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00:54
Hello friends, i wanted to discuss an issue i am facing and i want all of your different opinions and insights and advices. i am studying physics in my first semester and i am also studying mathematics.
Me being a perfectionist and trying to understand everything i learn about and not just learn the importnat and the end results, is turning out to be almost an impossible task with the immense Pensum i am required to reach.
Personally i think it is an error of this system we have. But now i am at crossroads. i either force myself to not focus on everything and just have to ignore or jump over some points i do not understand in order to actually pass the beurocracy of the univresity and the learning system.
Or just go made and let my grades sink deep and might even fail just because i am taking things seriously and as they should be taken. If i do the first choice, will i ever at some point feel fullfilment and those gaps and questions that i once had in the feutre will be answered? or is it literally impossible for us humans now adays to understand everything in the physics and keep a good overview and not forget everything? what should I do?
 
4 hours later…
04:51
@MadSpaceMemer you'll get better at working for long periods of time
which is necessary to keep up with this stuff while also understanding it well
(speaking as a physics/math major)
as a freshman it was torture, but by sophomore/junior year i got more used to spending several hours every day just reading textbooks
jumping over points i didn't understand was a mistake i made in freshman year. intuition is your best tool when faced with exams
 
2 hours later…
07:13
morning
 
3 hours later…
10:33
He was a mathematician!!
Hilbert's successor (fashion wise)
 
