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Thoughtsoc
2010-May-25, 03:08 AM
I'm fascinated by this scenario that is possible in theory only.

Imagine that you're approaching a sprial galaxy, tilted on its edge a bit, in a space ship traveling close to the speed of light or whatever. What initially appeared as a tiny smudge, obviously, would get larger and larger to your view until at some point it occupied the entire sky. Would it at that point appear as a feintly visible sprial-shaped smudge, or would it be sparking and brilliant at some point? Surely this is one of the most remarkable views to contemplate. I wish an artist would attempt a rendition.

As you could closer to the galaxy, it would resolve into a more or less typical night sky, I assume.

Jens
2010-May-25, 05:21 AM
It would no doubt be a spectacular view, and I think you basically have the ideas right. It would get bigger and bigger and eventually you'd start to be able to see individual stars on the side closest to you, but there would be a big blurry thing occupying half the sky. And as you got inside it the stars would pass overhead and little by little you'd start seeing something like our night sky. I guess it would be most impressive when you were close enough that it dominated the sky but far enough that you could still see it in one visual frame.

astromark
2010-May-25, 05:49 AM
In my minds eye ( imagination ) I can see what you speak of as can many other people. The ability to turn into the arms of a spiral and view the clouds become stars as you zoom in. Gene Roddenberry George Lucas Carl Sagan Stephen Spielberg and hundreds of us mortals have this ability to imagine. Unfortunately without the equipment to travel at c. or above it, is going to make it a very slow panorama... maybe one day....
Paint it your self... how hard could it be. Big and black with dots in a pattern... cloud like... easy :)

Van Rijn
2010-May-25, 05:56 AM
I'm fascinated by this scenario that is possible in theory only.

Imagine that you're approaching a sprial galaxy, tilted on its edge a bit, in a space ship traveling close to the speed of light or whatever.


If you're traveling close the speed of light you would have relativistic visual effects to contend with. See this page:

http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/SR/Spaceship/spaceship.html

The faster you go, the more distorted it would be. The reality is, we can get a better view with simulated views, or computer enhanced images. Our unassisted eyes aren't the best way to see the universe.

Jeff Root
2010-May-25, 06:28 AM
A large spiral like the Milky Way would appear brighter overall
than it does in our sky, but mainly because of the core. The arms
would have brightness comparable to what we see from Earth,
with probably many slightly brighter patches of star forming
regions like the Orion nebula.

Looking through a telescope at other galaxies is similar to what
you are asking about. The Sombrero Galaxy is pretty impressive.

-- Jeff, in Minneapolis

Murphy
2010-May-25, 11:56 PM
You could always just get Celestia (http://www.shatters.net/celestia/) for views like this... (Andromeda Galaxy from 113,000 LY way).

http://img594.imageshack.us/img594/8292/andromedagalaxy.png

Jeff Root
2010-May-26, 12:29 AM
That image is much brighter than what could be seen
directly with human eyes, though. It is essentially the same
as a photograph or CCD image, with light collected over a
period of time to make everything brighter.

-- Jeff, in Minneapolis

Galvatron
2010-May-27, 09:08 AM
Related question: Would we be able to see it moving (if we were stationary relative to the Galaxy, and it appeared a similar size to the image above)?

I can't really get my head round the speeds and distances involved.

Jeff Root
2010-May-27, 12:07 PM
I don't know any numbers for the Andromeda Galaxy, but the
stars in the Milky Way at Earth's distance from the center take
about 220-250 million years to make a full circuit. It wouldn't
be very different from watching from where we are: Most
changes would be very, very slow.

-- Jeff, in Minneapolis

joema
2010-May-27, 01:13 PM
...Would it at that point appear as a feintly visible sprial-shaped smudge, or would it be sparking and brilliant at some point?...
It would be much dimmer than is often depicted in fiction, artwork and movies. *Not* like the below photo from Empire Strikes Back.

The surface brightness of galaxies is very low: http://en.wikipedia.org/wiki/Surface_brightness

E.g, the Andromeda galaxy is close enough that it's quite large, from an angular standpoint. It is six times the diameter of the moon. Yet it's so dim your naked eye can only faintly see the central hub on a dark night.

This is obvious when you think about it. We are *inside* a galaxy, and can see the adjacent galactic arms edge-on from close range. Yet they are not blazing swaths of light across the night sky.

If you were at the right distance for certain globular clusters, that would look pretty impressive to the naked eye.

Murphy
2010-May-27, 06:15 PM
That image is much brighter than what could be seen
directly with human eyes, though. It is essentially the same
as a photograph or CCD image, with light collected over a
period of time to make everything brighter.

-- Jeff, in Minneapolis

Sure, that's because I turned up the Apparent magnitude to the maximum Celestia allows, 15.18.

Here's some pictures of the same scene (almost the same, it's hard to get to exactly the same position) with the magnitude limit set to 8 and then 6. I think that's more similar to what you would actually see.

http://img99.imageshack.us/img99/2884/andromedagalaxy8mag.png

http://img715.imageshack.us/img715/4695/andromedagalaxy6mag.png

antoniseb
2010-May-27, 07:04 PM
It is also worth noting that IF you were approaching at near the speed of light, the photons coming to you would be blue shifted significantly, and what you would see would be something in the far infrared, microwave, or radio range shifted into the visual range. The photons getting to your eyes would not necessarily show you stars... And the visible light from stars would be blue shifted to a range that would kill you if you didn't filter them out somehow.

Argos
2010-May-27, 07:14 PM
Galaxies as we see result from long photographic exposures. A real time observation wouldn´t be that glorious. The Magellanic clouds are very close, but all you see are faint smudges.

JustAFriend
2010-May-27, 07:31 PM
You could also just watch the last couple of minutes of "The Empire Strikes Back"

http://images3.wikia.nocookie.net/starwars/images/f/fc/Empireendshot.jpg