Topic: Astronomy of New Battlestar Galactica

[Desert Fox]

I had some thoughts on the new Battlestar Galactica.
I did not watch the end but my understanding is that it occurred in the Large Magellanic Cloud about 150 k years ago
If so, that would have been real close to the time of SN 1987a (considered to be about 168 k years ago.)
Wondering if that should have any effects

Second, I read that the Large Magellanic Cloud is suppose to have 1/100 the mass of the Milky Way.
I have read that we are expected to have about one supernova every 100 years so the Large Magellanic Cloud should have a supernova every 10,000 years.

Problem is that the composition is different. It is suppose to be low metallicity, meaning low amounts of anything other than hydrogen or helium. My understand that means stars tend to be more massive and burn out faster. Would the low metallicity mean more super novas?

Also related to the low metallicity, wouldn't the Large Magellanic Cloud have few planets? I was also thinking that, if the Large Magellanic Cloud is the core of what was once a galaxy, wouldn't the stars be closer packed together around a black hole?

[Doggy]

You got all that from BsG.. nice turn of thought. BSG takes place in this galaxy, if you had watched till the end the crew come to earth, mate with prehistoric population and spawn us who in turn once more create the 'cylons' and the cycle is repeated. Bit of a weak ending but was fun.
 On the subject of supernovas my thinking is the same as yours, more supermassive shortlived suns more super-duper novas. Wouldnt it be the same in the early universe, I imagine the skys would be like popping popcorn, if you had a planet from which to watch from. So is the LMC a 'proto galaxy', in a couple of billion years the composition would be quite different and more like our own galaxy as all those novas produce heavier particles? If the LMC is the remnant of a galaxy where did the heavy particles go?
 
   

[Obsequious]

Doggy, you are mistaken. There is nothing at all in the series finale to indicate that there was ever a prehistoric human population prior to the landing of the BSG people on Earth, and certainly nothing about the BSG folks mating with prehistoric humans. Furthermore, there is no indication that the humans spawned by them, that is to say, us modern humans, ever wind up building cylons.

What is implied, however, is that Mitochondrial Eve was a human/cylon hybrid, and all modern humans are therefore partly cylon.

[Doggy]

Sorry Obsequious, but as I remember it the crew land on the early earth and in one scene are watching the indiginous population from a ridge when a fact is thrown out that both crew and those they are watching are 'compatable'. I took this to mean the two would geneticaly mix or why bother mentioning it. And in the final scene as angel baltar and angel 6 walk around a modern city we are treated to T.vs showing lots of robots such as asimov and the like and the tag line what has come before will be again which I took to hint that we will go one to create an artificial life much like if not exactly like the cylons.
 Baltar and 6 are also seen reading over the shoulder of a guy (who I’ve read was series creator Ron Moore) at a National Geographic article about the bones of a woman known as mitochondrial Eve, the most recent common ancestor to all human life. She lived in Tanzenia. We of course know the bones are Hera’s, there we agree.
 Its been a few months since I last watched the show but I will dig out the DVD and watch again to system check my old feeble memory..
 

[Horseman]

So where are we getting the Large Magellanic Cloud bit?

[Obsequious]

Sorry Obsequious, but as I remember it the crew land on the early earth and in one scene are watching the indiginous population from a ridge when a fact is thrown out that both crew and those they are watching are 'compatable'. I took this to mean the two would geneticaly mix or why bother mentioning it. And in the final scene as angel baltar and angel 6 walk around a modern city we are treated to T.vs showing lots of robots such as asimov and the like and the tag line what has come before will be again which I took to hint that we will go one to create an artificial life much like if not exactly like the cylons.
 Baltar and 6 are also seen reading over the shoulder of a guy (who I’ve read was series creator Ron Moore) at a National Geographic article about the bones of a woman known as mitochondrial Eve, the most recent common ancestor to all human life. She lived in Tanzenia. We of course know the bones are Hera’s, there we agree.
 Its been a few months since I last watched the show but I will dig out the DVD and watch again to system check my old feeble memory..