2 hours later…
@JohnRennie Cédric Villani sounds like a pretty cool guy.
12:35
Can we count Natalie Portman as a mathematician? She does have an Erdős number of 5...
@PM2Ring being an Englishman I always feel slightly distrustful of flamboyance, though in Villani's case no-one can dispute his credentials as a mathematician. Whether he does equally well as a politician is another question.
He was a mathematician too.
^this guy was the reason for the famous $y = mx + c$. I don't use other forms, this form becomes enough for me to solve all the questions.
@JohnRennie I think I know this guy, probably he's an entrepreneur...?
@JMac Exasperating views of her with farrago narratives and purlie attitudes.We should to iron out our rifts instead demonize one another...
12:54
I am 5 reviews away from 20k in close. That is a lot of work
@KyleKanos I'm 278
@JohnRennie That cravat is a bit over the top, but hey, he's French. ;) Scientists & mathematicians tend to do ok in politics, if they don't get trampled by the other politicians. Unlike rock stars...
@AbhasKumarSinha I was there once. Probably like 5 years ago though
@KyleKanos I'd have to work for 5 years to get close to you. That's a good achievement btw.
@AbhasKumarSinha if you reviewed 20 questions a day, you'd hit 20k in 3 years.
12:59
@AbhasKumarSinha I agree that not demonizing each other is generally the best approach; but there are some instances where you have to call things out to actually make change happen. Climate change is really tricky in that regard, because there are legitimate concerns that we wont be able to fix the problems if they go too far. You also have to be aggressive when you're working against industries that have a lot of money to spend to influence people against you.
@KyleKanos ah okay...
@JMac I think the way India, and some of EU (germany) are working the way on Climate change, it'd be a no problem to us in few coming decades. Ofcourse, I can't say that part for US. They have tiny fraction of population and 60% of emissions, because that's helping them in economy.
same for Australia
More and more countries are ditching Fossil fuels which is major contributor to climate change...
@AbhasKumarSinha USA and China are two major contributors, and most people still buy things from them. The places that most need to change have high incentives to remain the same due to profits. Basically, they need to get Chinese residents and US residents to listen, or at very least would need their governments to start putting penalties on dealing with them. If not, you're basically just outsourcing the pollution, which doesn't remove the problem at all.
lecture hall^
@JMac I'd not compare China with USA, the efforts china has put in climate change in recent years, no other country is capable of that! Sometimes I'm amazed with the tremendous efforts they put!
@AbhasKumarSinha China still has very high greenhouse gas emissions. I'm not even sure what you mean about efforts in recent years. As far as I'm aware, they haven't had much push towards renewable resources as much as they've been pushing to reduce particulate in the air.
@JMac China has put incredible efforts to combact Climate Change in recent years. Well I'm impressed. That's a proof that monarchy is sometimes better than democracy!
13:20
@AbhasKumarSinha I would be very reluctant to paint the Chinese government in a positive light right now. They do some pretty awful things to their citizens. They also aren't even a monarchy.
@JMac see, their citizens are happy with it, I don't see a problem. If you understand a bit of geopolitics, then Dr Xi is someone who's very smart and they are doing good. The changes the China has brought in last decade, no country can bring even in 5 decades...
@AbhasKumarSinha ... besides all the protests, sure.
@JMac HK?
@JMac if you look at the root cause of the protest, you'll understand better, extradition bill was for the good.
@AbhasKumarSinha Well yeah, that's the obvious example of people being unhappy. Other things would be like all the restrictions on what people are able to do on the internet and stuff. People get in trouble for friggin Winnie the Pooh pictures. It's absurd.
@JMac see why extradition bill was introduced. - qr.ae/TWPfH8
13:28
@AbhasKumarSinha A single example of why the bill could be useful doesn't mean that it couldn't also be detrimental. Literally millions of citizens protested it. It seems pretty obvious that all the citizens aren't all happy. Just because they had a reason to introduce the bill, doesn't mean the bill also couldn't be bad for them (which is what concerned people and led to the protests).
@JMac Well believe it or not, that was only the single reason for the introduction of bill.
@AbhasKumarSinha Why is CO2 emissions per capita a useful metric? It seems pretty misleading to me. Eg, that graph makes Australia look almost as bad as the USA, even though they (the USA) have more than 12 times our population.
@PM2Ring Australia is as bad as USA. Why? Infrastrastructre problem. Well I neither see Australia getting better unlike USA. But, for the case of NZ - they are definitely improved a lot.
BTW, Australia has a lot of uranium, but we have no nuclear reactors producing power, for political reasons.
@AbhasKumarSinha If that was the only reason, then it makes perfect sense that people would protest... Why would they want a bill that puts many at risk if all it's doing is solving a problem with a single person.
13:32
@PM2Ring yes, a single person emits 16.5 MT per year. This is very severe.
@PM2Ring opposite for India, we have a lot of reactors but no uranium
@AbhasKumarSinha About a decade ago, our then left-wing federal government tried to introduce an emissions trading scheme, but that caused them to be kicked out, and we've had a right-wing federal government ever since. :(
@PM2Ring Your government is extremely conservative and quite religious right now, isn't it?
@PM2Ring present government did some good job too, like Sydney (experimental ofc)
@JMac no, liberal, if I recall correct...
@AbhasKumarSinha But our total population is less than 25 million. That's like 2 big cities in India. ;)
@PM2Ring that's the problem, lesser problem more emissions, India opposite - more population and less emission
13:37
@AbhasKumarSinha The Australian Liberal Party is a conservative party.
@PM2Ring lol? why? how? XD
@PM2Ring Yeah, I had to look that up and just was about to ask about that. They're called "Liberal" but from everything I heard they are fairly conservative.
@PM2Ring they have some long term plans ofc - nytimes.com/2019/06/21/world/australia/…
@PM2Ring then why they do like Modi? Morrison? he doesn't like conservatives...
@JMac Australia is a religious country?!! Didn't knew it...
@JMac Yes, it's conservative, with religious elements, but not like US "Bible belt" religious. It's a fairly secular country, although there is a minor religious party with enough power to have an influence on the balance of power between the two main parties, but that's mostly at the state level, not federal
@AbhasKumarSinha Australia is very multicultural, with a pretty good record of religious tolerance.
@PM2Ring NZ is doing good when we look at their track record. NZ and Aus are pretty same...
@PM2Ring do they have full majority?
13:43
@PM2Ring I guess I was thinking more along the lines of "religious undertones". I heard that a lot of the conservative nature of the government seemed fairly religious. Though yeah, not like the "Bible belt" religious. US is so religious that if you're not Christian you can't become president, essentially.
