At the limits of astrophysics - with Katy Clough

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Why does modern astronomy often sound like science fiction? And how do objects like supermassive black holes, wormholes and warp drives fit into our current understanding of physics?
Watch the Q&A here: • Q&A: At the limits of ...
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This event was recorded at the Royal Institution on 23 March 2023.
Much of modern astronomy sounds a lot like science fiction - gravitational ripples in the fabric of spacetime, supermassive black holes hiding at the centre of galaxies, habitable exoplanets within the reach of our telescopes…are there any limits to what is out there?
Whilst largely considered to be firmly in the category of fiction, such concepts are nevertheless based on solid scientific ideas about the curvature of spacetime from Einstein’s theory of general relativity. This theory is known to be hugely counter-intuitive, giving rise to singularities, event horizons and time dilation around black holes. In strong gravity regimes things behave very differently to the low gravity environment on the Earth, so our intuition, which is based on our everyday experience, can mislead us. Studying these objects can help us to challenge our understanding of what is “natural”, and better understand the extreme limits of gravitational theory.
Katy Clough is a lecturer and Ernest Rutherford Fellow in the School of Mathematical Sciences at Queen Mary University of London. She studies systems with strong dynamical gravity using numerical simulations, including black holes and the early universe. She is part of the fundamental physics working group for the future space based gravitational wave detector, LISA. Katy’s first degree was in Engineering and her degree in Physics was obtained from the Open University whilst working as a chartered accountant. After her PhD at King’s College London she worked in Goettingen in Germany and in Oxford University in postdoctoral positions. She believes that science is for everyone and that there is no right way to be a scientist.
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28 сен 2024

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Комментарии : 356

@rbee6507 6 месяцев назад

Every so often, I hear a discussion of this level and somehow it brings me an even higher level of enlightenment, curiosity, and inspiration! Amazing presentation, delivery, and insight. I agree with you wholeheartedly in your interpretation. Considering gravity as a force absolutely limited my thought and I hadn't even realized it before hearing you! Don't you worry...I am confident it will catch on very soon. Thank you SO much! All the love and appreciation to you Katy! This completely changed my way of viewing even the things I already knew. I wish you much success and discovery.

@Syntax753 Год назад

Lately, have been delving into learning more about astrophysics/quantum mechanics - and the RI impresses with every presentation. The lecture format with live demos always manages to offer alternative representations which has influenced my understanding across the videos. Coming from a classical maths background, I particularly enjoyed this one! Thank you for all the hard work putting this together! I still love you Newton ☺

@georgeangles6542 6 месяцев назад

There is no limit to how long I'd be able to listen to this woman speak. She's great💪💪

@real_DrDummkopf Год назад

As many of these I've seen as well as world science festival I've never actually explored the comments area of it and it paints a better picture other than just trying to get my own understanding. Thanks a million

@savage22bolt32 Год назад

I find a lot of interesting ideas & opinions in the comments section. Take them with a grain of salt, as they say. But reading comments enhances the the whole shabang.

@stevefromsaskatoon830 Год назад

Reading comments is by far my favorite thing about the internet

@JoimFormula Год назад

Kip Thorne should be credited for the accurate black hole visualization in Interstellar movie

@user-zc5ft9nw9b Месяц назад

It has always been known that Kip Thorne was the scientific consultant for the film Interstellar. So do you mean credited in the financial capacity?

@davidschneide5422 Год назад

Chandrasekhar left the U.K. for the U.S. in hopes of finding less racism. Amusing.

@abdessamadhasnaoui6887 8 месяцев назад

I loved the lecture.. Thank you for explaining these valuable things And thanks to Thé Royal Institution for making these lectures accessible for free And know that you researchers are and will be forever the best people thar have ever existed😃😃😃

@punditgi Год назад

Brilliant presentation! ❤🎉😊

@SimonDallender 3 месяца назад

This woman is entertaining, insightful and informative. I’m going to find more of her stuff now. Thank you RU-vid and thank you RI!! And Thank you Katy Clough!

