The Drake Equation simply oranizes the unknowns at the highest level. So each one of those terms could be expanded almost indefinitely with the particulars of each term.
Take for example the term Ne, the number of potentially life-supporting planets around each star. Not long ago we took that to mean planets in the habitable zones of sun-like stars. But now it looks like we should also consider moons of giant planets outside the habitable zone, planets gravitationally locked to red dwarf stars ( but maybe only if they are water worlds, but maybe not), etc. So Ne may break down into many terms describing the possible types of habitable planets around different star types. And each of those could have its own nested unknowns.
Think of the Drake equation more as a tool for organizing your thinking rather than a useful formula for finding a concrete number.
And that is still being pretty damn close, relatively speaking.
Also assumes that you are unable to detect these things many light years away, as we are more or less able to do now, much less in the future when such an undertaking is in use, and also assuming that they need to have pinpoint accuracy at all, as opposed to just heading to whatever star seems convenient as they approach the target galaxy.
Being off by billions of miles isn’t even a rounding error when you are talking about a quadrillion mile trip.
That’s going to be completely irrelevant for any sort of extra galactic endeavors.
Maybe. Apparently I can’t seem to get my head around it because I know that 85% of the Universe’s matter is dark matter. And if dark matter consists of black holes, I find it hard to believe they’re completely irrelevant.
Yes, I understand that travelling through virtual vacuum won’t be a problem (it is not an end in itself after all).
But once you approach and/or go through galactic space, chances are you’ll end up near a black hole.
If dark matter is made up black holes, that is.
No, chances are that you will not go anywhere near a black hole. Even if all dark matter is made of black holes (and the paper that this is based on doesn’t make that claim, and it also is at best a hypothesis that fits some models better than others, but also requires observations that have not been made in order to be viable.)
Space is big. Really big. Black holes are actually pretty small.
Two ways you end up near a black hole. You see one, and want to go check it out, or you head towards the very center of a galaxy.
I’m not sure at high speeds you can really see the black holes that do not lie at the center of the galaxy.
And if dark matter consists of black holes, there should quite a lot of them as this article states: “The 30-solar-mass behemoths would sit at the center; the more common littler ones would fill in the rest of the space. These clusters would lurk everywhere astronomers think dark matter is.”
The article says that black holes that are smaller than the ones at the center of galaxies should be the common ones, which therefore are supposed to be widespread “everywhere astronomers think dark matter is.” And they should really be scattered everywhere throughout galaxies because galaxies behave like discs, not like clusters of stars and accompanying celestial bodies.
Right, and once again, that article is complete hypothesis, not backed by the majority of the physics community, and while it explains one particular model slightly better than other hypothesis, it has many problems with it, and isn’t needed to explain the slight deviations from the model to observations that we do have.
I put it at maybe 5% chance that it’s right.
But, I have been giving the benefit of the doubt the last couple rounds and assuming that it does pan out. If that were the case, that would not make a difference. They would still be spread out across vast distances, where the chance of coming within light years of one would be minuscule.
When they say everywhere, they don’t mean that they take up all space, they mean that they could be anywhere. They are not saying that they are literally “everywhere”.
You truly are underestimating just how big space is.
There are lots of plausible hypotheses, that don’t contradict existing known data, for why we don’t see evidence of advanced ETs.
Why are we spending so long discussing a hypothesis (black hole clusters) that is nowhere near attaining that status?
Agreed.
And as mentioned upthread, and ignored, we have performed gravitational microlensing surveys.
To the extent that our galaxy could be littered with black holes, their size and/or distribution seem insufficient to affect most lines of sight across the entire galaxy.