Fifty years ago there were pretty strong ties between Christian denominations and the main parties. Eg, there was a strong Irish Catholic link to the left-wing Labor Party, mostly through its connections with the trade unions. But that's just a minor concern these days.
@JMac not true, the opposition is some hindu president, I think... Tulsi is her same. I don't know anything more...
@PM2Ring he's not that conservative, I think - facebook.com/watch/?v=1359002484282379
from an athiest POV^
@AbhasKumarSinha There are quite a few candidates for US president right now. Just because someone running isn't Christian, it doesn't really change my point about their likelihood of winning. US vote is heavily influenced by religion.
@JMac ah okay... I don't know much of USA. My areas of interest are only East Asian Nations...
@AbhasKumarSinha Wikipedia says "Ideologically, he identifies himself as a pragmatic conservative."
13:50
@PM2Ring I don't know much of Australia either... Just a bit of NZ.
@PM2Ring Well he happily says that we love being in multicultural society in the video
that's contradictory...
@AbhasKumarSinha I wouldn't say every conservative has to be opposed to multi-culturalism. I also wouldn't say every politician actually means what they say.
@JMac When you need some foreign leader to win elections (also when he helps), you are no one but Donald Trumph.... - youtu.be/2ZIgHxsAuWU?t=3485
@JMac See his speech... XD
@JMac DT Secured election this way...
@AbhasKumarSinha Why is it contradictory? What do you expect him to say? "All you non-Anglo people can go back where you came from"? Some of our top right-wing politicians in the past have had that sort of attitude, but it's frankly ridiculous, since Australia has been a cultural melting pot since the end of World War 2.
The conservatives don't want ethnic / religious tensions. It's bad for business. And they want good immigrants to come here & do the low grade jobs boost the workforce.
@AbhasKumarSinha I'm not sure how that's relevant to what I was talking about. Especially since that's a video from after Trump had won...?
@PM2Ring this happens only in case of multicultural societies. - en.wikipedia.org/wiki/…
@JMac very recent programme...
NZ benefitted Indians this way - en.wikipedia.org/wiki/…
14:05
@AbhasKumarSinha I'm not claiming there are no ethnic tensions here. FWIW, over the last 30 years I've lived in a couple of areas with high Indian populations, and things were mostly fine.
@PM2Ring Ethnic tensions are everywhere...
@JMac They are cheering Modi actually.. See when Donald Trumph comes everything silences...
Exactly. And in Australia we mostly do a pretty good job of stopping stuff from getting out of control. But incidents do happen.
30 years or so ago, we did have some bad ethnic violence here
@PM2Ring Australia is mostly british people who came to India during british era...
@AbhasKumarSinha I still don't see the relevance. You were saying Trump needs foreign governments to win, then pointed to a recent video of Trump from after the election saying he "secured the election that way".
@JMac that was a joke...
14:09
But it wasn't old Aussies vs new Aussies. It was immigrants from Yugoslavia, continuing their feuds from the old country.
@PM2Ring yogoslavia connection...? I don't know about it.,
@JMac that's Indian political party BJP's posters, I'm not sure what that means...? - youtube.com/watch?v=2ZIgHxsAuWU
@AbhasKumarSinha Ah, no. Most of the Aussies of British heritage (like me) don't have a connection with the British Raj. And there are now plenty of places in Australia where those of Anglo-Irish ancestry are in the minority. Eg, the suburb I live in is now very Asian, mostly Chinese, but also some Thai & Vietnamese.
@PM2Ring ah okay... Except for Kangaroos and British heritage people, most of them are immigrants..
@PM2Ring have you seen a kangaroo?
@AbhasKumarSinha Pretty sure the British heritage people also immigrated to Australia...
14:16
@AbhasKumarSinha Of course.
@PM2Ring are they aggressive when touching them?
@PM2Ring are they harmful? Have you touched them? I heard they are good boxers....
@JMac this line was lit! - youtu.be/2ZIgHxsAuWU?t=4113
I've lived in Sydney most of my life, but from 2010 to 2017 I lived outside Coffs Harbour. We'd sometimes get kangaroos in our yard in the early morning, grazing on the lawn. And in the nearby town of Woolgoolga, it was common to see kangaroos on the football field, and other green areas. It wasn't unusual to see one hop across the road.
@PM2Ring mostly like stray dogs in India... Have you touched them?
@AbhasKumarSinha I used to hand-feed "tame" kangaroos when I was a kid. You can't pat wild kangaroos: if people get too close they hop away. But you don't want to corner them: they can get aggressive if they feel trapped
@PM2Ring Are they pets?
14:24
If you're patient, you can get within say 5 or 6 metres of a mob of kangaroos, if they're used to humans (like the ones who live in Woolgoolga).
@PM2Ring do you have pet kangaroos?
@AbhasKumarSinha The ones I used to feed were sort-of pets. But these days it's not legal to keep them as pets. OTOH, people who work in wildlife rescue & rehab can have them as temporary pets.
@PM2Ring ah okay... are they in nz?
They aren't practical as pets. They need a lot of space, and they can easily jump a 3 metre fence.
@PM2Ring wooooooooow <3
14:29
@AbhasKumarSinha No. Like most marsupials, kangaroos are native to Australia. There are some marsupial species in Papua-New Guinea, including small relatives of kangaroos.
@PM2Ring oh okay, I'll be visiting NZ soon...
for glow worms cave
@AbhasKumarSinha The boxing thing is a bit of a myth. Over 100 years ago some people trained some kangaroos to box, but they aren't very good at it. They certainly don't fight by boxing...
@PM2Ring kangaroos don't box... ah okay
We do have glow-worm caves in Oz too, but I've never seen them myself. But I have seen fireflies. We used to get them from time to time in our garden in Coffs Harbour. But just small numbers, not a whole bush covered in them
@PM2Ring fireflies are very common here... in winter
next thing - BL Beach in India
14:36
@AbhasKumarSinha is that real or shopped
@SirCumference both are real!
@AbhasKumarSinha If a kangaroo is cornered by a human, they defend themselves with their feet, while balancing on their tail. You really don't want to get kicked by feet wirh sharp claws... especially by an animal that can jump a 3 metre fence.
oh wow
people in the boat stood out so much in the lighting i wasn't sure
@SirCumference yes.... I'll be visiting BL Beach this month.. (winter vacation) next year after exams, NZ for sure...
@PM2Ring ah okay... they have really longer tails..
@SirCumference doesn't that related to space...? Childish but that seems as beautiful as the universe...
Another nice glowing thing is bioluminescent micro-organisms in the water. I've only seen them once, on a full moon summer night when I was a kid, where a lagoon meets the sea. It was a very magical experience to swim through water that sparkled as you moved through it.
14:40
@AbhasKumarSinha sounds neat
@AbhasKumarSinha eh i've never even seen a clear night sky
@PM2Ring Yes... I'll go straight to beach to swim after late night in BL Beaches...
@SirCumference why?
i live in a city :/
i imagine it'd be very beautiful tho
@SirCumference lol, I live in a small town away from cities, silence everywhere, I can wander through forest whenever I like. I've spent most of my life here roaming through forest, climbing hills and trees before moving here which is pretty much a town covered all way between forest... :)
@SirCumference where you live?
@AbhasKumarSinha I grew up on NYC before college
welp i gotta go to mandatory class, later
@SirCumference okay...
@PM2Ring we do have a kind of glowing forest too
 