@MTSVW Год назад

This is the first time I’ve heard gravity explained as a product of curved time in a way that makes sense. I love the analogy of two people hiking north and meeting at the North Pole, and it looking like a force pushing them together even though it really isn’t.

@joskeguereza3714 Год назад

it doesn't really work though, if ONLY the north-south dimension was curved and the east-west dimension wasn't, then the students would never meet at the northpole. So i wonder if that means that both space and time have to be curved for it to work? interesting analogy though :)

@cloudpoint0 Год назад

It works if you choose an appropriate coordinate system. But curvature is purely a function the coordinate system you chose and not of the physical universe. Imagine an East and West Pole on Earth instead of the north-south coordinate system we have adopted, and indeed you can keep going north forever.

@davidgould9431 Год назад

@@cloudpoint0 In your example you can't keep going east or west forever. On a sphere, when you set two people off locally parallel and they keep going according to their local metric, they will always meet. Calling it east, north, banana or whatever is arbitrary: any two parallel travellers will eventually meet.

@cloudpoint0 Год назад

@@davidgould9431 The equator, the two tropics and the two polar circles never cross. Any two people on any of these separate paths will never meet. East and west are indeed forever since in the coordinate system we use on Earth there is no East and West Pole. "Locally parallel" is a semantically defined term that has meaning only in a specific coordinate system. Two people heading North on the curved surface of the Earth are not on parallel paths. They are headed toward a common arbitrarily defined coordinate point. They just think they moving in a parallel way because of the way words like north and south are defined.

@davidgould9431 Год назад

@@cloudpoint0"Semantically defined term". That's what semantics is: definitions. And coordinates have nothing to do with it. Coordinates are arbitrary and convertible one to another, so that's a non-starter. When talking about parallel lines, it's generally understood to be about straight lines which, on a sphere, are great circles. So lines of latitude are, on the sphere, curved because they aren't great circles. For example: concentric circles in flat, Euclidean space don't ever meet but are only locally parallel, not globally parallel. If you start two people pointing on lines of latitude and get them to each walk along the great circle in their respective directions they will meet. If you want to "semantically define" parallel according to your preference, that's fine: have a ball.

@mariam_tigress Год назад

I love how nonchalantly she talks about time space - like, we can fold it, no problem, it's punching through that is difficult

@toma5153 Год назад

A very enjoyable and practical lecture. I encourage more lectures like this.

@andreadelucia4969 Год назад

Such a wonderful and pleasant explanation, very kind, nice and professional at the same time. Thank you so much

@bilinguru Год назад

The universe is not expanding, but curving in the time direction. Love it! First time to hear it expressed this way, and it really helped me visualize what's going on.

@adairjanney7109 Год назад

except none of it is going on, they wont admit they made a huge error years ago which is why everything is so confusing, the CMB isnt real and most of the data that they base all of this on comes from data from the CMB which isnt even real, they never detected it at L2 that signal comes from the hydrogen bond in water which is why they should have known better when cobe got such a STRONG signal in polar orbit, it should have been a red flag but they didnt care

@yanikkunitsin1466 Год назад

Oh, it's Mitch more complex than that.

@adairjanney7109 Год назад

it isnt doing any such thing its all lies, the CMB doesnt exist at all they MISCORRECTLY applied the hydrogen bond to that signal and they wont admit it even though its beyond obvious and very provable see Dr Robitille for details. This is why cosmology is so broken

@yungsookevinhong7943 Год назад

Space time curvature is layer and layer sheet stacked or could it be explained as it’s density change, it is the high density to the low density to balance the spacing evenly. The universe is condense of physic. Therefore its has to balance to the low density as explain as the universe expansion phenomenon.

