Prática de Shadowing: What is time? - Aprenda a falar inglês com vídeo

What is time?

It's a difficult question, and part of the difficulty is that it can mean several different things.

It could mean, why does it feel like time passes?

And why does it feel like there is a special moment that we call now, which separates the past from the future?

A second meaning is, where does time come from?

And a third, what do we even mean by time?

I'll start with the third question because it's the easiest, meaning it'll only hurt your brain moderately.

In physics, we use the word time in two different ways.

The one refers to the role of time in Einstein's theories.

Einstein taught us that time is a coordinate, like space.

This means that time becomes a label to order events.

This time coordinate isn't uniquely fixed.

You can change it just like you can change coordinates in space where you can use, say, Euclidean or spherical coordinates.

You can make different choices for the time coordinate too.

This doesn't actually change time.

It's just a different way to describe the same thing.

This coordinate time in Einstein's theory is a way to describe what happens in our universe.

It isn't in any way directly related to our perception of time.

The second way we use the word time is in a constructive sense.

Time is what a clock measures.

But this brings up the question, what is a clock?

Clocks are made of matter, and from this matter, we identify some quantity that tells us how time passes.

For example, because the motion of the system recurs periodically, like, say, the swing of a pendulum, the beat of a heart,

or Kevin checking his phone.

In Einstein's theory, this matter time should correspond to the length of a particle's path in space -time.

It's also called the prop time.

In quantum physics, actually, we don't really know what time is.

Physicists have made attempts to define clocks in quantum physics to define time from that,

but I think it's fair to say that there is no general agreement on how to do it.

Let's then talk about the second question.

Where does time come from?

Maybe it just doesn't come from anything.

Maybe time just is.

It's one of the fundamental ingredients of the universe.

But another possibility is that time arises from something else.

We then say that time is emergent.

This is why you sometimes hear physicists say time is an illusion because it might come from something else.

But what's this something else?

One quite well -trodden path is that time is a consequence of causality.

Because for causality to make sense, you need an order in how things happen.

This causality -first approach has been pursued in a variety of ways in Raphael Sorkin's causal sets,

but also in Stephen Wolfram's hypergraphs and Felix Finster's causal fermion systems.

A completely different take comes from Julian Barber, who says that really fundamentally there's no such thing as time.

What's real is merely that the relations of particles to each other can differ, and time is the way that we order them so that it makes sense.

I don't really understand this, so please don't ask.

Somewhat more digestible is the idea that the universe was once a four -dimensional space, and at some boundary in that space, one of the dimensions turn to time.

This is what happens, for example, in the Hawking -Hartell No Boundary Proposal.

So it's quite possible that time ultimately comes from something else.

We just haven't really figured out how.

Let's then come to the most difficult of the questions.

Why do we have the feeling that time passes?

And why do we have the feeling that there is a special moment that we call now?

Part of this question asks about what's going on in the human brain.

How does the brain keep track of time?

Well, I'm a physicist and I don't have the slightest idea how the human brain works.

But basically, the issue is that we can remember the past, but not the future.

Einstein was bothered by this greatly and called it the problem of now.

In our maths, we don't have a now.

Do we need one?

On the one hand, one could argue that physics isn't meant to describe human's subjective experience, so who really cares?

On the other hand, if you believe that fundamentally everything, including the human brain, is made of particles,

then this Now experience must come from something.

There are only two ways to resolve this conundrum.

Either our perception of being in a particular moment doesn't correspond to anything in the fundamental structure of the universe.

Every moment is special when it happens, but all moments are the same in this, so none is special.

The other way to resolve the problem is to postulate a physical notion of now.

There is really only one example I know for this, which comes from George Ellis.

He says that what creates the present moment is the collapse of the wave function.

Personally, I lean towards the causality first interpretation and think that now doesn't have a fundamental meaning.

But maybe more importantly, this is a pretty big question

which most physicists don't take very seriously and I find this rather unfortunate.

I believe that causality is the key to understanding how nature fundamentally works.

I spend so much time thinking about time that I should be getting an interest rate.

And if it's really an illusion, then it's certainly doing an amazing disappearing act.

Come to think of it, though, the first key to understanding nature is clearly mathematics.

And while watching YouTube videos is a great entry point, if you want to really understand something,

you need to actively engage with the subject.

This is why I recommend you check out the science and maths courses on Brilliant.

All courses on Brilliant have interactive visualizations and come with follow -up questions.

What you see here is from their newly updated maths courses.

No matter how abstract the topic seems, Brilliant's courses have intuitive visualizations that really click into my brain.

I found it to be a highly effective way to build up knowledge.

And Brilliant covers a large variety of topics in science, computer science, and maths, from general scientific thinking to dedicated courses,

just what I'm interested in.

And of course, I have a special offer for viewers of this channel.

If you use my link brilliant .org slash Sabine or scan the QR code, you'll get 20 % off the annual premium subscription.

So go and check this out.

Thanks for watching.

See you tomorrow.

📺 Mesmo canal

✨ Vídeo recomendado

197 frases

We Know More About Time Than You Think

IELTS PrepTOEFL Prep+2

66 frases

What science can’t answer, according to physicist Jim Al-Khalili | Big Think

IELTS PrepTOEFL Prep+2

27 frases

How Einstein changed time forever | Jim Al-Khalili for Big Think

IELTS PrepTOEFL Prep+2

138 frases

TEST 30 PART 3 - LUYỆN TẬP VÀ THỰC HÀNH LISTENING - TỰ HỌC VSTEP

IELTS PrepTOEFL Prep+2

32 frases

There's a Giant Hole In Earth's History

IELTS PrepTOEFL Prep+2

28 frases

The Professor Who Taught People How To Think (1962)

IELTS PrepTOEFL Prep+2

133 frases

Hegel: Philosophy of world history and spirit

IELTS PrepTOEFL Prep+3

O que é a Técnica de Shadowing?

Shadowing é uma técnica de aprendizado de idiomas com base científica, originalmente desenvolvida para o treinamento de intérpretes profissionais. O método é simples, mas poderoso: você ouve áudio em inglês nativo e repete imediatamente em voz alta — como uma sombra seguindo o falante com 1-2 segundos de atraso. Pesquisas mostram melhora significativa na precisão da pronúncia, entonação, ritmo, sons conectados, compreensão auditiva e fluência na fala.

Técnica de shadowing: leia o guia completo passo a passo →

Prática de Shadowing: What is time? - Aprenda a falar inglês com vídeo

Mathematician Collapses All Functions to One Weird Formula

Superfluid Dark Matter

The End of Human Mathematics? AI's Recent Breakthrough -- And What's Next

We Can Now Simulate a Human Brain, Scientists Show

Make AI Believe in God to Keep Humans Safe, Scientist Argues

FINALLY: A Proof that Particles Take All Paths At Once?

AI Will End Philosophy, Physicist Claims

Does God exist? Science does not have an answer.

Our Solar System Lost Two Planets!

I was SO wrong about quantum computing.

We Know More About Time Than You Think

What science can’t answer, according to physicist Jim Al-Khalili | Big Think

ATOMS ENGLISH

How Einstein changed time forever | Jim Al-Khalili for Big Think

TEST 30 PART 3 - LUYỆN TẬP VÀ THỰC HÀNH LISTENING - TỰ HỌC VSTEP

Lucy: Time is Unity (HD CLIP)

O, Death!

There's a Giant Hole In Earth's History

What Is The Universe?

The Professor Who Taught People How To Think (1962)

Hegel: Philosophy of world history and spirit

Sobre esta lição

O que é a Técnica de Shadowing?