Quote:
Originally Posted by Mr.Coffee
I guess I gotta ask HOW scientists "know" about a lot of this stuff. I'm sure they know a lot but...
|
It's all about observation, creating models, testing predictions, refining models, etc. The amount of research out there is staggering. Check this out:
http://arxiv.org/year/astro-ph/08
That's an average of what, 800 papers submitted in the subject of astrophysics PER MONTH. Arxiv is I think an open venue unlike a journal, but gives you an idea of the level of activity.
Quote:
Originally Posted by Mr.Coffee
do they just sit there counting stars? And then make a guess?
|
Pretty much, they can point telescopes in different directions and count stars, types of stars, brightnesses, colours, distribution, etc etc.. I'm no expert, I'm sure evman could give exhaustive details on how they come up with their numbers.
Quote:
Originally Posted by Mr.Coffee
How do they even know about the approx. size of the universe. Like honestly how big are these telescopes? It just seems a little fishy to me that they can make earnest predictions on numbers of stars and stuff.
|
They use many different ways to measure things like this, if the numbers all agree then that means the number is better supported than a number derived from just one observation.
They use things like globular clusters, supernovae, stars called Cephids, etc and ultimately the red shift of things moving away from us to determine distances of things, since light moves at a specific speed.
It's very deep stuff, and very fascinating. I wish I'd been an astronomer or cosmologist or something like that.
Quote:
Originally Posted by Mr.Coffee
This stuff, I'm sure, is a lot more complex than I'm giving it any credit here but how do they know the universe has boundaries or "multiverses" (mentioned in this thread) or that there's more stars than pebbles of sand and stuff.
|
I don't think the universe has boundaries as such, does the surface of a sphere have a boundary? Multiverses are speculated but at this point it's all just that, speculation.
Quote:
Originally Posted by Mr.Coffee
Aren't a lot of these "knowns" still theories?
|
You say that like it's a bad thing. In science a theory means a well supported framework of facts and hypothesis that has explanatory power and makes predictions that can be confirmed (or not confirmed). A theory is not a pie-in-the-sky idea.