@danielpark4028 Год назад

This is so great Katy, moving in curved time is a really good analogy 👌🏼

@Vile_Entity_3545 Год назад

A lecturer that explains things in laymen’s terms. Give her a bigger chunk of taxpayers money (raise)

@vinnyvdalidemonet8527 Год назад

Dr. Clough did a fantastic job. Her explanations gave me a much better understanding to the space/time principles. She is a really good teacher. Her passion is contagious.

@gidi1899 Год назад

16:50 - how to explain to 2 galaxies moving away from each other: 1. they have different initial speeds 2. they have different mass 3. they are viewed rotating on a sphere from inside the sphere

@savage22bolt32 Год назад

I wonder where that famous desk has gone? Perhaps a little refinishing?

@phillipcoetzer8186 Год назад

I do actually have a question ... space time is treated as one thing when it is two entities if a wormhole is made on the time fabric we travel through time .. if a wormhole is made through space we travel through space ... how does time behave in the latter ... I assume understanding that will enhance our understanding of how time works. And it seems to me a space wormhole is indeed a blackhole ... what would a timehole look like?

@JustNow42 Год назад

Protest: time do not progress in the empty room. Time is a progression and in empty space there is no progression. There is random energy variations that when you immerse particles in it drive a progression. So the random variations has a spectrum that determine the speed of time when probed. A little like you do not know certain parameters of particles unless you measure them. Is that so difficult?

@ahsanmohammed1 Год назад

23:00 An astrophysicist saying, “I've got no sense of distance,” sounds a bit off to a layman like me.

@robdoty6903 3 месяца назад

16:45 really neat idea to explain the universe's expansion due to "inverse" curvature, so why do we even need dark energy to explain it?

@billdecat855 Год назад

ER=EPR this conjecture interests me insomuch as it somewhat says that wormholes = quantum entanglement.

@jasonhayward6965 Год назад

The real problem is PhD are trained to prove with experiments. But workers are trained to solve . So give workers technology to be able to look up the answers study new things and pound for pound the citizen scientists can rip apart and get an answer by solving it . While PhD are really only educating students.

@elenalosseva4912 5 месяцев назад

Amazing lecture!

@jeffroberts6865 Год назад

Katy says spacetime for the Universe overall is curved in the time direction so that galaxies mainly move apart as they go through time. This makes sense to me. However, does this mean from a topological perspective it is like a saddle shape? I had understood from previous readings and videos that it was regarded as mostly flat.

@jeffroberts6865 Год назад

She actually answers this in the Q&A video.

@ahsanmohammed1 Год назад

13:00 Two parallel lines going straight meet up at the North Pole? Seems they’re not parallel. Seems they’re angled to point to the North Pole. Shouldn’t parallel lines that start at the equator be going around the earth in perpetual parallellity?

@hrgwea Год назад

Unfortunately she used a bad analogy to explain space-time curvature. North is a single point, not a direction. Therefore two people walking north will always meet at the north pole because they started walking towards the same point. What she tried to do was to use north as a direction instead of as a point. So, if two people walk in the same direction starting from two different points, they should never meet each other if space-time was flat.

@rajeevgangal542 Год назад

Since both gravity and electrostatic equations are the same in form, is electromagnetic force not a force?

@yourguard4 Год назад

Only Newtons gravity has this form. And Newton thought of gravity as a force.

@djsarg7451 21 день назад

Very good. FYI: Know that much is theoretical. No one can be in a spacecraft anywhere near a black hole. For that matter, no one can really travel to another planet.

@Triring65 8 месяцев назад

I believe that the analogy of gravity is curvature of space and is not a force. Even if there is an indentation as acurvature of space, if there is no attracting force between two mass then the smaller mass should be able to stand still on the side of the hill. The only reason mass rolls down the hill is because gravity is actively attract the two mass.

