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/sci/ - Science & Math

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5039070 No.5039070 [Reply] [Original]

What do you think is the single most misunderstood fact is in physics?

If you could teach everyone just ONE fact in the world of physics, what would it be?

for me, pic is related to both.

>> No.5039073

Schrodinger's cat

>> No.5039075

>>5039070
Go on, what is missunderstood in your opinion?

>> No.5039096

That vacuums do not pull, everything else pushes. I know its well-known in the scientific community, but it isn't really taught anywhere. I did well in Chem too, I know my gas laws, but it still didn't dawn on me until I took a History of Science class. I realized as we discussed the siphon problem and the discovery that air has weight.

>> No.5039103

>>5039070

People who don't study physics have a different understanding of gravity. Gravity doesn't always work like this. Yes large bodies do work like this, but at a quantum level, it's not even close to the same.

>> No.5039108

>>5039096

>That vacuums do not pull, everything else pushes.

non-scientist here. can you explain more of this please? if possible can you give an analogy? I learn a lot better if you would use those.

>> No.5039140

>>5039108
Not the same anon, but what he's saying is that the "pull" most people believe is a vacuum is in fact the "pushing" of the more pressurized air into the less pressurized vacuum (high pressure travels to lower pressure when possible).

Not saying if I agree or disagree, just explaining.

>> No.5039160

>>5039140

thanks bro.

>> No.5039185

The age of the universe.

>> No.5039195

>What do you think is the single most misunderstood fact is in physics?

Without a doubt, it's the theory of the origin of the universe.

That's what I would teach people about. Make them understand that talking about "before the origin" makes absolutely no sense.

>> No.5039207

>>5039075
Not OP, but the picture doesn't have much to do with GR, unlike what most people think. What is being depicted is a gravity well, essentially a plot of the potential energy near the earth. It is not a depiction of how space-time warps due to gravity.

>> No.5039213
File: 91 KB, 298x400, 1266378158371.jpg [View same] [iqdb] [saucenao] [google]
5039213

>>5039195
>mfw people think big bang cosmology explains the origin of the universe

>> No.5039215

>>5039075
>>5039207
I've heard many people, on this board no less, that say that the analogy only works because gravity is pulling the mass down on the trampoline, and thus you're using gravity to explain gravity. They fail to realize the nature of the analogy

>> No.5039236
File: 2.94 MB, 1920x1920, cosm.jpg [View same] [iqdb] [saucenao] [google]
5039236

That the big bang is an expansion, not an explosion.

>> No.5039241

The picture makes it look like everything should go to the south pole when they fall to earth.

>> No.5039245

>>5039236
an explosion is an expansion

Woah.

>> No.5039254

>>5039245
I think if he were to "expand" he would say that the bb is an expansion of spacetime, not an explosion which would be an expansion of heated gases and the like.

>> No.5039261

>>5039245
Wat?
An explosion needs space to happen.
There was no space at the epoch of the big bang.

>> No.5039267

>>5039236

The Big Bang theory is just creationism in disguise. You have to suspend all the laws of physics in order for it to work, which is just the hallmark of a failed theory.

>> No.5039272
File: 73 KB, 640x578, 1345783208427.jpg [View same] [iqdb] [saucenao] [google]
5039272

>>5039267

>> No.5039274

>>5039267
Oh look, it's edgy hipster kid again.

How about you go ahead and list the ways in which it violates everything?

>> No.5039283

>>5039215
>>5039070
>tfw your high school chemistry teacher (yes my chemistry teacher) tried to teach this "relative" gravity using the trampoline example
>tfw your high school chemistry teacher was a preacher
>tfw when he taught evolution (yes, lol, he did) he made it a debate between classmates
>tfw american

>> No.5039285

>>5039274

Explain how the universe can expand from a single point into...wait, what was it expanding INTO, if not space? How can something expand when it has no volume? How can a supermassive black hole expand when it has an event horizon 40 light years across?

>> No.5039297
File: 130 KB, 500x332, klydonograph2.jpg [View same] [iqdb] [saucenao] [google]
5039297

>>5039285
It's expanding into itself.
Only valid answer.

>> No.5039303

>>5039285
>what was it expanding INTO, if not space?

The universe isn't a balloon. It doesn't have an "exterior," and so it doesn't have to expand into anything.

