Hacking The Cosmological Distance Ladder 

Just found this channel. I'm blown away that I haven't seen it until now. Great stuff.

appreciate you saying "facts don't care about your feelings" without saying it 😂

Fraser Cain is one of the best of making his and guests voices the same volume. Other similar channels are so bad at this and make listening almost impossible without raising and lowering the volume ever few seconds

It is always awesome to hear from Dr. Lewis! He does a great job of making these huge topics a bit more understandable by tiny brains such as myself.

David butlers playlist "how far away is it" really helps understand these vast distances

My nephew Henry is in 8th grade. I explained to him how today's telescopes are true technological marvels, but the telescopes he'll see in his lifetime will be almost unimaginably powerful, allowing astronomers to see all the way back to the beginning of time and the edge of the universe. "What do you think people will say then?" I asked him. His reply: "They'll say ,"Oh crap, more universe!'"

Everything you put up is a gem. Thank you, Mr. Fraser ❤

I really enjoy it when Fraser geeks out with the scientists on the front lines of discovery. Always a good time.

This was one of the best seminar - symposium - dialogues on astrophysics that I have ever seen by a far

Ohhh I can feel the hubble tension in the room

I wondered why I didn’t see this topic on the poll. Thanks for making a separate vid! Interesting AF🎉

Thanks!! Great guest Fraser. I'm watching this at 3am here...not a good stimulus for addressing insomnia..for me anyway. Cheers.

So you know sometimes teachers may chastise students for apparently daydreaming in class… when actually the topic of the class is so fascinating the listener’s mind wa(o)nders inescapably past some black (rabbit) hole’s event horizon… that’s me listening to this 😊 (thank goodness for pause & rewind buttons & well produced, thought provoking interviews like this :-)

I used to be obsessed with The Great Attractor but now I'm into The Axis of Evil (and I don't mean Iran, Iraq, and North Korea lol) and I wish a channel with rigorous ethical reputation like this one would cover The Axis of Evil some day. 🙏😁

An amazing conversation. Thanks!

I've been looking forward to this interview. Dr. Lewis has a really nice perspective on cosmology. His ideas relating to the application of these new instruments in measuring the Universe's historical expansion rate are fascinating.

Want to say thanks to Dr Lewis, I really love these discussions, this is fantastic.

I've only recently discovered your channel, working my way through your videos. You've earned a new subscriber, great content Mr Cain,thanks.

What a great conversation! Learned a lot today. Thank you, Fraser! 🔭

Incredible interview & discussion w Dr Lewis. Thank you Fraser.

What a great guy! What a great interview! Thank you!

@~58 min Taking ideas from many different perspectives is the key to solving really big problems.

Henrietta Swan Leavitt, a human computer who was not allowed to use a telescope because she was a woman, discovered the period-luminosity relationship for Cepheid variables, called Leavitt's Law. The accomplishments of Edwin Hubble, the American astronomer who established that the universe is expanding, also were made possible by Henrietta Swan Leavitt groundbreaking research. Hubble often said that Leavitt deserved the Nobel Prize for her work.

Great interview Fraser! Keep up the amazing work!

Excellent and informative interview. Thank you!

Great interview, It cleared up some things for me personally.

Fascinating conversation, as usual :)

Awesome talk, learned a lot!

Wow, I didn't know there was so many ladder steps on the distance ladder. Thanks for another great video. Enjoyed it, and learned!

Great one! Thanks, Fraser.

I still can't get my head around the fact that a Galaxy, far, far away, has been taking a million years to get to us and jet we can send Radio and what ever type of waves out and get info back in months.

Regarding the sephid variable stars, could there not easily be other properties of the stars that influence the measurement, such as metalicity and rotation for instance?

Thank you. 👍

red shift drift is an amazing idea. I hope we have a chance to see the results.

Nature rarely if ever repeats itself - I think it is really ballsy to assume such a thing as "Intrinsic brightness". That's one hell of an assumption that the region of space (density of fuel available etc.) around each Cephid Variable will be the same.

Dumb question here, I’m trying to wrap my head around a couple things. I always here how everything is accelerating away from us, this makes it sound like we are not moving which I understand we are. Is there anything that is just flying through space just parallel with us or our galaxy etc? Or possibly coming right at us? Like another galaxy or solar system heading right at us like a freight train??