@eldraque4556 3 месяца назад

totally excellent

@ImtiazKhan-xk9nh Год назад

This may be a stupid question, Katy explained that in 3d Spacetime time dimension is bent bringing the 2 students together as they move from Africa, so in 4d time this is bent which should bring convergence? further in her QA session she replies that time dimension derives this bent force from Dark energy, The very property of dark energy is expanding spacetime so isn't this counterintuitive? Dark energy is the very constituent of spacetime, so who is moving whom?, which came first? aplogies for my ignorance

@yanikkunitsin1466 Год назад

Dark energy, unlike say gravity, is a 'placeholder' term to explain discrepancy in calculation and not very well understood physical phenomena that we can detect and make experiments or link to other things.

@vladimirp2674 Год назад

Astronomically speaking, this is a bright one lecture! Space and time are actually questions, that i firstly met during my school days, when i went through primitive books, that historically speaking, become quite obsolete and old-fashioned, even pretty ridiculous, when i have a jerk to remind myself, how first things about physics were explored to me, so i rarely moved towards old stuff, on the other hand, such an inventive and wise approach, naturally, reorganized my knowledge though i am not these days particularly into it. Well done!

@ExecutiveChefLance Год назад

I studied Biochem and Microbiology but been hardcore into Quantum Physics and Cosmology for past few years. And currently I am obsessed with the fundamentals. Hate the Copenhagen Interpretation. There HAS to be A Reason even if that reason does point to why Probability is a Fundamental Building Block. I think if we truly understood these questions it would point to obvious answer in Cosmology. My opinion is Energy itself can only exist in the form of EM Wave. And that the transition of energy to matter around the Big Bang is what gives us the Perception of Time. (What Spacetime is, Why it warps when Matter is present is another crazy ) Therefore if you can see a standing EM Wave you aren't moving Forward In Time. Given that Energy Distribution is the Basis of Entropy. And High Entropy means Hidden Information. Energy itself reveals Information. So it makes no sense to be able to SEE Energy. At the basis of Energy is just Vibrating Quantum Fields. Energy is like a Movie and the Observer Effect is like seeing a slice of that movie. So we see it as Particle Nature. All entropic relations go from High Stable to Low Stable with an intermediate Chaos. That is what we see in the spectrum of Nature between Waves or Energy and Matter or Mass. That Intermediate Chaos, the Probability or what some QM Scientists refer to as Choices that split Realities. Its like a Law of Nature. You cannot have 100% determinism or Energy and Time itself doesn't make sense. Sorry for the rant just drank a really strong coffee. Maybe in 20 years I can hammer down the details the of my Universal Law of Energy, Time and Determinism.

@yungsookevinhong7943 Год назад

Weight is the actually measure of density of matter.

@garlicgherkin Год назад

No, density is mass/volume, and weight corresponds to just mass. So for instance Jupiter 'weighs' more than Earth (has more mass, over 300 times as much) but because its volume is so much greater, it has only 1/4 the density of Earth.

@orangetee5 Год назад

Loved it!! Thank you 😊

@0.618-0 Год назад

Cool talk Katy, very thought provoking. The stretchy fabric analogous model of gravity is misleading, gravity is like concentric rings around a sphere, with each concentric ring having a time and gravitational value, weakening the further away from the sphere. With space energy pushing on matter and matter energy pushing on space. Why are Spheres only created...what if Square massive forms were around, what would the gravity around a Square mass be. How could that even be calculated? 18:46

@0.618-0 Год назад

@STAFUS Interesting take on Gravity you have. Space time curvature should be called Spacetime Distortion. Gravity, I think, is a Spacetime Distortion. A distortion of density between matter on non matter. At the boundary layer, or surface of an astronomic body, Space Time , or non matter being evicted from the Volume the matter occupies when formed. it is pushed together by gravity. Mater doesn't pull on Spacetime, matter is riding the distortion field of spacetime toward the centre of the earth....

@0.618-0 Год назад

@STAFUS Gravity evoked twice..every action has an equal and opposite reaction.second law of energy conservation. Mass has matter and spacetime in each molecule doesn't it? As you pointed out, there is greater volume of spacetime vs matter around a planet, thus gravity accelerates matter to the centre of the mass. Thus spacetime distorts , and wants to revert back to the space ather occupies. Like a mass in a tub of water. the volume of mass pushes the water. ....

