The search for objective reality - with Jim Peebles
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- Опубліковано 9 тра 2024
- Join P. J. E. Peebles as he explores the big questions about the nature of science, and how we are discovering the nature of reality in successive approximations through increasingly rigorous scrutiny. Watch the Q&A here: • Q&A: The search for ob...
Jim's latest book 'The whole truth: a cosmologist's reflections on the search for objective reality' is available now: geni.us/JxMH0
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Scienists have questioned how reality could agree with physical theories that keep changing. Today, concepts like dark matter and dark energy further complicate and enrich the search for objective reality.
In this talk, Peebles will draw on a lifetime of experience as a leading physicist and using cosmology as an example for this personal reflection. Discover if the concept of objective reality is meaningful.
This livestream was recorded on 13 October 2022.
0:00 Introduction
1:16 Constructions in natural science
5:13 The objective reality of the speed of light
8:32 Is all of our physics technically wrong?
13:56 The inevitability of inventions
16:52 The expanding universe
23:01 Thermal radiation in the universe
27:55 Evidence for the evolution of the universe
46:20 Acoustic oscillations in the early universe
52:06 Exciting discoveries that haven't been discovered yet
Philip James Edwin Peebles is a Canadian-American physicist and theoretical cosmologist who is currently the Albert Einstein Professor in Science, Emeritus, at Princeton University. He is widely regarded as one of the world's leading theoretical cosmologists in the period since 1970, with major theoretical contributions to primordial nucleosynthesis, dark matter, the cosmic microwave background, and structure formation.
Peebles was awarded half of the Nobel Prize in Physics in 2019 for his theoretical discoveries in physical cosmology. He shared the prize with Michael Mayor and Didier Queloz for their discovery of an exoplanet orbiting a sun-like star.
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In my early years I was surrounded by some of the greatest minds of their generation. I was in awe of my elders who were also my care givers.
At 63, listening to this presentation, not only am I reminded of my childhood,, I find myself in such awe that has matured to reverence. I still love my seniors. Especially those who can spin a yarn sharing our path of discovery.
Thank You
Excellent and sage orator. Thank you for the opportunity for this most valuable insight.
Not many Sages around today
I am no genius. But occasionally I have had ideas that I think are original, only to find a short time later that at least one other person (often with more brain power than me) has had the same idea decades before me. This is a consequence of the curiosity of human beings. We are all imagining solutions and ideas and we are so numerous that inevitably 2 or more people will have similar ideas.
great comment!! i think about this all the time!!! i have to be the first ever to think of something!! A lot of time i just say to myself, “well i’m sure someone else tried that or thought of that before so it can’t be correct or true” lmao
Yes! As a kid , I thought about the center of galaxies containing black holes and it appears to be true
Always write down or type your ideas and saved them. You may have a unique perspective on an idea many people generally think of but you may find a discovery in the slight difference you thought of compared to others.
Why is it that the first comments under a science video are always a bunch of anti-science weirdos?! Are y'all *lost*?!
Awesome channel with awsome content as always say. Excellent job!!!
Knowing the unknowable ...thats mindboggling! To see a black hole appear in the equation, and only now knowing that they "saw" a black hole... These equations can show us every still "hidden" reality of the universe! I think that is truly awesome!! ..And thank you for explaining that to my totally non mathematical mind;!! 👌🏽👍🏽👽💥💥💥
Outstanding and inspiring presentation by one of the great scientists of this time. I've known of him from this association with Penzes and Wilson and the public recognition of CMB.
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Like how you play with Maxwell's statement. Fresh minds will move foreward to the same outlook, but still must not under estimate the possible progress in humanity.
have you guys considered adding subtitles
Bruno Latour is saying that the existence of somatostatin is confirmed by observations in the laboratory and NOT by social constructs. Bruno Latour is a sociologist, and presumably knows nothing of chemistry. So far so good. Then Jim Pebbles says he will not attempt to interpret this statement, even though I think Bruno's meaning is crystal clear.
