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I'm a Particle Astrophysicist, ask me anything
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Tsadkiel
Aliastra
Gallente Federation
#1 - 2012-02-03 21:38:06 UTC
greetings!

I am currently working on my PhD in Particle Astrophysics and recent events have shown me that i need way, WAY more experience explaining sciencey type stuff to people. SO, i figure, where better to practice then on the forums of a Sci-Fi game =D

ask away!
Amaroq Dricaldari
Ministry of War
Amarr Empire
#2 - 2012-02-03 21:39:01 UTC
Why can't one change the past and correct their mistakes?

This is my signature. There are many like it, but this one is mine.
Drop-Me-Own-Stocks Darius
Caldari Provisions
Caldari State
#3 - 2012-02-03 21:39:38 UTC
What is the thaumic equivalent to string theory?
Who would like to buy a melon?  Madame, would you like to buy a--   ...oh. I see you've already got some.   Who would like to buy a melon?
Kiroma Halandri
Brutor Tribe
Minmatar Republic
#4 - 2012-02-03 21:40:39 UTC
How much wood would a wood chuck chuck if wood chucks could chuck would?
[center]I'm not Anti-Social,    **I just don't like you.[/center]**
Tsadkiel
Aliastra
Gallente Federation
#5 - 2012-02-03 21:41:03 UTC
There are a number of possibilities but the most likely is simple causality. if you went to the past to correct your mistakes then in the future, you wouldn't have any mistakes to go back and correct, so you wouldn't go back to correct them, but then you WOULD have mistakes etc... *goes cross eyed*
Amaroq Dricaldari
Ministry of War
Amarr Empire
#6 - 2012-02-03 21:41:49 UTC
Kiroma Halandri wrote:
How much wood would a wood chuck chuck if wood chucks could chuck would?

Why do you have to be such an ass all of the time?

This is my signature. There are many like it, but this one is mine.
Tsadkiel
Aliastra
Gallente Federation
#7 - 2012-02-03 21:43:40 UTC
if by thaumic you mean thaumaturgic, then who cares?! you have MAGIC!!
Tsadkiel
Aliastra
Gallente Federation
#8 - 2012-02-03 21:45:42 UTC
Kiroma Halandri wrote:
How much wood would a wood chuck chuck if wood chucks could chuck would?


that depends on the chucking rate, which we would have to measure. we then multiply by the average lifetime of said woodchuck to get the answer...
Tsadkiel
Aliastra
Gallente Federation
#9 - 2012-02-03 21:48:35 UTC
but seriously though, no one's curious? ; ; i needs the practice!
Amaroq Dricaldari
Ministry of War
Amarr Empire
#10 - 2012-02-03 21:55:03 UTC  |  Edited by: Amaroq Dricaldari
Tsadkiel wrote:
if by thaumic you mean thaumaturgic, then who cares?! you have MAGIC!!

So THAT is where the word 'magic' comes from. Drop the 'thau' and the 'tur'...
Tsadkiel wrote:
but seriously though, no one's curious? ; ; i needs the practice!

I am curious, but I really wish I could go back in time and fix all of my mistakes on these forums. Unfortunately, I can't. I can only move in three of the many dimensions that make up this universe. I have absolutely no idea how those Hypercube Factories do it.

But yeah, I think we need some more serious posters.

This is my signature. There are many like it, but this one is mine.
Jiska Ensa
Estrale Frontiers
#11 - 2012-02-03 22:05:40 UTC
Explain in simple terms so my idiot brain can handle it, how the Big Bang (expansion, inflation, zero-point energy, whatever) occurs in the "infinite universe" model...
Tsadkiel
Aliastra
Gallente Federation
#12 - 2012-02-03 22:10:01 UTC
dimensions are always fun to talk about :3 extra spacial dimensions add some really interesting consequences to the world.

consider this.

imagine you are holding a rectangular block (like a lego brick or something). the brick has three spacial dimensions: Length, Width, and Depth. if we shine a light over the brick we get a shadow, which is a two dimensional projection of our three dimensional brick. if we change the orientation of the brick with respect to the light, the area of the shadow changes, but it is still just a projection of the SAME OBJECT.

now, suppose we have an object that has many MANY spacial dimensions and we try to observe it. what we will see is a three dimensional projection of that object. if we were to move around that object, its volume may change, but it is still just a projection of the SAME OBJECT.

what does this mean?
the TARDIS may not be mathematically impossible, and if we ever get the ability to build objects in multiple spacial dimensions, then we can make things that are bigger on the inside than they are on the outside.

