ASTRO: IC 2184 Galaxies in confusion

Markarian 8/IC 2184 is a pair of colliding galaxies in Camelopardalis
about 160 million light-years distant. It may look like it consists of
3 or 4 galaxies, but this is due to my lack of resolution. The Hubble
space telescope has looked at this one. I did a quick and dirty process
of a mono image I found at the Hubble Legacy site rotated to closely
match my image's orientation. It shows it is just two interacting
galaxies in which the interaction has created several bright star clouds
in the debris field of the collision. It appears the action is just
beginning with the major wreck still well into the future. The CGCG
says of it "Triple system in halo." While the CGPG says: "Blue
post-eruptive quadruple of 2 bar-shaped and 2 spherical compacts." So I
don't feel bad that it does appear to be 3 or 4 objects in my image.
Those authors apparently had little better resolution than I do to work
with. Markarian seems to have the most accurate description: "Two
tightly merged double galaxies. Seems to be a nest of blue objects."
He seems to realize it is only 2 galaxies though doesn't seem to desire
to speculate what the rest of the blue objects are in that nest. NED
classifies both as S?

This is a very barren section of sky for galaxies. That two galaxies
would collide in such a empty region of space seems highly unlikely, yet
it did happen. They even appear to be of about the same size. No other
galaxy in the image has any distance data at NED. NED only lists 11
galaxies in my field omitting one of the brightest, a blue smudge of a
galaxy near the top a bit left of center. Hundreds of faint background
galaxies are missed as well.

This object was suggested to me by Sakib Rasool.

The Luminance frames were taken binned 1x1 for a resolution of 0.5" per
pixel. Color data was binned 2x2, my usual bin mode. The seeing wasn't
quite up to 0.5" however so I've reduced the image down to 0.67" per
pixel. That's what I normally enlarge 1" per pixel images to. In this
case I reduced it to that level. I did make a cropped image at the full
0.5" resolution though it doesn't seem to show any more detail than the
0.67" per pixel image. This one needs a night far better than I get
even on the best of nights.

14" LX200R @ f/10, L=4x20'x1 RGB=3x10', STL-11000XM, Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

I forgot the HST image. Here it is.

Rick
--
Prefix is correct. Domain is arvig dot net[/quote]

Trying again with the HST image. I forgot it first time. Second try
made some servers but not my own USENET server for some reason. Sorry
if you get it twice.

Rick
--
Prefix is correct. Domain is arvig dot net

On Sun, 03 Feb 2013 12:09:05 -0600, Rick Johnson wrote:

Trying again with the HST image. I forgot it first time. Second try
made some servers but not my own USENET server for some reason. Sorry
if you get it twice.

Rick

Fascinating images. I am trying to imagine what it would be like to live on a
planet in one of these galaxies, stars whizzing past your solar system at
tremendous velocities, new stars in the sky every night and every day. Stars
visible in the daytime to rival your own sun. Dust clouds crashing through your
star's heliosphere. It might be a short life but it would be eventful.

On 2/3/2013 1:33 PM, Geoff wrote:
On Sun, 03 Feb 2013 12:09:05 -0600, Rick Johnson wrote:

Trying again with the HST image. I forgot it first time. Second try
made some servers but not my own USENET server for some reason. Sorry
if you get it twice.

Rick

Fascinating images. I am trying to imagine what it would be like to live on a
planet in one of these galaxies, stars whizzing past your solar system at
tremendous velocities, new stars in the sky every night and every day. Stars
visible in the daytime to rival your own sun. Dust clouds crashing through your
star's heliosphere. It might be a short life but it would be eventful.


I really doubt you'd notice much happening. It takes hundreds of
thousands of years for these changes to occur. New stars don't happen
over night nor whiz past us at high apparent speed. I suppose if your
lifespan was 100 centuries (ours) but experienced time so slowly a
century is like our year then you might see some changes but even then
they'd be slow and not obvious. When galaxies collide stars themselves
are little bothered by the affair. Dust and gas collide but the star's
solar wind should pretty well keep all that at bay. Guess in a few
billion years some beings in our galaxy will get a chance to see this
first hand when we collide with M31. By then earth will not be
habitable by anything like us as the sun will be far too hot for beings
like us anyway.

