A Brief History Of Time: The Pioneering Work Of Stephen Hawking | Naked Science | Spark
//Summary - Level-C2//
A renowned physicist, Stephen Hawking dedicated his life to understanding the universe's origins despite battling ALS. He sought a "theory of everything" to unify general relativity and quantum mechanics. The universe began from a singularity, similar to the black holes that emit Hawking radiation. String theory emerged as a leading candidate, suggesting that extra dimensions weaken gravity, allowing the universe to expand. The Large Hadron Collider could provide empirical evidence by recreating post-Big Bang conditions, potentially supporting Hawking's and string theory's explanations of the universe's origin.
//SUMMARY//
i)
The article discusses Stephen Hawking's quest to discover the universe's origins and develop a "theory of everything" explaining the cosmos, from the smallest particles to the giant galaxies.
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It highlights Hawking's determination despite his battle with ALS, which left him paralysed. The article recounts his early work on the Big Bang theory and black holes, noting how he reversed Roger Penrose's singularity theorem to suggest that the universe could have originated from an expanding singularity.
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Hawking's groundbreaking realisation that black holes emit radiation (Hawking radiation) challenged the idea that nothing could escape black holes and suggested a way to unite quantum mechanics and general relativity.
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The video also explores the challenges of combining these two fundamental theories, as quantum mechanics governs the very small, while general relativity governs the very large. Hawking's work aims to bridge this gap, which remains one of the most significant challenges in theoretical physics.
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String theory, proposed by other physicists, is emerging as a possible solution. It suggests that all matter comprises tiny vibrating strings, and the universe has additional hidden dimensions.
This theory could explain why gravity is weaker than other forces by suggesting that it extends into these extra dimensions.
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The article concludes by looking forward to experiments at the Large Hadron Collider, which will recreate conditions similar to the Big Bang.
These experiments could provide evidence for string theory and Hawking's ideas, offering insights into the universe's earliest moments and the fundamental nature of reality.
//Part of the Main article//
00:06
1)
Stephen Hawking is the most famous scientist in the world.
He's on a quest to answer the biggest question of all: how everything in the universe came to be - if we could find the answer, we'd know the mind of God.
Hawking's goal is to discover a blueprint for the universe, but he's locked in a battle with an illness that has left him paralysed and progressing. Can he unlock the secret of creation before his time runs out?
01:03
2)
Out Steven Hawking is one of the greatest minds of all time. He is on a quest to understand the moment of creation when the universe was born 20 years ago.
He wrote a book on the subject, which became an international bestseller. It promises that he will soon have a robust single theory that will explain all the mysteries of the cosmos.
Why did the universe come into being, and will it continue to do so? Will it ever end?
It's a Theory of Everything.
We are getting close to answering the eight ancient questions: Why are we here? Where did we come from?
Steven's determination to find answers has kept him alive far longer than any doctor predicted. He is tremendously determined to solve the universe's problems.
01:52
3)
That's one of the critical factors that's kept him going all these years, but he's living on borrowed time. The idea that my father had a very short lifespan was always there.
I think it was there every day. Parking won't rest until he unlocks the mystery of how the universe came to be.
My goal is simple: it's a complete understanding of the universe, why it is the way it is, and why it exists. I was born in 1942
02:38
4)
Steven Hawking has always been fascinated by the world around him. As a healthy child, he wonders what the stars are made of.
As a teenager, he wanted to discover where the universe came from. In the 1960s, scientists have yet to answer this question.
Many believe our universe had no beginning. It is timeless and unchanging, but a new theory is gaining ground. Everything in our universe exploded from a tiny point like a shower of fireworks. Scientists nicknamed it the Big Bang.
03:27
5)
But how can we suddenly go from nothing to everything in one moment of creation? 20-year-old Steven Hawking's first mission is to find out.
According to his old friend Kip Thorn, he had just started his PhD at Cambridge University in 1962 and was eager to prove himself.
It wasn't evident then that he would come to the Tower above all the rest of us, but around this time, Hawking notices that he is becoming very clumsy; a visit to the hospital leads to a startling diagnosis, the doctors discovered.
04:15
6)
He has amyotrophic lateral sclerosis or ALS. The disease wastes away his muscles soon; he will be paralysed entirely within two years, and he will be dead. Hawking was just 21.
His dream of unravelling the mysteries of the universe collapses around him. I had just been diagnosed with ALS, and I didn't know if I would live long enough to finish my doctorate.
It is the darkest period of his life. According to his daughter, Lucy Hawking, he became very depressed, and unfortunately, he was casting around for a PhD topic at the time.
05:07
7)
But he didn't see any point in continuing. Everything seems bleak and hopeless to him, but Hawking meets Lucy's mother.
Hawking is in love despite his death; getting engaged and married to her was the turning point that turned around, gave him hope, and made him decide he was a career. Hawking sets out to discover the universe's origin before his time runs out. Does the universe have a beginning?
