Distance to Galaxies

Hello, all, and perhaps an astrophysics 101 question: When measuring
the distance from, say, earth to another galaxy is it the distance to
the outermost star(s) in that galaxy or its galactic center? (Perhaps
with such great distances this is moot?) Thanks for your time and
comment. Sincerely,
--
J. B. Wood e-mail:

On Friday, September 23, 2016 at 6:20:49 AM UTC-7, J.B. Wood wrote:
Hello, all, and perhaps an astrophysics 101 question: When measuring
the distance from, say, earth to another galaxy is it the distance to
the outermost star(s) in that galaxy or its galactic center? (Perhaps
with such great distances this is moot?) Thanks for your time and
comment. Sincerely,
--
J. B. Wood e-mail:

i'm going to guess the Center

and yes,
it may be a moot point,
since we're talking 100's of light years, if not 1000's

marc

"J.B. Wood" wrote in message ...
Hello, all, and perhaps an astrophysics 101 question: When measuring the
distance from, say, earth to another galaxy is it the distance to the
outermost star(s) in that galaxy or its galactic center? (Perhaps with
such great distances this is moot?) Thanks for your time and comment.
Sincerely,
J. B. Wood e-mail:

I'd tend to think it is kind'a moot.

Google - nearest galaxy to milky way
"Andromeda galaxy. At a distance of about 2.5 million light years,
the Andromeda galaxy (also known as NGC 224 and M31) is the
nearest galaxy to the Earth apart from smaller companion galaxies
such as the Magellanic Clouds. Like the Milky Way, Andromeda
is a spiral galaxy.
BBC Universe - The Andromeda galaxy is our galactic neighbour"
http://www.bbc.co.uk/science/space/u...meda_galaxyBBC

Google - width of milky way galaxy
"100,000 light years
The Milky Way is about --- km (about 100,000 light years or about 30 kpc)
across. The Sun does not lie near the center of our Galaxy. It lies about
8 kpc from the center on what is known as the Sagittarius arm of the
Milky Way.
Milky Way Galaxy - The Cosmic Distance Scale - NASA
imagine.gsfc.nasa.gov/features/cosmic/milkyway_info.html

meanwhile --
Andromeda Galaxy (M31): Location, Characteristics & Images
www.space.com › Science & Astronomy
Space.com
May 8, 2012 - The Andromeda galaxy is the most distant object in
the sky that you ... The visible fuzzy patch of stars stretches about as
long as the width of the ...

Who discovered the Andromeda galaxy and how?
His result placed the Andromeda Nebula far outside our galaxy at a
distance of about 450,000 parsecs (1,500,000 ly). Edwin Hubble
settled the debate in 1925 when he identified extra-galactic Cepheid
variable stars for the first time on astronomical photos of M31.

J.B. Wood wrote:
Hello, all, and perhaps an astrophysics 101 question: When measuring
the distance from, say, earth to another galaxy is it the distance to
the outermost star(s) in that galaxy or its galactic center? (Perhaps
with such great distances this is moot?) Thanks for your time and
comment. Sincerely,


I think you will find that all reported distances are appoximations only, so
any differences will still be just as inaccurate.

The nearest one is Andromeda at 2.5 million light years distant !
Light goes very fast. If you circumnavigate the globe along the
equator, then light could do it well over 7 times a second. Even at
that speed, it would take 2,500 milenia to reach Andromeda. If you
think all the way back to the Romans, then that's only about 2
milenia. Just a bit of perspective ...

On Monday, September 26, 2016 at 4:08:35 PM UTC-7, SteveGG wrote:
The nearest one is Andromeda at 2.5 million light years distant !
Light goes very fast. If you circumnavigate the globe along the
equator, then light could do it well over 7 times a second. Even at
that speed, it would take 2,500 milenia to reach Andromeda. If you
think all the way back to the Romans, then that's only about 2
milenia. Just a bit of perspective ...

why use your system when ours uses faster than light speed. we get there in under a day, idiot. You take the very very slow rout.

Sorry. All science (you've heard of that) agrees, we'll always be
limited to 3E8 meters / second.

On 09/27/2016 08:11 AM, SteveGG wrote:
Sorry. All science (you've heard of that) agrees, we'll always be
limited to 3E8 meters / second.


Hello, and OTOH, if we could realize an "Alcubierre Drive" form of
propulsion we just might be able to beat "c". Sincerely,

--
J. B. Wood e-mail:

Not going to happen, ever !