Who Wouldn't Chat Inside This Thread

[Disco King]

Originally Posted by Elijah Moon

All that space talk made my head sleepy. Who wants to talk about their caffeine intake? I've cut right back lately. I just have one coffee in the morning, and if I have tea/coffee after that I make it decaf. I found caffeine was giving me palpitations, and even a relatively low amount would make me a bit fidgety and on edge. I feel better having cut back.

Caffeine has very little effect on me. I can down coffees or have energy drinks and still sleep like a baby minutes after.

If I have, like, several energy drinks, I might feel something. But at that point, it just makes me anxious and sad and less productive.

I've been having this problem recently where my Adderall makes me not go to sleep. It's not so much "not being able to fall asleep" as "procrastinating on sleep" or being so hyper-focused on something that I don't let myself sleep. Day three of getting between 0-2 hours of sleep. I hate it, because I look so old and gross and puffy without sleep and my appearance is affecting my self-esteem. But the positives of Adderall outweigh the negatives so far because I literally can't do anything involved without it, which makes me even more sad because then I beat myself up for not getting anything one and wasting my finite life and already missing out on so much.

Originally Posted by LaBelle

I live in a country where we don't usually have thermostats and houses are very poorly insulated, in my house it's usually colder during the winter and warmer during the summer than outside.
On cold days my blanket is my best friend.

I live in a developed country and still live in a home with abysmal temperature control. If its hot outside, its unbearably hot inside. If its cold outside, it's cold inside.

The law here says that the landlord is required to ensure that my home is at least 22° C. Unless it's exceptionally cold outside. Then it's allowed to drop to 16° C. My roommate has a thermal camera, and parts of the home were colder than that last winter. I don't think there's any law about an upper temperature limit, but that same roommate clocked a part of his room as 33° C.

It feels like there's nothing we can do, because the home is too old to even really replace the boiler or the radial heat system with HVAC, I guess (I've been told… I know nothing about this stuff). So, escalating the issue would just probably invite conflict into our lives over something we can't even fix anyway, and I don't want to move out because the rental market is insane right now.

[MyOneAndOnly]

Originally Posted by vixnix

We’ve had a pretty good run with most things in Paris and I’m enjoying myself. The heat here is nothing compared to summer in Sydney and we survived a few summers there without air con. But it is expensive and there are lots of tourists. We did the tourist stuff last time. This time we rented bikes from a place in the 15eme, not really a tourist area…and rode them through the city, Bois de Vincennes, and then along the Marne. It was the most beautiful ride I’ve ever done. And the ride from here to the venue is beautiful, along the Marne again. It’s semi-rural - big old farm houses and horses grazing. Our AirBnB is in Noisy-Le-Grand and going to the supermarket we’re the only tourists, everyone is really patient and helpful. There’s a lot of social housing around us and a significant migrant presence with a lot of Muslims and people of African descent. I really like it. Our apartment is brand new - there’s so much construction going on. We can see two cranes from our balcony and a building being constructed next door. I love it. Not the Eiffel Tower side of Paris.

We’re going to Euro Disney for my younger son. I am not looking forward to that.

Most of my traveling in Europe hasn't been typical tourist fare. I wouldn't know what tourist experience is like I'm Germany because I lived there as a kid, and my time there as an adult has been work related. Same for Spain, UK, etc. I've never done that tourist thing in those countries. More like driving around rural Andalusia and Basque region to inspect orchards.

But the times I've been in Paris I ended up in tourist hotels. Really wish I could have done apt rentals instead.

[ilikeplanets]

I would talk to every astronomy major I could in college, knowing I was too stupid to pass a calculus or physics class. I had to settle for majoring in English, so I I could write about why I like space, while decorating my binders with stars and planets.