2 hours later…
16:58
@JohnRennie could you help me with a very basic gr question?
@JakeRose I can try ...
0
Q: General Relativity tenor confusion

Jake RoseI think this likely comes down to the following expression, $$g’^{ab}e’_a e’_b = \delta ^a_b $$ Is this in agreement with the Einstein summation convention? Because even though the two indices are summed over, they still appear on the right. This leads to issues when trying to rearrange for $g...

@john
@JohnRennie
Is that an abuse of einstein?
@JakeRose hmm, now you're asking. The left hand side should be a scalar not a tensor, so I don't see how it can equal $\delta_b^a$.
It comes from a question in my example sheet of the form
$$g'(e'_a,e'_b)=\delta ^a_b$$
17:22
Numerically it's true, but I think writing the right hand side as a tensor is a bit dubious.
I don't know how mathematicians would write this, but I'd write something more like $\delta(a,b)$ to make it clear it isn't a tensor.
How would you then rearrange for g' using that notation?
Don't know ...
I think I'd need to see the original problem.
17:39
@JohnRennie
@JohnRennie And anyone else with rep on Astro. This answer needs flagging astronomy.stackexchange.com/a/33850/16685
@PM2Ring done!
> According to a Lee Smolin book there are actual people who've proposed serious theories like this. Minus the one-upping Satan part.
@JakeRose I don't know enough about the mathematical formalism of differential geometry to help. Sorry :-(
you can scratch out the "According to a Lee Smolin book" part, Zack
it's 100% real
heck, one of them won a Nobel prize and used to be a regular on PSE
17:45
't Hooft?
@JohnRennie have we had any other Nobel prize winners? ;-)
I may win a Nobel prize one day (though that would be one hell of alternate universe)
I don't have a problem with 't Hooft working on those sorts of theories. He's quite open that he thinks it's a long shot and he's only doing it because he's old and venerable enough that he can get away with it.
He isn't preaching it to the masses, so it's far from a crackpot approach. I get the impression he's doing it just for his own interest.
Whereas Smolin seems firmly convinced he is right and is happy to write books to prove it.
18:33
@JakeRose @Slereah might be interested
Is SMBC still a thing, or was that an old comic @EmilioPisanty?
@KyleKanos It's still a thing, that one is relatively fresh
@KyleKanos that one's two days old
dunno if it's a 'thing' or not
Ah. I've not gone to that site in a few years at least
Around the time he started doing videos too
@JohnRennie true that
vzn
vzn
18:57
lol TIL "Others say that Satan created these fossils in order to deceive us." bibleandscience.com/science/ageofearth.htm
 
2 hours later…
20:46
@EmilioPisanty is that the sun lol? (or a flying coin?)
21:03
@NovaliumCompany that's how SMBC draws God

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