Edge of the great rift - views

[shield]

Okay - question for the astronomers

If a ship was in an empty hex on the edge of the great rift - what would the view outside look like. I imagine that looking back into the bulk of the Imperium would just look like a normal night sky - but what about looking into the rift. There is about 50 parsecs of nothing before you find the next stars. Could you perceive the rift or would it still look like the normal night sky

 

[Ben W Bell]

You wouldn't really see much difference. You're only missing a hundred or so stars from the sky, you won't notice the difference unless you're counting. Remember some of the brightest stars in the sky are further away than the duller closer ones. The human eye can't really tell how far away they are, only how bright. On the edge of the galaxy looking out it'll be noticeable, on the edge of the rift you won't know in either direction.

 

[Fritz_Brown]

I think "up" or "down" is where you might notice a difference. Where you would have lots of stars in the normal "lens" of the galaxy, in the rift, you would see mostly empty sky. I agree that looking across to the next arm would be anti-climactic.

 

[Enoki]

That pretty much covers it. It might look more like the Southern sky than Northern sky on Earth though. The "Backbone of Night" or, the actual Milky Way is only visible there. It is a much thicker band of stars than you see anywhere in the Northern Hemisphere.

But, you really couldn't tell it was rift as the human eye is resolving at infinite and the stars would all still be just specks in the visible 'sky'.

 

[flykiller]

my understanding is that almost all stars visible to the naked eye from earth are within 40 light years, and that ordinary stars beyond that distance are almost invisible except as a haze where they exist in great numbers - for example the "milky way" one sees when looking edge-on into our local galaxy. examples of exceptions are sirius (1200 light years distant) and deneb (1600 light years distant).

based on this if one were to look across a void of 50 parsecs one would see nothing except a haze where the local galaxy is, and a handful of distant bright stars.

noting that the spinward marches seem to be near deneb, imtu that star is extreamly bright and noticable from all locations within the spinard marches. it plays a role in all the local religions and is the primary navigation reference in all maneuver and jump calculations.

 

[aramis]

my understanding is that almost all stars visible to the naked eye from earth are within 40 light years, and that ordinary stars beyond that distance are almost invisible except as a haze where they exist in great numbers - for example the "milky way" one sees when looking edge-on into our local galaxy.

Your understanding is wrong.

Your examples are wrong, too.
Sirius is 8.6 LY.
Deneb's distance is not yet fixed - estimates range from 1550-2300LY

Of the list of the 91 brightest stars seen from earth on wikipedia, 81 are more than 40LY. 59 are greater than 100LY. (and past 100 LY, distances become increasingly inaccurate.)

On atlasoftheuniverse.com's list of 300, 15 are 40LY or less, and 80 are under 100.

 

[Ben W Bell]

Just thinking of the Orion constellation alone, which most people can pick out in the sky.

The brightest two are the top left and bottom right, Betelgeuse and Rigel. Betelgeuse is 643 light years (give or take a hundred or so), and Rigel is 840 light years, give or take 80 or so.

The other distinctive features, all easily visible to the naked eye even in a light polluted city, consist of

Orions Belt (Alnitak, Alnilam and Mintaka) are 800, 1359 and 900 light years respectively.

The next most distinctive is of course the great nebula or M42 at approx 1344 ly.

Heck even Polaris is around 434 ly away (though even now it's debated exactly how far.)

Just looking at those numbers, most of them aren't even in the Third Imperium (M42 being 420 parsecs away) from a Traveller perspective yet they're among the most obvious things in the night sky.

And lets not forget the Andromeda Galaxy which is just very very very far away but also readily visible even in light pollution (well the galactic core is.)

 

[flykiller]

our sun visible at less than 55ly
http://uk.answers.yahoo.com/question/index?qid=20110701001728AADmiGd

visible stars
http://en.wikipedia.org/wiki/Apparent_magnitude

every star within 50 light years
http://www.atlasoftheuniverse.com/50lys.html

If a ship was in an empty hex on the edge of the great rift - what would the view outside look like.

go to a bright location in a city or equivilant. the number of individual stars bright enough to be seen there will be about equal to the total number seen from across a 50 parsec rift. now add in the haze of the milky way galaxy, and perhaps a few small puffy hazes of some outside galaxies. that is what would be seen.

from a planet on the boundary of such a rift the nighttime view would be compelling. the view would rotate between the full sky and the empty sky, or the one pole sky would be full while the opposite pole sky would be almost empty. entire religions would arise to explain it, migrations might be based upon it, mating seasons might be timed by it.

 

[Ben W Bell]

No I don't believe you can tell the difference. Honestly if we had an area of space in our local area 40 ly wide with absolutely no stars in it we would be hard pressed to notice, even with modern technology and a really really dark location.

I do astronomy from my balcony overhanging one of the busiest roads in Canada right in the centre of the country's largest city, and I can see a lot. Dark sky locations enable you to see the difference between galactic core direction and rim direction, however a gap with no stars of a few parsecs, completely undetectable to the human eye. In the scheme of what stars you can see in the sky, even a 100 parsec void means nothing. We can barely even see some of our closest stellar neighbours so distance is pretty much meaningless, only age and magnitude of the stars.

 

[flykiller]

We can barely even see some of our closest stellar neighbours so distance is pretty much meaningless, only age and magnitude of the stars.

I think you mean "apparent magnitude" and distance most certainly plays a role in that. observe that our sun, a typical star, would be undetectable to the human eye at a distance of 55ly. "some of our closest stellar neighbors" are undetectable to the human eye for exactly the same reason - the light they emit from the distance they are at is undetectable to the human eye. now at 50+ parsecs - 200+ light years - any star less than 16 times brighter than our sun will be equally undetectable to the human eye.

a view across a 200ly rift will have few visible stars.

 

[HG_B]

from a planet on the boundary of such a rift the nighttime view would be compelling. the view would rotate between the full sky and the empty sky, or the one pole sky would be full while the opposite pole sky would be almost empty. entire religions would arise to explain it, migrations might be based upon it, mating seasons might be timed by it.

Nope. You wouldn't even notice.

 

[Frankymole]

You wouldn't really see much difference. You're only missing a hundred or so stars from the sky, you won't notice the difference unless you're counting. Remember some of the brightest stars in the sky are further away than the duller closer ones. The human eye can't really tell how far away they are, only how bright. On the edge of the galaxy looking out it'll be noticeable, on the edge of the rift you won't know in either direction.

And those stars may even look brighter or more common if there is less obscuring interstellar dust in the rift. Plus, there's the Milky Way as you look through the galactic disk.