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Essay on Realistic Space Combat I Wrote
- Thread starter Memphet'ran
- Start date
She/Her
Well, gravity waves are fairly low-powered. Our sun is estimated to put out about 200 watts of it, which is only slightly more power than the radiation emitted by most lightbulbs.
magic9mushroom
BEST END.
Gravity waves =/= Gravitational waves.
I was referring to the latter.
As for the figure alguLoD mentioned about the Sun, that's not actually correct. The Sun does not emit gravitational waves (because it's symmetric about its axis of rotation). The 200W figure is IIRC for the Earth-Sun system (as the Earth orbits the Sun). The Sun-Jupiter system gives off about 5000 watts, due to the larger mass of Jupiter.
We haven't detected any gravitational waves directly (despite building gigantic detectors), but we have detected the energy loss due to them (since they cause inspiraling of orbits). You see, while the power from Sun-Jupiter is rather tiny, the power from two neutron stars in an orbit smaller than Mercury's is not.
She/Her
What? Oh, come on. That's more insane than having Dark Matter and Dark Energy refer to completely different phenomenon, despite the whole E=MC^2 thing. (not referring to you. Can't those bloody scientists just call it something else? Damn.)
Huh. I got my number from another SpaceBattler, IIRC, in my own Plasma Shielding thread a while back when the discussion briefly swerved towards how you could see through the damn thing, so I'm honestly not surprised my numbers are off. Hm.
We haven't detected any gravitational waves directly (despite building gigantic detectors), but we have detected the energy loss due to them (since they cause inspiraling of orbits). You see, while the power from Sun-Jupiter is rather tiny, the power from two neutron stars in an orbit smaller than Mercury's is not.[/QUOTE]
magic9mushroom
BEST END.
The problem was that "gravity waves" became an accepted term before we knew of the existence of "gravitational waves".
It tripped me up, too, when I first did climate science (and learned about gravity waves there).
Did you intend to respond to this? You've left it in there.Me said:
She/Her
Well, no, I couldn't really think of anything to respond to that, TBH.
The bad thing about there being a reason is that my rage is just completely misdirected and I know it and I just keep raging anyway.
Of course there is, just as there is such a thing as electromagnetic radiation, for largely the same exact reasons. It'd be far moreThere's such a thing as gravitational radiation?
if there were none.Is that sarcasm or what? Dark matter and dark energy are very, very different things independent of one another, so it is very helpful to call them by different names. They only thing they have in common is that they are both electromagnetically non-interactive: they're dark. Dark matter is almost certainty massive particles of some sort, hence 'dark matter' is a very natural moniker. Dark energy is not even remotely like that.
Energy (including mass) is just one of 10 components that describe how a given distribution gravitates. If you think E = mc² makes them all such distributions interchangeable, you are very mistaken--for example, the gravitational effects of dark energy caused by its pressure are three times that of those causes by its energy density.
Quite the reverse: even pretending they are in any way equivalent is absolutely insane.
magic9mushroom
BEST END.
His point is not that the concepts (I'm hesitant to call something which is a complete black box anything more concrete) are similar, but that the terms for such different concepts are so similar, just as "gravity waves" and "gravitational waves" are very similar names for very different concepts.
They're not similar at all, and besides, then why would he say that the nomenclature is "insane"? Gravity and gravitation are very often used interchangeably, so it invites even physicists to conflate "gravity waves" and "gravitational waves", and I've seen astrophysicists do exactly that. This is indeed very peculiar.
But it's hard to see how "dark matter" and "dark energy" are in any way confusing, since
1) Matter and energy are completely different concepts.
2) Even for someone who does not understand that matter and mass are different things, under standard relativistic usage, mass and energy are not equivalent either.
Why not? Dark matter in particular has loads of independent measurements.
magic9mushroom
BEST END.
If you won't accept that the terms "dark matter" and "dark energy" are similar, then I doubt I can convince you of it. However, I can assure you that most laymen will disagree with you.
Bwahahaha. Show me a box with dark matter inside it, or a direct survey for it, and we'll talk.
I don't think that's an appropriate litmus test for whether scientific nomenclature is insane, though being able to conceptualize that matter and energy are different things should be a very basic skill even for a layman.
You serious? When you have a half-dozen independent types of data predicting a dark matter distribution and manage to cross-check with each other, it's pretty hard to call that 'just conceptual.' Now that's insane. Things like the Bullet Cluster and MACS J0025.4-1222 are as direct as most things in astrophysics ever get.
magic9mushroom
BEST END.