[Joey Goldberg]

mods, please add a question mark to the end of this thread title

if you do not I will plant a bomb in the building

thanks

[redbreegull]

Originally Posted by TheAlter

I’m tempted to drop my end-of-the-world html code and fuck this harrible harrible thread up for good

get bent, dickcheese

[ilikeplanets]

Originally Posted by TheAlter

I’m tempted to drop my end-of-the-world html code and fuck this harrible harrible thread up for good

Or you could talk about something. Drop a topic instead of just reacting! What interests you, Alterboi?

[yo soy el mejor]

Originally Posted by Disco King

I think that if the holographic principle is true, then information would be printed on the boundary of any arbitrary large boundary of space, not just cosmological horizons (so, it was probably misleading for me to even bring cosmological horizons up when holography isn't peculiar to them).

Because the Hubble Horizon is the boundary between particles moving subluminally and particles moving superluminally from an observer, it's true that the observer would only be able to observe particles beyond the horizon via light/signals emitted from them in the past before they crossed the horizon. I don't know if that observer would be able to use information on the interior boundary to describe the volume surrounding them outside (I think the principle only applies to bounded regions), but a different observer would have a different Hubble Horizon, and that observer might be able to observe (part of) a different observer's Hubble Horizon and see its information encoded on the surface.

As for the Particle Horizon, anything outside of it cannot have a causal influence on you, so if something is outside of your horizon, you would have to be outside of its horizon as well, I think. So, I don't think there's any theoretical observer who could look at the surface of your horizon and gain info about you.



Yeah, because of time dilation, observers outside the black hole never actually see anything pass it. They see things approach it and move slower and slower until they just freeze at the event horizon (well, the gravitational redshift would be so intense that they don't really "see" the freezing, but you know). But if you're an observer crossing an event horizon, you don't even notice and it seems no different from the space just outside of it. Because of the intense curvature of spacetime, it's pretty much like the observer outside the event horizon can't see anything inside because from her perspective, the events inside don't even ever happen. It's like, a set of events punched out of the universe for them, even though they happen for the people inside.

I don't know if the phenomena of things just "freezing" at the event horizon is related to the phenomena of information being encoded on its surface, though. I mean, it sounds plausible that they are related (the information is on the surface because all the shit just froze there), but I've never heard it expressed in that way, so maybe it's not. That's a cool connection to draw, though. I don't think I've thought of that.

With the Hubble Horizon, even though we can never observe the current state of any particle outside of it, we can still observe the paststates of some of the particles via information reaching us that was emitted before the particle crossed the horizon. So, we can know about some things outside the Hubble Horizon, we just can't ever observe them as they are right now. The Particle Horizon, however, is the boundary between us and things that have not had time to reach us since the beginning of the universe. It represents the boundaries of the observable universe. Yeah, we just can't know about anything outside of it, even its past states.

I don't think you can "move toward the edge" of the Hubble Horizon, because if you move, your whole Hubble Volume moves with you.



Stephen Hawking pretty much realized that black holes should evaporate due to the interaction of relativistic and quantum phenomena in very curved spacetimes. Quantum physics tells us that particles are excitations in fields. A wavefunction describes the probability of a particle being in a certain place. In vacuums, there are still a bunch of waves in the field, but they mostly tend to cancel out, which is why there are barely any particles and the space is "empty."

But near the event horizon of a black hole, the very curved space time pretty much eliminates some possibilities of where the particles could be, meaning that instead of the waves all cancelling each other out, now you have some waves that aren't canceled out, which means you have particles now. The region that these particles "form" in is larger than the event horizon, so they don't all fall back into the black hole. Many of them escape and fly away from the black hole. So, black holes radiate particles (mostly photons) the same way any physical body radiates thermal energy (like how a hot iron radiates visible light, or you and I radiate infrared light, or a star radiates all sorts of light). This is called "Hawking Radiation." Because the wavelength of light radiated by something is proportional to its temperature (the hotter the object, the shorter the wavelength), a black hole can be said to have temperature.

But of course, due to conservation of energy, the energy for those particles that just emerge has to come from somewhere. A black hole isn't really an object so much as a region of spacetime, but that region has a lot of energy due to the high curvature of spacetime. So, the energy comes from the spacetime curvature, and the area of curvature is reduced as more Hawking Radiation is emitted to keep the energy balanced. This means that the black hole is shrinking.

