Basil

Re: Average Seperation

Well' date=' yes, if you look at the [b']next paragraph[/b] of the link I posted you will find that covered. The paragraphs above cover the other possibilities: they exist but they are hiding, and they exist and are inhabiting all those UFOs and flying saucers buzzing around.

The first line from that paragraph:

"Others argue that the conditions for life, or at least complex life, are rare."

I'm suggesting not that they're rare per se, but that they have only recently (from an astronomic POV) come into being. Thus, there's a growing number of sentients out there, but not yet so many we ought to have been visited.

BTW, after re-reading that page, I notice there's a highly important assumption to the Fermi Paradox: sentient species continue indefinately, or at least for a very, very long time. Yet the Drake Equation leaves the question of "how long" up to the user to decide.

If FTL is impossible, and a sentient species dies off (for whatever reason) in a few thousand years, there is no paradox; we haven't been visited because nobody's run into us before they died off, and odds are we won't ever be.

Yeah, the Fermi Paradox is a very interesting thing. Makes me think about all sorts of things!

Re: Something Star Hero needs, but hasn't.

Yes' date=' I noticed that too. I decided for myself that the rubber science explanation of hyperspace and the Hyperdrive are wrong, and the stats for the hyperdrives given are correct- both is not possible. [/quote']

Yeah, I noticed that.

 

I believe for actually mapping the described hyperspace physics one would have to buy the Hyperdrive not as Teleportation' date=' but as normal movement plus Megascale and ignore "not for FTL" rule on that.[/quote']

I disagree. The fact that a ship in Hyperspace is undetectable, but that two (or more) ships in Hyperspace can interact, combined with better Hyperdrives letting one stay in Hyperspace longer leads me to think that the Power that best models this is Extra-Dimensional Movement. It has to be linked to FTL with the -0 Lim "Only Relative To Real Space". That would cover the text's description, and I can't see any other way to. Certainly the power write-up given on Terran Empire p.160 (and Alein Wars p.126-127) doesn't come close.

 

The STL drive would have to be another one- possibly an antimatter drive of some kind, or maybe a "particle accelerator neutrino drive" (which would have the convenience of not being a _very_ potent weapon, since neutrinos are harmelss particles).

 

Now that's maybe actually an idea: Building a particle acclerator of high output, powering it with a fusion reactor, and using it as a drive. Based on current technology, it would be very low-thrust, of course, but advanced versions might become better at that too. The impulse would be near light speed. Of course, one would have to miniaturize particle accelerator technology, but that is not completely unthinkable...

 

Edit: Oops. I just reinvented the ion drive. Sorry

LOL. At least you didn't reinvent the wheel.

 

Actually, I think Solar Hero ought to cover (at least in general terms) all the known and theorized STL drives: rockets (chemical, electric/ion, nuclear [constant & pulsed], antimatter), light sails, ramjets (Bussard, catalytic, RAIR), beamed energy, electormagnetic "rails", pellet stream, etc.

 

Hey, Steve L.! I recommend The Starflight Handbook: A Pioneer's Guide to Interstellar Travel by Eugene Mallove and Grefory Matloff. Has solid info, clearly presented. Although it's aimed at interstellar flight, the info is highly usefull for interplanetary flight. Good stuff for Solar Hero.

 

Oh, and it also goes into speculation about FTL!

Re: Average Seperation

Well, there is another possible approach, but it's a lot less "dramatic" or "romantic" than things like the Berserker speculation.

 

There's been a theory for a long time that the reason life appeared so quickly/early on Earth is that the first living things (microbes) arrived in one or more of the comets that brought the water that makes up Earth's oceans. We also know that rocks from one planet, cast off by a large impact event, may make their way to another planet in the same solar system...Mars rocks have been found on Earth, for example.

 

Put these two together, and consider this:

 

Perhaps life arose in a couple of dozen places scatter around the galaxy. Impacts on those first life-bearing worlds scattered rocks (containing microbes) from those planets out into space. Some of those got sling-shotted out of their native solar system by a too-close encounter with another planet. Drifting through space for a few billion years, they eventually fall into the gravity well of other planets with the potential for life, and "seed" them.

 

In this way, you could have a couple of dozen "bubbles" of life-bearing worlds in the galaxy, with the older/more advanced worlds near the center and the newer, less advanced worlds that had been "colonized" by the ultimate Slow Boat To China spread out from there. In fact, once life got a foothold on a new world, impact events on that world might end up spreading further "lifeboats" even farther afield. Each "bubble" would be a bit like an oasis in a desert, with large streches of empty/non-life-bearing systems in between.

