumens (if "brighest" implies visible light) ... but where? Is this restricted to stars we can see with the naked eye? See with some particular amateur, professional, or government-funded telescope? Or do you mean in the whole observable universe?

Also, does "is" imply the object's existence and status in the present tense? (So much of what we see in the sky, after all, no longer exists.)

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Re: 1644: "Stargazing"

Postby orthogon » Thu Feb 18, 2016 7:26 am UTC

ps.02 wrote:Also, does "is" imply the object's existence and status in the present tense? (So much of what we see in the sky, after all, no longer exists.)

"Welcome to Stargazing Live with Bill Clinton!"
xtifr wrote:... and orthogon merely sounds undecided.

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Re: 1644: "Stargazing"

Postby Soupspoon » Thu Feb 18, 2016 10:43 am UTC

sonar1313 wrote:What actually is the brightest star in the sky?

I think "in the sky" does sort of indicate "as seen through the local atmospheric bubble", without being prefix by the qualification of 'night'. For us, therefore, it's the Sun. For those on the ISS, whichever star shines most brightly through the Earth's atmosphere - which will continually change, although the most noticeable candidate, twice every 90 minutes or so, will be the Sun. For Jovians (who aren't so deep that they don't anything up through their atmosphere) it'll be the Sun. For Europans, staring up through the ice, they probably would first notice Jupiter; but, as it hasn't yet been converted into a star by the monoliths, the next brightest object would be the Sun. I suppose we could work out if Plutonians have an obvious brighter star in their sky than their sun (but they've probably been keeping their heads down, recently, to avoid being seen!), and I suspect the 'Nineans' have a few good solid alternate candidates (if not a good solid atmosphere, right now!), but historically-speaking might well still consider The Sun worthy of special consideration.

For any other given alien race on their own alien planet orbiting around their own alien star(s)... They'd probably say "The Sun" (semantically translated from their own lingo), although that'd refer probably to the (primary?) star in their own system, outside of any particularly busy patch of the galaxy. But it'd be interesting to find some that don't think this.

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Re: 1644: "Stargazing"

Postby Neil_Boekend » Thu Feb 18, 2016 11:00 am UTC

ps.02 wrote:Also, does "is" imply the object's existence and status in the present tense? (So much of what we see in the sky, after all, no longer exists.)

Most of the objects in our sky are within our milkyway. Those objects are, at most, about 100,000 light year away. Thus the info we have on them is, at most, 100,000 year old. Stars get much older than that, so the amount of stars that will have gone supernova or to some other stellar end will be limited.
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Re: 1644: "Stargazing"

Postby PM 2Ring » Fri Feb 19, 2016 5:15 am UTC

Neil_Boekend wrote:
ps.02 wrote:Also, does "is" imply the object's existence and status in the present tense? (So much of what we see in the sky, after all, no longer exists.)

Most of the objects in our sky are within our milkyway. Those objects are, at most, about 100,000 light year away. Thus the info we have on them is, at most, 100,000 year old. Stars get much older than that, so the amount of stars that will have gone supernova or to some other stellar end will be limited.


Indeed. We've done this before: Ancient Stars thread

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Re: 1644: "Stargazing"

Postby Copper Bezel » Fri Feb 19, 2016 6:28 am UTC

So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

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Re: 1644: "Stargazing"

Postby NotAllThere » Fri Feb 19, 2016 7:29 am UTC

HES wrote:+1 for the Infinite Monkey Cage. There a plenty of people here who would enjoy it.

I can't stand prof. Cox. Cheeky, chirpy chappy. *shudder*

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Re: 1644: "Stargazing"

Postby ijuin » Fri Feb 19, 2016 9:29 am UTC

sonar1313 wrote:Wait a minute, I think that branch of the conversation tree is more interesting than all that. What actually is the brightest star in the sky? It's neither the Sun nor Sirius, probably; they just happen to be the ones that are brightest from Earth. But if you could make all else equal, which star really would be the brightest?


