APOD: Unraveling NGC 3169 (2015 Nov 06)

[APOD Robot]

Unraveling NGC 3169

Explanation: Spiral galaxy NGC 3169 appears to be unraveling in this cosmic scene, played out some 70 million light-years away just below bright star Regulus toward the faint constellation Sextans. Its beautiful spiral arms are distorted into sweeping tidal tails as NGC 3169 (top) and neighboring NGC 3166 interact gravitationally, a common fate even for bright galaxies in the local universe. In fact, drawn out stellar arcs and plumes, indications of gravitational interactions, seem rampant in the deep and colorful galaxy group photo. The picture spans 20 arc minutes, or about 400,000 light-years at the group's estimated distance, and includes smaller, dimmer NGC 3165 at bottom right. NGC 3169 is also known to shine across the spectrum from radio to X-rays, harboring an active galactic nucleus that is likely the site of a supermassive black hole.

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[Ann]

That's a lovely image of two galaxies that have danced together too long and violently, embraced too many times, and spent almost all of their youthful fire. Like a couple who lived too hard, they are now on the decline. They are on the fast track from bright blue bluster to the red and dead retirement home.

Ann

[MikeInOz]

Any idea how long it would take for a star at the edge of an unravelling galaxy to find itself in intergalactic space? And what consequences for the star?

[Ann]

Any idea how long it would take for a star at the edge of an unravelling galaxy to find itself in intergalactic space? And what consequences for the star?

Well, a star can't move faster than the speed of light, so if it was originally located, say, twenty thousand light-years from the "edge" of the galaxy (whatever we mean by such an "edge"), it can't take less than twenty thousand years for it end up in intergalactic space. (But I'm sure the math whizzes at this site can give you a better answer.)

What would be the consequences for the star, if it was flung out of its parent galaxy?

That's an easy one. None.

Ann

[Boomer12k]

3169 looks like it has been knocked, "cockeyed"...and the other one is very disrupted...

Hopefully merger will see some rebirth...

:---[===] *

[neufer]

Any idea how long it would take for a star at the edge of an unraveling galaxy to find itself in intergalactic space? And what consequences for the star?

NGC 3166 and 3169 are a gravitationally bound galactic pair
according to http://www.billionsandbillions.com/ngc_3166-69.html
in which case the answer may be never.

However, orbital galactic rotational periods are on the order
of 250,000,000 years so escape times would be comparable.

[Zelaza]

What's going on here?
This picture is a cropped version of APOD from March 28, 2013 and the commentary is exactly the same. But the attribution is different.

[Joe Stieber]

What's going on here?
This picture is a cropped version of APOD from March 28, 2013 and the commentary is exactly the same. But the attribution is different.

Today's picture (06-November-2015) does not look like the same picture as 28-March-2013, rather, it's the same objects by a different photographer, hence the attribution is different. In any case, since the objects are the same the text could be recycled, although it's not exactly the same (e.g., the relative location of NGC 3169 has been appropriately changed from "left" to "top").

[starsurfer]

What's going on here?
This picture is a cropped version of APOD from March 28, 2013 and the commentary is exactly the same. But the attribution is different.

Today's picture (06-November-2015) does not look like the same picture as 28-March-2015, rather, it's the same objects by a different photographer, hence the attribution is different. In any case, since the objects are the same the text could be recycled, although it's not exactly the same (e.g., the relative location of NGC 3169 has been appropriately changed from "left" to "top").

The description also mentions that the galaxy NGC 3165 can be seen but that isn't visible in this image.

[neufer]

The description also mentions that the galaxy NGC 3165 can be seen but that isn't visible in this image.

Today's APOD Explanation appears to be unraveling as in this comic scene.

[BMAONE23]

Any idea how long it would take for a star at the edge of an unravelling galaxy to find itself in intergalactic space? And what consequences for the star?

Well, a star can't move faster than the speed of light, so if it was originally located, say, twenty thousand light-years from the "edge" of the galaxy (whatever we mean by such an "edge"), it can't take less than twenty thousand years for it end up in intergalactic space. (But I'm sure the math whizzes at this site can give you a better answer.)

