Quote:
Originally Posted by BrianTheMick2
We look* objects that we pretty much know the luminosity** of. This is akin to your flashlight, except that we have the make, model and serial number of that flashlight and have put in a set of fresh batteries. The ones that are less bright (given that we know how luminous they are) are more distant. This seems fairly obvious if you have a rudimentary understanding of geometry.***
This seems like a circular argument to me--at the very least it is raising red flags. You say "we look at objects we know the luminosity of" ... well how could you know the luminosity of it unless you looked at it before?
Also, this is nowhere in the same universe as knowing the make, model, and serial number of a flashlight. No one on earth has left even this solar system. Not a soul on the planet has experienced life in a different galaxy, or traveled even 1/100000^100000'th of the distances were talking about. And you want me to believe our understanding about it is similar
at all to our understanding of an object that we ourselves invented, know how to create, can take apart, dissect, repair, use, feel, see, etc? Our understanding of the one and the other are in completely different realms. As Hume said, the further you get away from things you can interact with directly, the lower your confidence should be in your conclusions about them.
Quote:
Originally Posted by BrianTheMick2
The ones that are more distant (via the above) have more redshift than the ones that are less distant. Given that we also know the wavelengths various things give off when they aren't in relative motion to us****, it is a relatively simple calculation to figure out their apparent motion relative to us.
This is rubbing me the wrong way for a number of reasons. Once objects are far enough away from us, they wont move enough to be measurable in our lifetime. What I mean is, if I want to calculate how far a ship is out to sea, ... well, I wont get into this here and now. Again, it seems circular.
We don't know what wavelengths various distant things give off, and it is wrong to say that we do. We know what they are when they reach Earth, that is to say, when we measure them. We can use induction to draw certain conclusions that may or may not be true from this using life experience we have, but it is not a testable hypothesis--we cannot travel to a distant galaxy and measure anything because we cannot travel to a distant galaxy. We are stuck in a glass bowl looking out and licking up the scraps of information that happen to ping us, but we cannot go out into the field and collect samples, we cannot interact, we cannot change one star while holding the control constant, and the conclusions about the universe we make from inside our bowl must be, due to the nature of our situation, rudimentary at best.
Quote:
Originally Posted by BrianTheMick2
It is the opposite of very far from the truth.
Unless, of course, you are only saying that we don't see things except for through direct observation with no analysis of those observations. That is fine, but I'm curious whether you believe in things like atoms and chemical reactions and electricity and female orgasms. The models we have created to explain those phenomena that we can directly see all certainly make less sense than an expanding universe.
It doesn't matter if they make sense if they are true. What does matter is that they cannot contain any contradictions. If they require us to assume A and not A then I don't need to read any more about them because I know where it will end up.
edit: I don't think you should have used atoms as your example, you should have used a deity or higher power. Atomic theory is a testable hypothesis, and if real, something we can manipulate, control, test, observe, change, shoot lasers at, draw things with, etc. A deity, however, is something we cannot interact with and is an untestable hypothesis and is therefore of no use to science. Conclusions about distant galaxies are somewhere in the middle, where we cannot interact with them, but we can observe whatever they sent our way in the past.
Last edited by Ryanb9; 04-24-2020 at 11:00 PM.