3:49 AM
Shysics

5 hours later…
8:26 AM
… or with an epidemiologist or any other exploratory data analyst

8:46 AM
He just used the Banach-Tarski paradox

2 hours later…
10:18 AM
If I was born yesterday and you were born tomorrow, how many cows have a flu in South Asia?
I have a sore throat... it's quite torturous.

3 hours later…
12:55 PM
:-)

Me trying to cook up happiness

1:53 PM
@ACuriousMind hi,
Is time, can be be negative, as universe is expanding, time shift symmetry also change is the time reversal is possible.

2:19 PM
There are no known instance in cosmological history where the arrow of time reversed.
There are also no known instance, barring phase transitions, where time translation symmetry is broken

3:18 PM
What arrow of time do you even mean
"Arrow of time" can refer to like half a dozen thing

3:44 PM
@Slereah can you send me the book info again

There it is
Thank you
The librarians I went to ask had that look about them like "An interlibrary loan? Why did this caveman wander into our multimedia emporium"
I went to see the local head caveman of the library but apparently asking for a loan in the US was beyond their powers

why wouldnt they digitize it for you

4:21 PM
ugh, dropped my coffee right after buying it
today's gonna be great

moral of the story is dont buy coffee

or don't buy droppable things i suppose
but for real it'd be awesome if someone came up with coffee you don't need to drink
like maybe a coffee food

ok I should be more clear: At least the thermodynamic arrow of time is not known to have reversed during cosmological evolution so far, in answering Yuvrak question on whether time reversal is possible
I don't know what happened to the other arrow of times in cosmological history, especially the quantum ones

i'm not really a thermodynamics expert but i'm not sure how well the second law is expected to hold at that scale when some of the others fail
i guess it's a matter of occam's razor, since we haven't seen any violations of it

indeed

4:42 PM
@SirCumference There are enough stimulants you only need to snort ;)

@RyanUnger good question
More importantly, why don't they digitize all their thesis?

Hi, everybody.

hey

The recent xkcd has potential to be cited many times on this site in the future...

The card analogy is also v. useful with respect to probabilities
If a creationist tell you that such protein only has one change out of $10^100$ to appear
Take out a deck of cards
And under his amazed eyes
Pick out a combination of cards that only has one chance out of $52!$ to appear
Wizardry

5:27 PM
Banach-Tarski is is nonsense, right?
Right?

@DanielSank Depends on your axiom system

5:59 PM
@Slereah Thanks for the references on (2+1)-D gravity and junction conditions, made significant progress. Was wondering if you knew any papers which talk about computing the Einstein-Hilbert action with a source placed at the screen (at some r=R)?

@NaveenBalaji What?

You had suggested Carlip's book on (2+1)-D black holes, I was referring to that
As for the action question, we consider a spacetime with a source on a screen (shell at r=R). Now, at $V^{-}$ there's gonna be flat space and at $V^{+}$ space is gonna be Schwarzschild-like. I was wondering what the contribution of the source, say J(R), would be to the action.

1 hour later…
7:09 PM
@ACuriousMind Maybe I should start a meta post suggesting we make a new vote to close reason where the close banner is just a link to this comic
On a somewhat more serious note, would there be any way to have the site make some warning pop up if a user is making a question and types the words "My attempt"? I feel like usually questions that have that phrase are just "check my work" questions that should be closed.

7:44 PM
@NaveenBalaji It's a matter source
So a matter term
The action of a 2D shell is going to be the Nambu-Goto string action
Or Polyakov

4 hours later…
11:21 PM
@DanielSank Why do you think Banach-Tarski is nonsense? It doesn't apply to physical objects made of atoms, though. It only works on mathematical objects made of a continuous substance. It's trivial to construct a bijection between a 1×1×1 cube & a 2×2×2 cube.
Banach-Tarski is interesting because it says you can perform that bijection using a dissection into a small number of subsets that are translated (no rotation is required). But those subsets aren't simply connected, they're Cantor dusts, IIRC.

Worst part is
If you assume the negation of the axiom of choice
You still get horrible nonsense

> All justification has to come to an end somewhere.
Wittgenstein

Here is a cute dissection "paradox" I first saw in a Martin Gardner column, it was possibly an April Fools Day article.
2
He said that it works by virtue of Banach-Tarski, but of course he was only joking. In this dissection a 5×13 rectangle is transformed into a 8×8 square. Can you see how it works? If you're on a mobile device, you need to go to the desktop view to enable the display of the SVG animation, otherwise you'll just see the source code.
@Slereah I choose not to assume the negation of the axiom of choice. ;)

11:36 PM
Peano's axioms are best rly

i think all axioms ever are false

This sentence is false.

Axioms are axiomatically true. But you can ask if a given set of axioms are internally consistent.

consistency is overrated

what rates higher?

11:43 PM
Consistency is useful; completeness is overrated.

is there something wrong with defining all statements as false

rating is overrated :P

if a set of axioms is inconsistent then you just need to add more truth values :P
whatever happened to things like this, no one does research on this stuff anymore

looks like it leads to fuzzy numbers