05:46
8)
Or if so, what are they like? Scientists remain sceptical that something can come from nothing, as the Big Bang predicts. Hawking wants to find out. His first break came in 1965.
He attends a lecture by a brilliant mathematician named Roger Penrose. Hawking hears something that sparks his interest. Steven is in the audience at the back of the room and asks pertinent questions.
06:34
9)
And difficult questions: Penrose suggests something astonishing: there is a hole in space where massive objects disappear. If matter disappears into nothing, it may also appear from nothing.
This could be Hawking's first step towards proving the Big Bang, but how can a hole in space exist? The answer could be li with gravity.
Einstein's general theory of relativity says that gravity is not just a force of attraction. It bends space Oxford Stanford University Pedro Ferrera sFerrerathe effects of gravity on the universe Einstein. Einstein that gravity was not this force that acts between two bodies.
07:26
10)
It was something much more elegant and beautiful. Einstein pictures space and time as cloth planets and stars press on this cloth to create depressions.
In a stroke of genius, he realises that gravity is not a force but the bends in this cloth. The expressions pull objects towards them. Let's imagine this rubber sheet is space.
The glass balls I hold in my hand are planets and stars. Placing a planet or star in the universe's space will create a depression; the more extensive the object you put, the more significant the depression. Imagine that the Earth is a coin.
08:17
11)
And I'm just going to send it coasting around our sun. It's going to settle nicely into an orbit. It's just following the deformed nature of the fabric of space.
That's what gravity is, Einstein, and what Einstein realised. So what we experience as gravity is the curve of spacetime around us. The theory of relativity is forcing us to change our ideas of space fundamentally.
09:03
12)
When this fabric is stretched to the breaking point, something dramatic happens: a hole in space opens up a hole into which things can disappear.
This chain of events starts when a star dies. When a star 20 times the size of the sun dies, it starts to collapse, getting smaller and denser. This has a drastic effect on the fabric of spacetime.
When you stretch this fabric to the breaking point, something dramatic happens on the fabric of spacetime.
If you can imagine what that means in terms of the fabric of spacetime, you're just squeezing it incredibly hard—so hard that it almost tears.
At that point, the depression is so deep that nothing can climb out, not even light. If that star is big enough, this is known as a black hole.
09:51
13)
It'll collapse to a tiny minute Point that is incredibly dense. It'll leave it to create a dip in space so deep that if an object tries to pass by.
It'll be sucked in, and it'll be sucked down into that point that's a black hole. Roger Penrose discovers that at the centre of a black hole is a point of Pure Gravity.
It's called a singularity. As you go into a black hole, you will encounter something which goes against the laws of physics, as we previously understood.
10:36
14)
You could roughly say a singularity is where space and time end and a singularity is like a drain or a hole in space. Everything that falls disappears—hawking wonders if the opposite could be accurate.
According to the Big Bang theory, the whole universe suddenly sprang from the point of nothing.
Could This hole be the key to explaining how this happened? In a moment of genius, he sees the solution. It's elegantly simple. I soon realised that if you reverse the direction of time, you get a black hole.
11:21
15)
And Panos theorem, the collapse became an expansion instead of sucking everything in a reverse black hole explodes out in a shower of space.
Matter and time precisely as the Big Bang theory predicts against the Sea of Scepticism hulking proves the universe suddenly appeared from nothing. It sprang from inside a singularity.
The debate is over whether the universe must have had a beginning in time. Pen. Ros and I finally proved this based on Einstein's theory of relativity, and Hawking found the origin of time.
Still, he hasn't found a way to stop it ticking.
12:07
16)
He's now 26 years old. His disease has progressed to the muscles in his legs. He can no longer walk, but his brain is alive with questions. Hawking now knows that a moment of creation happened but not what caused it to explode into being.
This will prove his greatest challenge, yet can he find the answer before his body collapses? Steven Hawking has discovered where the universe began: a tiny hole in space known as a singularity that exploded in a big bang to create everything in the universe.
13:09
17)
But he doesn't understand what made it explode. Why are we where we come from? To find the origin of Einstein's swing, he used his general theory of relativity to explain how gravity acts on prominent objects like stars and planets.
Still, when the universe was born, it was smaller than an atom, so he needed the theory of minimal quantum mechanics to understand how it grew.
The problem is that atoms are unpredictable. They don't follow the ordered rules of gravity, and the theories of general relativity and quantum mechanics are incompatible.
14:00
18)
Unfortunately, although these two theories are known to be compatible, they can't both be right at NASA's Goddard Space Flight Centre. Kim Weaver is interested in the conflict between the theories.
This ball can be used to represent the tension or the battle that is going on between general relativity and quantum mechanics. In quantum physics, the surface is smooth. It means a large-scale general relativity gravity acts on a vast scale.
A Brief History Of Time: The Pioneering Work Of Stephen Hawking | Naked Science | Spark
https://www.youtube.com/watch?v=EllbltLLnzo&t=763s
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