Death Practices

[Whipsnade]

Originally posted by Genjuro:
Antares supernova seems like a good idea for an alternative TU timeline. Huge exodus from the area, people who stayed in-area (in deep bunkers, orbital stations hiding behind stars, etc?)...

Genjuro,

As Mal pointed out, the entire region is pretty much screwed. I don't remember the precise details after +3 years but I do remember that no deep bunkers or hiding behind astronomical bodies is going to work. Antares is gone and the region around it out to hundreds of light-years is as good as dead. They're on death row just waiting for the wave front to hit.

As for evacuations, hundreds of billions approaching trillions remember? It won't happen in any appreciable sense.

Then after the supernova the necroship can move in to circle the post-supernova star, thus preserving the ancient rites, the church, and the entire faith.

Nice bits regarding all the different SD sects, cults, and schisms but I needed to address the bit I quoted above.

Antares is going to throw off huge parts of itself and, before it does that, it's going to expand at a mind-boggling rate. Just how that expansion and all those fragments will effect the star's 100D limit is unknown, but they will screw with anyone's attempts to jump away or jump back in.

Whether you hold to the strict 'dimension' explanation of the 100D limit, the tidal explanation, or something else Antares' supernova will play havoc with them all.

It's going to take careful observations form several points light-months out to even begin to try and survey what's left of Antares to try and produce a jump plot.

I did scribble a few ideas concerning SD fanatics buying ships in order to 'return' to Antares, deliberately jumping to their deaths out of religious fervor. The truly fanatical will even hijack ships for the purpose. And this will be taking place while every starship in the region will be busy with the doomed-to-fail evacuations.

Such a setting would be a slow motion train wreck. A region centered on Antares out to ~75 parsecs or more is under a death sentence. Staying within the Imperium's borders that's roughly a distance spinward through Corridor in to Deneb and rimward into the Old Expanses. The Imperium is basically dead, the only question is when the carrion eaters will start in on the corpse.

Of course, all that depends on Real World astrophysics and Real World astrophysics only apply to your personal Traveller universe as much as you wish them to do so.


Have fun,
Bill

 

[Malenfant]

Originally posted by Bill Cameron:
As Mal pointed out, the entire region is pretty much screwed. I don't remember the precise details after +3 years but I do remember that no deep bunkers or hiding behind astronomical bodies is going to work. Antares is gone and the region around it out to hundreds of light-years is as good as dead. They're on death row just waiting for the wave front to hit.

IIRC if you were actually on the planet orbiting Antares (which we had as a satellite of a brown dwarf orbiting two thousand AU from the star itself) then you'd have to put up with horrendous levels of radiation combined with a sustained luminosity of about 10 billion Sols for several weeks. Bunkers ain't gonna work in that onslaught. I guess you could hide behind a planet, but there's no many neutrinos being blasted out by the supernova that even though they don't normally damage you, you're probably going to be fried by those. (IIRC, they have a very low probability of interacting with normal matter. But when you're talking about THAT MANY of them, you're going to get the crap ionised out of you). Plus, just to hammer it home, we figured that every square metre of the planet exposed to the blast (and remember it's rotating) is going to get the equivalent of 0.27 Megatons of TNT per second slamming into it... for about 20 hours. Not a nice place to be

.

As for evacuations, hundreds of billions approaching trillions remember? It won't happen in any appreciable sense.

Well the systems around Antares are going to have to suddenly pack up and leave in a relative hurry (they'll only have a few years warning). The ones further away have longer to prepare though.

Antares is going to throw off huge parts of itself and, before it does that, it's going to expand at a mind-boggling rate. Just how that expansion and all those fragments will effect the star's 100D limit is unknown, but they will screw with anyone's attempts to jump away or jump back in.