@0.618-0 Год назад

@STAFUS I was referring to your statement in points 2 and 3. explain your logic as you seem to contradict your initial statement with this latter statement

@0.618-0 Год назад

@STAFUS curved spacetime being gravity can easily be disproved. How... you say Einstein is wrong about curved spacetime, Edington did not proove light bends around an eclipse? You explain yourself

@0.618-0 Год назад

@stafus Higher Density does repel, the reaction to rhat, the second law of Newton, spacetime curves and evokes an acceleration called gravity , against matter within the bulk...so there it's logical that density of mass, and the tensor of spacetime causes acceleration on mass. General theory of relativity..

@rudyvanderhoeven9628 Год назад

At last I understand

@ЮрийАндрейцев-й1з Год назад

it is going to be an extremely curious talk, thank you so much

@kano6325 Год назад

Research scientist has processor

@quranjadeed 3 месяца назад

If we can’t imagine space time as a whole, can we at least imagine a slice of it?

@milkmanproductions1837 Год назад

What is the void that the universe stays in? And can we fill it or escape it? And if the universe has all these holes in it, why is it not deflating?

@loweha69 Год назад

Dr Clough, we need another lecture about what you mentioned in the last minute! :-) Great lecture!

@ricocapili6990 Год назад

As the lecture points out the universe moves in an expanding direction. There is no point of reference from the outside only from the visible inside with the red shifting bodies. My theory is our universe has reached its tipping point of not reversing but bending back to its origin like a boomerang returning to the thrower in several dimensions. Heading destruction while our twin counter balance universe awaits creation.

@SonicImmersion_ Год назад

The time dimension of spacetime is curved by mass. Rather than the spatial dimenions of spacetime being curved by mass. I love watching talks such as this, because of opportunities to learn something that hadn't occurred to me before. Now, I want to go learn more about time curvature.

@EduardoRodriguez-du2vd Год назад

In my impression, "curved space" implies a deformation of space with respect to something. But "curved time" cannot be the same and different from "curved space". Curved Time can only affect the pace of time passage. Apparently, she thinks that curved time is the inverse of curved space. There is a problem here with the idea of time. :)

@yanikkunitsin1466 Год назад

You should research basic general relativity concepts. 'Pace of time' is meaningless.

@crazywickedcustoms7272 Год назад

Thank you , I learned alot

@JoimFormula Год назад

Also, Alcubierre should be credited for the warp drive idea

@sunroad7228 Год назад

E=mc² - If it is a constant, then all the universe would know about it - Mass, Energy and all the rest... "A derived Value must not violate the Concept of its Value. In any system of energy, Control is what consumes energy the most. No energy store holds enough energy to extract an amount of energy equal to the total energy it stores. No system of energy can deliver sum useful energy in excess of the total energy put into constructing it. This universal truth applies to all systems. Energy, like time, flows from past to future".

@gbail9566 3 месяца назад

Is it possible that a wormhole is two different event horizons smashed together, were that possible?

@QuesoDePalo Год назад

Beautiful!

@OlNeb-k2b 7 месяцев назад

She mixes analogies around the 19 minute mark, if the galaxies are 1 Mega Parsec and 70 meters at 1 second then rolling the clock back isn’t like “what’s further south than the South Pole?”. If at 1 second they are 1 MP + 70 then at negative 1 second they are -1 MP + 70 closer. Hopefully. I think anyone who reads this knows what I’m trying to say, wind the clock back galaxies get closer, that “space” decreases. So the whole “walking on the globe” thing is not a good way to picture what you’re saying when taking your other imagining into consideration.

@hochathanfire0001 Год назад

Why does matter, mass curve space-time?

