Question about abnormal matter

[Kaziarl]

I'm specifically wondering about Dark Matter. From what I know according to todays science dark matter is pretty much a theory. A "we think it's there but can't see it" thing.

However, in trek at least once they come across a Dark Matter Nebula. Now, nebulae make stars, and eventually planets. So, my question is could there be a solar system made of dark matter? And if so, could there be life? And again, if so, what kind?

 

[Timo]

Well, the idea behind dark matter is essentially one of dark mass: we can see that the universe (according to our potentially faulty cosmological models) or at least the Milky Way (according to much simpler and probably correct models) has more gravity than the visible matter can account for. So dark matter is "anything that isn't visible to us today and has mass".

By that definition, any star system we cannot see today would be "dark matter". We can see stars, so none of those qualify as dark matter as such - but perhaps the star has invisible (that is, very dark) planets circling it in surprising abundance, explaining some of the extra gravity? That'd be a perfectly possible "dark star system", although it wouldn't explain more than a tiny fraction of the extra gravity.

OTOH, even objects that we can see, such as nebulae, may have something inside them that we cannot see or recognize as the source of gravity. In Star Trek, nebulae tend to be very dense, bright and often surprisingly compact in size - all hints that they have more gravity than they ought to. So perhaps there's dark matter there in addition to the known gases, possibly even enough of it to explain a significant fraction of the "missing" gravity of our galaxy. Whether that matter would accrue inside stars and planets when those are born out of the nebulae is unknown - but again, Trek is famous for dense asteroid belts and small planetoids that have surprisingly much surface gravity to facilitate our heroes walking on them, or breathing an atmosphere that clings to that surface. Perhaps there's dark matter there, too?

Trek also has mastered the artificial creation or negation of gravity. Perhaps the dark matter of the universe is actually exhausts and byproducts from all the advanced civilizations that process gravity, and have done so for billions of years? Wouldn't explain broader cosmology, as dark matter supposedly has existed on universe-wide scale long before technology could plausibly have emerged. Could explain the galaxies, though.

But as dark matter is just matter we haven't seen so far, with mass/gravity, it's probably perfectly possible to have life-as-we-know-it built out of matter that contains a smidgen of dark matter, the only effect being a bit of extra mass. That's more or less the definition: dark matter doesn't have any effects on anything except through its mass - that's why it's dark/invisible to us.

...Of course, all sorts of dark matter could interact with the rest of the universe through ways we don't recognize today, such as subspace radiation or warp attraction or nadion interaction or whatever futuristic Trek phenomena we have. Star systems containing significant amounts of that stuff would then have all sorts of weird effects on our heroes, or at least on our heroes' technology...

Timo Saloniemi

 

[Christopher]

I'm specifically wondering about Dark Matter. From what I know according to todays science dark matter is pretty much a theory. A "we think it's there but can't see it" thing.

However, in trek at least once they come across a Dark Matter Nebula. Now, nebulae make stars, and eventually planets. So, my question is could there be a solar system made of dark matter? And if so, could there be life? And again, if so, what kind?

No, there couldn't be. The reason "dark matter" is so hard to detect is because it's non-interacting except through gravitational effects. Its particles don't form into solid objects but just float around as loose clouds of intangible stuff.

And yes, we do know this. Dark matter is not just a guess. We've verified its existence through observation; we can't see it, but we can see its gravitational effects, such as the gravity-lensing of objects behind it and the effect it has on the rotational velocity of galaxies. And dark matter isn't just normal matter we can't see. Observations have ruled that out. Certainly there are plenty of normal-matter bodies out there that we haven't detected yet, but if the dark matter consisted mainly of dark compact objects, it would have an observational profile that doesn't fit the data. For instance, a galaxy surrounded by such a thick cloud of dark planetoids, or MACHOs (massive compact halo objects), would appear dimmer because of all that stuff in the way. But that isn't what we observe. The mass is unquestionably there, and is four times as abundant as ordinary matter, but the vast majority of it must be something other than ordinary (baryonic) matter, most likely WIMPs (weakly interacting massive particles -- yes, scientists love frivolous names for things).

For more: http://en.wikipedia.org/wiki/Dark_matter

True, some of what we call "dark matter" today is baryonic matter like brown dwarfs and dust clouds and black holes, but we only call it that because we haven't found it yet. It makes no sense that people in the 24th century who are actually visiting a nebula of non-illuminated baryonic matter would call it "dark matter," any more than a present-day map of North America would label it "Terra Incognita." So the "dark matter nebula" from that episode would have to be made of non-baryonic matter, since that's the only thing that might still be called "dark matter" that far in the future. (Personally I doubt the term will endure once we definitively identify the stuff and can describe it more accurately, but it's possible it might survive as a vernacular term.)

 

[Timo]

...Or get a new meaning. All sorts of phenomena might be plausibly called "dark matter" today, without in any way being related to the cosmological mystery of missing gravity sources (say, carbon-soot-covered asteroids, or low-albedo industrial powders, or whatever). The same should be true of tomorrow.

So, if missing gravity sources cease to be an issue of scientific debate by the 24th century, it should be perfectly valid in TNG "In Theory" to dub a type of matter that is invisible until illuminated by a special trick "dark matter".

(Really, it should be all right to refer to the torpedo trick that illuminated the nebula "the big bang", too, even if 24th century cosmologists continue to believe in an originating explosion; all big bangs are big bangs, even if one of them has a special meaning.)

The dark matter in ENT "First Flight" would be more an issue of old Earthling terminology persisting. It's a bit unlikely that Vulcans would have a concept of dark matter in the cosmological sense, but quite possible that Vulcans speaking English would use this term to describe a type of matter (or matter-analogue) that was one of the things old Earthling scientists were not seeing when agonizing about the missing mass.

Timo Saloniemi

 

[Myasishchev]

In any event, the words "dark matter asteroid" make me want to puke.