When I look at the Milky Way, what am I looking at?

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SUMMARY

When observing the Milky Way, viewers are generally looking towards the center of the galaxy, specifically in the direction of the constellation Sagittarius. The Milky Way spans approximately 100,000 light years, and while the farthest visible stars are around 4,000 light years away, the galactic core is obscured by dust and gas. Observations of the core are primarily made through infrared, gamma rays, and X-rays, as visible light is blocked. The brightest part of the Milky Way is located in the direction of Sagittarius, especially visible during summer in the northern hemisphere.

PREREQUISITES
  • Understanding of basic astronomical concepts, including galaxies and constellations.
  • Familiarity with the Milky Way's structure and dimensions.
  • Knowledge of observational astronomy techniques, particularly infrared and gamma-ray observations.
  • Awareness of the effects of interstellar dust on visibility in astronomy.
NEXT STEPS
  • Research the role of interstellar dust in obscuring astronomical observations.
  • Explore the use of infrared telescopes in observing the galactic core.
  • Learn about the constellations surrounding the Milky Way, particularly Sagittarius and Taurus/Auriga.
  • Investigate the characteristics of nearby dwarf galaxies, such as the Small and Large Magellanic Clouds.
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Astronomy enthusiasts, amateur stargazers, and educators seeking to understand the structure of the Milky Way and the challenges of observing its core.

kmm
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More specifically, when I look at the milky way am I seeing another arm of the galaxy or am I looking towards the center of the galaxy? I'm having a hard time finding a specific answer to this question. Thanks!
 
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Well, the farthest away star visible to the naked eye is about 4,000 light years away but the milky way is 100,000 light years across and we are something like 1/3rd of the way from the edge towards the center, so you're not seeing much of it.

A few of the things you see are galaxies that are as much as 2 to 3 million light years away, but they are so small that they look like stars, I'm pretty sure.
 
Thanks! Ok so I won't actually see the center of the galaxy, but are you saying that I actually am I looking towards the center of the galaxy?
 
phy_infinite said:
Thanks! Ok so I won't actually see the center of the galaxy, but are you saying that I actually am I looking towards the center of the galaxy?

I THINK, but don't know for sure, that yes we are looking towards the center when we look at the center of the white band that is the Milky Way as we see it. You definitely can't see anywhere near as far as the center without a telescope.

Some of our astronomers can likely provide a more solid answer, so I hope one of them will jump in here.
 
phy_infinite said:
...when I look at the milky way am I seeing another arm of the galaxy or am I looking towards the center of the galaxy? I'm having a hard time finding a specific answer to this question. Thanks!

It depends on which part of the Milky Way you are observing. In the direction of Sagittarius lies the galactic center. If you were viewing the constellations of Taurus/Auriga, you would be looking in the opposite direction towards the edge of the galaxy.

Try using this map to orient yourself:
http://maps.nationalgeographic.com/maps/print-collection/milky-way.html
 
Jimmy said:
It depends on which part of the Milky Way you are observing. In the direction of Sagittarius lies the galactic center. If you were viewing the constellations of Taurus/Auriga, you would be looking in the opposite direction towards the edge of the galaxy.

Try using this map to orient yourself:
http://maps.nationalgeographic.com/maps/print-collection/milky-way.html

I'm referring to what phinds said. As he said, "..when we look at the center of the white band that is the Milky Way as we see it." In that case am I looking towards the center?
 
Jimmy said:
It depends on which part of the Milky Way you are observing. In the direction of Sagittarius lies the galactic center. If you were viewing the constellations of Taurus/Auriga, you would be looking in the opposite direction towards the edge of the galaxy.

...

Yes correct

phy_infinite

the thing that stops us seeing the core of our galaxy isn't the distance, its all the dust and gas
that is between us and it.
We observe the core by the infrared light, gamma rays and X-rays that are emitted from it
we cannot see the visible light because of the intervening dust etc

Dave
 
davenn said:
phy_infinite

the thing that stops us seeing the core of our galaxy isn't the distance, its all the dust and gas
that is between us and it.
We observe the core by the infrared light, gamma rays and X-rays that are emitted from it
we cannot see the visible light because of the intervening dust etc

Dave

I understand why I can't see the core of our galaxy. I only want to know that when I look at the center of the white band in the sky, whether or not I am looking in the direction of the core of the galaxy.
 
The center of the galaxy is in the direction of the constellation Sagittarius.
 
  • #10
phy_infinite said:
I only want to know that when I look at the center of the white band in the sky, whether or not I am looking in the direction of the core of the galaxy.

The band of the Milky Way surrounds us so there really isn't a center in that sense. In the summer—for the northern hemisphere—the galactic center can be seen* in the direction of Sagittarius. It will be the brightest part of the MW. In the winter, the sun obscures our view of the center but you can still see the faint glow of the spiral arms away from the center if you are at a dark site.

Winter MW left, Summer MW right:
http://twanight.org/newTWAN/photos/3001899.jpg

* The galactic center can't really be seen visually due to the intervening gas and dust, as davenn pointed out in post #7. I simply mean that that is the direction in which the center lies.
 
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  • #11
Cool! Thanks for the clarification Jimmy!
 
  • #12
phinds said:
A few of the things you see are galaxies that are as much as 2 to 3 million light years away, but they are so small that they look like stars, I'm pretty sure.

Any galaxy that is small enough to be star sized is much too dim to be seen by the naked eye. The Small and Large Magellenic Clouds (close dwarf galaxies visible from the souther hemisphere) and the Andromeda galaxy is visible as patches of dim light from a dark site and the Triangelum Galaxy is visible from a very dark site if you have good enough eyes. If you count Omega Centauri as a dwarf galaxy that one is very easy from a darkish site (also an southern object and almost star sized). On top of that there is a couple of galaxies that might just about be possible if you have extremely good eyes and skies.

More info on wikipedia
 
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  • #13
glappkaeft said:
Any galaxy that is small enough to be star sized is much too dim to be seen by the naked eye.

OK, my "pretty sure" was wrong. Thanks for that correction.
 

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