♪♫ caek's corner ♪♫

dear caek,

i was wondering about space. so if the universe exploded and stars are just explosive accretions of mass and eventually everything will be really far apart from everything else, why is it all going to collapse sometime?

or is some stuff getting farther away from other stuff at a significantly faster or slower rate? because maybe then the combined mass of the entire universe would be enough to decelerate one of the more rapidly escaping densities such that it would fall back into some orbit---do this with everything in the universe and it eventually just settles into a steady state, right?

anyway thanks for being a scientist,

gbx

what is the difference btw space and time?

why does it matter what's happening in space when ppl are suffering here on earth

Are you the kind of guy who can pull off wearing all-white shoes, white pants, and a white shirt?

dear caek,

if you were in a film then who would play you?

^^relevant to my interests xp to lamp but this works too

i think maybe time and space are the same thing because at some point it is impossible to reconcile velocity and position.

i think if you take a space journey at a speed of .4 c you can come back to earth and play yourself as a baby

goin on a star voyage...movie star, that is!

is "space" an appropriate answer to "whats yr fav color" i mean is space a color cause pretty sure it is u might want to look into that

dear caek,

if you were in a film then who would play you?

dude from match point??? http://www.tribute.ca/tribute_objects/images/stars/matthew_goode.jpg

i was wondering about space. so if the universe exploded and stars are just explosive accretions of mass and eventually everything will be really far apart from everything else, why is it all going to collapse sometime?

it's not certain that it will, but if it does it will be due to gravity. there are three things: (i) the force of the big bang, which was big, maybe too big for anything to overcome and is still totally dominant on intergalactic scales; (ii) gravity, which adds up to quite a lot given enough time and everything in the universe to work with; and the third thing, which acts in the same way as the explosion (i.e. drives things apart) is ~~dark energy~~, which no one really understands and if basically some bullshit to sell new scientist [*]

so the question is, when you add these three together, what is the ultimate fate: collape, expansion, or exquisitely balanced steady state. i am not a cosmologist, so this is not really my area, but my understanding is that the latest thinking is that it's the last one, yeah. but the steady state we're headed for has galaxies much further apart than they are now, and is going to be an extremely boring place.

[*] this is not entirely fair. there's pretty good evidence that something other than just (i) and (ii) are happening, but we have no idea what, so we call it dark energy.

what is the difference btw space and time?

― Lamp, Saturday, December 5, 2009 9:37 PM (11 minutes ago) Bookmark Suggest Ban Permalink

in relativity, the only difference is you cannot travel backwards in time. it is otherwise identical to the other dimensions. in the real world, time is time and space is space, and the difference is obvious although i once did get so perfectly drunk that i was experiencing the world in derivatives with respect to time. totally amazing.

why does it matter what's happening in space when ppl are suffering here on earth

― harbl, Saturday, December 5, 2009 9:39 PM (11 minutes ago) Bookmark Suggest Ban Permalink

it absolutely does not matter what is happening in space, other than to the extent that knowing about it makes people happy. anyone who tells you that pure astronomy is anything other than culture is lying. i feel v. strongly about this and get into many arguments with astronomy geeks at work. i think it is totally dishonest to suggest that what astronomers do is important in the true sense of the word.

oh yeah i can def understand that. it's why i quit doing math&physics after undergrad. thanks 4 ur time ; )

Are you the kind of guy who can pull off wearing all-white shoes, white pants, and a white shirt?

― big darn deal (Z S), Saturday, December 5, 2009 9:40 PM (13 minutes ago) Bookmark Suggest Ban Permalink

i always wore white chuck taylors between the ages of 16 and 25 and that looked ok, but i have a very fair complexion (i got hospitalised with sunstroke in cornwall once), so i don't think that would be a good look for me. i think it works well for pierce brosnan though. he has amazing hair imo.

oh yeah i can def understand that. it's why i quit doing math&physics after undergrad. thanks 4 ur time ; )

― harbl, Saturday, December 5, 2009 9:57 PM (45 seconds ago) Bookmark Suggest Ban Permalink

it's the same reason i quit philosophy early in my undergrad. both astronomy and philosophy don't matter at all, but worrying about whether we exist or not did seem to be taking the piss a bit.

what is the best galaxy and why

pics ok

dear caek,

if you were in a film then who would play you?

