Starship Asterisk*

This dance is to the death.

BDanielMayfield wrote: ↑Sun Aug 11, 2019 9:12 am

This dance is to the death.

That's one way of looking at it. I can see the point being made; that ultimately there will come to be only one galaxy whereas now there are two, but that is a rather negative take IMO.

This is also a magnificently constructive, creative process. Look at all those bluish bright patches in the tidal streams around both galaxies. These are the areas of the most intense star formation. The light from the bright blue (especially) and bluish-white areas primarily come from the brightest stars, the ones that are said to "live fast and die young", but that is also describing an immensely creative process, for that is where the most heavy elements are being forged, later to be ejected out into the interstellar medium. The ever more enriched dust in these galaxies will continue to produce later generations of stars, and since planet formation is a by-product of star formation, literally billions of of planets might will likely result from this galactic merger.

Galactic "collisions" are way more constructive than destructive. They are hyper-productive, massively beneficial mergers. How's that for positive spin?

Bruce

Ann wrote:I read once that complexity happens on the way to uniformity and heat death.

BDanielMayfield wrote: ↑Sun Aug 11, 2019 1:47 pm

Ann wrote:I read once that complexity happens on the way to uniformity and heat death.

But, as we know, one shouldn't trust everything one reads.

I don't even let forecasts of ultimate heat death 'bring me down'.

Human reasoning on both the deep past and the deep future is handicapped by lack of information.

Bruce

Ann wrote: ↑Sun Aug 11, 2019 2:29 pm

BDanielMayfield wrote: ↑Sun Aug 11, 2019 1:47 pm

Ann wrote:I read once that complexity happens on the way to uniformity and heat death.

But, as we know, one shouldn't trust everything one reads.

I don't even let forecasts of ultimate heat death 'bring me down'.

Human reasoning on both the deep past and the deep future is handicapped by lack of information.

Bruce

To each his (or her) own, Bruce!

Ann

Leon1949Green wrote: ↑Sun Aug 11, 2019 1:23 pm Regarding the more distant galaxy not interacting with Arp 87. Now that we understand that the disc of our Milky Way is a bit distorted, what is being looked at to determine who we've encountered already to cause it to be that way? Thanks!

BDanielMayfield wrote: ↑Sun Aug 11, 2019 3:29 pm

Leon1949Green wrote: ↑Sun Aug 11, 2019 1:23 pm
Regarding the more distant galaxy not interacting with Arp 87. Now that we understand that the disc of our Milky Way is a bit distorted, what is being looked at to determine who we've encountered already to cause it to be that way? Thanks!

Are the Magellanic Clouds massive enough to have caused this warp in the MW?

BDanielMayfield wrote: ↑Sun Aug 11, 2019 3:14 pm

Ann wrote: ↑Sun Aug 11, 2019 2:29 pm

BDanielMayfield wrote: ↑Sun Aug 11, 2019 1:47 pm
But, as we know, one shouldn't trust everything one reads.

I don't even let forecasts of ultimate heat death 'bring me down'.

Human reasoning on both the deep past and the deep future is handicapped by lack of information.

To each his (or her) own, Bruce!

That is the nicest agree to disagree I've ever received. Thanks.

https://en.wikipedia.org/wiki/Jedem_das_Seine wrote:

---

<<"Jedem das Seine" is the literal German translation of Latin suum cuique, a fundamental juridical concept meaning "to each his own" or "to each what he deserves". Jedem das Seine has been an idiomatic German expression for several centuries. For example, it is found in the works of Martin Luther and contemporaries. It appears in the title of a cantata by Johann Sebastian Bach, Nur jedem das Seine (BWV 163), first performed at Weimar in 1715. Some nineteenth-century comedies bear the title Jedem das Seine, including works by Johann Friedrich Rochlitz and Caroline Bernstein. It is similar to "Whatever is, is right" employed by Leibniz, Hegel, and Scrope.

An ironic twist on the proverb, "jedem das Seine, mir das Meiste" ("to each his own, to me the most"), has been known in the reservoir of German idioms for a long time, including its inclusion in Carl Zuckmayer's 1931 play The Captain of Köpenick.

In 1937, the Nazis constructed the Buchenwald concentration camp, 7 km from Weimar, Germany. The motto Jedem das Seine was placed in the camp's main entrance gate. The gates were designed by Franz Ehrlich, a former student of the Bauhaus art school, who had been imprisoned in the camp because he was a communist.>>

ems57fcva wrote: ↑Sun Aug 11, 2019 7:05 pm I am not seeing merging galaxies. NGC 3808B certainly came close to and has interacted with NGC 3808A. But I am not seeing a well-established bridge linking the galaxies. Instead I am seeing a lot of gas in front of NGC 3808A and then gas going around NCG 3808B. A connection may remain between the two, but it is tenuous at best. I read what I am seeing as indicating that NGC 3808B is coming most straight towards us, and is not gravitationally bound to NGC 3808A.

Chris Peterson wrote: ↑Sun Aug 11, 2019 8:09 pm
The likelihood that a pair of galaxies would be coincidentally passing each other close enough to interact, with sufficient relative velocities that they are not in closed orbits around each other, seems vanishingly small. Indeed, I don't think any such galaxies have ever been observed. Galaxies form in clusters, with the members gravitationally bound.

