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Do 'Ultracool' Brown Dwarfs Surround Us?
astroengine writes "The recent discovery of two very cool 'T-class' brown dwarfs in our cosmic neighborhood has prompted speculation that there may be many more ultracool 'failed stars' nearby (abstract). Not only are these objects themselves very interesting to study, should there be many such brown dwarfs spanning interstellar space. Perhaps they could be used as 'stepping stones' to the stars."
Especially if they manage to show a link between this research, the fairly regular extinction events over the history of the planet, and The Nemesis Hypothetical Star...
Do not look into laser with remaining eye.
Yeah, sure. Because when you're on a 100 year cruise to colonize Sirius the thing you really want to do
with your intertia is slow down and stop at your local brown dwarf to pick up a pack of Coke and some cigs.
I can't believe how racist slashdot has become. They may be ultra cool, but calling them brown is inciting hate. African American little people is the PC term.
In order to have elements beyond carbon one needs a bigger star than our yellow sun. Large stars tend to supernova and become brown dwarfs or black holes in some cases. Some stars fail and become brown dwarfs as well. But you can still get hydrogen from them from solar winds for spacecraft.
It is hard to detect them because the brown dwarfs are Earth size and do not give off much heat or light. Our sun Sol is supposed to have a companion star nearby called Nemesis that is a brown dwarf and throws asteroids at our solar system.
Tut! Oh God! Why didn't we think of this! It's so obvious! That's where all our research money has gone to waste, assuming that we are omnipotent in our calculations and not including error ranges!
Hell, let's just assume that that 83% (or thereabouts) of all matter in the universe being "missing" is just us overlooking that there might be planets on every star (and the fact that the biggest planet in our own Solar System weighs less than 0.1% that of the Sun).
God, it's so obvious. Why did we never take this into account in any of our billion-dollar-funded research programs filled with (quite literally) rocket-scientists?
Or maybe we did, you pillock...
There will never be any interstellar trade. The distances and velocities involved require energy expenditures vastly higher than the cost of any valuables you may wish to transport. You might say the costs will be "astronomical". The only movement between stars will be radio signals and initial colony ships.
P.S. we infer most of the mass of the universe through the movement of things we can observe (because all mass bends space-time) - and we get a pretty god-damn accurate picture of what MUST be in it's local neighbourhood for it to act like it does. The fact we can't see the mass itself is neither here nor there - we're literally looking at how a galaxy (BILLIONS OF STARS!) behaves and inferring how much it and it's surroundings must weigh in order to act like that. There's about 170 billion galaxies to look at.
On those scales, extra planets and a few missing stars don't even factor into the error ranges because they are so inconsequential. Hell a couple of extra galaxies doesn't even register.
The idea of Y-class brown dwarf stars are neat and all, but this whole 'stepping stone' idea is not really explained. Why would we use these as stepping stones? Is there an advantage to it? I don't understand why we would use them is all.
I call it 'The Aristocrats'
Information may be what is traded. But self-replicating mining and factory machines can bring ship building and fuel mining costs to essentially zero. Then the only cost is time of assembly and time of transit. Maybe there is something physical that would be worth it.
The number of extra planets or dark stars you would need to matter, *would* show up because there would need to be soo many. They have been looked for you know. For example if there are millions more of these cold brown dwarfs than what we already have estimated, then the average distance to them would be so small that we would be able to observe many of them (probably would imply at least a few within the ort cloud). We would see many more micro-lensing events ... etc etc.
You can't have your cake and eat it too. If there is enough to explain dark matter, there is more than enough that observing them would be quite trivial.
On top of all that, such objects do not explain other observations of dark matter. In particular, the bullet cluster. We can in fact "see" dark matter.
If information wants to be free, why does my internet connection cost so much?
So these brown dwarfs are essentially big balls of (mostly) hydrogen with the centers under tremendous pressures and temperatures but not quite hot enough to "light" (in a fusion sense). Well what would happen if you managed to drop a fusion bomb on it? (On or near the surface where the temperatures are low but the high gravity might still compress the hydrogen into the megabar range).
While (probably) it would just fizzle, could the concentrated energy ignite just enough so the whole star went boom? (Like a Type I supernova?). I mean the "temperature" of an H-Bomb is in the hundreds of millions of degrees maybe it just requires one tiny (if an H-Bomb is "tiny") spark. Just like you can pour millions of gallons of gasoline on a barely sub-critical mass of Uranium and it won't go bang but one small neutron generator and you've got a mushroom cloud. While the impacts of asteroid and larger bodies could deliver a lot more energy, an H-Bomb could do so more INTENSELY.
I guess this is what the first H-Bomb scientists were worried about when they feared the first H-Bomb *might* ignite the water vapor in the atmosphere and consume the entire world. Just how easy would it be to blow one of these things up? Could you do it with even smaller cooler less dense bodies, say Jupiter (as proposed by sci-fi writer Charles Sheffield) or Neptune? (Tried it on earth, nope doesn't work). Lastly, our sun is already alite, but the RATE of fusion reaction is very slow (each gram of the sun produces far less energy per time than, say, a live elephant). Could we speed it up? Could an H-Bomb (or a suitably powerful laser such as was used in one of the Man-Kzinti war sci-fi books) trigger a local (or maybe not so local) explosion?
I guess this was the general idea behind the movie "Sunshine" (good movie). Seems they had some sort of very dense (causing a local gravitational field) fission bomb to re-ignite the sun. Wish they had a companion book to flesh out some of the details.
Anyway I know these ideas are probably non-sensical to any physicist but don't have enough math and physics knowledge to calculate it for myself. If anyone of you is so inclined and it won't take much time or effort, I'd appreciate the debunking (or not!) of this idle speculation.
(For even crazier speculation, how about igniting all that supposedly great fusion fuel Helium-3 that is just lying around on the lunar surface? Would it be enough to blow the moon out of orbit a la "Space 1999"?)