Let’s say an alien civilization around a nearby star system with one or more exoplanets – say, Vega, because why not – pointed their telescopes towards Sol. Would it even be visible to the Vegans’ naked eyes? What other stars would be visible in our “constellation”?
There are G-type stars with discernable exoplanets visible from here. Our sun would certainly be visible from those as would the presence of planets in our solar system.
The presence of a civilization on Earth, on the other hand, would not be so easily seen from those stars if they had our level of technology.
ETA: In our ‘constellation’, any decent sized star in our vicinity would likely also be visible, but it’s hard to say - stars in constellations aren’t necessarily close together and a lot of it depends on the quality of the interstellar medium (a cloud of dust in the right place will obscure a bright star) and how big the star is
I don’t know enough about space to give you a factual answer, but I did see that Vega is a mere 25 light years away from Sol, so… I don’t see why it wouldn’t be visible from Vega, given how much we can see with our naked eyes.
Although Vega was mentioned originally, it’s not a fair comparison since it’s 40 times as luminous as our Sun.
Alpha Centauri A is a better equivalent, since it’s the same spectral class as our Sun and only a little more luminous, but the naked-eye star Alpha Centauri also includes its binary partner “B” (which cannot be distinguished from “A” with the naked eye). But the binary is the third brightest star in the sky, so I reckon that each of the pair by themselves would also be naked-eye visible.
So an Alpha Centauran could probably see our Sun as a normal mediocre brightness naked-eye visible star.
A star very similar in size, color, and brightness to our sun is in the tip of Orion’s upraised club: Chi 1 Orionis.
It’s a 4th magnitude star from where we sit, and it’s about 28 light years away. You can see it in the sky even in the NYC suburbs on a clear moonless night, and you’d see it very easily on a clear night out in the Arizona desert.
Using the game Elite Dangerous as my guide, I’ve hopped to Sol (a G type star) from up to 50 LY away, and every time, Sol was very visible, at least as visible as other stars in the sky.
(See the Elite Dangerous thread in the Game Room forum for more info about this awesome, astronomically-realistic space game)
The Sun has an absolute magnitude of 4.83. What is absolute magnitude? It’s the magnitude the star would have if it were exactly 10 parsecs (32.6 light years) away. 4.83 makes for a dim, but still naked-eye star. From stars closer than that, it’ll be brighter. From Alpha Centauri, the Sun will be one of the brightest stars in the sky. Sirius will be the brightest from AlphaC, though.
This is a pet peeve of mine, and I don’t intend to attack anyone personally, but I’d like to say that I find the use of the word “Sol” as a name for our Sun affected. Yes, I know, it pops up in science fiction, but I think all it does is try to impress by using a Latin word for something that doesn’t need one. The IAU calls it nothing but “the Sun” (note the capital S).
The problem is that the word “sun” has two different meanings: It can mean our own specific star, or it can mean the star that any given planet orbits. Thus, for instance, an observer on a planet orbiting tau Ceti would need to wait for the sun to set to be able to see the Sun. And yes, I know that there’s capitalization to distinguish them, but that’s not really much of a useful distinction, especially not in speech.
Similar objections exist for “Earth” and “Moon”, which is why the same people who use “Sol” also often use “Terra” and “Luna”. And yes, we know that those are just the direct Latin translations of the words we’re avoiding, but since those Latin words are no longer used for the uncapitalized meanings, it’s OK.
That is a problem we would not have if we spoke Spanish.
BTW: When in Science Fiction, when a “sol” pops up I interpret it as the duration of a day on Mars.
I think it’s also worth emphasizing how near “nearby” is, in cosmic terms.
Of the 200 billion or so stars in our galaxy, only 150 or so, within about 50 light years, are close enough to see the Sun / sol without the use of a telescope. And for most of those it wouldn’t be easy to spot.
When you look at the night sky, you are basically just seeing the giant stars of our galaxy (plus Andromeda, and globular clusters), not stars like ours.
In the first Foundation novel, Isaac Asimov has someone speculate (in the stilted pronunciation of the late Empire) on the identity of humanity’s home world:
“Of cohse, no one knows exactly which system it is - lost in the mists of antiquity. Theah ah theawies, howevah. Siwius, some say. Othahs insist on Alpha Centauwi, oah on Sol, oah on 61 Cygni - all in the Siwius sectah, you see.”
There is, of course, an irony in the sense that the Bayer and Flamsteed designations used here are based on the appearance of the constellations and stars from Earth, so a civilization that has forgotten that humanity hails from Earth would not name these objects such. I’m sure Asimov was aware of that but decided that th line was so good it was worth this slight inaccuracy.
Or people have simply forgotten the origins of the names.
You can also extrapolate from this by noting that doubling the distance to the star increases its apparent magnitude (so decreasing the brightness) by about 1.5. So at 65 light-years away, the Sun would be about magnitude 6.3, which is right on the border of being visible to the unaided eye on a clear night. Conversely, at 8 light-years away, it would have a magnitude of 1.8, which would make it roughly as bright as the two brightest stars in the Big Dipper (Alioth and Dubhe) — one of the more prominent stars but still not impressively bright.