Well, for comparison the Crab Nebula (M1) is 6,300ly from Earth, exploded about 1000 years ago, and is currently 10ly in diameter and still expanding at 1,800 km/s. ( http://www.seds.org/messier/m/m001.html )

If you're talking about during the event itself, the 100D limit just goes nuts. The problem is that most of the star's mass is now in an ever thinning, expanding shell of material that's getting closer to the planet. We decided that the 100D limit is measured from the surface of that shell until it drops below a critical density, at which point it snaps back to 100D from the neutron star that's now where the star was. Though I think that happens after the planet is roasted anyway, so it's moot for the people trying to leave at the time.

I'll check with Paul and see if I can actually release all the stuff I did on the project. The destruction is quite mind-boggling

.

 

[Whipsnade]

Originally posted by Malenfant:
Well the systems around Antares are going to have to suddenly pack up and leave in a relative hurry (they'll only have a few years warning). The ones further away have longer to prepare though.

Mal,

The closest inhabited system was Guugapirka, one parsec off, Red Zone, UWP pop code of 5. IIRC, we figured the population were 'indians', i.e. a minor race native to the planet, because of the poor conditions there; X550544-4.

That's 100,000 to 999,999 sophonts to move. It's ~3.26ly off, giving us 1190.715 days at 365.25 days per year to move them. We'd need to shift between ~84 to ~840 per day. Easy enough I suppose.

Two parsecs off, or 6.52 years, are two worlds with even smaller populations; 100 to 999 and 10,000 to 99,999 respectively. Easy enough to shft them, maybe 3 or 4 trips with those transport squadrons that move Imperial Army corps.

Three parsecs off, or 9.78 years, we run into trouble. Five worlds total, one with a pop code of 7 and another with a pop code of 6. On the biggest world alone we'd have to shift between ~2800 and ~28,000 people each day during those 9.78 years in order to evacuate that world in time. Concentrate all our shipping there and we might get it down. Of course every ship working there won't be working anywhere else.

Five parsecs out is a world with a population numbering in the billions. There we'd have to shift ~168,000 to ~1,680,000 per day in the ~16.3 years we have. That definitely isn't going to happen.

It's a train wreck all right.


Bill

 

[veltyen]

At 5 parsecs (approximately 1 million au) my first thought was that maybe you could bunker down.

Going with the figures Malenfant gave for Antares secondary
2000 au = 0.27 megaton /sec/m^2 for 20 hours

At a million au that would be 250,000 times weaker
(5000 squared). That is still a ton/sec/m^2 of TNT for 20 hours. I guess that's the subsector gone. At those energy levels you might be able to survive in a system ship by hiding in the shadow of a large gas giant or a star, but nothing directly exposed is going to survive without hundreds of kilometres of reinforced structure to hide behind.

The other option is jumping over the front of the wave, just leaving you with the residual luminosity to deal with.

10 billion sols at 2000 au is 40,000 sols at 5 parsecs. Still far too much to survive.

So how far do you need to run?
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Planet - distance - wavefront(mass tnt) - residual luminosity (sols)
Antares beta 0.01 pc 0.27 mT 10^10
Subsector 5 pc 1 T 40,000
Sector 20 pc 60 kg 2500
Nearby Sectors 60 pc 7 kg 300
Domain Sectors 100 pc 2 kg 100
Empire wide 400 pc 100 g 6
Distant Empires 1000 pc 27 g 1
Safety? 3000 pc 3 g 0.1
Galaxy wide 15000 pc 0.1 g 0.004</pre>[/QUOTE]"Nearby Sectors" is the edge of a circle approximately 9 sectors in size centred on Antares
"Domain Sectors" is an area 25 sectors in size
"Empire Wide" is an area 400 sectors in size
"Distant Empires" is an area 2500 sectors in size
"Galaxy wide" is an area roughly the size of the milky way centred on Antares

So the question is, where are you running too?

Jumping past the wavefront at 1000 pc may be doable, and depending on planetary orientation bunkers may be doable before that.

 

[Anthony]

Originally posted by Bill Cameron:
Five parsecs out is a world with a population numbering in the billions. There we'd have to shift ~168,000 to ~1,680,000 per day in the ~16.3 years we have. That definitely isn't going to happen.