The most luminous star that is visible to the unaided human eye from Earth is Alnilam, known also as Epsilon Orionis, the center star in Orion's Belt, with a luminosity approximately 4.0 * 10^5 times as bright as Sol.

The most luminous star whose luminosity has been confirmed is R136a1, a star in the Large Magellanic Cloud about 163k light years from Earth, with a luminosity approximately 8.7 * 10^6 times that of Sol.

The above, of course, excludes stars undergoing transient events such as nova or supernova explosions.

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Re: 1644: "Stargazing"

Postby The Moomin » Fri Feb 19, 2016 9:53 am UTC

Copper Bezel wrote:And, for completeness' sake....


Does this mean that the gravitational waves detected could actually be from nearby colliding or exploding geese rather than black holes really far away?
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Re: 1644: "Stargazing"

Postby xtifr » Fri Feb 19, 2016 10:12 am UTC

Soupspoon wrote: I suppose we could work out if Plutonians have an obvious brighter star in their sky than their sun (but they've probably been keeping their heads down, recently, to avoid being seen!), and I suspect the 'Nineans' have a few good solid alternate candidates (if not a good solid atmosphere, right now!), but historically-speaking might well still consider The Sun worthy of special consideration.


I don't think so. Alpha Centauri is about the same size as our sun, and at 4 ly away, it still manages to be one of the brightest things in the sky. (Among non-local stars, only Sirius and Canopus are brighter.) Pluto and planet nine are way, way closer to the sun than that, so the sun is still going to be the brightest thing in the sky, by far.

Doing some very rough back of the napkin calculations*...you'd have to be over 2 ly from Sol before it would be outshone by Sirius. The Oort cloud doesn't go that far, let alone the Kuiper belt, where Planet nine is found. Checking actual distances...Pluto is less than a light day away. I don't know about planet nine, but I doubt it's as far as a light week. So, yeah, my initial reaction was correct.

* Sirius has a relative magnitude about one point higher (lower, in the backwards way they measure these things) than Alpha C.'s, which is a brightness factor of about 2.5 (fifth root of 100). Alpha C. is just over 4 ly away. Going half the distance to Alpha C. should make it four times brighter—inverse square. Four is more than 2.5. So at 2 ly,, Alpha C. would be brighter than Sirius. Thus, at 2 ly, Sol—same size, remember—would still be brighter than Sirius as well. And Sirius is far enough away that its variations in brightness would be negligible in comparison. So even if you went 2 ly towards Sirius, Sol should still be brighter.
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Re: 1644: "Stargazing"

Postby Neil_Boekend » Fri Feb 19, 2016 10:35 am UTC

The Moomin wrote:
Copper Bezel wrote:And, for completeness' sake....


Does this mean that the gravitational waves detected could actually be from nearby colliding or exploding geese rather than black holes really far away?

Or a massive amount of space-geese colliding Really far away?
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Re: 1644: "Stargazing"

Postby Soupspoon » Fri Feb 19, 2016 5:28 pm UTC

Neil_Boekend wrote:Or a massive amount of space-geese colliding Really far away?

A mole of geese? (Messy.)
A goose of moles? (Kinky.)

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Re: 1644: "Stargazing"

Postby orthogon » Fri Feb 19, 2016 6:12 pm UTC

xtifr wrote:[Pluto and planet nine are way, way closer to the sun than that, so the sun is still going to be the brightest thing in the sky, by far..

I remember being struck by a simulated view from Pluto that showed the sun as "just a bright star". But according to the Great Wiki, the luminosity of a (main sequence) star goes with its mass to the power 3.5 or so. That means that as a star gets further away, it can maintain the same apparent brightness with only a gradual increase in mass, countering the inverse square spreading loss with a mass that's only the 2/3.5 power of distance. Meanwhile the gravitational field falls off with the inverse square law and is only proportional to the mass, so the net effect is that a star of equal apparent brightness provides a gravitational field that goes with the (2/3.5-2) power of distance. I think this means that it's quite easy for a nearby star to exert a strong gravitational pull without being especially bright, or even visible. Conversely, for distant stars, their bark is worse than their gravitational bite, as it were. Presumably this is what makes it plausible that Sol might be part of a binary system without its binary partner being visible.
xtifr wrote:... and orthogon merely sounds undecided.

