Astronomers Watched a Star Disappear. Now JWST Might Have Some Answers
universetoday.com
universetoday.com
I sure hope one of them wasn't called Dudley Bose [1].
Figure 8 looks weird, how they fit a parameterized model to 3 points?
(The blackbody is a smooth single hump, while the PAH spectrum are the jagged atomic and molecular lines coming from quantum mechanical effects, which have discrete energies.)
And the assignment of blackbody temperature (T = 500 K). This is how many free parameters, fit to three points?
(I'm aware that the emission spectrum for (their specific chosen model of) PAH dust has a fixed shape. That's not my confusion).
In principle, you could fit every single atomic/molecular spectrum to the data and falsify everything else based on some goodness of fit test, but no one does this.
Another thing about these molecular spectra is this: if there is an emission line missing, then it cannot be the spectrum you are fitting. These things do not change with environment, and can only be red or blue shifted due to special relativity. Every PAH spectrum must have the same lines. It's like a fingerprint.
There have only been two in our galaxy in relatively modern history, 19th century
Dark Forest makes no sense.
If you are an intelligence capable of faster-than-light interstellar travel, capable of snuffing out stars, capable of collapsing dimensions-- you don't care about anyone else. Nobody's going to compete with you for resources.
Scarcity no longer exists. All you care about is energy and you have mastered it. Energy is practically infinite to you. You can sit off to the side of black holes or neutron stars harvesting energy from their relativistic jets.
Finding or controlling a consistent supply of physical matter, least of all individual stars and planets, is no longer relevant to you. You can just pluck individual hydrogen atoms out of the interstellar void and rearrange them using your sources of near-infinite energy to transform them into million-kilometer-wide cubes of whatever you want.
If someone makes it to your level of mastery of the cosmos, you would just share the locations of any of the other several hundred billion sources of free and limitless energy.
You ain't killing a star because an inhabitant of one of its planets might take your planet over. You haven't needed to live on planets for billions of years. You can construct atomically-perfect structures of arbitrary size and composition out of what we perceive to be the nothingness of space.
You don't need dirt.
Except other intelligences at similar level to you. And, you first need to get there.
It's worth re-reading the core axiom of the Dark Forest theory, as given in the books. They included communication delay (light lag) and unpredictably rapid pace of technological advancement. The latter may or may not be true in the real world. It could be that we're on the final parts exponential-looking part of an S-curve, and everyone at our level would follow the same trajectory. Or it could be that we're riding an actual exponent. Or we may be 5 minutes from hitting singularity. In the latter scenario, a more advanced civilization has good reasons to believe the less advanced civilization may overtake them between the former learning about existence of the latter, and the latter learning about existence of the former. An immediate first strike would make sense then.
> You don't need dirt.
It's never about dirt. It's about having something some others may want, and not being certain they won't kill you to get it.
I'm not sure that's true. Evolution is competitive. An advanced race may decide to remove potential competitors before they become a threat.
I'm not saying I agree with the dark forest. I just wanted to assert that the dark forest idea isn't limited to "we have something they want". It could also include. "They're jerks"
I'm not convinced. There is a big difference between infinite and merely very large. I think the demand for energy will grow with the supply, as it has for us.
I think if we apply what is happening on Earth that is not going to be true.
It seems as though per-capita energy consumption increases to a certain point, and then stops. In the US it peaked in the 1970s and has fallen such that even with the intervening population increases US energy demand has barely increased.
Depending on who is counting energy consumption (this is all sources of energy not just utility electricity) either peaked or plateaued in 2017-2018.
In the US, EU, and Japan energy consumption is decreasing (and it is decreasing faster than population loss in Japan). There are a number of reasons for this but mostly it's efficiency improvements-- which still count!
I think there is only so much consumption that a TYPICAL human being can do. Only so much heating and cooling, only so much travel, only so many hot showers. Everyone gets to that point, and then stops. They don't reach that level and start setting up tesla coils for funsies.
Once they reach that apex, efficiency improvements start to decrease overall consumption.
If population predictions pan out and a shift to more efficient energy production and storage techniques continue, I'm willing to bet that in a century the world will be using less energy than it is today.
Same thing for hyper-dimensional interstellar megagods. There are only so many 100km x 100km x 100km cubes of atomically-pure gold one needs in their collection.
While this is my understanding too I would dispute the cause. Energy use did not peak because demand simply levels out at some point, it peaked because energy return on investment is declining. This is a thermodynamic inevitability barring a breakthrough of the same magnitude as the one-time fossil pulse whose apex we have (arguably) just traversed.
> [..] a more likely model is that the 2009 brightening was caused by a stellar merger. What appeared to be a bright massive star was a star system that brightened as two stars merged, then faded.
But wouldn't it be cool if this was because someone brute-forced the nine billion names of god?
For those unfamiliar: Pandora's Star is by Peter F Hamilton. It details humanity's encounter with a star system that is completely enclosed in an impenetrable exotic matter/energy shell. It's fantastic sci-fi, a great adventure with fun characters, loads of bizarre future stuff, and very cool action.
Highly, highly recommend!
From a distance, the now-enclosed star seems to wink out in a very brief time.
And indeed, the brightening is Probably from the construction phase of the sphere.
Excellent books, I've read them like a dozen times.