At that distance and time, you can probably build a planetary shield; it's a big project but not impossible. Incidentally, not sure where Mal's estimate of the destructive radius comes from; quick checking around the WWW suggests a kill radius of less than 10pc for a type II supernova (see http://en.wikipedia.org/wiki/Supernova and some of its references).

If you don't object to a rather high misjump chance, a ship in the planetary umbra can survive long enough to jump out.

 

[Whipsnade]

Veltyen,

I guess you now know why the project was dropped.

Even using Traveller's goofy rectangular sectors; 32pc x 40 pc, all of Charted Space is within the 'Distant Empire' zone of 1000pc.

I suppose portions of the Zhodani Core Route may survive but everything from the spinward edge of the Heirate to the trailing edge of the 2,000 Worlds and from the coreward edge of the Extents to the rimward edge of the Confederation and beyond is toast. All of it, with the possible exception of the last Zhodani Core Expedition.


Bill

 

[Madarin Dude]

The one thing I can see is that before cremation a piece of hair or skin or what not is removed so that DNA can be read.

 

[cheepicus]

I didn't realize the devastation would show up so severely on the level of parsecs (my astrophysics instincts are not great). Is the 6ish year warning really the limit or might it be improved greatly by astrophysicists of the far future?

 

[mike wightman]

Two ways I can think of to survive this:

planetary black globe generatot plus lots of capacitors

build a pocket universe and hide in it quick.

Any chance the Imperium could advance 10 tech levels in a few decades?

A more resonable suggestion would be to hide under water in bunkers cut into the oceas floor, lined with bonded superdense armour.

An Imperial warship with armour factor 15 is impervious to nuclear warheads - get as much of your population onto them as possible.

Still, the chances of more than a few surviviors in the medium term are quite remote.

What if another effect of the supernova is to make jump space more difficult to access - or even inaccessible. Or the revers - it makes it easier.

 

[mike wightman]

By the way, I did a web search like Anthony:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980521a.html

which leads to this:

http://stupendous.rit.edu/richmond/answers/snrisks.txt

Neither mentions the destruction of the Earth's ozone layer and then mass extinctions caused by our own sun's UV.

 

[Whipsnade]

Originally posted by Madarin Dude:
The one thing I can see is that before cremation a piece of hair or skin or what not is removed so that DNA can be read.

Madarin Dude,

Yes, but how to you 'fingerprint' the ashes themself?

Cremated human remains aren't of great size, only about the siz of a 2 kilo can of coffee. Imagine opening a 5dTon shipping container(1) and finding three thousand or so 'cans' with no labels, no documentation, no nothing.

Would TL15 tech be able to sort them out? Our TL7-8 tech cannot. There have been cases in the US recently of poorly managed crematoriums loosing track of, among other things, the remains they handle leaving the authorities with the impossible task of identification.

You can quickly google up the story of a rural Georgian funeral parlor from a few years back. Not only did they loose track of cremated remains, they had storage 'issues' regarding other kinds of remains too. The news accounts read like something Poe or Lovecraft could have written.


Have fun,
Bill

1 - Only 3,000 in 5dTons because of the packaging requirements.

 

[Malenfant]

Well we know for sure that a supernova about 1900 pc from Earth (ie the Crab Nebula explosion) can't harm us. Frankly, I disbelieve any estimate that says that we'd be fine if a supernova blew up 10pc from Earth - there's all the secondary effects of the supernova (e.g. destruction of ozone layer, ionisation of atmosphere etc) that can still kill us quite nicely.

I'd say that 100-500pc would be a good "minimum safe distance" to use if factoring all the other effects in. If you're living in a shielded cavern under a vacuum world, obviously your survivability is going to be increased - I'm mostly talking about habitable earthlike worlds being most at risk here.