 

That would let you build clusters of worlds reasonably close together without resorting to just "statistical clustering", and you wouldn't have to drastically increase the number of civilizations, either.

 

It might well also have the effect of making "good" real estate (those worlds already 'seeded' by microorganisms which went on to convert the primordial atmosphere, etc. into something desirable as living space for higher life forms) a rather scarce commodity, worth fighting over. And if all the available "seeded" worlds in a particular bubble have been taken/used, a civilization looking for more breathing room might well take the extreme measure of crossing a large expanse of empty "star desert" and start trying to colonize/conquer worlds in the next "oasis".

 

Thoughts?

An interesting varient on Hoyle's theory.

One thing: the life within each "bubble" would be based on similar chemistry, but that in another bubble might be based on very, very different chemistry.

However, it should be reasonably easy to deliberately "seed" new planets (at least, those that *could* support life). While some sapients might "cross the desert," I would think most would put their efforts into "vitaforming" (altering to support/have life) planets that got missed.

Re: Something Star Hero needs, but hasn't.

After reading this thread (as it is so far), I have to agree that a build system does not belong in Star Hero. Star Hero covers an entire genre, and a build system limits it too much. In fact, I think the percentages for systems given on page 192ff and elsewhere should not have been given, or given as a range, with suggestions as to when/where to use the high end, middle, and low end of the ranges.

However, for Alien Wars, Terran Empire, and the upcoming prequel Solar Hero, I think a build system is imperitive. This is, after all, a specific setting, and there should be a coherent design to things. IMO, that design should be told to the players in that setting. And when that setting is supposed to be "hard(-ish) SF," it's even more necessary.

This is especially important so that when (not if) the players want their characters to build their own starship (or radically refit one), the GM isn't forced to say "No, you can only have what's on this list".

It might seem you can just tell the poor GM "figure out the points, and make them pay those &/or pay X credits/solars/BUCS/whatever." But that's not good enough, it seems to me.

You just know someone's going to go "How much cargo space is there?" or "Can we fit a Mark XXII wizzbang in where the old Mark III was? If not, can we tear down a wall and canniblize some space from the cargo bay/staterooms/galley/etc.?"

I would just like to point out that chemical rockets are modern technology and not really the stuff of science fiction (the operative word being fiction).

However, Alien Wars and specifically states that rockets (chemical, nuclear) are the only STL drives used. So how they must work is important to understand.

I had originally started on a section breaking down the systems of starships while working on Spacer's Toolkit' date=' but it became apparent early on that it would not be included in the final book. I'll see if I can dig up what I wrote.[/quote']

That sounds very interesting! Would you please hunt it up?

 

I just wanted to throw in this little tidbit.

 

We [as a society] know quite a bit about the universe. However, I think it would be a mistake to demand that all technology in your campaign have some kind of analogous relationship with current science and understanding.

True. However, two points:

1) To suggest that there be some sort of "how do you build a starship" system exist and be told to the players, in a specific setting, is much different from saying that setting, or the entire genre book hew to physics as we know it.

2) If a RPG book says that rockets are the STL existant, then that book ought to be written with some understanding of, and respect for, the physics of rockets.

 

600 years ago' date=' everyone thought they knew quite a bit about the universe too...and they also thought the world was flat.[/quote']

More than 2000 years ago the Greeks proved the Earth is round. That knowledge was never lost. There may, 600 years ago, been a substantial number of people who were unaware of that knowledge, but those who paid any heed to then-current knowledge knew better.

After all, the sailors on Columbus's ships did not fear they would "fall off the edge of the world". They, common sailors, knew the world was round. They feared, correctly, that the ships they were on -- indeed, even the best ships then available -- could not survive a voyage of the length it would take to reach "Cathay". If they hadn't run into something, they would have starved, or been forced to turn back.

 

RPJesus, "zero point energy" is the idea, from quantum mechanics, that matter/energy is being constantly created and destroyed, on a time scale of attoseconds, from "empty space"; this is mostly in the form of matter-antimatter pairs, though the hypothesis requires "anti-energy" to be formed, to cancel out the energy interacting matter-antimatter pairs would produce. Note, that at this time scale, it does not effect the universe, not even on the atomic level. However, goes the speculation, if there were some way to separate out the antimatter, and keep it, you could interact it with regular matter at macroscopic time-scales. Even more theoretically, if you could neutralize the "anti-energy", the energy would be there for your use. However, no-one can even speculate on how to do either, so the whole idea is pretty much useless.