Our galaxy is currently tearing apart a dwarf but it is happening on the
other side hidden by dust and distance. It wasn't even discovered until
recently. The time scales needed are beyond what our limited lifetimes
allow us to really understand they are so huge.

Rick

--
Prefix is correct. Domain is arvig dot net

On Tue, 05 Feb 2013 00:21:28 -0600, Rick Johnson wrote:

On 2/3/2013 1:33 PM, Geoff wrote:
On Sun, 03 Feb 2013 12:09:05 -0600, Rick Johnson wrote:

Trying again with the HST image. I forgot it first time. Second try
made some servers but not my own USENET server for some reason. Sorry
if you get it twice.

Rick

Fascinating images. I am trying to imagine what it would be like to live on a
planet in one of these galaxies, stars whizzing past your solar system at
tremendous velocities, new stars in the sky every night and every day. Stars
visible in the daytime to rival your own sun. Dust clouds crashing through your
star's heliosphere. It might be a short life but it would be eventful.


I really doubt you'd notice much happening. It takes hundreds of
thousands of years for these changes to occur. New stars don't happen
over night nor whiz past us at high apparent speed. I suppose if your
lifespan was 100 centuries (ours) but experienced time so slowly a
century is like our year then you might see some changes but even then
they'd be slow and not obvious. When galaxies collide stars themselves
are little bothered by the affair. Dust and gas collide but the star's
solar wind should pretty well keep all that at bay. Guess in a few
billion years some beings in our galaxy will get a chance to see this
first hand when we collide with M31. By then earth will not be
habitable by anything like us as the sun will be far too hot for beings
like us anyway.

Our galaxy is currently tearing apart a dwarf but it is happening on the
other side hidden by dust and distance. It wasn't even discovered until
recently. The time scales needed are beyond what our limited lifetimes
allow us to really understand they are so huge.

Rick

Man you sure know how to spoil a fantasy, Rick.

I'm sure there would be some changes observable in a human lifetime. Dust moats
creating new stars would be a good start. I envisioned high relative velocities
between the stars of one galaxy against the stars of the other, rather than our
current neighborhood where the stars are drifting together in their orbit around
the galactic center. A star moving in the opposite direction from our stellar
neighborhood would have some impressive relative motion if it was only a few or
a dozen light-years distant. Nebulae would probably vary in brightness as the
dust collided at millions of miles per hour, we'd be seeing shock-wave effects,
I'm sure.

Ya gotta think outside the box, Rick! Like Asimov did when he wrote "Nightfall".

Regards,
ke6qh.

On 2/5/2013 2:17 AM, Geoff wrote:
On Tue, 05 Feb 2013 00:21:28 -0600, Rick Johnson wrote:

On 2/3/2013 1:33 PM, Geoff wrote:
On Sun, 03 Feb 2013 12:09:05 -0600, Rick Johnson wrote:

Trying again with the HST image. I forgot it first time. Second try
made some servers but not my own USENET server for some reason. Sorry
if you get it twice.

Rick

Fascinating images. I am trying to imagine what it would be like to live on a
planet in one of these galaxies, stars whizzing past your solar system at
tremendous velocities, new stars in the sky every night and every day. Stars
visible in the daytime to rival your own sun. Dust clouds crashing through your
star's heliosphere. It might be a short life but it would be eventful.


I really doubt you'd notice much happening. It takes hundreds of
thousands of years for these changes to occur. New stars don't happen
over night nor whiz past us at high apparent speed. I suppose if your
lifespan was 100 centuries (ours) but experienced time so slowly a
century is like our year then you might see some changes but even then
they'd be slow and not obvious. When galaxies collide stars themselves
are little bothered by the affair. Dust and gas collide but the star's
solar wind should pretty well keep all that at bay. Guess in a few
billion years some beings in our galaxy will get a chance to see this
first hand when we collide with M31. By then earth will not be
habitable by anything like us as the sun will be far too hot for beings
like us anyway.

Our galaxy is currently tearing apart a dwarf but it is happening on the
other side hidden by dust and distance. It wasn't even discovered until
recently. The time scales needed are beyond what our limited lifetimes
allow us to really understand they are so huge.

