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How Do We Know the Timeline of the Universe?
StartsWithABang writes The history of the Universe happened in a well-known order: inflation ends, matter wins out over antimatter, the electroweak symmetry breaks, antimatter annihilates away, atomic nuclei form, then neutral atoms, stars, galaxies, and eventually us. But scientists and science magazines often publish timelines of the Universe with incredibly precise times describing when these various events occur. Here's how we arrive at those values, along with the rarely-publicized uncertainties.
We pretend we do, but it was actually re-created yesterday after the reboot of God's Second Life server farm.
Think of it as a perfect sphere.
Early Universe ideas? Not fact. Not "well-known". Guesses.
That's... really selling science - and the scientific method - way short.
It's not "guesses", it's hypotheses, which are by their nature our best explanations of something given our current understanding of how those things work.
Calling these "guesses" reduces all the science that's actually going on and puts it on the same level as Joe Schmoe's wild-ass guessing on subjects he's not familiar with.
There is a world of difference between Joe guessing what happened in the early days of the universe and a scientist that has devoted several years of his life studying the matter putting forth a hypothesis of what happened.
Please don't paint these as the same thing, it's just doing the anti-science folk a service, and the rest of us a disservice.
"Total destruction the only solution" - Bob Marley
LOL. Hypothesis is just a fancy way to say "here's my guess". Whether put forward by Joe Schmoe or Johnatan P. Schmoe, PhD it means the same thing.
It really doesn't.
A hypothesis has to make sense, has to be based on observation and/or our best current knowledge of the subject matter. Ideally it is testable somehow, even if only mathematically or theoretically.
A guess doesn't have to have any of those constraints. "Aliens did it" is a guess, but it's not a hypothesis.
"Total destruction the only solution" - Bob Marley
Disclaimer: I work in a cosmology department. What you've just written is total bullshit.
We make predictions, and they work. I could tear apart the nonsense you've written, but instead let me just point to the facts:
http://xkcd.com/54/
http://sci.esa.int/planck/5155...
http://www.astro.virginia.edu/...
I could go on an on posting pretty pictures and graphs matching data, but let me just say that we work incredibly hard to make predictions from our models, we test those predictions against observations and test many of our systems to over 5 sigma. To say that what we're doing is just guessing is frankly insulting to a lot of incredibly hard working people. We /predicted/ the CMB then observed it. We predicted the power spectrum then observed it. We predict the population densities of stars at certain redshifts, point telescopes and damned well count the things and find them to match. We predict galactic rotations, lensing effects, (integrated) Sachs-Wolfe effects and a hundred
other little things, and we damned well test them, lining up our models against observations. We certainly haven't got everything right yet - there's a lot of room for investigation as to what went on before inflation, say, or exactly what type of matter dark matter is (but before you say we know nothing about it, I suggest you educate yourself - we don't know what it comprises, but we have damned good bounds on certain properties like its ratio of pressure to density). We don't know why the cosmological constant takes the value it does, but a whole host of checks all come up with the same number.
So no, we don't have "Guesses". We have repeatedly tested hypotheses from which we observe consistent data and find heavy statistical significance. What you've done is insult a lot of incredibly hard working, very smart people who are very serious about their work.
You can understand it to the level of detail you are willing to spend on. So in this case "The Right Stuff" is mostly time.
You want to spend 5 minutes understanding cosmology, you're going to understand it at the comic book level, same as any other field of study.
The thing is our knowledge of the universe is so infinitesimally small that really it would be far fairer to call it a guess than a Hypothesis.
How do you know it is "infinitesimally small"?
That's sound bite cosmology. We don't ever know what we don't know.
The idea that there are certain types of stars that have certain compositions, and certain sizes and will likely have a lifespan of a certain number of years is a theory that has worked pretty well. We add to it when we find something that doesn't quite fit, and we modify to it as needed. Wanna see scientists get excited? When something doesn't fit, and they have to go back to figure out why. That's a happy scientist. Wouldn't be a happy politician or theologian though
But we do know some things about the universe. We'll never know it all, thank goodness, but a lot of physics pieces are falling into place.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.