>How can a supermassive black hole expand when it has an event horizon 40 light years across?

What does the size of its event horizon have to do with anything? If it absorbs mass, it will expand and its event horizon will also increase in diameter.

>> No.5039311

>>5039297

That's not a valid answer.

>>5039303

So if it doesn't expand into anything then it doesn't expand. Your answer is contradictory.

>> No.5039322

>>5039311
>So if it doesn't expand into anything then it doesn't expand.

This is a false premise, and a fallacy of personal incredulity.

The universe can expand without expanding into something else.

>> No.5039328

>>5039311
It didn't expand into anything, but its interior size increased. It was expanding by virtue of its size increasing, but there was never anything besides the universe itself. It wasn't just empty space. It was nothing. NOTHING. Empty space is something. Nothing is not empty space, it is nothing. So, when the universe expanded. it grew in size and rather than replacing space occupied by nothing it created brand new space that never existed before.

>> No.5039331

>>5039311
Then no answer is valid.
Have fun, kid.

>> No.5039332

>>5039311
Expansion means the distance between the galaxies is getting larger. Doesn't necessarily mean that the universe has a size that's growing -- it could be infinite. Also, remember that you have to use general relativity (dynamic geometry) not Euclid here.

>> No.5039336

>>5039140
It's kind of like osmosis or air pressure systems. The high pressure air pushes into the low pressure system. Just like matter pushes into vacuums, but does not get "sucked in".

>> No.5039338

>>5039311

Intrinsic expansion doesn't require an outside space to expand into. You clearly can't grasp the concept and I'm no educator, so have fun with your state of confusion.

>> No.5039359

Pleb here. Is there something outside of the universe? Is this known?

>> No.5039365

>>5039359
Ideas of that sort have been theorised but not known

>> No.5039368

>>5039359
If it were outside the universe, wouldn't it be part of the universe?

Anyway, there's a limit to how far away we can observe.

>> No.5039369

>>5039359

>Is there something outside of the universe?

By definition no.

>> No.5039387

>>5039359

The universe is everything that exists. If something "existed" outside of it, it would by definition be part of the universe.

eg: Say we discover something on the "other side" of the fabric of spacetime. This doesn't mean something's outside the universe. It means there's more to the universe than we thought there was and that the spaceitme fabric is not actually the universe's boundary.

>> No.5039408

>>5039387
Holy shit
>timandericbrainexplosion.gif

>> No.5039411

>>5039387
It could be another universe to ours.

>> No.5039420

>>5039411

There cannot be other universes than THE universe, by definition.

Don't confuse layman's terms with the scientific.

>> No.5039430

>>5039420
How come there can't be other universes?

(not the other anon)

>> No.5039444

>>5039420
Of course there can be other universes.

>> No.5039449

>>5039420
That's not exactly a technical term.

>> No.5039461

uni meaning one

>> No.5039457

>>5039449

It's the scientific definition of what the universe is.

"The entirety of everything that exists."

No other definition is acceptable in a scientific context. We do not change the way nature works through semantics.

Motherfucking rigor, yo.

>> No.5039466

>>5039430
It higly depends on what you think an universe is. If the universe is EVERYTHING -by definition- then "others" makes no sense, they would be part of it.

>> No.5039470

The most misunderstood fact?

I guess the notion that it's possible to break established laws of physics. All the kids who grew up watching lazy writer sci fi expect us to just upend or somehow prove wrong the last 400 years of observation.

>oh, space elevators, oh FTL, oh, wormholes, oh dyson spheres, oh, type three civilizations, oh alcubierre drive

It's like they've never read anything but space opera.

Shit shows like doctor who are a part of the problem and you can tell they're catering to total retards with snakes on a plane type plots such as "Dinosaurs on a Spaceship".

>> No.5039478

>>5039470
>the notion that it's possible to break established laws of physics

Hmm, I think I do not understand. This happened quite a few times - e.g. relativity and quantum theory.

>> No.5039485

>>5039478

Well you demonstrate your extreme ignorance of the subject.

Exactly what of newton's discoveries were proven wrong by relativity?

All of current physics rests on the shoulders of giants. Einstein merely extrapolated upon newton's work.

>> No.5039487

that a vacuum contains something that we don't know about yet

>> No.5039488

>>5039070
The infinite energy, perpetual motion myth proponents.

