APOD: NGC 2683: Edge On Spiral Galaxy (2014 Feb 05)

[Cousin Ricky]

I don't understand what flying saucers have to do with Vietnamese skylore, nor what connection you have to Vietnam.

My Vietnamese sign is the cat, and NGC 2683 is in Lynx. I have no connection to Vietnam, but I do like the Al Stewart song, “Year of the Cat.”

[Ann]

. . . This galaxy is somewhat bland and poor in star formation. Or, to put it somewhat differently, this flying saucer lacks its red nebulae brake lights.

Ann --
Just wondering. Do edge-on galaxies show us less nebulae in general, or can we see them fine in most edge-on galaxies? I'm wondering if this galaxy is perhaps more rich in them than we can see, just that the dust lanes block our view.

Edge-on galaxies are not all the same, of course, just like face-on galaxies are not all the same. Some have a lot of bright and obvious red emission nebulae, while others have none that we can see.

Like Rob Gendler pointed out, NGC 2683 probably doesn't have a lot of emission nebulae at all. At least not in the part of it that we can see. But the very regular shape of NGC 2683 suggests, to me at least, that the galaxy likely doesn't contain a lot of star formation overall.

Ann

[Beyond]

The Hyades and the Pleiades didn't give it away? (OK, maybe the bits of Auriga and Orion in the field might be confusing.)

You've got all that stuff in that small space? No wonder i couldn't tell anything. But even if i did recognize some of it, i still wouldn't have known what you were talking about, even though i spent almost a year and a half in Vietnam. And what's those two gray rectangles??

[geckzilla]

And what's those two gray rectangles??

=

How to use the =

2+2=4

This was a bit of a social movement on Facebook a while back and changing your profile picture to an equal sign was originally support for marriage equality but it may have branched out beyond just that.

[Nitpicker]

I thought they were monoliths from 2001: A Space Odyssey. Either that or a statement saying that starsigns are bull.

[neufer]

And what's those two gray rectangles??

=

How to use the =

2+2=4

[b][color=#0000FF]Robert Recorde[/color][/b]

---

<<Robert Recorde (ca. 1512–1558) was a Welsh physician & mathematician.

Recorde: 1) invented the "equals" sign (=),

• 2) introduced the pre-existing "plus" sign (+) to English speakers and
  3) popularized the name zenzizenzizenzic to represent the eighth power of a number

In his 1557 work _The Whetstone of Witte_ Recorde recorded that
zenzizenzizenzic "doeth represent the square of squares squaredly" .

(The root word for Recorde's notation is zenzic, which is a German spelling of the medieval Italian word censo, meaning "squared".)>>

[Cousin Ricky]

You've got all that stuff in that small space? No wonder i couldn't tell anything. But even if i did recognize some of it, i still wouldn't have known what you were talking about, even though i spent almost a year and a half in Vietnam. And what's those two gray rectangles??

It's no good if you have to explain it.

My tropical sign = Taurus = bull = what I think of astrology. In the avatar, north is 30&deg; clockwise from vertical.
My year of birth = 1963 CE = Chinese year of the rabbit = Lepus.
My year of birth = 1963 CE = Vietnamese year of the cat = Lynx.

And yes, the equal sign is slacktivist support for marriage equality, but rather than completely replace my avatar, I just worked the equal sign into the design.

[Beyond]

Thanks for the explanation. I try to ignore all that kinda stuff whenever possible.

[Tumbleweed]

So you don't believe that the vast majority of the universe (Dark Matter) through which the galaxies move, or in which the galaxies move, is a reality?

Dark matter and ordinary matter are gravitationally bound. There's nothing to suggest that galaxies are moving through larger fields of dark matter. The exception is in galaxy clusters, where the entire cluster supports a dark matter halo. But I've seen nothing to suggest any morphological impact on the galaxies within those clusters (e.g. warped edges or tumbling).

And while galaxies might (and it's far from certain) show motion on more than a single axis, I wouldn't characterize them as tumbling, and I'd certainly not associate it with the influence of any intergalactic medium.

Dark Matter and ordinary matter may affect each other, but to say they are gravitationally bound is a stretch. Ordinary matter affects other ordinary matter in gravity but they are not bound .. if so rockets could not leave earth's gravity field.

How do you account for the warped edges clearly visible in many galaxies?

Did you look into the urls I posted?

[Chris Peterson]

Dark Matter and ordinary matter may affect each other, but to say they are gravitationally bound is a stretch. Ordinary matter affects other ordinary matter in gravity but they are not bound .. if so rockets could not leave earth's gravity field.

Rockets don't leave Earth's gravity field. Bodies are gravitationally connected even if they aren't in closed orbits... that is, even if their relative velocity exceeds their escape velocity. The material in a galaxy is certainly gravitationally bound, and that includes both the ordinary matter and the dark matter halo. In the case of galaxies, they are certainly bound by any reasonable definition, being in mutually closed orbits.

How do you account for the warped edges clearly visible in many galaxies?

Collisions. Possibly internal tidal interactions. But not interactions with some sort of tenuous intergalactic medium.

Did you look into the urls I posted?

Yes.

[Anthony Barreiro]

...My tropical sign = Taurus = bull = what I think of astrology. In the avatar, north is 30&deg; clockwise from vertical.
My year of birth = 1963 CE = Chinese year of the rabbit = Lepus.
My year of birth = 1963 CE = Vietnamese year of the cat = Lynx. ...

I didn't know that Vietnamese astrology uses different animals than Chinese astrology for some years. According to http://www.asiafinest.com/forum/index.p ... pic=254721, there are three differences:

Chinese........Vietnamese
Rabbit..........Cat
Ox..............Water buffalo
Sheep..........Goat

Given the history of Chinese occupation and subjugation of Vietnam, I guess it makes sense that the Vietnamese would want to customize the zodiac for their own land.

And by the way, not everyone who was born in 1963 is a Rabbit (or a Cat). Lunar new year (Tet) was on January 25, 1963, so Western Capricorns and Aquarians born before that date are Tigers. Imagine being a Tiger in a grade school class full of Rabbits!

[geckzilla]

If it was direct response to "Chinese occupation and subjugation" it would be a lot more different, don't you think? Unless you suppose they were just a little upset by such actions and decided that rabbits were out and cats were in.

[Anthony Barreiro]

If it was direct response to "Chinese occupation and subjugation" it would be a lot more different, don't you think? Unless you suppose they were just a little upset by such actions and decided that rabbits were out and cats were in.

We're getting further from astronomy than I usually like to wander on the starship asterisk, but ... . The relationship between Vietnam and China is very complicated and ambivalent. A lot of learning came from China to Vietnam. Many people whose families have lived in Vietnam for many generations are ethnically Chinese.