As it shrinks, it gets hotter and hotter, because even though the total curved area is smaller, the curvature itself gets bigger. So, it emits more and more radiation until the black hole is all out of energy and it disappears. So, even though nothing can "escape" from within a black hole, it can still spill out all it's energy and disappear. This takes so long that it has probably never happened to a single black hole yet (unless there are primordial black holes).

Now here's where the paradox comes in. Quantum physics tells us that the information about a system is always preserved because wavefunction evolutions are deterministic. We call this "unitarity." Pretty much, every ending condition should have unique initial conditions, so you should be able to use the laws of physics to retrodict what the initial state of any wavefunction was. But it seems like Hawking Radiation would violate this. Say you had a black hole formed from 1,000 soloar masses of cupcakes, and another black hole formed from 1,000 solar masses of unsold Cyr CDs. An observer looking at these black holes would have no way of telling which is which, because they both have the same mass, and therefore surface area and temperature. They wouldn't be able to use any information to retrodict what the initial states that led to either black hole were. All the information exists, but its inaccessible inside. But if black holes radiate photons and spill all their information out, then that information looks the same for any black hole of the same mass, because it's determined solely by it's temperature, which is determined by its surface area, which is determined by its mass. The light radiated by both black holes would look exactly the same, so it would carry no information that could distinguish the cupcake black hole from the Oh So Bright black hole. But the information isn't "trapped inside" the black holes anymore, because they released it all and don't exist anymore. So, it looks like the information was just destroyed forever, and there exists no information hiding anywhere that could in principle be used to tell the holes apart. When two unique initial states devolve into the same final state, somebody who has access only to that final state cannot know which initial state it evolved from. The information to do that doesn't exist.

So, it seems that Hawking Radiation defies what we think is a fundamental law of physics.

Unless… the information about what fell into the black hole is always encoded on its surface, like the holographic principle supposes. Small correlations in variations of entropy on the surface would contain all the information required to tell the cupcake black hole and Cyr black hole apart. Which is unfortunate if true, because it means that even if we throw every SP2 album into a black hole, we can never erase them from the universe's memory. The holographic principle is a solution to the black-hole information paradox that allows unitarity to be preserved even if Hawking Radiation is real.

Why do scientists think the holographic principle is plausible? AdS-CFT Correspondence. Pretty much, we have these two different theories that weren't created to explain the same thing. One is Anti-de Sitter space, meant to solve certain Einstein equations for spacetimes with negative curvature. The other is Conformal Field Theory, which is a group of quantum field theories with… well, I don't really know what they are about, but I know they have applications to condensed-matter physics. In the '90s, scientists realized that even though AdS describes the surfaces of volumes and CFT describes the volumes themselves, one can make equivalent statements using either theory. They correspond. You can say the same thing using a statement about surfaces in AdS as you can using a statement about the volumes they circumscribe using CFT. Which means that we can make all the same statements using just two dimensions rather than three. Like all the information within that 3D volume is imprinted or encoded or "projected" onto its 2D surface. Because the entropy of a black hole scales with its surface area rather than its volume, this seems to apply to black holes. So, it seems that all the information about the volume of a black hole exists on its surface, meaning that the information about its initial states and contents is always preserved.

This is just stuff I've gleaned from pop-sci literature, so I do not know anything more in-depth about AdS or CFT, or know why the energy for Hawking Radiation has to come from the black hole and not something else, or… anything that requires actual deep understanding. I just know the simplified explanations for laymen like me. The account of Hawking Radiation I gave is at least less simplified and more accurate than the common version we mostly hear of "pairs of virtual particles forming near a black hole, and the negative-mass particle falling into the black hole and the positive-pair one escaping," but I'm sure the version I gave is still an illustrative metaphor. I think with this stuff, the only way to "truly understand" (if even then) is to know the math, because without the math, we just have to use familiar kinds of entities to describe an area of science that the math tells us is not populated by the familiar kinds of entities. I dunno, I'm kinda bummed that life is too short for me to ever seriously study this field and I will likely never have a real understanding of this stuff unless I decide to do another undergrad and graduate degrees and be a student until I'm 55.

shit fuckers can type!