Great talk

The problem in essence is that we don't understand quantum gravity. The gravity that we sense here in ourspace time is a dynamic equilibrium of field flux that to us seems as flat as a pancake. But in the earliest universe particularly as the transition between inflation and expansion occurs, our only sense is that space settled down after 300,000 years (which if you think about it after the light cone expanded 3 x 10E20 meters we can see CMBR. In general relativity the spacetime variances propogate at c, in all directions all the time, which means even by the time we get to CMBR its pretty flat. But there's a problem CMBR is a relatively low resolution view of the heavens. And that snapshot was taken when the universe was (13.8/.0003)^3 or 100 trillion times more dense and at a time when things like dark matter effect would be much higher in small areas. We see that massive blue stars are forming much larger than thought possible. And so the problem is that we have been used to examining stars within 9 billion ly from earth, but this secondary inflation begins after 9 billion ly. And so the new telescopes allow us to see stars and star formation. So we can boil this down to a simpler statistical problem. If you are extrapolating something, lets say we fire a cannon ball from say a high place earth, we can extrapolate its path based on fixed surface gravity and a flat earth, but beyond an elevation of say 500 km, that balls motion will begin deviate, also if the ball moves futher away its course will deviate. We can correct for that by modeling a curved surface and using newtons gravity. But at some point far enough away from the surface that objects motion is going to be effected by the moon, then the sun, the other planets, the objects in the local star cluster, then the galaxy itself. Extraploting gravitational effects is therefore adding into the equations known parameters and then crunching out answers. But at some point N-body problems are beyond the computational ability of the best computers. And so for objects at great distance we cannot see the parameters, and in particukar we cannot see dark matter, only its effects. If we go back to the CNBR universe when the density if everything is 100 trillion times greater, hiw good is our ability to extrapolate backwards. And so with new instrumentation the errors of old measurements become more clear because the new instruments are seeing the actual data the old instruments extrapolated into. Those instruments need time to explore the nuances. But there is a secondary problem that as you peer outward in space you reach a point that as the c*t = c(13.8 - x) t in billions of years where x is the age of the universe when that objects light is generated but the problem is that a t approaches 13.8 billion years red shift rapidly increaes and so does density. Thus extrapolating into that curvature, say 12.8 to 13.8 bly , will have more error than extrapolating into the the region 8 to 9 bly away. And so the hubble tension is not so much a problem in that it means that as the instruments become more precise, we are seeing new things we previously guessed about. And so now as anomalies are seen people will look for new pieces of the puzzle and try to fit them together and eventually they will find a few pieces (parameters) that cause errors in the old observations that can be added to the equations. My problem is this however. Spacetime appears to be a self stabilizing flux, its able to expand or contract based on its state . This all make sense when D = mean density of space and dD/dt is very small. But what happens when dD/dt is changing rapidly, can we use our experiences and observations of spacetime to extrapolate backwards in time and predict how all of physics is going to work.

Sounds familiar. Most of my teachers were worried about my intrinsic brightness

Once again a great interview! One variable we don’t understand what is the CMB xpanding into.. thats unknown physics. Maybe something is sucking the universe out as opposed to dark energy we can’t see.

If the gravity wells in the early universe were deeper than we thought (time dilation from quasars) then the total time since the CMB measurements is not uniform from then until now. If dark matter condensed causing rapid galaxy formation then began to evaporate once stars ,AGN, etc were formed

How much did the density fluctuations and ripples affect the time that atomic hydrogen started forming? Were there places where there was hydrogen condensation and then rereionization?

I'm confused by the statement at the beginning of this video. You stated that as we look at objects that are farther away they're moving even faster away from us. Isn't that exactly what we should expect?

Fraiser, I have a question you cannot answer.Talking about the constants of the universe, "Are they actually constant, or are there variations over various areas, distances, timelines?" We have not seen any significant variations of these constants over our investigations. But were we looking for them? If we can seek ( in LIGO )a fraction of the diameter of a proton, yet we're discovering continuity in the WAVES OF GRAVITY? we're about to observe variations in gravity waves with periods over thousands or millions of years, to see orbits of mega black holes of similar wavelengths. "ARE THE CONSTANTS OF THE UNIVERSE ACTUALLY CONSTANTS, AND IF SO WHY ARE THEY SO STABLE. What answers for the stiffness of the constancy?" Maybe the universe is not expanding, but maybe TIME is imperceptibly slowing down, and we just haven't seen it yet.