What would be the consequences for the star, if it was flung out of its parent galaxy?

That's an easy one. None.

Ann

There could be a wonderful consequence for the astronomers living on any habitable planet in that system, in one direction of the night sky there would be 2 magnificent galaxies to examine close up and in the other the grand expanse of the rest of the universe to ponder over with no localized sources in the way

[MikeInOz]

Any idea how long it would take for a star at the edge of an unravelling galaxy to find itself in intergalactic space? And what consequences for the star?

Well, a star can't move faster than the speed of light, so if it was originally located, say, twenty thousand light-years from the "edge" of the galaxy (whatever we mean by such an "edge"), it can't take less than twenty thousand years for it end up in intergalactic space. (But I'm sure the math whizzes at this site can give you a better answer.)

What would be the consequences for the star, if it was flung out of its parent galaxy?

That's an easy one. None.

Ann

There could be a wonderful consequence for the astronomers living on any habitable planet in that system, in one direction of the night sky there would be 2 magnificent galaxies to examine close up and in the other the grand expanse of the rest of the universe to ponder over with no localized sources in the way

And what about the astrologers whose zodiac would be rapidly changing!

[Chris Peterson]

And what about the astrologers whose zodiac would be rapidly changing!

We're looking at shifts that are significant only over tens of millions of years. Nobody would know they were being flung out of a galaxy until they had developed a technology about as advanced as our own.

[heehaw]

The description also mentions that the galaxy NGC 3165 can be seen but that isn't visible in this image.

Today's APOD Explanation appears to be unraveling as in this comic scene.

OH, thanks, I'd not seen that in years! But I don't consider it a comic scene. Have you ever wanted to strangle spellcheckers? Wait until Hal gets you!

[neufer]

And what about the astrologers whose zodiac would be rapidly changing!

Quadruple tidal gravitational forces drop off as the inverse cube of the distance
Hence, the local zodiac, itself, would change very slowly; and basically:

• We will all go together when we go.
  Ev'ry Capricorn and every Virgo.
  Universal bereavement,
  An inspiring achievement,
  Yes, we all will go together when we go.

[neufer]

Wait until Hal gets you!

HAL had me at "Give me your answer do."

[Ann]

And what about the astrologers whose zodiac would be rapidly changing!

Quadruple tidal gravitational forces drop off as the inverse cube of the distance
Hence, the local zodiac, itself, would change very slowly; and basically:

• We will all go together when we go.
  Ev'ry Capricorn and every Virgo.
  Universal bereavement,
  An inspiring achievement,
  Yes, we all will go together when we go.

Click to play embedded YouTube video.

Yes, everyone probably remembers it, but it's good enough to listen to again.

Ann

[DavidLeodis]

I would be grateful if someone could please confirm or not that the "smaller, dimmer NGC 3165 at bottom right" is visible in the image. Before I read this discussion I thought it must be the faint smudge just below and right of NGC 3166, but the APOD of March 28 2013 shows a bright object close to there (possibly just cut off in the APOD of November 6 2015) that may be NGC 3165 (the March 28 2013 image also has the smudge).

[neufer]

I would be grateful if someone could please confirm or not
that the "smaller, dimmer NGC 3165 at bottom right" is visible in the image.

• NOT

---

<<NGC 3165 ist eine Spiralgalaxie (Sdm) im Sternbild Sextant. Sie wurde 1856 von William Parsons entdeckt. Die Galaxie NGC 3165 interagiert mit den Galaxien NGC 3166 und NGC 3169, wie in dem rechten Bild zu sehen ist.

http://cseligman.com/text/atlas/ngc31a.htm#3165

NGC 3165 (klein, rechts unten) neben NCG 3166 (rechts) und NGC 3169 (links) aufgenommen mit dem Wide Field Imager des MPG/ESO 2.2-Meter Teleskop im La-Silla-Observatorium.>>

[DavidLeodis]

Thanks neufer for the confirmation that NGC 3165 is not in the image .