Apparent Motion of Distant Objects

[jerrythebiker]

I am an avid APOD viewer. I was wondering about how fast things are moving in the universe and how we might perceive apparent changes in location or appearance of distant objects. Has anyone ever done comparisons as to how objects in the universe appear now as compared to when they were first imaged? For example, do today's Hubble images of objects discovered in the late 19th century or early 20th century, differ in any way if superimposed on the older images? I think this would be an interesting APOD entry. I realize that imaging today is much sharper than that of the past, but with today's technology perhaps older images can be made sharper with computer enhancement. Would we be able to visually perceive differences in objects such as the Horsehead Nebula, Andromeda Galaxy, any face-on galaxies and their corresponding foreground stars, etc;.

[Chris Peterson]

I am an avid APOD viewer. I was wondering about how fast things are moving in the universe and how we might perceive apparent changes in location or appearance of distant objects. Has anyone ever done comparisons as to how objects in the universe appear now as compared to when they were first imaged? For example, do today's Hubble images of objects discovered in the late 19th century or early 20th century, differ in any way if superimposed on the older images? I think this would be an interesting APOD entry. I realize that imaging today is much sharper than that of the past, but with today's technology perhaps older images can be made sharper with computer enhancement. Would we be able to visually perceive differences in objects such as the Horsehead Nebula, Andromeda Galaxy, any face-on galaxies and their corresponding foreground stars, etc;.

We can see many changes within our galaxy, over periods ranging from months to decades. We see stars change position because of their proper motion, we see the shapes and intensity of nebulas change because they are expanding or being deformed, we see stars orbiting the black hole at the center of the galaxy (that's probably the most distant positional change we detect). There have been APODs published over the last few years showing time sequences of supernova remnants.

AFAIK, we haven't been watching long enough to see any significant structural changes outside our own galaxy, however.

[neufer]

We can see many changes within our galaxy, over periods ranging from months to decades. We see stars change position because of their proper motion, we see the shapes and intensity of nebulas change because they are expanding or being deformed, we see stars orbiting the black hole at the center of the galaxy (that's probably the most distant positional change we detect). There have been APODs published over the last few years showing time sequences of supernova remnants.

AFAIK, we haven't been watching long enough to see any significant structural changes outside our own galaxy, however.

<<The Galactic Center is located about 7.6 kiloparsecs away from the Earth.>>

<<SN 1987A was a supernova in the outskirts of the Tarantula Nebula in the Large Magellanic Cloud.
It occurred approximately 51.4 kiloparsecs from Earth>>


http://en.wikipedia.org/wiki/SN_1987A

[astrolabe]

Hello neufer!

You NEVER cease to amaze me