[redbreegull]

who wouldn't shit inside this thread

[MyOneAndOnly]

[vixnix]

Originally Posted by TheAlter

Uhm let’s see: do you think vixnix’s stay in the infamous Parisian banlieue of Noisy-le-Grand will end up in a full blown assault or just a friendlier, traditional purse-snatching?

Let’s discuss

No offence, but people like you with passé racist takes are the fucking plague

[Plasticine Rap Star]

I'm going to a music festival next week with my sister and her boyfriend. It's a three hour drive. What song should I sing all the way there to test their patience?

[Plasticine Rap Star]

No I won't do that. I'm quite looking forward to it, though. Not many big name artists there, but there's a lot going on. Johnny Marr is playing, and also Gaz Coombes from Supergrass, and quite a few bands I am familiar with but not that into. There's other stuff happening, like a silent disco, and lots of cool food places. Should be a fun few days.

[vixnix]

Originally Posted by MyOneAndOnly

Most of my traveling in Europe hasn't been typical tourist fare. I wouldn't know what tourist experience is like I'm Germany because I lived there as a kid, and my time there as an adult has been work related. Same for Spain, UK, etc. I've never done that tourist thing in those countries. More like driving around rural Andalusia and Basque region to inspect orchards.

But the times I've been in Paris I ended up in tourist hotels. Really wish I could have done apt rentals instead.

It’s a great city, out of the tourist traps. Come back. We stayed near Duroc station last time, to be more central, and still ended up making a bunch of metro transfers to get around. Plus, urine and vomit on the street. And bedbugs. And it was a good hotel. But Paris just has a bedbugs problem.

Noisy-le-grand is quite far out and we only chose to stay here to be close to Lac Vaires-Sur-Marne but we’ve loved it here.

We’re shifting to another AirBnB in Boulogne-Billancourt for the last few days now the racing has finished. Still outside the peripherique - just keen to see another side of the city

[vixnix]

The last one was in Nanterre but whatever.

Have you spent a lot of time in Paris? Where do you live now?

[vixnix]

Looks pretty out of the way for something IN the city

I tend to avoid expat areas if I can. But thanks anyway, will look

Why have you been to Paris so many times? Are you French and do you live in some other shittier town nearby?

[redbreegull]

Originally Posted by TheAlter

“U R rAcIsT” lol


Noisy-le-Grand, Seine-Saint-Denis that’s were all the riots come from.

you are racist though. at least own it, coward

[ilikeplanets]

But is he racist and French?

[ovary]

i may have fungal acne

[mxzombie]

Thank god for this change of topic

[ilikeplanets]

Originally Posted by TheAlter

Never give advice.

Now I definitely think you're from Paris!

[ovary]

my kid has hoof and mouth

we're falling apart

[mxzombie]

hand, foot, and mouth disease


unless your child is one of the lucky few livestock species susceptible to hoof-and-mouth

[mxzombie]

and NO, that isn't racist

[ovary]

i think i know whether my own child has feet or hooves

[Joey Goldberg]

everybody "thinks" they'd know that

that's why it's such an epidemic

[redbreegull]

Originally Posted by ovary

i think i know whether my own child has feet or hooves

is your kid a one, two, or three toed ungulate? this is important

[redbreegull]

because it determines if my religion allows me to eat him

[ovary]

now i'm wondering if my fungal acne is actually hoof and mouth and i am patient zero

whole town has the hoof and mouth

i am disease

[ovary]

alright guys new dawn new day. i just washed my ass and i'm about to smear jock itch cream all over my forehead and chest wish me luck

[redbreegull]

i just bought weed legally in Maryland. I've waited half my life. I blasted Geek USA on the way home