― caek, Saturday, December 5, 2009 9:42 PM (17 minutes ago) Bookmark Suggest Ban Permalink

great question. the answer is simon pegg.

dear caek,

what is your favourite john updike quote about astronomy?

although i once did get so perfectly drunk that i was experiencing the world in derivatives with respect to time. totally amazing

o_O

caek: does the massiveness of space ever seem sinister to u?

is "space" an appropriate answer to "whats yr fav color" i mean is space a color cause pretty sure it is u might want to look into that

― ice cr?m, Saturday, December 5, 2009 9:46 PM (14 minutes ago) Bookmark Suggest Ban Permalink

that question has an answer thanks to the nerds at at&t bell labs:

http://i50.photobucket.com/albums/f325/caek/bellhorn.jpg

they may not do mms messaging or tethered mode, but this is cool:

http://lambda.gsfc.nasa.gov/product/map/current/pub_papers/fiveyear/basic_results/images/med/gh5_f12_PPT_M.png

what is the best galaxy and why

pics ok

― crazy farting throwback jersey (gbx), Saturday, December 5, 2009 9:59 PM (8 minutes ago) Bookmark Suggest Ban Permalink

imma get back to you on that one.

dear caek,

what is your favourite john updike quote about astronomy?

― caek, Saturday, December 5, 2009 10:00 PM (7 minutes ago) Bookmark Suggest Ban Permalink

caek: does the massiveness of space ever seem sinister to u?

― Lamp, Saturday, December 5, 2009 10:05 PM (2 minutes ago) Bookmark Suggest Ban Permalink

It is not true that developments in physics go ignored by professional humanists or by the common man. The basic facts get to us all and frame the way we think and even feel. The picture physics paints of the material universe is arresting enough to make the newspapers but far from flattering to our individual identities. Astronomy is what we have now instead of theology. The terrors are less, but the comforts are nil.

-- John Updike, 2005 iirc, Physics Today

seriously though (i) yes, terrifying moments of clarity every year or two (ii) listen to this short story, it will only take you 15 minutes and it is pretty much on the money about the end of time: http://freakytrigger.co.uk/ft/2008/04/a-bite-of-stars-a-slug-of-time-and-thou-episode-5/

a favourite galaxy:

NGC 1300

http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0501/ngc1300_hst_c30g90.jpg

itt a strange man asks you if you saw the massive bar and dust lanes and flocculene on that galaxy

Can you explain a bit more about forces? Like, for instance, is gravity subject to relativity rules - if something starts increasing in mass really fast (uh pretend this is possible I guess), do nearby object start feeling the extra tug immediately, or only after exactly (distance/speed of light) seconds? I guess it must be the latter but why does that make any sense?

M104 (aka the Sombrero galaxy)

http://www.strw.leidenuniv.nl/~broek/pictures/sombrero_galaxy.jpg

she's a beaut

whoa it's like a plate!

M104 u r a treat

how many of the stars i see are actually galaxies

http://i49.tinypic.com/2ez2rs6.jpg

forces are propogated by massless particles. e.g. the electromagnetic force, which is the force that dominates our lives, keeps us warm, prevents us from walking through doors, etc., is propagated by the best known massless particle, the photon.

massless particles travel at exactly the speed of light. therefore forces can only propagate at the speed of light, you are correct.

there is a thought experiment about this involving the sun suddenly disappearing. if this happened then the earth would stay on its orbit for 8 minutes, before suddenly flying off into space, because that's how long light takes to reach us.

the reason all this makes sense is complicated and difficult to explain without getting into special relativity, which is not my strongest subject, and not something i've ever been good at teaching. but perhaps if you're comfortable with the idea that you can't send information at faster than the speed of light, then it would make sense to you that you can't have forces that operate faster than that (or instantaneously) because they could be used to transmit information at faster than the speed of light.

this wikipedia article makes a decent stab at this. of course once you throw in quantum mechanics all hope of understanding this is lost, because that stuff makes no fucking sense whatsoever.

how many of the stars i see are actually galaxies

― crazy farting throwback jersey (gbx), Saturday, December 5, 2009 10:22 PM (5 minutes ago) Bookmark Suggest Ban Permalink

not many. with the naked eye, in a dark place, you can see andromeda (m31):

http://www.tcd.ie/Physics/Schools/what/galaxies/m31_ware_big.jpg

and m33:

http://www.astrogb.com/images/galleria/M33.jpg

in the southern hemisphere you can see the small and large magellanic clouds, which are galaxies too.

however, there are a lot of galaxies. this is the hubble ultra deep field, which is not very pretty, but may give you an idea for how many;

http://imgsrc.hubblesite.org/hu/db/images/hs-2004-07-a-large_web.jpg

pretty much everything you see there (except the two twinkling things, which are stars, is a galaxy. there are about 10,000 in that image. that images is 1 ten millionth of the total area of the sky. and the hubble is only seeing a tiny fraction of them.

http://i49.tinypic.com/2ez2rs6.jpg

No : (. Law 4: "if thermal undershorts are worn, they are of the same main colour as the shorts"

dear caek,

what is a cool video about angular momentum?

great question. i would have to say:

https://www.youtube.com/watch?v=r__nGqGpTD8

I'd agree with you, xp, but Keith Hackett says: "Yes. Let the substitution go ahead because there's also nothing in the laws to prevent playing in furry trousers – and there's no reason for you to intervene because the trousers are clearly not dangerous to either the player or his opponents. You should monitor the situation though in case problems do occur – at which point you'd have the authority to have him removed, even if the side have used all their substitutes."