NEAT!
Lutz Major
Austriae Est Imperare Orbi Universo
#13 - 2012-02-03 22:17:48 UTC
What's your thesis about?
Amaroq Dricaldari
Ministry of War
Amarr Empire
#14 - 2012-02-03 22:23:32 UTC
Tsadkiel wrote:
dimensions are always fun to talk about :3 extra spacial dimensions add some really interesting consequences to the world.

consider this.

imagine you are holding a rectangular block (like a lego brick or something). the brick has three spacial dimensions: Length, Width, and Depth. if we shine a light over the brick we get a shadow, which is a two dimensional projection of our three dimensional brick. if we change the orientation of the brick with respect to the light, the area of the shadow changes, but it is still just a projection of the SAME OBJECT.

now, suppose we have an object that has many MANY spacial dimensions and we try to observe it. what we will see is a three dimensional projection of that object. if we were to move around that object, its volume may change, but it is still just a projection of the SAME OBJECT.

what does this mean?
the TARDIS may not be mathematically impossible, and if we ever get the ability to build objects in multiple spacial dimensions, then we can make things that are bigger on the inside than they are on the outside.

NEAT!

I know all of that already. That is how the Cargo Containers in EVE work.

But thanks for attempting to enlighten me.

This is my signature. There are many like it, but this one is mine.
Tsadkiel
Aliastra
Gallente Federation
#15 - 2012-02-03 22:33:42 UTC  |  Edited by: Tsadkiel
Jiska Ensa wrote:
Explain in simple terms so my idiot brain can handle it, how the Big Bang (expansion, inflation, zero-point energy, whatever) occurs in the "infinite universe" model...



this one is a doosy but it is a good one. before i say anything i think it is important to point out that there is a limit to our knowledge of the early universe and the questions like "why did the big bang happen" and "what happened before the big bang" are the holy grails of modern cosmology. to be frank, we don't know yet. there are several ideas out there but few if any are even testable yet.

that said, let's begin! there is a lot to put here so i will probably post and edit in chunks. there is also a lot more to it than this. i'm cutting out a lot of the fiddly bits for the sake of time and understanding.

1) In The Beginning... (1E-43 to ~ 1E-37 seconds after the big bang)

this is the earliest part of the universe's life that we THINK we MIGHT have evidence to support. the time ranges here are usually measured in Plank seconds which, theoretically, is the minimum increment of time that we can measure in this universe. a Plank second is about 5.4E-44 seconds. if you are not familiar with scientific notation, this means it is a decimial point, followed by 43 zeroes, and then 54.

.000000000000000000000000000000000000000000054 seconds is one Plank second

or to put it another way, there are more Plank seconds in ONE SECOND, than there have been seconds since the beginning of time. at this point, the universe is smaller than a single atom, and contains all the energy that the universe could theoretically ever contain. all of the fundamental forces (Gravitational, Electromagnetic, Strong, and Weak) are unified except possibly gravity. this is quite literally the beginning of time and space as we currently understand it.

2) INFLATION! (1E-37 to ~ 1E-33 seconds after the big bang)

"shortly" after the beginning, something very unusual happens. the expansion of the universe triggers something akin to a phase transition (akin to water evaporating) in the primordial universe, and it expands briefly at a rate faster than the speed of light. now, this is quite the head scratcher for a lot of people and at this point a great deal of Einstein usually gets misquoted. without getting too far into it, just keep in mind that SPACE-TIME itself is expanding. a meter then is not the same as a meter now. moving along...