It's an appropriate litmus test for whether scientific nomenclature is confusing to a layman.
Since, you know, laymen will get confused if you talk about dark matter and dark energy without explaining that they're different.
Oh, don't be so retardedly ridiculous. "Dark matter" and "Dark energy" are both placeholders for "unknown cause of this phenomenon" (though the phenomena in question are different - specifically "dark matter" is "the cause of some things appearing to have more mass than they should" and "dark energy" is "the cause of the universe expanding faster than it should").
They are phenomena - concepts. "Most things" in astrophysics have sound explicatory theories, which the phenomena dubbed "dark matter" and "dark energy" do NOT.
She/Her
Indeed. A strangely large amount of people seem insistent that dark matter is indeed some sort of matter - but it could simply be that our equations regarding how gravity works is wrong. Not saying that it is - I'm neutral on the issue since, after all, we have no idea what dark matter (or dark energy, for that matter) really is.
magic9mushroom
BEST END.
Hence my ubiquitous scare quotes.
A qualifier not present in the discussion before, but okay.
Nonsense. Dark Matter is a placeholder in a certain sense, but to make an analogy of sorts, just in the same sense that "UNSUB" is a placeholder in a stereotypical murder investigation. There's certainty that it exists, very little uncertainty that it is matter, but lots of uncertainty about its identity. That's something quite different from the merely conceptual: it's completely analogous to observing that an object exists but not being sure what it is made of.
There are lots of ideas of what it could be that are coherent with other physics, some of which we can work with in a lab, though for many not yet. I also object to the phrasing "more mass than they should", which suggests that there is a scientific argument of non-negligible validity that predicts how much mass there "should" be. That is simply not true.
Dark energy is similar, but with more uncertainty on all counts.
magic9mushroom
BEST END.
From my limited experience, I believe alguLoD to be a layman.
What. Dark matter is an "explanation" for "the galaxy has X mass as observed by non-diminishing rotational velocity. We can predict Y mass from what we can see and our assumptions of the ratio of luminous to non-luminous matter. X >> Y therefore something weird is going on." So basically they said "There is probably X-Y mass that we have no clue about, let's call it "dark matter" until we have more of a clue."
It is ENTIRELY based on assumptions and calculations of how much mass there "should" be. "Dark matter" is the unknown CAUSE for an observed EFFECT.
"The universe is accelerating its expansion at X rate. Known physics says it should be accelerating at Y rate (negative, I believe?). Clearly there is some unknown effect at work here; let's call it "dark energy"."
She/Her
@Re: DM/DE discussion.
Oh, I know perfectly well the difference between Dark Matter and Energy, I simply find the terminology employed rather stupid.
Oh, I know perfectly well the difference between Dark Matter and Energy, I simply find the terminology employed rather stupid.
Yeah, I suppose I am a layman, though with the unusually extensive knowledge of theoretical and/or high-level physics that usually comes to people who frequent this particular subforum.
magic9mushroom
BEST END.
Me too, and I've actually done enough astrophysics to have had to work with "dark matter" calculations in lab classes.
Yeah, I suspected as much. You're a quick study, though.
Not even nearly. When I said a half-dozen different types of evidence, I wasn't exaggerating (actually, more the reverse). Dark matter is a prediction of galactic rotation curves (and also velocity dispersion in galaxies), sure, and if that was it, the "maybe it's just wrong" would be a very reasonable point of view. But that isn't it. We observe DM from the behavior of galactic clusters and superclusters as well--and it fits exactly what we get from observing the stars in the galaxies themselves. We observe DM from gravitational lensing. We find it in the cosmic microwave backround multiple independent ways. There are several additional consistency checks that constrain both the amount and type dark of matter, such as supernovae and hydrogen transition lines from galaxies and quasars, and DM meets those very well. The worst one so far is our understanding of galaxy formation, but it's an outlier to a very consistent and robust picture.
So? Such a prediction is only as good as our assumptions, and generally such "a priori" assumptions have been complete and utter bullshit. You know there's going to be some dark matter, because particle reactions produce it all the time. You could try to to estimate its amount based on that, but there are problems:
1) The conditions in the distant past are way different and on a much higher energy scale than anything you did in the lab.