So I asked Mrs K to arbitrate and she said: "Yes, for the humour value."

xxxxpost

The abyss gazes also...

These pictures - they are amazing.

xxp, some people are pragmatists or intentionalists, myself i am a textualist.

dear caek, what is a pretty thought about people and stars and shit?

For many years I put up a Day of the Dead altar every November 1 in my Mexico City apartment. I did this in collaboration with the woman who used to take care of it and me; Señora Jacinta Cruz Ilescas, a Zapotec woman from a village in highland Oaxaca where traditional dress has long disappeared and only Spanish is now spoken. In a fever of creative ambition, we would find new ways each year to suspend cloth backdrops on a bare wall. We would pin paper cutouts to the cloth; wrap and stack shoeboxes to create small free-standing altars on the larger one; surround portraits of the departed with fruits and the fruit with flowers and small plates of the favorite traditional foods of the deceased. Then we would fit a dozen prayer candles among the dense display of offerings and try to make the whole thing fireproof.

Finally, after we had admired the result and pointed out the current altar's virtues with regard to the previous year's, Señora Jacinta would invariably say, "Ah, señora, but if we were in my pueblo, we would be able to uproot a vine chock-full of jicamas, and make an arch for the altar with it. That way it would be right." Years ago, I read that the Maya people of southern Mexico also make a ceremonial arch from jicama vines, and they still remember why. The radish-like jicamas, which hang down from the vines, and have brown skins but are white on the inside, represent the stars of the Milky Way.

Another cool food-space connection: galaktoboureko! but that's probably just because it's Greek.

i think it is totally dishonest to suggest that what astronomers do is important in the true sense of the word.

― caek, Saturday, December 5, 2009 9:53 PM (1 hour ago) Bookmark

i think this about a lot of intellectual careers (incl. my own, if i ever manage to have a career), but as long as you're honest about it, it's ok to do something just because it's really interesting and somebody's willing to pay for it.

yeah, i agree. i've done my phd during a weird time, and i think it's worse than usual at the moment. funding situations occasionally become so desperate (e.g. now) that you see people convincing themselves that what they do is v. important so that they can convince other people. i think this is disastrously counter-productive, both for the long term attitude of the public toward science (i genuinely worry about what's going to happen when the science results start coming out of the LHC and the electorate are going to be like 'are you fucking kidding me?') and for our internal intellectual health (as big bad betrand russell said, "One of the symptoms of an approaching nervous breakdown is the belief that one's work is terribly important.")

Another cool food-space connection: galaktoboureko! but that's probably just because it's Greek.

galak = milk, hence the milky way is a galaxy. i was not aware of those cakes though. they look good!

awesome thread!

w/r/t: https://www.youtube.com/watch?v=r__nGqGpTD8

do you, caek, condone the practice of dress shirts tucked into shorts?

I do not condone the practice of adult men wearing short trousers at all, but that is next level. I condemn it!

I do not condone the practice of adult men wearing short trousers at all

says the referee

dear caek, what was a cool astronomy picture you saw today?

gravity gets so much respect because it was the first 'invisible' force that was detected and quantified and also because we instinctively respect massive objects like stars and planets more than subatomic particles

"also someone tell me where proxima centauri's oort cloud is on that graph"

Proxima Centauri is a red dwarf star with a mass about 12.5% of the Sun's mass

I'd guess not very far at all, but also simultaneously much further than you'd expect!

awesome

i looked this up. apparently we have never observed an oort cloud around another star system, but based on what we know about how the one around the sun formed we would expect many/most stars to have one. given ours gets half way to proxima centauri it's not out of the question they overlap if PC does have one.

oort fite!