 

 

Except for Steven Hawkings using it to theorize radiating black holes.

Re: Something Star Hero needs, but hasn't.

A couple of short notes regarding my long, math-filled post:

1) I refered to "the end velocity" for simplicity. In fact, what the formula uses in "delta-V", which is the total change in velocity. A rocket that accelerates to 10,000 m/s, spins around, slows to a stop, speeds back up going the way it came from, up to 10,000 m/s, the spins around a decelerates to a stop exactly where it started from has an "end velocity" of 0 m/s, but a delta-V of 40,0000 m/s. And it's 40,000 m/s you'd use in the formula.

2) from Alien Wars p.125, repeated in Terran Empire p.158:

"Trvel within Hyperspace depends on two things: first, a ship's normal propulsion (since the ship has to propel itself through Hyperspace);..." Thus, the whole matter of propellent mass fraction applies to FTL as well as STL.

Frankly, I don't think the writer thought things through at all.

Re: Alien Wars: Before hyperdrive, there was...

errr... ummmm... Mars? ok. maybe not.

 

well, to be honest, in my attempt to not back the guy who writes Solar Hero into a corner, i muffed it up. the description should include a passage along the following:

 

Member nations of the United Earth in the year 2104 passed the Colony Act, which states the colony is the sole responsibility of the member nation, not the United Earth government, yadda, yadda, yadda, and at a later date, when the nation-states of Earth became parts of a one-world government, the Colony Act was then interpreted to apply to Senate Worlds also.

That'd work.

Of course it raises the question: when does Earth get a one-world government? Also, what of the UN's "no exploitation of outer space" treaty (I forget its proper name)? In fact, how does that debating group called "The United Nations" turn into "the United Earth" -- of course, those questions don't have to be answered now. That's what "Solar Hero" is for.

Re: Alien Wars: Before hyperdrive, there was...

Another option might be giving Earth an actual Antimatter infrastructure and letting starships use antimatter photon drives. Those would have an exhaust speed of near c (light speed), and that'd significantly reduce the amount of propellant needed.

 

That kind of fuel would not be "easy to obtain", though.

It'd also be a ***** to store! It would be dangerous in the extreme, be subject to "shrinkage", etc.

Also, the "antimatter photonic" rocket idea (advanced by Eugen Sänger in the 1950's) is unworkable. The current thinking is to use antiprotons only, and either "channel" the pions produced when they interact with protons, via a "magnetic nozzle", or to use the interaction to heat a propellent (such as hydrogen, water, methane, etc.) and have that "fly out the back". Either one means a noteworthy amount of propellent.

BTW, according to The Starflight Handbook, for anitmatter rockets (for use in the Solar System, mind you!) to be feasible, the cost of making antiprotons has to come down to ~$10 million per milligram, and the current (1989) cost is $100 billion per milligram.

Re: Alien Wars: Before hyperdrive, there was...

We are. My official explanation is I don't want to say anything now that would tie my hands later. It may take a while' date=' but I do want to get around to publishing those other settings at [i']some[/i] point. Even if I wanted to delve back into it right now and come up with a quickie quasi-plausible answer I could back off of later, I don't have the time right now -- gotta finish up HC. But I'll see if I can find the time after that.

Well, that's a & to me.

Re: Alien Wars: Before hyperdrive, there was...

Or to take a refrence directly from a Hero Book

 

Galactic Champions by Darren Watts, P.25

"In the year 2149, Humanity developed true portable fusion energy sources, allowing ships to travel between planets at previously unthinkable speeds."

 

Apparently the first human colony was founded on Mars on 2093.

Now there's some info that ought to have been in Alien Wars (& maybe Terran Empire). That gives some highly useful background info.

It goes on to say that hyperdrive was invented in 2203' date=' which allowed travel at 20% faster than the speed of light. It was not until 11 years later (in 2214) that the first human colony outside the Sol system was founded on Alpha Centauri IV.[/quote']

Then what are the Senate Worlds in 2104???

 

So it sounds to me like the earliest colonies were probably created using very slow chemical or Ion drives. These drives were replaced by (i'm guessing) much more powerful particle drives powered by fusion reactions.