@ExcretumTaurum Год назад

Since you like Deep Space Nine, the following seems apt is response to wormholes and temporal paradoxes: “I hate temporal mechanics” - Chief O’Brien to Chief O’Brien

@chyldstudios Год назад

Excellent lecture.

@jemhoare2105 Год назад

If space expands more quickly above me than below me do I move downwards?

@schmetterling4477 Год назад

Relative to what? Things above or thing below you? ;-)

@gidi1899 Год назад

21:36 - I would like to say "Nothing bigger/heavier/softer than light can travel faster than the speed of light"

@peartreedu Год назад

I completely agree that we should teach kids the understanding of gravity that they would need to learn when they get older. If you teach them that gravity is a force, then they have unlearn that way of thinking when they get older, which is very hard to do. Teach the current theory to from the very beginning; but, also teach them how gravity was originally perceived.

@user-zh5oo1vv7l Год назад

What a fantastic lecturer. Thanks for taking the time to teach Dr Clough

@Robertnight888 Год назад

Although it’s a month ago for me to see ie a time difference ! From my understanding of the talk, I can only understand that the word space should be killed and realise that we live in time. Time curves, galaxies exist in time. Please, why do we need space ? Period.

@brian554xx Год назад

Utterly delightful, and she captures some of the nuances I so often see missed. Nice.

@ryanlange6766 Год назад

DS9 is indeed the greatest of the Treks...excellent lecture

@RobertojavierSilvaharth-ub3pz 23 дня назад

Einstein assumed nothing can go faster than light and the speed of light is constant. When people say "we know" this assertions are true, it's a bit of a strech. Consider this: light bends when travelling about an object; this has been proven to be true. Also true is the fact that an object in circular motion undergoes constant tangential acceleration about the center of its orbit imparted upon it by the centripetal force that causes the change of direction in it's path. It stands to reason that a force is altering the direction in which the photons are travelling on their path about the object, thus experiencing centripetal acceleration.

@gorillagaming1117 Год назад

Can we inject exotic matter into regular matter to enhance our travel speed through said matter, maybe exceeding what people believe the highest achievable speed could be?

@jonathanrose456 Год назад

Wouldn’t it be time creating the impression of 4 dimensions? Space curved as a result of time, not part of spacetime?

@paulgrosse7631 Год назад

Your Wormholes and FTL travel assume that exotic mater/energy require the side effect of being able to travel backwards in time. Why? Suppose that it didn't and look at it again. Remember, Newton was completely right until we found a bit that didn't quite work as expected (relativistic velocities) and then the new theory steps in with Einstein. Suppose that we need to look into the areas that Einsteinian physics are starting to stray - possibly because the maths required for Einstein's equations is a bit flaky in these newly extended areas and there is some maths that would describe it better, waiting to be found.

@saad-kb3er Год назад

What a brilliant exposition! One of the best talks I have heard.

@googleboy7 Год назад

Ì suspect the major obstacle to warp speed travel can be summed up in two words: Colission avoidance! Shalom/gw

@garywalls5181 Год назад

Isn’t time simply the measurement of your movement through space?

@randomdazz Год назад

You may not have to send a signal to the front of the bubble - if you are generating the centre of the bubble from your ship - surly the signal just has to end the generation of it - but be careful it doesn't collapse like in the simulation

@maxziebell4013 Год назад

I like the visualization in computers as a 3d grid deformed by mass

@EleventhDivision11 Год назад

She is awesome. Love her energy and I can tell she enjoys what she does!

@kevinashwell9384 Год назад

Hi Hi Hi Courtney Courtney hi hi hi hi hi

@kevinashwell9384 Год назад

Hi Hi Hi Courtney Courtney 9:08 9:08 min min wait for for for for for 9:13 min min

@kevinashwell9384 Год назад

Hi Hi Hi Hi Hi Hi Hi Hi Hi Hi Hi Hi

@ebptube Год назад

The electron has mass but no size, so how is it not a black hole?

