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Galaxies on a String, plotting backwards (APOD 31 Jul 2008)

Posted: Thu Jul 31, 2008 11:17 am
by henk21cm
When looking at http://apod.nasa.gov/apod/ap080731.html, NGC 5216 looks a spiral galaxy, while i wonder: is NGC 5218 an elliptical system? Indeed, both are slightly crumpled. Similar strings as in todays APOD can be seen in simulations of collisions.

Plotting backwards (APOD 31 Jul 2008)

Posted: Thu Jul 31, 2008 12:33 pm
by CharlieNNC
If enough galaxy measurements have been taken over the years to assume which direction the majority of galaxies are going, is it possible to plot backwards and see at what point in the universe, according to the theory at least, where all movement outward began? Is it known where our own Milky Way is in this train of movement outward? Are there a string of galaxies 'behind' us pointing to the origin, along with a sting 'up front' showing where we are headed?

Charlie in NC

Posted: Thu Jul 31, 2008 1:51 pm
by bystander
As a general rule, all points in the universe are moving away from all other points. There is no center of the universe, and no Restaurant at the End of the Universe. NGC 5216/NGC 5218 are exceptions to the rule, as are Andromeda and the Milky Way and many of the galaxies in the Atlas of Peculiar Galaxies. There is a region of space, known as the Great Attractor, towards which the majority of matter in our general region of the universe seems to be headed.

http://nedwww.ipac.caltech.edu/level5/A ... tents.html
http://antwrp.gsfc.nasa.gov/apod/ap000104.html

Posted: Thu Jul 31, 2008 2:05 pm
by zbvhs
Have any signs of tidal interactions been found in the two Magellanic Clouds? Are they companion galaxies or just outlying regions of the Milky Way?

Posted: Thu Jul 31, 2008 2:12 pm
by emc
http://apod.nasa.gov/apod/ap080731.html

Looks like they're dancing to me.

Posted: Thu Jul 31, 2008 2:22 pm
by bystander
zbvhs wrote:Have any signs of tidal interactions been found in the two Magellanic Clouds? Are they companion galaxies or just outlying regions of the Milky Way?
APOD: 1998 Aug 26 - The Magellanic Stream
Wikipedia: The Magellanic Stream

Posted: Thu Jul 31, 2008 5:12 pm
by BMAONE23
Other local streams

http://antwrp.gsfc.nasa.gov/apod/ap030930.html
Sagittarious Dwarf stream

http://antwrp.gsfc.nasa.gov/apod/ap031117.html
Canis Major Dwarf stream

Posted: Thu Jul 31, 2008 11:50 pm
by pauln
Have you tried to imagine how the night sky might look if your home star happened to be somewhere along that string?!?

You would have a faint "milky way", which would be the string as it stretched away across the sky. At each end of the "milky way" would be a vast galaxy stretching across a substantial portion of the night sky. The rest of the night sky would be dark and empty with far fewer stars than we can see from our location inside a galaxy.

Posted: Fri Aug 01, 2008 12:05 am
by apodman
Lundmark's Nebula - The "Second Galaxy," which collided with the "Milky Way" or "First Galaxy" 2 billion years ago, leading to the large populations of planets nurtured by Arisia and discovered by Eddore. Home of the Eddorians, the Ploorans, and the major races of their empire, including the Eich, the Thralians, and the Kalonians. Historical Note: Knut Lundmark was an early 20th-Century Swedish astronomer. It is possible that Lundmark's Nebula is intended to refer to the Wolf-Lundmark-Melotte Galaxy, though Lundmark made numerous other contributions to the study of other galaxies.

Okay, this galactic collision and all that goes with it is fiction. Then again, something like it actually could have happened. The description above is from the http://en.wikipedia.org/wiki/Lensman_series article.

Posted: Fri Aug 01, 2008 4:48 am
by ta152h0
they found the bloody worm hole, pass the beer, please. :D