IT usually involves magnetism, so I wish I could teach magnetism.

>> No.5039494

>>5039485
Galilei transformations don't work at fast velocities anymore. I would consider this as broken, since neither Newton nor Galilei stated that their laws only hold for slow reference frames.

I know, semantics and shit, blahblah.

>> No.5039495

>>5039470
What's wrong with doctor who ?

>> No.5039509

>>5039494

They still hold for the non-relativistic context in which they were originally observed. When laymen talk of breaking the laws of physics, they actually think observed phenomena will suddenly work entirely differently.

All science is like this. It never "breaks" so much as we keep discovering new phenomena and interactions between them.

Newton's notion of gravity will continue to correctly describe a falling apple on Earth's surface a million years from now.

>> No.5039512

>>5039495

It's for autistic children.

And every single season finale is solved by an ass-pull.

How did they do it last season? Wasn't it some Eddie murphy is actually a robot being piloted by very small eddie murphies sort of thing?

Yeah. that was a satisfying end. Or maybe the Doctor Donna technobabble asspull?

It's just a horrible show for hipsters who think they're clever and quirky and want something to imitate. Thick glasses went up in popularity during tenant's run, and now i see faggots wearing bowties.

Oh, and the weeping angels are based on a complete retard's interpretation of the observer effect.

>> No.5039518

>>5039512

Actor quit on us or needs to be fired? LOL regeneration.

>> No.5039519

>>5039509

Oh yeah, but don't tell the singularitarian zealots. They think we're arrogant for saying that we know anything about the universe. They would deny thermodynamics if it benefited them.

>> No.5039521

>>5039512

>Stop liking what I don't like!

>> No.5039522

>>5039485

In Newtonian mechanics forces travel instantaneously. It wasn't until Einstein's gravitational wave equations that it was determined that gravity traveled at the speed of light. Newton was dead wrong on that count.

>> No.5039525

>>5039518

Everyone is going to die and it's 5 minutes from the end of the season?

Asspull ahoy! We must be worse than star trek voyager and just make shit up until the status quo is back!

just like harry potter, every doctor who season begins and ends the same way.

>> No.5039526

>>5039522

>gravity traveled at the speed of light

is this really confirmed?

>> No.5039528

>>5039521

>this in response to a well reasoned argument

Yep. Keep proving that only autists like the show.

>> No.5039531

>>5039522

Oh, so that invalidated F=MA?

What did that observation invalidate? Do the planets no longer revolve like Keppler described?

>> No.5039543

>>5039531
They never fully did. Mars innit.

>> No.5039544

>>5039531
>Do the planets no longer revolve like Keppler described?

Acutally yes - you can not explain the perihelium (perihelion) shift of Mercury using the classical celestial mechanics. GR is needed for that.

>> No.5039552

>>5039522

That didn't break any laws of physics though, now did it?

Newton's theory about them was simply incomplete. It still held within the limits to his ability to accurately to observe them.

We've got far more accurate instruments today yet even now our theories are surely incomplete. Due to the nature of information they will never be complete, but we can certainly keep improving them.

>>5039526

Jupiter/quasar experiment.

Made a lot of futurists very, very unhappy because they were depending on gravity for FTL comms and/or travel.

>> No.5039556

I only watch it for the hot companions

>> No.5039558

>>5039544

So what? that doesn't mean GR invalidated newtonian or keplers mechanics. It simply expanded upon it.

>i can't figure out this tensor function, algebra must be wrong!

>> No.5039568

>>5039558
>So what? that doesn't mean GR invalidated newtonian or keplers mechanics.

Again .. semantics. What does it take to break a physical law then? Newtonian physics can not correctly describe the orbit of Mercury. So it's not broken? How "well" does a law have to work to be considered a law?

>> No.5039570

meant Mercury, d'oh

>> No.5039577

any sentence that begins with "well, in a parallel universe..."

>> No.5039575

>>5039528

>It's for autistic children.
Sound like a good argument

>And every single season finale is solved by an ass-pull.
I've never seen it, but so what? It's fucking fiction.
>It's just a horrible show for hipsters who think they're clever and quirky and want something to imitate.
Some really good well grounded points there too.
> Thick glasses went up in popularity during tenant's run, and now i see faggots wearing bowties.
Holy fuck, I don't how to refute this!
>Oh, and the weeping angels are based on a complete retard's interpretation of the observer effect.
There is something you don't understand about fiction.