Rick

Man you sure know how to spoil a fantasy, Rick.

I'm sure there would be some changes observable in a human lifetime. Dust moats
creating new stars would be a good start. I envisioned high relative velocities
between the stars of one galaxy against the stars of the other, rather than our
current neighborhood where the stars are drifting together in their orbit around
the galactic center. A star moving in the opposite direction from our stellar
neighborhood would have some impressive relative motion if it was only a few or
a dozen light-years distant. Nebulae would probably vary in brightness as the
dust collided at millions of miles per hour, we'd be seeing shock-wave effects,
I'm sure.

Ya gotta think outside the box, Rick! Like Asimov did when he wrote "Nightfall".

Regards,
ke6qh.

Nightfall doesn't involve change, the sky has always been there, just
hidden by ever present daylight. He has to set conditions on their
culture that are difficult to accept to cause them to go mad when they
finally see a sky of bright stars. He ignores that their light would
make the sky like dusk (not Stars like Dust) reducing the impact greatly
but as to number seen and apparent brightness in relation to the sky.
Makes a good story however.

What you are talking about is a change. Those changes could be measured
by scientists with the right instruments but would be totally missed by
the casual observer. A few million years into the collision massive
stars that were formed early on would now be dying so they would see a
higher number of super nova popping off. One every few decades rather
than one every few hundred years, but again they'd not really see any
change, this would be the norm for them. They'd get annoyed when one
doesn't happen "on schedule" same as we are overdue for one at our much
lower rate.

We do have a star flying by us like you describe. It is called
Barnard's star and is only 6 light years away, the second closest system
known after the Proxima Centauri system (a triple star). It can be seen
in Ophiuchus. But you don't notice it speeding by for two reasons. One
it is too faint to be seen by the human eye (though is a typical star!)
at a magnitude of about 9.4 (25 times fainter than a 6th magnitude star
we can barely see naked eye) and even if we could see it it is moving
only 10.3" of arc a year. If it were bright enough it would take a
careful naked eye observer with a very accurate star chart to notice any
movement even after 20 years. Another high speed run-away star is
Archturus. It is a 1st magnitude star with a motion typical of what
you'd see in your depiction. Edmund Halley discovered this in 1718 when
he carefully compared star charts of his day to those made by Hipparchus
over 1800 years earlier. He also noted a couple other stars, Sirius and
Aldebaran had moved about one moon diameter in over 1800 years. Not
exactly Nightfall obvious to the typical citizen.

It would take very good observations by scientists to see such a
collision was taking place. The average person wouldn't see anything
much different than we see. Of course there'd be a very few star
systems that might get a very close pass and a citizen might then see
some movement of a star among many in their lifetime but this would be
exceedingly rare and then to have such a planet inhabited by sentient
beings even far rarer. It could happen but highly unlikely and would,
most likely, involve only one star.

Also, astronomers, with telescopes that can accurately measure star
positions would find far more moving stars than we have making
astrometry an interesting challenge until they discovered Quasars to
anchor the sky so they had a truly fixed sky. Though that's what
astronomers do here as well but the need would be greater in a colliding
system.

Barnard's star can be seen to move easily over say 5 years as shown in
my animation made from 5 years worth of images of the star, once each
summer.
http://www.prairieastronomyclub.org/...son/BS2012.GIF

Unless you knew it was doing this I doubt the average amateur would
notice the movement visually. He'd have have made an image or chart a
year earlier then just happened to have done so on the one of very few
such fields. Most of the "colliding" stars would be far to distant to
show much movement that quickly so there'd be few stars moving like we
see Barnard's move.

You really have to sit back at a large distance and imagine over
millions of years to see the vision you describe. Something astronomers
do do. Astronomers do this when studying such events. Nothing wrong
with a good writer or poet condensing this so it fits the mind of the
typical reader. It is about the only way to get the idea across to our
woefully science illiterate public but the astronomer can see an even
more grand picture of it in his mind that doesn't need to be hyped up.
To me it is even grander than any writer can describe.

Rick


--
Prefix is correct. Domain is arvig dot net