 

Fusion power plants allowed STL travel for about 60 years before hyperdrive was invented, but that there was no permanent human presence outside of our solar system during that time.

The problem with even fusion power plants is the propellent fraction has to be enormously high, or the travel times are enormously long. Or, you don't settle outside the Solar System at all.

Of course, even inside the Solar System, travel times are high between planets. And the easiest way to go faster that Hohmann orbits is not fusion-powered (near) constant acceleration, but light sails.

 

I'm sorry, but I'm just not buying the whole timeline for Alien Wars. I know it's jsut a game, and hand-waving is expected and perfectly fine. But in a supposedly gritty, "realistic" sub-genre like Military SF, a good deal of 'respect' for physics-as-we-know-it is a desideratum. And on lthe whole matter of propulsion, Alien Wars falls down on the job.

Re: Alien Wars: Before hyperdrive, there was...

Yeah' date=' I'm here, but I'm not the person to give you an official explanation... however, when working on ALIEN WARS, I based the past on the Hero Universe document (that you can find here: http://www.herogames.com/FreeStuff/freedocs/HeroUniverse.pdf)[/quote']

I have that on my hard-drive, but never thought to look at it. Thanks for the reminder.

Still, it brings up the question: What "Senate Worlds" are there in 2104? If we accept a speed of 0.2c, a ship starting TODAY would reach only 10 ly by 2104 (the date of The Colony Act). That gives a choice of 7 star systems: Alpha Centauri A/B/C, Barnard's Star, Wolf 359, LP 263-64, UV Ceti A/B, Procyon A/B, and Gl 729. Note that the last of those is 9.56 ly away. It would take 95.6 years to get there, *and* 9.56 years for a message to get back to Earth, for a total "trip time" of 105.16 years. A ship leaving TODAY would not be known (for sure) to have colonized until 2109, 5 years after The Colony Act.

 

To quote from the section on Solar Hero: "Solar Hero is a hard SF/low SF setting limited to our solar system' date=' with perhaps tentative, slower-than-light (sleeper ship, generation ships, and the like) journeys to nearby systems...."[/quote']

I hope that some more attention will be paid to the laws of physics in Solar Hero. There are some ways to fudge things without getting too far from reality-as-we-know it, but there's lots and lots of ways to really drop the ball on realism. :|

 

From the same document' date=' FTL-drives first come into use in the first few years of the Interstellar Era (starting in 2200 and described in the same document linked above), and that's the Alpha Class Hyperdrive.[/quote']

OK, guess I've been answered. Frankly, I like AW and TE, but the whole chemical/nuclear-rockets-don't-need-propellent fluff just gets under my skin.

Re: Alien Wars: Before hyperdrive, there was...

Well' date=' give them some kind of Russard ramjet, the'd have some 10% of lightspeed. Colonizing a new system would thus come down to a matter of decades.[/quote']

 

There are problems with Bussard ramjets. The Starflight Handbook gives that 0.1c figure, but it's copyright 1989, and I believe it is now thought Bussard ramjets could not achieve above circa 0.05c, if they're possible at all (which many now doubt). Also, they would need to get up to circa 0.01-0.02 c before they'd "kick over", and that would have to be achieved by rockets, solar sails, or what-have-you.

 

Even at 0.1c, it would take 44 years to get to Alpha Centauri (or 43 for Proxima, but I don't see that being settled until Alpha A/B settles it). If "The Colony Act" is in 2104, the colonizing ship heading to Alpha Centauri must leave by 2056 (to account for one way signal from Alpha Centauri to Earth). Actually, if Alpha Centauri has a representative in the Senate, he/she will be a native of the Solar System (rather like Uganda, say, sending a Canadian to the UN--a Canadian who can never get to Uganda). Add in the problem of 8.8 year round-trip time for communication, and the whole thing looks curiouser and curiouser.

 

Note, that if Bussard (and catalytic) ramjets are not possible, you throw in the whole propellent mass problem.

 

Frankly, IMO, what Alien Wars and Terran Empire needs is to take the Reactionless Drive from Terran Empire (p.158ff) and have them invented 5 centuries earlier. With a propellent-less drive in the mid 21st century, there's no need to worry about how a real-world STL works.

 

You still have decades between star systems, but that's cool for certain sorts of settings.