So tell me again, what part of your argument was valid?

>> No.5039584

>>5039568
the laws will always be the same
approximations and theories will change and become more accurate through rigor

>> No.5039595
File: 23 KB, 921x606, picard-facepalm.jpg [View same] [iqdb] [saucenao] [google]
5039595

>sometimes i wish i could bitch slap all the people that think the the earth is 2012 year old

>> No.5039590

>>5039568

Something that contradicts it?

Just because Mendel didn't know what DNA was doesn't mean that Punnet squares don't work.

The perihelion of mercury doesn't invalidate anything. Sheesh.

>> No.5039592

>>5039526

Gravitational waves themselves have not been observed, but the equations that give rise to them do work perfectly (i.e. within the margin of error) in every case we have observed.

However, if General Relativity is wrong and gravitational waves do travel superluminally (note that this doesn't mean spacetime can't travel superluminally: see the universe at 100 billion lightyears, or see the Alcubierre drive metric), that would prove my point even more that past physicists can be flat-out wrong.

Also quantum gravity allows both interaction between electromagnetism and gravity, and changes in the topology of spacetime (wormholes), at the Planck scale of energy density (which is ridiculously massive).

No, we aren't done with physics yet.

>> No.5039593

>>5039575

Keep being a petulant cunt. It suits you.

>> No.5039598

>>5039592

>quantum gravity

Pretty sure we're still a long way from understanding that.

And we are done with many aspects of physics. Thermodynamics, for example. No amount of engineering will ever make a 100% efficient anything.

>> No.5039603

>>5039568

It would help if you were even arguing about the correct thing. All of the arguments in this thread on this topic have concerned the accuracy of applying that law, and not the law itself:

"Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them."

We've added on to the above to explain things in context, but never have we invalidated the above work.

>> No.5039610

>>5039556
The only "hot" companion was Emily/Amy.

>> No.5039643

is one of them "the earth is round" and the other "there are weird bendy white lines passing through the universe in a grid"?

>> No.5039650

>>5039643

The earth is round. It's just not a sphere.

But yeah, the science channel and its butchered analogies have caused great harm.

>> No.5039820

>>5039336
How come our faces explode in space?

>> No.5040032

>>5039070
Either the big bang theory or the theory of evolution.
Those are theories though (nothing in science can be 100% proven and be fact etc,etc)

In terms of fact though, it would definitely be the laws of thermodynamics. Without a doubt

>> No.5040061

>>5039820
For the same reason raindrops are shaped like tears.

>> No.5040130
File: 37 KB, 410x369, 1346477892280.jpg [View same] [iqdb] [saucenao] [google]
5040130

>>5039650

I don't watch the Science Channel. How do they butcher or misrepresent the spacetime fabric and/or gravity?

>> No.5040169

>>5039575
>>And every single season finale is solved by an ass-pull.
I've never seen it, but so what? It's fucking fiction.

The problem with 'every season finale being solved by an ass-pull' is that it's unsatisfying. It's alright if season finales are solved by something established in the show's universe, but deus ex machina happening or creating new things in the show's universe is unsatisfying and lazy/unplanned writing.

>> No.5040170

>>5040130
The picture OP gives is normally used to explain how mass bends Space Time. It is misrepresented because they use a two dimensional space, whereas our universe has three prominent dimensions of space.

>> No.5041409
File: 32 KB, 330x250, 1345863479594.jpg [View same] [iqdb] [saucenao] [google]
5041409

>>5040170

Ah, thanks. So they fail to point out that the "bending sheet of cloth" (or "gridlines in spaaaace") is just an analogy. And make it seem like things "fall down" into the cloth (using gravity to explain gravity)

>> No.5041606

Muh Thorium

>> No.5041621

Energy=Force*Distance. It's a pretty simple one, but I hate listening to people talk about energy when they have no fucking idea what it is.

>> No.5041673

>>5041621
the irony

>> No.5041694

>>5041621
lel.

i agree its the most misunderstood thing in physics. and you just proved it.

its not something physical, its not the ability to do work, you dont get "pure energy". you cant get free energy, its justs the quantity that is conserved. thats all. its a collection of variables that dont change. why do people not understand it? people dont walk around saying matter can transform into pure momentum, or pure electrical charge. why energy?