 

[Anthony]

Originally posted by Malenfant:
Frankly, I disbelieve any estimate that says that we'd be fine if a supernova blew up 10pc from Earth - there's all the secondary effects of the supernova (e.g. destruction of ozone layer, ionisation of atmosphere etc) that can still kill us quite nicely.

See http://xxx.lanl.gov/abs/astro-ph/0211361 :

We find that for the combined ozone depletion roughly to double the ``biologically active'' UV flux received at the surface of the Earth, the supernova must occur at <8 pc

This is a study, done in 2002, of supernova effects, focusing specifically on atmospheric effects.

 

[Malenfant]

Interesting link, but there are some significant uncertainties in that paper though (not least of which is that atmospheric composition and density can change the outcome quite a bit, along with the radiation output of the supernova itself).

Still, given that I'd say that the "minimum safe distance" - speaking generally here, considering we have worlds with thinner and thicker atmospheres than Earth, and different compositions - is going to be 50-100pc. Call me unnecessarily conservative about it if you will, but I sure would want specific calculations made for specific planets near specific supernovae before I'd feel safe on any of them .

Either way, even if you call it at 50pc then that's still a lot of worlds that are in trouble.

 

[Anthony]

I don't call it 50pc. If 8 pc is an uncertain threat to earth, then 1/40 the dose is no threat. It might be as much as 20 pc for thin atmospheres. It's probably about 2 pc for thick atmospheres; a planet with a thick atmosphere doesn't really need an ozone layer at all.

 

[Malenfant]

Like I said, I'm being conservative. If 8pc is an "uncertain" threat to Earth (and that is given specific assumed values for a supernova) then I'd feel much safer over-compensating by a large degree. I'm simply not convinced by the calculations in that paper, there are too many uncertainties, unknowns, and variables for my liking.

Personally, the only thing that would convince me that you're right is if a star within 50pc were to go supernova (and there are no candidate stars for that anyway) and we survived it unscathed.

 

[aramis]

It also didn't mention protection effects of the solar wind.

A hypernova sounds like a good way to wipe out the 3I; a suitable replacement for Virus...

 

[Anthony]

Originally posted by Malenfant:
Like I said, I'm being conservative. If 8pc is an "uncertain" threat to Earth (and that is given specific assumed values for a supernova) then I'd feel much safer over-compensating by a large degree.

Even the pessimistic estimates were only in the 20 parsec range. I see nothing wrong with a margin of safety, but a factor of 40 is absurd.

Based on supernova frequency, the kill radius can't exceed ~20 pc, since that would result in a mass extinction every 100 MYr on average, which would be visible in the fossil record. At 50 pc, we'd be getting one every 6 MYr, which is clearly not true.

 

[aramis]

Let's consider for a moment that we've got two different "kill radii" being bandied:

The 100Pc deep space kills, and the 10-20 Pc surface kills.

Henceforth, all numbers in this post are SWAGs, based upon the references above and some wild postulations of my own...

A nova could and probably would wipe out any deep space facilities (Calibration points, Oort cloud bases) out to at least 100 Pc, and maybe even past that.

In system, we have solar magnetosphere, solar wind pressure, and higher density medium to provide (very limited) protection; Probably still going to be lethal out to 50 Pc from the nova in the out-system, probably still lethal in the inner system out to 40 Pc...

A weak magnetosphere and trace atmosphere is likely to be just a bit more protection, say 5 Pc less...

A Standard atmosphere and decent magnetosphere shove that down to 20 or fewer Pc (the mass die-off frequencies would tend to imply around 10-15 Pc; about 1 die-off per 200MY, not all as thorough as each other... Perhaps you just explained the end of the dinosaurs....)


Dense atmospheres and stronger magnetospheres would likely make even lower distances survivable, probably just a couple more Pc...

 

[Anthony]

Originally posted by Aramis:
Let's consider for a moment that we've got two different "kill radii" being bandied:

The 100Pc deep space kills, and the 10-20 Pc surface kills.

Traveller starships are functionally impervious to a type II supernova at less than a parsec.