EDIT: Of course, you also have to treat "Flight" as acceleration, not velocity. At 600"/Turn (100 m/s), it takes 47.4 years to go 1 AU, which is useless even inside the Solar System (and way slower than what we can already do).

Re: Average Seperation

There is always the Beserker Hypothesis' date=' one of the standard answers to the [b']Fermi Paradox[/b]. It says the reason that the entire galaxy (including Earth) was not colonized billions of years ago by the first intelligent specie to evolve is because Something Awful is prowling the galaxy, annihilating intelligent species as it goes. Actually probably more like a swarm of Something Awfuls.

 

Imagine that the planet killers move slower than light in million year long patrol routes. If they are sparce enough, this could lead to wide swaths of stars without civilizations. This means the surviving civilizations would be more closely clustered than one would expect (i.e., clustered into corridores in between the barren swaths).

 

Or as an alternate, you might argue that the civilizations were clustered due to Dr. Geoffrey Landis' Percolation Hypothesis

Great reading there! Thanks a lot!

The Percolation Hypothesis is a fascinating idea. Just one problem from the Science Fiction POV: it requires that there be no FTL (or, at least, that FTL be not a whole lot faster than c, and that the FTL drive can't go faster than some specific number).

There is, BTW, another 'solution' to the Fermi Paradox. If it took the galaxy about 5 billion years to build up a fraction of trans-helium elements sufficient for life-bearing planets to form, and if it takes at least, say, 4 billion years for technological sapients to evolve, then Homo sapiens sapiens is among the first, and we haven't been visited because our 'predecessors' haven't gotten this far.

One thing about this speculation: in the Drake Equation it is no longer Lc/Lg, but Lc/Le, where Le is the time during which technological sapients could have evolved. If that is 1 billion years, the Drake Equation's result is mutiplied by 10!.

A counter-intuitive result to put it mildly.

Re: Average Seperation

So the overall total is about 8.17 * 10^12 for the disk and bulge. (This is about 45% higher than the figure you gave).

Well, the Star Hero approach deals with a "habitable zone" for the galaxy, similar to the "green zone" around a star -- the area in which a habitable planet can exist. For example, in the core of the galaxy, the radiation level is too high, and the frequent close passes of stars are unlikely to leave stable planetary systems intact.

 

If you rule out those parts of the galaxy unlikely to host planets where "life as we know it" could exist, then you get quite a bit less than the actual volume of the physical galaxy.

If you look at my first post, you will see I determined the volume of the Galactic Habitable Zone from the figures given in Star Hero. Thus, its size is a different matter from the size for the galaxy as a whole.

BTW, Dust Raven: I just realized I didn't use the numbers (15,000 ly and 35,000 ly) you gave in your original post. Using those, the volume of the GHZ is about 3.14 * 10^12 cubic ly. Also, there's only about 86 billion stars in that volume, so there's only about 2100 civilizations. These two changes lead to an average separation of --- 1140 ly. The two factors balance out, after all.

Re: Average Seperation

The method I found on some website or other is to use the following simplistic equation:

dist = cube_root( galactic_volume / num_civs)

that is, take the volume of the galactic habitable zone, divide it by the number of technological civilizations, find the cube root, and the result is the average distance between civilizations, in the same units as the volume. If your calculator does not have a cube root button, use the X to the Y power button, and use 0.33333333333 for "Y" (i.e., divide galactic volume by num civs, press the x to the y button, enter 0.33333333, and press the "=" button).

Which is what I said, I just also explained why.

So taking Basil's galactic volume as 3.64e12 cubic light years divided by 2450 civilizations' date=' take the cube root, and the result is an average separation of 1140 light years. [i'](3.62e12 is a more compact way of saying 3.62 x 10^12)[/i]

Again, just what I said.

BTW, I prefer "3.62 * 10^12" because it's clear to anyone who's done enough arithmetic to recognize "^" as the "to the power of" symbol. I'd use superscripts if I knew how to do them on these boards. OTOH, "3.62c12" is only known to those who've used some specific computer programs.

There is more at these websites:

http://www.projectrho.com/smap05d.html

http://www.projectrho.com/rocket/rocket3ab.html (scroll down to "Interstellar Empires")

 

I read somewhere that the entire galaxy has a volume of 5.65e12 cubic light years, counting both the galactic habitable zone and the low-rent districts of the core and the rim.