Perhaps the DVD contained deleted scenes which weren't originally broadcast? That must be the case, as I'm sure I saw no scene in which BSG folk observed indigenous humans and no scene implying that modern humans were going to start building cylons or something like cylons.

[vociferous]

I had some thoughts on the new Battlestar Galactica.
I did not watch the end but my understanding is that it occurred in the Large Magellanic Cloud about 150 k years ago
If so, that would have been real close to the time of SN 1987a (considered to be about 168 k years ago.)
Wondering if that should have any effects

Second, I read that the Large Magellanic Cloud is suppose to have 1/100 the mass of the Milky Way.
I have read that we are expected to have about one supernova every 100 years so the Large Magellanic Cloud should have a supernova every 10,000 years.

Problem is that the composition is different. It is suppose to be low metallicity, meaning low amounts of anything other than hydrogen or helium. My understand that means stars tend to be more massive and burn out faster. Would the low metallicity mean more super novas?

Also related to the low metallicity, wouldn't the Large Magellanic Cloud have few planets? I was also thinking that, if the Large Magellanic Cloud is the core of what was once a galaxy, wouldn't the stars be closer packed together around a black hole?

High metallicity stars are ones created by molecular clouds which have been "seeded" by earlier generations of stars, mostly by supernovae.  If a star has low metallicity, it means that it was created from molecular clouds that have not been "seeded" nearly to the same degree. 

I am not aware of any connection between metallicity and the rate of supernovae, although there are obviously specific cases whether the two are related, like in very old clusters whose large stars have all burned out and in which there is not sufficient molecular clouds to create many new ones (think globular clusters).

Interestingly enough, recent evidence indicates that the Magellanic clouds are not satellite galaxies and are not gravitationally bound to the Milky Way.  They just happen to be nearby right now. 

[Desert Fox]

Are they moving fast enough away that they will NOT become trapped?
As far as nBSG being in the Large Magellanic Cloud, it is what a friend told me 

[vociferous]

Are they moving fast enough away that they will NOT become trapped?
As far as nBSG being in the Large Magellanic Cloud, it is what a friend told me

That is what not gravitationally bound means.


A gravitationally bound object would be in orbit of the Milky Way.  The International Space Station is gravitationally bound to Earth.  Voyager I and II are not. 

[Desert Fox]

From what I understand, the Milky Way and Andromeda are slowly getting ready to merge. . . .
I think they are considered gravity bound.

[vociferous]

From what I understand, the Milky Way and Andromeda are slowly getting ready to merge. . . .
I think they are considered gravity bound.

Gravitationally bound objects are those which are in some sort of orbit.  It is difficult to say whether Andromeda and the Milky Way are gravitationally bound, as they cannot be considered particles if they collide. 

With some caveats and conditions, I would say they probably would be considered gravitationally bound, assuming predictions about their collisions have been accurately forecast.

The Magellanic Clouds, on the other hand, are likely to depart our galaxy never to return. 

[Desert Fox]

Have to wonder if they might not have formed somewhere other than the local group then.

[vociferous]

Have to wonder if they might not have formed somewhere other than the local group then.

I'm not sure why you would think that.  It does not have a highly erratic orbit, to the best of my knowledge.

However, I do not know much about intergalactic orbital mechanics, so I am not really qualified to comment on it without further research. 

[Doggy]

Listening to naked astonomy pod I was informed that super-novas can be the cause of star formation as the gas's are compressed, an event called sequential star formation I think, although there is a threshold where if enough go pop 'close' together the energy released is enough to expel the gas's out into intergalatic space..

[vociferous]

Listening to naked astonomy pod I was informed that super-novas can be the cause of star formation as the gas's are compressed, an event called sequential star formation I think, although there is a threshold where if enough go pop 'close' together the energy released is enough to expel the gas's out into intergalatic space..

Supernovae blow the envelope apart, which makes me think any immediate star formation is very unlikely, but I suppose there might be some effect where supernovae compress or change the composition of a nearby molecular cloud in such a way as to seed it so as several fragments collapse.

I would be interested in what the empirical basis is for such a theory.