Very interesting bits in this talk about how these discoveries where made, some of which I haven't heard about at all before. However interesting as those bits were in their own right, I am at a loss to see what most of it has to do with the framing question of the talk: whether or to what degree scientific knowledge is socially constructed. What was the actual point he was trying to make? Was all that just to say there is an objective reality and he thinks of models/theories of modern physics as approximations to that? Is that all? Because sure, I generally agree, but that's pretty broad and doesn't really say much about how or how much the way we think about this reality or with what approximations we come up with is influenced by culture/language/society. It doesn't strictly contradict what Latour says in the initial quote either, so does he agree with it or was that supposed to be an argument against that?
But does the act of examining science's social constructs affect the social constructs?
ha-ha... Quantum sociology...
But just forget about...
Now, see... I've already forgotten, but I think the name rhymes with Goon, or Loon, or baboon, something like that.
If the universe would be seen to expand wherever you are therefore no centre point exists does that mean no boundary exists?
Thats an excellent question. That could be the case, but regardless if the universe is an open (boundless) universe (infinite universe), or a closed (bound) universe. (Spherical universe) There would be no center and boundary.
Doesn't matter, we can never see or test it.
A boundary is not ruled out but it would be beyond what we can see at this time
@@barretprivateer8768 not with that attitude...lol, you don't know what you don't know we keep going untill what end? Who knows....isn't it great?
@@brandonsmith1838 well, we will definitely not find out in our lifetime, thats for sure. Our current understanding of physics tells us that stepping out of the observable is impossible since there is no way for us to travel faster than light. Keep in mind that not only the universe seems to be growing, but the observable universe is also growing, meaning if you come any closer to its boundary, the boundary grows even further. Therefore we are (at least for the foreseeable future) bound to the observable universe and cannot travel or even see beyond it
❤🎉❤🎉❤🎉
Watched all of it 45:12
If this is the kind of thing you like then you'll like this kind of thing 😜
Circular reasoning does have a certain appeal.
I just don't think that this idea of multiple 'discoveries' indicates that something 'real' must have been discovered, because they were 'independently' discovered. No one person discovers anything. The 'discoverer' is standing on the shoulders of his/her predecessors and this is why many people can make the same 'discovery'. The current culture and more specifically recent research at the time inevitably leads to the last step taken to make the so called discovery. We love heros and want to claim that one or at most a few people deserve all the credit for 'discoveries', but this is just not how scientific progress works. It's a group effort.
Exactly.. No one is an island 😁☮️
This may be the dumbest thing I've ever read. Thanks for the effort or lack thereof.
True, several scientists came up with nearly all the parts of Einstein's relativity before he finally put all the parts together. It's why the Lorentz-Fitzgerald contraction is not called the Einstein contraction.
When I was younger, Vesto Melvin Slipher was a well known name in astronomy, as one of the first to find evidence that the "spiral nebulae" were separate galaxies, and not part of our Milky Way. But ever since the Hubble telescope was built, he's gotten so much credit that you'd think he was the only person involved in figuring out that the universe was expanding.
I honestly don’t get your point.
How does more than one person discovering something independently and that something being then verified independently (even if built on previous work, as it has to) by different means not make it a fair approximation (as precise as the current technology allows you to measure reality) of reality?
To me, the expansion of space looks like a universal 'curvature' of space/ time (so not a 'flat' spacetime).. As in ( over long distances and time)
When taking time into account parallel lines don't stay parallel, they diverge ..
Triangles don't add up to 180°, like in 'flat' space..
( all of this is an open question 🤷?)☮️
Melvin Slipher is a good name.
Melvin _Vesto_ Slipher is an amazing name.
Actually his name was Vesto Melvin Slipher.
Does it mean that the space inside our atoms nucleus is alsoexanding
Yes, which is remarkable... But it's not actually "space", but a region of very low (statistical) density of matter.
Since I am so ignorant, I do not understand what constraints would be imposed by the limits of the Planck's constant. As how could anything smaller than that be expanding?
Just ignore my Reply. I know nothing.
No, it only happens at very large cosmological scales of distances and very small forces of gravity between objects. Its effect is very weak comparatively.
Once an object is bound to another by enough gravity, intermolecular or subatomic forces, it no longer experiences this expansion/receding away from the objects it is bound to.
However, the distances between objects in space can be so inconceivably large, with how fast gravity drops in strength and how 'weak' it naturally already is, the effect of this expansion can be measured from the light we receive of those objects (since light unimpeded can travel infinitely far and does not rapidly fade like gravity does).
like a fish in water gets to go up down back and forwards and left and right take him out the water and everything just got bigger?