Using "The Cambridge Atlas of Astronomy", we get the following dimensions for the galaxy (all are approximate):

Central Bulge:

Diameter: 6 kiloparsecs

Thickness: 1 kiloparsec

Disk:

Diameter: 30 kiloparsecs

Thickness: 300 parsecs

Halo:

Diameter: 30 kiloparsecs

Converting to lightyears (and giving radii as appropriate):

Central Bulge:

Radius (actually semi-major axis): 10,000 ly

Thickness (actually minor axis): 3000 ly

Disk:

Radius: 50,000 ly

Thickness: 1000 ly

Halo:

Radius: 50,000 ly

(NB: the radius of the Halo may actually be 60,000 ly or more, but I'd rather use the more conservative value)

The Central Bulge is an oblate sphereoid, so the formula is (pi)*(4/3)*(semi-major axis squared)*(semi-minor axis), which is about 6.28 * 10^11 ly. The whole disk is a cylindar with a hole through it: (pi)*(50,000^2 - 10,000^2)*(1000) = about 7.54 * 10^12.

So the overall total is about 8.17 * 10^12 for the disk and bulge. (This is about 45% higher than the figure you gave).

The halo + disk + bulge (or grand total) volume is (pi)*(4/3)*(50,000^3), or about 5.24 * 10^14. Which is about 64 times as big as the disk+bulge. However, the density of stars is around 1/100,000 or less.

Re: Alien Wars: Before hyperdrive, there was...

Just looked it up- you are correct. The Colony Act pased the UE Senate in 2104' date=' (no typo, the year is repeated in the text), "nearly a hundred years before the invention of Hyperdrive technology".[/quote']

Yes, it does. That still does not answer the question: "What FTL, if any, existed before 'Hyperdrive' in the **OFFICIAL** time-line."

 

IIRC' date=' the Colony Act was passed *before* FTL was readily available. Early colonization used long-term sleeper ships.[/quote']

Could you tell me where you got that from? I can't find anything in either "Alien Wars" nor "Terran Empire" regarding pre-'Hyperdrive' propulsion, other than admitting rockets existed "way back when" (BTW, why only chemical and nuclear? Ion, solar-sails, beamed energy, Bussard & catalytic ramjets, etc. are all currently-known possibilities).

 

As for "0.5 g" rockets, I've treated the problem of propellent mass in another thread. Any craft with a reasonable propellent mass fraction will either take *centuries* to reach the *nearest* stars, or require an energy source of staggering power *and mass*. And if you have a gigaton power source (plus support for it and the people to run it, and the people to take care of them, etc.), having a propellent *fraction* below 0.0001 will not help, and the propellent *mass* becomes ludicrous (along with the mass of the craft). So, no matter how fast your exhaust velocity is, you'll spend 95%+ of the time coasting.

 

Frankly, without a rubber-science STL, colonizing even handful of star systems is a 4-5 century project. *At* *best*.

 

So the question remains, what is Herogames' OFFICIAL explanation?

 

Mr. Long? Mr. Thomas? Are you listening?

5th Edition, page 166, says "At the GM's option, a character can shape his Explosion like a Cone (loses 1 DC per 2") or a Line (loses 1 DC per 3") for the same +1/2 value,..."

Assuming a GM allows this, does this change the fall-off-distance increase for additional +1/4? That is, does one say "well, with a spherical Explosion, for a further +1/4, the DCs fall of more slowly by the same amount as the basic Explosion, therefore for a 'channeled' Explosion, the DCs should also fall off more slowly by the basic amount."? Or does one say "+1/4 is 1" more slowly, no matter if the Explosion is spherical or 'channelled'."?

That is, does changing to a Cone or Line give a one-time boost to the fall-off distance, or does it change the unit-of-measure for the basic & the improved fall-off distance?

To give a specific example, If I have:

EB, 8d6, Explosion (Cone, +1/2)

I would subtract the first die at 2" out, the second die and 4" out, the third at 6" out, etc.

With:

EB, 8d6, Explosion (Cone, one level of increase, +3/4)

Would I subtract the first die at 4", the second at 8", etc., or the first at 3", the second at 6", etc?

Re: Something Star Hero needs, but hasn't.

[snipping a lot, to get to the point I want to respond to]

{Warning. Numberchrunching example follows. If you are not interested in such things, move on to the next curly brackets}

 

For example, there is _no_ chemical rocket with an acceleration in the range of 0.1 g or above that can burn for a month. That is due to the exhaust velocities inolved, which are a function of the energy provided by fuel and oxidant. The best available chemical rockets use almost all of the energy provided, which allows for an exhaust velocity of perhaps 4500 meters/second.