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Re: 1644: "Stargazing"

Postby pixeldigger » Fri Feb 19, 2016 9:06 pm UTC

sonar1313 wrote:Wait a minute, I think that branch of the conversation tree is more interesting than all that. What actually is the brightest star in the sky? It's neither the Sun nor Sirius, probably; they just happen to be the ones that are brightest from Earth. But if you could make all else equal, which star really would be the brightest?

I like this reference site

they are in order of visible magnitude, but the Absolute magnitude is listed there as well.

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Re: 1644: "Stargazing"

Postby xtifr » Sat Feb 20, 2016 7:23 pm UTC

The brightest (absolute magnitude) star in the sky is statistically almost certainly unobservable, either because it's so far away or because it's obscured (by dust/stars/galaxies). Probably both. Ironically, most of the so-called "observable universe" is not observable by us!

Heck, big chunks of our own galaxy aren't directly observable by us. Let alone parts of remote ones.

Of course, some of the currently technically-unobservable parts of the universe could become observable if we developed and deployed the right technologies, but I'm pretty confident that most of them will remain unobservable for my lifetime. (Since I have no intention of being put aboard an untested ramscoop and launched into the remote unknown future.)
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Re: 1644: "Stargazing"

Postby ijuin » Sat Feb 20, 2016 9:55 pm UTC

I do. Sign me up! So long, and thanks for all the fish!

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Re: 1644: "Stargazing"

Postby stopmadnessnow » Fri Mar 04, 2016 1:11 pm UTC

We are all lost in space. Some of us do need a Cox.
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Re: 1644: "Stargazing"

Postby pogrmman » Thu Jun 30, 2016 3:18 pm UTC

ijuin wrote:
sonar1313 wrote:Wait a minute, I think that branch of the conversation tree is more interesting than all that. What actually is the brightest star in the sky? It's neither the Sun nor Sirius, probably; they just happen to be the ones that are brightest from Earth. But if you could make all else equal, which star really would be the brightest?


The most luminous star that is visible to the unaided human eye from Earth is Alnilam, known also as Epsilon Orionis, the center star in Orion's Belt, with a luminosity approximately 4.0 * 10^5 times as bright as Sol.

The most luminous star whose luminosity has been confirmed is R136a1, a star in the Large Magellanic Cloud about 163k light years from Earth, with a luminosity approximately 8.7 * 10^6 times that of Sol.

The above, of course, excludes stars undergoing transient events such as nova or supernova explosions.


Eta Carinae is a magnitude ~5 star, but it's luminosity is around 5.0 x 10^6 of that of the sun (according to Wikipedia, which cites the Monthly Notices of the Royal Astronomical Society). That would make it more luminous than Alnilam, and the most luminous star visible to the naked eye. It may not be in the northern celestial hemisphere, so many can't see it, and at magnitude ~5, some people won't be able to see it due to light pollution. However, it is visible to the naked eye.

Also, there are several naked eye (barely) Wolf-Rayet stars with luminosities over 1.0 x 10^6 times that of the sun. Also, some blue supergiants too.

In the northern celestial hemisphere, it appears that 68 Cygni is the most luminous naked eye star at magnitude ~5 and around a million times the Sun's luminosity.

ijuin
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Re: 1644: "Stargazing"

Postby ijuin » Mon Jul 04, 2016 5:15 am UTC

68 Cygni is a variable star, and Eta Carinae A is likewise undergoing short-term events that enhance its luminosity, so while they may at times be much brighter, Epsilon Orionis is the most luminous stable main-sequence-phase naked-eye star.


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