2) If you ignore that and do it anyway, doing so takes the physics well outside its domain of tested validity. Physicists work in effective field theories for a reason--it works on particular scale because it's made that way; expecting it to do so out of it is just nuts.
In short, making such assumptions is precisely the kind of ad hoc wild extrapolations that you're accusing DM of doing. A more sane method would be to actually go out there and look, measure DM amount, distribution and type, and use then try to falsify it by using more independent observations of completely different things. That's how normal science works. That's how DM works. And once you've done that, you can use that data to constrain your hypotheses about how particle physics works on higher scales instead of making wild guesses and acting as if they had non-negligible shred of validity.
Your ignorance is not amusing.
Vastly exaggerated. The cosmological constant has been part of general relativity all along--it's literally a constant of integration in some derivations thereof, that people have generally ignored and put it in as zero by hand. Eight decades later, people finally found evidence that it isn't zero.
You're literally flailing against the most accepted theories in cosmology. Because you know what the reference model for Big Bang is? ΛCDM. That's cosmological constant (dark energy) + cold dark matter. Which would fine if you actually had something physically substantive to say, but you don't.
ETA:
My point is that the reason you've given for finding it stupid shows that you misunderstand both matter and energy. Dark matter is matter. As far as we can tell, dark energy is vacuum. m9m correctly points out that what sounds stupid to layman is often quite different than what sounds stupid to non-laymen (or just more informed laymen, as the case may be), it does not change the fact that many such judgments are mistaken.
I'm sorry, but I have to bring this up, since I couldn't find any other mention on this thread. Why no mention of electronic warfare and sabotage? You can't seriously believe that "space pirates" or other criminals (or terrorists) would be above using tech knowledge that would disable or misdirect defensive and scanning automata?
Barring a cultural AI phobia (which would pretty much completely counter your argument against the feasibility of "space pirates") there is no way to protect completely against sabotage or hacking attempts. That Reagan missile defense system would be a boon to someone who wanted to destroy a continent. Instead of having to waste an entire ship on North America, someone who with enough motivation could hack the entire automated defense network and crash every one into the planet at once, likely ending all life living on the surface.
You raise some very good points, but you should never put too much faith in constructed systems working for all situations, especially when talking about anarchists.
EDIT: I hope I don't seem rude. I think you nailed the rest of it.
Barring a cultural AI phobia (which would pretty much completely counter your argument against the feasibility of "space pirates") there is no way to protect completely against sabotage or hacking attempts. That Reagan missile defense system would be a boon to someone who wanted to destroy a continent. Instead of having to waste an entire ship on North America, someone who with enough motivation could hack the entire automated defense network and crash every one into the planet at once, likely ending all life living on the surface.
You raise some very good points, but you should never put too much faith in constructed systems working for all situations, especially when talking about anarchists.
EDIT: I hope I don't seem rude. I think you nailed the rest of it.
Duzzit
Fleet Admiral, UNSC
Because strictly speaking the document was more on space combat of ship vs ship more than anything else.
Incidentally, I'd assume that defence satellites and networks are not connected to the bloody internet/have wireless access left open for people to get through in the first place.
Also, how would AI phobia counter 'space pirates' exactly?
EDIT: Also guys/girls, I apologise to responding to what might technically be a necro, but I felt it something to respond to.
Incidentally, I'd assume that defence satellites and networks are not connected to the bloody internet/have wireless access left open for people to get through in the first place.
Also, how would AI phobia counter 'space pirates' exactly?
EDIT: Also guys/girls, I apologise to responding to what might technically be a necro, but I felt it something to respond to.
Apologies if this is Necro, and more apologies if my Qs here have been addressed elsewhere in the site.
Interstellar battles are unrealistic - ignoring the interstellar travel is physically impossible (too much fuel to conduct a trip, etc), the initial premise of the essay is knowing where the enemy is, and where the enemy is going. At interstellar distances, it is unrealistic to expect to be able to achieve twice the speeds your enemy can achieve - with such technological mismatch, there would be no conflict. We're left with considering interplanetary sorties.
The primary reason to not just asteroid-bomb the target planet (as mentioned in the original essay, especially with regards to piracy) is a need to minimize damage to the target system in some way. (Otherwise you just go Ender Wiggen on their behinds and call it done.) This leaves a situation where two combatants, both with footholds in the same system, are battling. I find it unrealistic to think, at this level, that both parties have perfect observation of the entire system, but obviously must have some.