 

To compute how much reaction mass we need for a given ship for a one-seconds-burn, we can use the simple formula:

 

shipsmass * velocitychangepersecond= reactionmassconsumptionpersecond * exhaustvelocity

 

For said Centauri class battleship, that is

 

100 000 tons * 5 m/s = reactionmassconsumptionpersecond * 4500 m/s

 

So

reactionmassconsumptionpersecond = 500 000/4500 tons

 

which is close to a hundred tons. For one second. A month has a _lot_ of seconds. (And one cannot simply multiply since the reaction mass for the last seconds has to be accelerated all the way until it is used, increasing the ship's initial mass and requiring a logarithmic equation for the actual computation.)

 

Even if one assumes that the exhaust velocity of Alien Wars rockets is much higher (which is actually not possible for a chemical rocket, simply because there is not more energy in that kind of propulsion system), there is no way a 100 000 tons ship can be in that range with its propulsion data if it uses chemical rockets.

 

{End of numberchrunching example}

Actually, it's a LOT worse than this. For any craft accelerated by "throwing stuff out the back" (BTW that "stuff" is known as propellent), there is a formula that relates the velocity the craft reaches, the velocity of the propellent, the total 'take off' mass, and the 'end' mass (that is, the mass of everything that isn't "thrown out the back").

Conventionally, the ratio (take-off mass/end mass) is called R.

Using e (the base of the natural logarithms), we take e^(end velocity/velocity of the propellant) = R.

Now, if the craft accelerates at 5 m/s for 30 days, it's final velocity is 12,960,000 m/s. Burning Be-H2 in O2 gives the fastest chemical propellent velocity (7050 m/s). Stick in the numbers, and you get R = 2 * 10^798. Which means, to get one picogram to do what the Centauri-class does, requires a f**king GAZILLION universes of propellent.

It is estimated that fusion rockets with have propellent velocities of 25,000 to 2,000,000 m/s. The slowest of those gives R=1.4 * 10^225, which is still impossible.

The fastest gives R=652; IOW the 100,000 ton craft needs over 65 million tons of propellent---the mass of a small asteroid. OTOH, if we assume the 100,000 tons is *starting mass*, then the end mass is about 153 tons; not useful at all.

And note: all of this is utterly fixed by the laws of physics. If you want a craft that isn't nearly-all propellent, you need a "rubber-(pseudo)-science" STL. Which would, it seems to me, work against the whole feel of Alien Wars.

Two technical notes: 12,960,000 is about 4.3% of the speed of light; although slight relativistic effects would occur at that speed, we can ignore it for this discussion (especially since relativistic rocket formulae are a pain).

Second, all the above facts & formulae come from The Starflight Handbook: A Pioneer's Guide to Interstellar Travel, by Eugene Mallove & Gregory Matloff. The authors are professors, and experts in rocketry. So yeah, this really is how rockets work.

...what? IOW, what FTL existed before "hyperdrive", in the 'official' Terran Empire/Alien Wars timeline?

Alien Wars, page 125, boxed text, gives the introduction of the Class Alpha Hypredrive as happening in 2203. Yet on page 7 it says The Colony Act was passed by the Senate on 2104. Obviously, something preceded Hyperdrive.

OK, I'll bet 2104 is a typo for 2204. Still, with Alpha Centauri 4.4 ly away, and Class Alpha going 1.2 ly per year, it would take 3.7 years for a spaceship to get to Alpha Centauri. Obviously, there is no way hyperdrive was the first FTL.

So, what is the ***OFFICIAL*** answer to "what FTL came before Class Alpha Hyperdrive?"

Or is this a lack of continuity to the TE/AW timeline?

Re: Average Seperation

I was reading through Star Hero and came across the Drake Equation. An excellent tool I must say' date=' but when running the numbers it says the number of technological civilazations have an "average seperation" of X light years. How is this average seperation determined? It doesn't really go into that...[/quote']

 

What you have to do is figure the volume of the Galactic Habitable Zone, divide by the number of civilizations, treat each species' volume as a cube, and find the distance from center to center; this is the length of a side of that cube.

 

A cylinder 37,000 ly in radius, 1000 ly thick, with a 14,500 ly radius hole through it, is about 3.64 * 10^12 cubic ly. 125 civilizations "have" about 2.91 * 10^10 cubic ly each, for a distance of ~3080 ly.