@SnoopyDoofie Год назад

Not sure why she says the universe is curved when virtually every authoritative source says it's flat.

@alanparkinson549 Год назад

A great lecture, what I've seen of it so far at least, but I have to say it really p's me off when Queen Mary staff lie by saying that Queen Mary COLLEGE is a university in its own right. It is not, it is a college of the University of London. Imperial College doesn't call itself Imperial University, University College does not call itself University University. Harumph!

@RippleEffectProductions Год назад

I have a query in mind which is boggling me a lot. On one hand we say that when we look into space let's say through hubble you are looking at the past or seeing the near to formation of Universe after Big Band. Now the graph you showed that the Galaxies are moving apart like in 1 sec at the rate 1 Mpc + 70 Kms....The problem arises here which needs to be answered that with passing of 1 sec , you see more deeper the past of the creation of Universe. Or I would simplify my question for better understanding that why we consider it getting apart. Infact those galaxies were apart in the past and now may be coming closer as the light needs time to reach us. But please support your answer other than referring me the image from Cosmic Background. I would be obliged if this weird anamoly be answered with some solid theory. In my opinion the Universe created from singularity and will be collapsed again to Singularity. And so the Cylce continues. Regards Farrukh from Pakistan

@yanikkunitsin1466 Год назад

No, after 1 second it's previous age +1 second

@RippleEffectProductions Год назад

@@yanikkunitsin1466 If it is true what you said then please explain that the light takes 8 mins to reach to earth from sun. Now at present we are continuously watching sun. if sun happens to die or stop shining we ill be observing that after 8 mins on earth. so how this postulate comes true i.e. previous age + 1 sec in this case. So it is always the past in relative terms whatever the case maybe...The fact is we only know less than 5% of the Universe and that too with more conjectures than the answers themselves. It's near to impossible to write whole concept here in comments section though. TC.. Regards

@jondor654 11 месяцев назад

Partial attempt an ad hoc . Assume we are observing a photographer taking a close up of a flower. We can observe the light transit time from the flower to the lens ,i.e. from t1 until t2.The flower is already older by the time shutter captures the image. Say we were observing prior to these events , we could observe the previous photons racing away behind the camera body representing an even younger flower, or if two cameras at different distances took an image at the same time ,these images would be of different ages of the flower . So the age differential in image representation is related to distance as I understand it. I hope this does not confuse (myself) but the "camera" as a transducer sees the sequential photon stream at point of impact, nowhere else .This obvious point may preclude some conflicting intuitions that can confuse me. Open to correction here.

@jondor654 11 месяцев назад

I did not address your question .Excuse

@jondor654 11 месяцев назад

If one stays at the point of observation say of a stream of photons from t1 to t2. This sequence will represent the evolution of the target at that historical time , say the image shows diverging then they were diverging when those photons were emitted. This excludes unaccountable distortions on the journey.

@phenixorbitall3917 Год назад

Brillant! :)

@stellarwind1946 Год назад

The absolute worst thing in the world is when you see Ad 1 of 2 with no option to skip.

@extremesis Год назад

51:30 "Dammit Tim, I'm an astrophysicist not an Engineer"

@rwm1980 Год назад

Winderful presentation

@ElinT13 Год назад

Very nice and informative lecture! Thanks very much!

@RogerWhite-mj8bu 3 месяца назад

every hour, i hear a different story by experts, they are mental excapees

@rbee6507 6 месяцев назад

Also, I must give specific thanks for not shying away from, or sugarcoating, the effect racism played in Chandrasekhar not being given the consideration, respect, and good faith he very much so deserved. Especially stating how it set discovery back, potentially for 40 +/- years...that is a shameful amount of time wasted given the span of human life, and far from a rare occasion in the history of the world and science. Fortunately, I believe those solely digressive and blatantly emergent showings of racism are officially behind society, even globally for the most part at that level. I remain confident that humanity's best is still ahead of us, for a very long time.