So we have two ships, who are somewhere in their orbits around the stellar primary. We'll assume they're between planets. They become aware of one another, and a decision is made to engage. They have human crews, and are equipped generally as described by Memphet'ran - missiles, lasers, ablative armor, and generally whoever gets a missile through first wins. What do the captains do?
They play cat and mouse.
The one closer to a system, preferably with rings and moons, hits his engines to 3 gs, aiming to reach the moons as fast as possible. The (now) pursuing captain immediately knows the destination; she also accelerates to 3 gs. If they start in similar orbits, the two play a game of chicken - who will be the first to turn their ship around and begin their insertion burn, so they don't fly past the target and expend unnecessary amounts of fuel to return to a reasonable solar orbit. Supposing they are coming from drastically different orbits, there is little to no chance of inter-planetary interception. They both insert into the planet's moon system safely.
They both know where the other inserted - pretty obvious from those burns. They were both a roughly equivalent distance away, so no time to set up an ambush. Both are in orbit around the planet, but where? One inserts near the plane of the rings and moons. The other chose a polar orbit, outside the radius of the rings. From here they hunt - who can be the first to see the other, without themselves being seen? The polar orbit has it easier to see, but they are also seen more easily. The captain who chose the moons has opportunities to use the moons as shields for short burns, not staying in a single orbit for too long.
To draw inspiration for realistic space combat, we don't look at battleships - we look at submarines.
In space.
Interstellar battles are unrealistic - ignoring the interstellar travel is physically impossible (too much fuel to conduct a trip, etc), the initial premise of the essay is knowing where the enemy is, and where the enemy is going. At interstellar distances, it is unrealistic to expect to be able to achieve twice the speeds your enemy can achieve - with such technological mismatch, there would be no conflict. We're left with considering interplanetary sorties.
The primary reason to not just asteroid-bomb the target planet (as mentioned in the original essay, especially with regards to piracy) is a need to minimize damage to the target system in some way. (Otherwise you just go Ender Wiggen on their behinds and call it done.) This leaves a situation where two combatants, both with footholds in the same system, are battling. I find it unrealistic to think, at this level, that both parties have perfect observation of the entire system, but obviously must have some.
So we have two ships, who are somewhere in their orbits around the stellar primary. We'll assume they're between planets. They become aware of one another, and a decision is made to engage. They have human crews, and are equipped generally as described by Memphet'ran - missiles, lasers, ablative armor, and generally whoever gets a missile through first wins. What do the captains do?
They play cat and mouse.
The one closer to a system, preferably with rings and moons, hits his engines to 3 gs, aiming to reach the moons as fast as possible. The (now) pursuing captain immediately knows the destination; she also accelerates to 3 gs. If they start in similar orbits, the two play a game of chicken - who will be the first to turn their ship around and begin their insertion burn, so they don't fly past the target and expend unnecessary amounts of fuel to return to a reasonable solar orbit. Supposing they are coming from drastically different orbits, there is little to no chance of inter-planetary interception. They both insert into the planet's moon system safely.
They both know where the other inserted - pretty obvious from those burns. They were both a roughly equivalent distance away, so no time to set up an ambush. Both are in orbit around the planet, but where? One inserts near the plane of the rings and moons. The other chose a polar orbit, outside the radius of the rings. From here they hunt - who can be the first to see the other, without themselves being seen? The polar orbit has it easier to see, but they are also seen more easily. The captain who chose the moons has opportunities to use the moons as shields for short burns, not staying in a single orbit for too long.
To draw inspiration for realistic space combat, we don't look at battleships - we look at submarines.
In space.
Apologies again, for the double post:
I found this thread after chatting with some friends discussing a space combat video game we'd like to make, after deciding we'd like to play a game whose core mechanic is "Orbital Mechanics". The notes and super-prototype code are at https://gist.github.com/DavidSouther/5390171 ; as I've only just found this site, and haven't read a single thread beyond this, I'd appreciate any introduction people might be willing or able to give.
I found this thread after chatting with some friends discussing a space combat video game we'd like to make, after deciding we'd like to play a game whose core mechanic is "Orbital Mechanics". The notes and super-prototype code are at https://gist.github.com/DavidSouther/5390171 ; as I've only just found this site, and haven't read a single thread beyond this, I'd appreciate any introduction people might be willing or able to give.