DL MARTIN wrote: ↑Sun Aug 11, 2019 8:30 pm Without context doubt remains that 2+2=4. In other words, until astronomers know what happens between then and now, claims of certainty are dubious.

neufer wrote: ↑Sun Aug 11, 2019 6:13 pm

BDanielMayfield wrote: ↑Sun Aug 11, 2019 3:29 pm

Leon1949Green wrote: ↑Sun Aug 11, 2019 1:23 pm
Regarding the more distant galaxy not interacting with Arp 87. Now that we understand that the disc of our Milky Way is a bit distorted, what is being looked at to determine who we've encountered already to cause it to be that way? Thanks!

Are the Magellanic Clouds massive enough to have caused this warp in the MW?

The problem is their distance (and, to some extent, low angular motion).
Gravitational tidal forces drop off inversely with distance CUBED.

Paper wrote:In summary, the orbital distributions for Antlia 2 have a signicant tail of low pericenters of 10 kpc for a
range of Milky Way masses commonly cited in the literature (from ~10¹²to 2x10¹²M☉).
A close interaction of this kind with a 1:100 mass ratio perturber is sufficient to explain the planar disturbances observed in the outer
HI disk of the Milky Way. Moreover, the phase of the disturbances has a flat radial variation for the HI data,
as do the Antlia 2 simulations with low pericenters, independently confirming that low pericenters are needed
to match the disturbances manifest in the outer gas disk of the Galaxy. We show that the tidal strength of the
Sgr dwarf is insucient to explain the disturbances in the outer gas of the Galaxy. Of the other tidal players of
the Milky Way, the Large and Small Magellanic Clouds are too distant and have not approached closer in the
recent past (Besla et al. 2007; Besla et al. 2012) to account for this level of Fourier power in the outer HI disk.
Thus, Antlia 2 is likely the driver of the observed large perturbations on the outskirts of our Galaxy.

S&T article wrote: But not everybody agrees with this conclusion. Vasily Belokurov (University of Cambridge, UK) cites a series of less than probable assumptions required for the Antlia 2 scenario. “Their simulations are rather simple and are produced for one realization of Antlia 2 only,” Belokurov explains. “There are already constraints on the mass of Antlia 2 and at the moment the mass appears lower than what they need.”

Leon1949Green wrote: ↑Sun Aug 11, 2019 1:23 pm Regarding the more distant galaxy not interacting with Arp 87. Now that we understand that the disc of our Milky Way is a bit distorted, what is being looked at to determine who we've encountered already to cause it to be that way? Thanks!

Ann wrote: ↑Mon Aug 12, 2019 1:31 am
Alter-ego, I didn't see your post before I posted mine.

Thanks for pointing out the Antlia 2 dwarf galaxy as the likely culprit behind our galaxy's unusual shape!

https://www.etymonline.com/search?q=insouciant wrote:
insouciant (adj.) 1828, from French insouciant "careless, thoughtless, heedless,"

from in- "not" (see in- (1)) + souciant "caring," present participle of soucier "to care,"
from Latin sollicitare "to agitate" (see solicit).

pferkul wrote: ↑Mon Aug 12, 2019 2:33 pm The word "violent" all depends on your point of view. On the one hand, altering the course of a hundred billion suns requires titanic forces, but on the other, the interaction of galaxies appears like puffs of smoke gently mingling over the course of a billion years.

Chris Peterson wrote: ↑Mon Aug 12, 2019 2:43 pm

pferkul wrote: ↑Mon Aug 12, 2019 2:33 pm The word "violent" all depends on your point of view. On the one hand, altering the course of a hundred billion suns requires titanic forces, but on the other, the interaction of galaxies appears like puffs of smoke gently mingling over the course of a billion years.

Except that puffs of smoke don't interact with each other to create temperatures high enough to initiate nuclear fusion.

BDanielMayfield wrote: ↑Mon Aug 12, 2019 5:35 pm

Chris Peterson wrote: ↑Mon Aug 12, 2019 2:43 pm

pferkul wrote: ↑Mon Aug 12, 2019 2:33 pm The word "violent" all depends on your point of view. On the one hand, altering the course of a hundred billion suns requires titanic forces, but on the other, the interaction of galaxies appears like puffs of smoke gently mingling over the course of a billion years.

Except that puffs of smoke don't interact with each other to create temperatures high enough to initiate nuclear fusion.

But pferkul has a good point too. When galaxies "collide" their stars, having such vast distances between them in the first place, will almost never collide. The "violence" of an event that takes a billion or more years to occur is overstated for dramatic effect.

Bruce

Chris Peterson wrote: ↑Mon Aug 12, 2019 5:44 pm

BDanielMayfield wrote: ↑Mon Aug 12, 2019 5:35 pm
When galaxies "collide" their stars, having such vast distances between them in the first place, will almost never collide. The "violence" of an event that takes a billion or more years to occur is overstated for dramatic effect.

The "violence" I see describes the collisions of gas and dust, not stars. And the time scale seems to me irrelevant. I don't think it's unreasonable to describe as "violent" any physical process that releases a lot of energy over a relatively short period of time, regardless of the spatial scale, regardless of the temporal scale.