@richardzeitz54 Год назад

Gravity is not a force! But peeps keep talking about gravitons. I don't believe in 'em. Are you saying their might not be such a thing as gravitons? I wondered how a particle could change the passage of time. If there's a planet to my right, time will pass more slowly on my right side. So, if my right side is going slower than my left side, I should turn to the right...Still trying to visualize curved time....ouch!

@michaelprochnau7128 Год назад

surprised the R.I. published this as an addition to their catalog. Usually the speakers stay within the field of reality and not Roddenberry or Asimov. I'll stay tuned for the next lectures in the series.

@ttls14 Год назад

Well presented, question is where is the scientific theory/ advancement?, surely it's time for intellectuals to move away from presentkng existing knowledge.

@fredturk6447 Год назад

I thought the jokes about PhD students were not appropriate. Einstein’s general theory of relativity describes the deformation of the geometry of space but it does not describe the mechanism. What bends space? Quantum mechanics and string theory suggest there maybe a graviton particle involved and presumably an associated field so we maybe back to a force? The metal ball rolling around on a rubber sheet is a nice analogy and you could argue that the tension in the rubber is analogy to a deformation in some sort of field that is responsible for gravitational attraction. Also I though more care was needed talking about black holes. We know that black holes have entropy and hence a temperature related to their surface area. We know they evaporate according to Hawking. Do black holes really destroy information, or is that information retained in a holographic fashion on the event horizon? That’s I believe what Leonard Susskind and others think allowing for conservation of information. I don’t get the usefulness of “curved time”, it seems simpler to use the current idea that there is a scale factor a(t) which describes the expansion of space over time. You can blow up a balloon with some points or a grid on it and show they all move apart. We don’t know if the universe will continue to expand or collapse back on itself but at present it seems more likely to keep expanding and at a faster rate. Bottom line, I think the presenter may have tried to dumb things down too much to the point where it might be misleading. I am not an expert here please correct me if I am wrong!

@GBuckne Год назад

.. galaxies have been observed red shifted faster than light, so more than likely the universe is expanding if not how do you account for the velocities, time is not curved, time is the measurement of motion, more than likely space is curved because it is an energy attracted to massive objects, time is infused with curvature because gravity mediates the curvature of space to mass and slows motion...

@techslugz Год назад

Give me one pleeeeaaaase 🎉🎉🎉 ❤🎉❤ it looks like a real good alternative to an s23. I got an s22+ at the moment 😊🙃😮🙃😮😅😊

@pleappleappleap 11 месяцев назад

I can imagine 4D spacetime without any trouble at all. Just imagine a 3D space. Then animate that image.

@mrpopo8298 11 месяцев назад

lol, bro, that's still 3D.

@pleappleappleap 11 месяцев назад

@@mrpopo8298 No, it isn't. A non-moving 3D space is 3D. Add motion over time, and you have your fourth dimension. If you don't buy that, you don't buy the entire concept of spacetime.

@gidi1899 Год назад

13:06 - You do realize you told your mates to walk in a strait direction, not in a strait line. - otherwise they would require a road that doesn't change it's height In general I agree, that even a road that doesn't change it's distance with respect to the earth core center, is not strait, but also curves with respect to the sun center, and the galaxy center, and .... But, I wish you were clear on that, "a strait direction" != "a strait line"

@yungsookevinhong7943 Год назад

Blackhole is non meta mass that actually making the Space time layer fold.

@addisondraper6444 Год назад

I was very impressed by this talk. It's not very often that you find someone who calls themselves a scientist who is willing to admit that they actually do know everything and couldn't possibly be wrong (like every other "scientist" who has ever lived). Smart.

@Bobby-fj8mk Год назад

don't you mean - do NOT know everything ?

@robokill387 Год назад

Actually, most scientists accept that they don't know everything and that they could be wrong. That's why they got into science to begin with - there's no point in studying something that you think you already know everything about.