as the universe expands, it "cools". eventually the amount of energy per unit volume in the universe reaches a certain threshold, and it literally condenses into the first elementary particles (concisely referred to as a quark-gluon plasma). these particles were the first matter and antimatter of the universe. yes, antimatter. not sci-fi. interactions between matter and antimatter result in a perfect reaction known as Annihilation, in which both particles are converted into pure energy. in the primordial universe this happens allllllll the time. LUCKILY, for reasons i wont get into, for about every billion particles of antimatter, there were roughly a billion and ONE particles of matter. these leftovers are what makes up all of the current matter in our universe

3) The Middle Bit(1E-33 seconds to ~ 3 minutes after the big bang)

the universe continues to expand and cool and as it does more particles form. quarks eventually become confined to hadrons (protons, neutrons, and all their exotic cousins). later down the line, the annihilation of leptons slows and we get most of the leptons we have today (the electron, the muon, and the tau). SNORE
Tsadkiel
Aliastra
Gallente Federation
#16 - 2012-02-03 22:33:57 UTC  |  Edited by: Tsadkiel
4) Nucleosynthesis (3 to ~ 20 minutes after the big bang)

eventually, the hadrons cool enough to fall under the effects of the Strong Nuclear force, get bound together, and form the first atomic nuclei! these aren't atoms yet though, their energy is too high to form stable orbits with electrons. that bit is going to take a while...

5) Foggyness (20 minutes to ~ 380,000 years after the big bang

SO! at this point, if you could see the universe, it would look cloudy. VERY CLOUDY. milky and goopy also come to mind as possible adjectives. but WHY does it look this way? well, while all of this is going on, photons of light are also trekking around everywhere, but because the density is so high, they can't travel very far. in the lab we would say that "their mean free path is very small" which is just a fancy way of saying they are bouncing around all the time. eventually though, the universe cools enough that electrons can form stable orbits around nuclei which causes a rapid increase in the mean free path of the photons leading to...

6) The CMB! (around 380,000 years);

The Cosmic Microwave Background is field of radiation that we pick up from all locations in the sky. it is formed from those very photons that were bouncing around in the fog. why does it look the way it does? well, imagine you are swimming underwater in the middle of an ocean of milk (weird, i know, but roll with it). you can't really see any thing because the milk is opaque. now imagine that somehow, all of the milk turned into crystal clear water simultaneously. what would you see? what would it look like? you would see a receding wall of milk, moving away from you at the speed of light! this is because of the time it takes for distant light to reach you. even though everything became transparent simultaneously, the light that can now move freely a light year away from you still takes a year to reach your eyes.

the discovery of the CMB is without a doubt one of the most monumental in the history of physics. the different colors you see in the picture are areas of different radiation intensity, which corresponds to temperature and therefore, mass density! the image is an image of the universe only 380,000 years after the universe was born!


7) And all the rest (380,000 years to present)

bake in normal gravity for 13.75 billion years
garnish with life
serve with cake
Tsadkiel
Aliastra
Gallente Federation
#17 - 2012-02-03 22:35:40 UTC
Lutz Major wrote:
What's your thesis about?


i'm hunting for Gamma Ray Bursts using HAWC!

BAM!
Amaroq Dricaldari
Ministry of War
Amarr Empire
#18 - 2012-02-03 23:50:34 UTC
Gamma Ray Bursts?!

WE'RE ALL GONNA DIE!

This is my signature. There are many like it, but this one is mine.
Tsadkiel
Aliastra
Gallente Federation
#19 - 2012-02-03 23:58:30 UTC  |  Edited by: Tsadkiel
well, yes, but probably not from GRBs. their distance and energy suggests that they are primarily an early universe phenomena. if one were to kill us it would have to happen in our universe and just happen to be pointing at us (GRBs emit radiation in two beams pointing in opposite directions)
W1rlW1nd
WirlWind
#20 - 2012-02-03 23:59:10 UTC
Tsadkiel wrote:
Kiroma Halandri wrote:
How much wood would a wood chuck chuck if wood chucks could chuck would?


that depends on the chucking rate, which we would have to measure. we then multiply by the average lifetime of said woodchuck to get the answer...



The real answer to this is of course self relevant:

A. A wood chuck could chuck as much wood as a wood chuck could chuck if a wood chuck could chuck wood.
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