Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: acecharly on 05/06/2013 18:36:16
-
As above is there any idea what is beyond our central region from which we are obscured?
Cheers
Ace
-
More galaxies ... http://en.wikipedia.org/wiki/Local_Group
-
As above is there any idea what is beyond our central region from which we are obscured?
I don't know how they know what's on the other side of the galactic nucleus, but this 'map' was created by the NASA astronomer-artist Robert Hurt.
...http://galaxymap.org/drupal/node/171 (http://galaxymap.org/drupal/node/171)
Ps. i have just spotted our sun on the map
-
Our galaxy is thought to be a spiral galaxy with loosely-wound arms, and a straight bar across the center.
It's pretty hard to see through the dust and gas in the disk of our Milky Way galaxy using visible light.
However, infra-red and microwaves penetrate this more easily, allowing astronomers to pick out several spiral arms.
How they look in visible light is extrapolated from looking at the stars in our spiral arm, and the parts of adjacent arms that we can see - as well as looking at nearby spiral galaxies like Andromeda.
It is even harder to see through the denser stars and gas near the center of the galaxy, and so astronomers extrapolate the spiral arms they can see, and assume that they join up, and assume that they consist of similar types of stars to parts of the spiral arms that they can see.
The extrapolated parts of the spiral arms are shown as dotted lines in the diagram at: http://en.wikipedia.org/wiki/Milky_way#Spiral_arms
-
The structure of neutral hydrogen molecules at 21cm wavelength can be observed quite easily across the galaxy and there is no significant obscuration by stars or dust. This gives clear indication of the spiral arms not visible in normal light.
-
Some recent studies have provided more detail to the galactic map by looking at emission lines of Carbon Monoxide, which exists in dust clouds in the arms of the Milky Way galaxy.
The authors suggest that the Hydrogen line is rather noisy, because there is so much Hydrogen in the galaxy, and suggest that mapping molecular gas clouds may be a better way to pick out the spiral arms.
See: http://www.scientificamerican.com/article.cfm?id=new-spiral-arm-milky-way
-
WISE 1049-5319 appears in the sky close to the galactic plane which is densely populated by stars; the abundance of light sources makes it difficult to spot faint objects. This explains why an object so near to the Sun was not discovered in earlier searches
http://en.wikipedia.org/wiki/WISE_1049-5319#Discovery
This binary system is right on a door step and we have only just confirmed its existence. Gives you an idea of how hard it is to see dim objects against the light drenched backdrop of the galactic plane.