180,000 civilizations "have" about 2.02 * 10^7 cubic ly each, for a distance of ~272 ly. (The figures in Terran Empire are significantly off.)

 

If it makes it easier for anyone (I love math, but anything to save time) I've established my universes stats as follows:

 

The galaxy is if similar size and composition as the Milky Way. I'm only taking into account stars in the Galactic Habitably Zone (approx 15,000 ly to 35,000 ly from the galactic center).

 

N* = 100 billion (stars in the GHZ)

fp = .5 (stars of proper age/type)

Np = 10 (average number of planets per star)

fh = .07 (planets suitable for life)

fl = .7 (lifebearing planets)

fc = .1 (lifebearing planets that develop technology)

Lc/Lg = .000001 (ratio of the average age of a technological civilization to the age of the galaxy)

 

This gives me approximately 2,450 technological civilizations (I haven't figured out how many of these have actually developed FTL technology yet though). Technically I'm fudging it a bit, and calling fc the proportion of lifebearing planets the develop intelligent life (which theoretically will develop technology, but hasn't necessarily done so). This allows for a number of pre-industrial worlds. But that's not really important right now...

 

All I need to know is how far apart these civilizations are on average. I need to know this so I can decide how fast to allow FTL travel.

 

Thanks in advance!

 

With 2450 civilizations, each "has" about 1.49 * 10^9 cubic ly, for a distance of ~1140 ly.

 

Hope that helps!

Re: Superhero Images

Okay, anyone can upload now. You can also create sub-albums.

 

And self-sufficiency is good. This is just for people who don't have their own server, don't want to bother setting one up, or who want a backup in case they have a hard drive failure or something.

Out of interest, are you going to allow hot-linking (aka image hosting) on your server? Freewebs, unfortunately, doesn't allow that. :/

If not, people can always upload their full sized images to your site (or Freewebs), and make their own thumbnail-sized copies and upload those to the boards, if they want to give an idea of the pic to readers here.

Re: Superhero Images

Well guys, you may have noticed a few changes regarding artwork (i.e. attachments). The reason is here:

http://www.herogames.com/forums/showthread.php?p=512912#post512912

 

The gist of it is, we are each limited now to 1MB worth of attachments. For some of you, that might not seem such a big deal, but for the board's artists, this really sucks. To give you an idea I am currently at 15.52 MB, which means I have to delete more than 14.52 MB worth of art before I can post anything new. I guess I will need to start with the oldest stuff first.

 

This means that after everyone has deleted their old stuff, the art threads will unravel. So I hope that everyone has had a chance to view what is there.

Unfortunately, I haven't, having come to these boards in only the last few months, and only found out about this and the other art threads in the last week.

As I said in that thread, I suggest using freewebs.com to hold your pictures, and link from there. Their website and uploading function is self explanatory. And they're free!

And Blue, I know it's a ****load of work, but I for one would deeply love to get a chance to find any&all of your artwork I haven't yet found.

Re: Opinions requested on an application of Side Effects

{much snippage occurs}

Was that a request for a translation? If so, I'd go with "Laedo ergo sum."

 

Unless you mean "I am being hurt, therefore I am" (i.e., you want the subjunctive); that would be "Laedor ergo sum."

::Sigh:: There's a major brain-fart.

"Laedor" is correct--not because it's the subjunctive, which it isn't, but because it's the passive.

Sorry if I caused any confusion.

Re: Cartoon Hero

I suggest cheecking out the online store.I have to warn you though' date='Adventurer's Club predates the Fourth Edition,so anything from before AC#15 or so will need a major conversion job.[/quote']

 

Actually, it predates the 5th edition; some predate the 4th, but not issue #27. Actually, issue #27 was the last issue.

Re: Cartoon Hero

You can find some ideas re. cartoon heroes in Adventurers Club #27, in the article "Funny Animal Champions."

HTH

Re: Opinions requested on an application of Side Effects

{much snippage occureth}

Ultimately, I talked to the GM about it, and he said he'd allow the character to use the Bouncing An Attack rules for any of his arrows due to their SFX, even though some of the Powers the arrows represent aren't normally ones you'd consider "bounceable" (Drain, Entangle, etc.). So I just bought 5-point Combat Skill Levels with RSR and "Only For Bouncing Attacks (-1)"

Well, that does make things simpler.