Andoortagain

thoughts on this?

https://en.wikipedia.org/wiki/Entropic_gravity

Never heard of it. Looks clever in the best and worst ways.

write a better lede

https://www.science.org/content/article/near-disaster-federal-nuclear-weapons-laboratory-takes-hidden-toll-america-s-arsenal

Technicians at the government's Los Alamos National Laboratory settled on what seemed like a surefire way to win praise from their bosses in August 2011: In a hi-tech testing and manufacturing building pivotal to sustaining America's nuclear arsenal, they gathered eight rods painstakingly crafted out of plutonium, and positioned them side-by-side on a table to photograph how nice they looked.

it can't be done

Homer Simpson on the job

pics or it didn't happen

There are pics in the article

https://frinkiac.com/video/S05E03/99U3CK0l_3KajDa3RTOkLp_iB00=.gif

terrifying story, astonishing that intelliegent and qualified people can get so lax around that stuff. not all bad news though, "undermining the nation's ability to fabricate the cores of new nuclear weapons" oh no.

maybe sterilize the galaxy

Now at 140% of my usual brightness! #Betelgeuse pic.twitter.com/pi9BPLijtj

— Betelgeuse Status (@betelbot) April 24, 2023

yesss

Now at 156% of my usual brightness! #Betelgeuse pic.twitter.com/rs527QaW1m

— Betelgeuse Status (@betelbot) April 27, 2023

is this just observing the increased brightness from what has already occurred at some point in the middle ages? it's all way too too big.

yeah if it went supernova it happend ~500 years ago, done deal

It'll probably go off while it's hidden by the sun, ruining any chance of seeing the show.

what if it turns us all into piles of salt

nice to think about

https://www.youtube.com/watch?v=kya_LXa_y1E

i remember you saying exactly this about 15 years ago lol

oh wait it's in this thread lol. 13 years

there is an AMSR quality to listening to true believer physicists talking bout string theory. You know u don't need to engage with the science because u know it's ludicrous nonsense, so it does have a relaxing quality for me during bouts of insomnia!

the dolorous priests of string theory!

perhaps not a very scientifically nuanced take - but it sure does feel like they were just making this shit up as they went along!

they definitely had some gaps to fill with uh portentous speculation

hawking started this.

― caek, Thursday, March 4, 2010 10:03 AM (thirteen years ago) bookmarkflaglink

lmao

hawking started this. bitcoin fixes this.

if you have time for a 1000 pager then this is canon

https://en.wikipedia.org/wiki/The_Making_of_the_Atomic_Bomb

string theory is when you just want more dimensions and i do

wasn't it something like the existence of 26 dimensions they theorised? lol is that enough for you!

wait till you hear about hilbert spaces

I'd have theorised about 36 dimensions because it's a beautiful number

the right idea on >= 4 dimensions

I'm laughing so hard at this slide a friend sent me from one of Geoff Hinton's courses;

"To deal with hyper-planes in a 14-dimensional space, visualize a 3-D space and say 'fourteen' to yourself very loudly. Everyone does it." pic.twitter.com/nTakZArbsD

— Robbie Barrat (@videodrome) June 10, 2018

that's why we need more of them

I have a buddy that talks about the 'multiverse' being a probability rather than a possibility

it's great if you're a screenwriter but c'mon man

the observable physical universe, or at least the current understanding of it, just isn't overawing and huge enough for some people - they want more!

Here is a thing that I have read and that I am not sure I believe: If you accept that more than one universe exists, you are almost inexorably drawn to the conclusion that an infinite number of them exist. With all the extant possibilities.

The reasoning goes that there is no logical boundary short of infinity. Like, if the total number is 52, one might ask, "why not 51 or 53?" Arbitraryness creeps in.

Hence, the suspicion that the number is either one, or infinite.

Personally I see no reason why the answer can't be 3 or 47 or 576.

The universe has no obligation to make sense to us.

sure (but no way it's 3 ffs)

also tbh the multiverse is a different thing than dimensions

Mark s what is your beef with the tripleverse

sucky number, get rid

I'd like to think we're in one of the posher universes, instead of the dumpy, cold, sandy ones

Here is a thing that I have read and that I am not sure I believe: If you accept that more than one universe exists, you are almost inexorably drawn to the conclusion that an infinite number of them exist. With all the extant possibilities.

https://en.wikipedia.org/wiki/Zero_one_infinity_rule

as many universes as gecs

so there's no set limit to the number of universes but rather it's limited to the capacity of the servers these universes are running on

Hey trinities are ok

https://www.youtube.com/watch?v=J8lRKCw2_Pk

The past and the present and the future

Big daddy, son, and spook

Peter, Paul, and Mary

RGB

Etc.

Etc

betelgeuse has now gone from the night sky (i.e. it's in the direction of the sun) for the next six months, so if it's still getting brighter we have no way of knowing.

this did happen tho https://en.wikipedia.org/wiki/SN_2023ixf

when come back bring superpie