Alarmed_Economics_90 t1_j1dgao2 wrote
Once you figure out that the Universe is expanding, (Hubble did this when he figured out the "red shift" on stars via the Doppler effect) all you need to do is measure the expansion rate today and use the laws of physics to determine how the expansion rate must have changed over time (looking at the oldest stars we can see...) Then you just extrapolate all the way back until you achieve the conditions of the hot Big Bang itself.
pete_68 t1_j1dh05z wrote
If only we knew the laws of physics. Sadly, we still only have an estimate that works pretty well, but has a lot of holes in it. We don't know the Hubble "constant". Is it 73 or 67 km/s/Mpc? Depends how you determine it.
Is Dark Matter real? Maybe. Maybe not.
We can't explain the constants of physics.
There's a lot of unknowns. The age of the universe being one of them. It's all theoretical right now.
Alarmed_Economics_90 t1_j1dhqap wrote
Yeah, scientists just guess, since they're not sure. /s
There are margins of error that are taken into account when values aren't known exactly. That doesn't mean we just have no darn idea. "It's all theoretical" is wildly inaccurate. The margin of error on the age of the universe is like 1% - so that's a lot, but it's not, like, "could just be anything, we have no idea."
pete_68 t1_j1djqrq wrote
"Calculating the age of the universe is accurate only if the assumptions built into the models being used to estimate it are also accurate. " - Wikipedia
So yeah assuming the model is accurate. But that's an assumption. Not a known.
Alarmed_Economics_90 t1_j1ejm32 wrote
I assume you left out the rest of the paragraph because you don't know what Bayesian and Strong Priors means.
The inaccuracy is quantifiable if you do.
pete_68 t1_j1ew9vg wrote
I assume, based on the arrogance and presumptuousness of your comment that you have a GUT all figured out and have reconciled the disparities in Hubble values.
Alarmed_Economics_90 t1_j1exr11 wrote
That's called "a straw man" argument, with a bonus false dichotomy.
Pretending that we don't know anything because we don't know everything is a glaring indicator of ignorance - not only of the topic at hand, but more generally of a weak grasp of epistemology and argumentation.
MisterLupov t1_j1di9mu wrote
It is not "just theoretical"
Hubble constant, despite what its name suggests, has been shown to not be a constant already, we know it's increasing. Dark matter is 99.9% a certainty, we observe it's consequences and interactions. We only need to experience it first hand to say it's real, that's called being prudent. We can actually explain lots of constants in physics.
Dumguy1214 t1_j1dj4q8 wrote
thats it, science is what we know at the time
I am 43, I remember kids books talking about the universe being 7 billion years old
I wonder after 20 years what people will think of us
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