What is our nearest galaxy?

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What is our nearest galaxy?

Postby vivian maxine on January 2nd, 2016, 11:53 am 

Given two seconds to answer that, I and my friend to whom I posed the question both said Andromeda. Last night I found that isn't fact. The Magellan Clouds are closer. That sent me searching. Why do so many of us instantly say Andromeda? It gets mentioned more often. But what it says is not that Andromeda is the closest. It says Andromeda is the closest spiral galaxy.

That's fine. Can someone tell us why the word "spiral" causes all this extra mention which unintentionally misleads some of us? Is there something special that makes it more worthy of mention? The only time I hear Magellan Cloud mentioned is when my friend in Sydney describes them.

Thank you for thoughts.
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Re: What is our nearest galaxy?

Postby Braininvat on January 2nd, 2016, 12:58 pm 

The Sagittarius Dwarf Elliptical is also closer than Andromeda. All three are dwarf galaxies, which may account for their lower "status" as galaxies. The SDE is actually in a polar orbit around the Milky Way and its orbit penetrates the spiral disk of our galaxy. The Magellanics don't do this, and though they are experiencing a lot of tidal effects (ripping and tearing sort of thing) from the MW, they will eventually part ways with us. They are considered "young" galaxies, in the sense that they are gas-rich (lots of hydrogen and helium) and metal-poor. The reason they are metal-poor is that they have had very few supernovae. Supernovae are good at generating lots of metallic elements and blasting them out into the local area. So, as galaxies age, there are more stars (of a certain massiveness) reaching the end of their cycle, reaching a stage where their cores are starting to fuse lighter atoms into much heavier ones, and then going nova, adding metal.
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Re: What is our nearest galaxy?

Postby vivian maxine on January 2nd, 2016, 1:08 pm 

Braininvat » January 2nd, 2016, 11:58 am wrote:The Sagittarius Dwarf Elliptical is also closer than Andromeda. All three are dwarf galaxies, which may account for their lower "status" as galaxies. The SDE is actually in a polar orbit around the Milky Way and its orbit penetrates the spiral disk of our galaxy. The Magellanics don't do this, and though they are experiencing a lot of tidal effects (ripping and tearing sort of thing) from the MW, they will eventually part ways with us. They are considered "young" galaxies, in the sense that they are gas-rich (lots of hydrogen and helium) and metal-poor. The reason they are metal-poor is that they have had very few supernovae. Supernovae are good at generating lots of metallic elements and blasting them out into the local area. So, as galaxies age, there are more stars (of a certain massiveness) reaching the end of their cycle, reaching a stage where their cores are starting to fuse lighter atoms into much heavier ones, and then going nova, adding metal.



Great, Biv. Thank you very much. I wonder if the SDE penetrating our disk is why the writer of one web site called it a "companion" galaxy. Does that make sense? I think the exact words were "may be a companion galaxy". You say it is moving away. The young do leave home eventually. :-)
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Re: What is our nearest galaxy?

Postby Watson on January 2nd, 2016, 1:52 pm 

I think part of it could be that we are a spiral and Andromeda is the nearest like galaxy. Or just the closest magor galaxy.
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Re: What is our nearest galaxy?

Postby vivian maxine on January 2nd, 2016, 2:06 pm 

Watson » January 2nd, 2016, 12:52 pm wrote:I think part of it could be that we are a spiral and Andromeda is the nearest like galaxy. Or just the closest magor galaxy.


And our two galaxies are coming together while the others are leaving. Can't you just see those arms on each galaxy merging smoothly and we end up twice as large.?
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Re: What is our nearest galaxy?

Postby Watson on January 2nd, 2016, 2:17 pm 

Like a big galactic hug? Like a bug hugs a windshield.
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Re: What is our nearest galaxy?

Postby vivian maxine on January 2nd, 2016, 2:20 pm 

Watson » January 2nd, 2016, 1:17 pm wrote:Like a big galactic hug? Like a bug hugs a windshield.


Right. Arms joining together as smoothly as cogs in a wheel. Oval galaxies can't to that.
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Re: What is our nearest galaxy?

Postby Dave_Oblad on January 2nd, 2016, 8:14 pm 

Hi All,

Here is what Science believes it would look like in Ultra Fast Motion. This simulation runs at about 1 millions years per second. My biggest objection to the realism is trying to locate the orchestra and choir.



https://www.youtube.com/watch?v=PrIk6dKcdoU

Since there is so much Space between Stars, they would be rather few Star Systems getting mangled. It's a Gravity thing..lol.

Best wishes,
Dave :^)
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Re: What is our nearest galaxy?

Postby vivian maxine on January 3rd, 2016, 8:12 am 

Thanks. I'm sitting here telling myself that they just traded places. Then, suddenly, they were re-joining. Interesting.
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Re: What is our nearest galaxy?

Postby SciameriKen on January 3rd, 2016, 10:05 am 

I think people are just forward looking - aren't we going to crash and merge with Andromeda pretty soon? So that would make it pretty close
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