Hate these remote versions
Дякую за відео
To describe Maxwell's Equations as "simple" is a real understatement. They are a theory that's compatible with Einsteins special relativity equations long before Einstein came up with his theory and they are Tensor equations of terrible complexity and not easy to calculate at all. The integral versions are not easy either.
Maxwell's equations should change because the magnetic field in them is actually an electric field. 😮
That's all very well and good but the red shift can also be accounted for by the concept of the variable light speed theory. Speed of light at one time was considerably faster than it is and has dropped and would also result in the appearance of a red shift. The beautiful thing about that is you don't need to have the universe expanding, no hyperinflation where you have to make believe that space travels faster than the speed of light and it's expansion and you also have the benefit of not requiring dark energy or dark matter. Combining the variable light speed theory of the universe along with modified Newtonian Dynamics or MOND, which by the way has had some recent success in terms of observation supporting it, means that we have a much more simplified explanation of the universe. Let's apply Occam's razor here shall we?
No. Occam's razor is not a mandatory rule that must applied at all times without fail.
@@toby9999 true but it's a good idea here
carbon nitride is a cyanogen
What if light has no intrinsic speed?
Can a body in space such as an asteroid or a planet exist without being referenced by light or light field?
Jim forgot to tell us that water is wet 💦.
I am so tired of these zoom lectures instead of the ones at the Royal Institution. At least if you're allowing these subpar lectures to be part of your brand, at least have minimum requirements for audio quality of the microphone used...
Consider the following:
a. Numbers: Modern science does not even know how numbers and certain mathematical constants exist for math to do what math does. (And nobody as of yet has been able to show me how numbers and certain mathematical constants can come from the Standard Model Of Particle Physics).
b. Space: Modern science does not even know what 'space' actually is nor how it could actually expand.
c. Time: Modern science does not even know what 'time' actually is nor how it could actually vary.
d. Gravity: Modern science does not even know what 'gravity' actually is nor how gravity actually does what it appears to do.
e. Speed of Light: 'Speed', distance divided by time, distance being two points in space with space between those two points. But yet, here again, modern science does not even know what space and time actually are that makes up 'speed' and they also claim that space can expand and time can vary, so how could they truly know even what the speed of light actually is that they utilize in many of the formulas? Speed of light should also vary depending upon what space and time it was in. And if the speed of light can vary in space and time, how then do far away astronomical observations actually work that are based upon light and the speed of light that could vary in actual reality?
Well, it depends on what you're eyes are locked onto on said cellphone... Ironically, your students' eyes are locked on Tik Tok or whatever (nothing meaningful) and me, a non-student on your campus, is watching this and other educational things, but I'll never have a chance at an education in that school.
Good observation. I saw a video that TikTok in China is entirely educational and focused on science. I think there are also age and time restrictions. Meanwhile, as you alluded, the rest of the world is watching pets do funny things.
@@d.e.7467 Exactly
2 things. one. I would not currently encourage people, of any age to aspire to attending university. Universities have seriously degraded the quality of their education by caving into the extreme minorities.
two. You can use the Internet with its tic toc, YT, Curiosity Stream, Brilliant etc, to teach yourself. You might say as you are uneducated you don't know what you need to learn, but this would be wrong. Let your curiosity lead you step by step from one idea to another and into different fields as you fancy. You will find your way to knowledge. Good luck.
Badass @@mayflowerlash11
When I see a term like objective reality I'm very suspicious. It's like absolute truth. Something is either true or false. When someone amplifies a maximum you have the right to suspect what they are trying to get you to believe. In translation it's an attempt to prohibit skepticism, challenges, or even questions.
☮️ Without a love for the subject matter I couldn't have made it to the end.. Maybe his lack of practicing his talk 🤷? It was So hard to hear & grasp the knowledge, as the bulk of the talk was simply unlistenable .. I really wanted to listen to his knowledge but the bulk of the talk was more distracting than educational.. I So apologise but I hope the criticisms might help improve future talks 🥲
Hmm... I felt the opposite! I really appreciated the history of discoveries, with names and faces of the discoverers. His presentation kept me captivated all the way through. I really enjoyed his perspective as it came from a lifetime of study and thought.
Nothing is expending. It’s tired light+ something else. Maybe photons get rest mass and slow down
LOL