Thanks a lot from Barcelona for this super-interesting interview. I have a very simple question about cosmology: The CMB is the farthest thing we can see, as the radiation we receive today has been traveling for 13.7 billion years. From what distance did the CMB light that we receive today started? Thanks a lot!

What bout measuring g-ripples of one frequency within the multiple alternate g-ripples and quantizing the frequencies in order to range the sources in a multiple triangulation mode ?

I won't watch it now, but I like the thumbnail

L Krauss did speculate that redshift may change historically due to proximity of matter.

TRGB for the win!

Fraser, I appreciate that you've cut out the introductions (who are you, what do you do). It wasn't bad or anything, but I prefer the current brief intro by you, and then the jump straight into the interview. I trust this doesn't come across as criticism...I mean it wholly complimentary!

11:33… Gaia! What took so long Fraser? 😂

In the early universe would dark energy not be less dense relatively to matter? Could that not account for it having a different effect on the universe at early time?

How does one know the error bar? How is it measured and calculated? How does "I'm not certain" translate to a specific number?

A spectrometer can always be calibrated to atomic lines whose source is here on earth. I don't see how even replacing a spectrometer entirely is a valid concern.

plot twist: the Hubble constant has some variance to it, so it's not a constant; it's a variable, varying through the twisting and turning of the expansion of the universe.

I wonder if these things could affect the accuracy of Cepheid stars, dust and gas occlusion and Quantum electrodynamic effects on electromagnetic waves which could also affect redshift and the perceived expansion of space time…🤔

Supernova explosions are not uniformly circular. Some areas are denser and move outward faster than others. Perhaps the Big Bang was similar. Did some areas expand faster? Could a non-uniform expansion give different results depending where you look?

What about building a machine that measure distances to stars, and we send to mars, so we measure both from earth and from mars, wouldn't that make measurements much more accurate?

Not understanding black body radiation would be a far bigger crisis than the Hubble tension, since if BB is wrong, then thermodynamics, quantum mechanics, special relativity are not compatible.

How "wide" is a gamma-ray burst? Is it a beam, like a laser, or more like a cone?

If we assume for a moment that hyperinflation (or similar foundation) of the early Universe theory is wrong and something else explains our observations. Would this change the expansion calculations from the CMB?

All the time if there is all the time, I try to connect all areas of science and philosophy but this creates serious problems in communications with specialists, especially those who think there is only one way to think or not think.

One of the things that has always bothered me is the number of significant digits the age of the universe or the distance to the cosmic event horizon you hear from popsci sources. I routinely hear 3 or 4 sig fig estimates and I would guess it's more like 1 or 2.

51:00 "Set out" or received at different times? The light leaves when the light leaves. How long it gets here is the difference.

Is it possible dark matter and energy is a part of a higher dimensional level, influencing our 3D space/time dimension ?

Looking through a lens of physics always suffers from the particulate crystallography imbued by the inherent model characteristics. Try twisting that crystal, nematic, cholesteric or otherwise. If you need to look at distant things you need a lot of polishing of your lens. If, on the other hand, you can "grow" a pre-programmed lens to impart the precise characterics you require, then you can observe your target. Just need to differentiate this attitude towards the Fourier conclusion as regards the physics principle. Every ruler has an error bar +/- 50% of the smallest increment. 'jus 'sayin

Figuring out the exact amount of quantum drag a photon has will make all possible speeds, distances and curvatures calculable. It's a simple solution we can solve with in the next decade. ;O)-

Einstens left over math used to pre program cmb input to image may not even be a constant it could be something else no one knows

Does Universe Today / this channel sell any pins? I love this channel and would love to add a pin to my pin collection on my backpack

There seems to be a consensus that space-time is not flat; it has slight negative curvature. This means that spherical shells have more than 4pi steradians of solid angle. Since the distance ladder began with parallax angles, it concerns me than none of you describe how space-time's negative curvature has been corrected in your distance measurements. Sol's and earth's gravitational acceleration will also affect the light's trajectory and this GR effect also doesn't seem to have been considered. Possibly even Sagitarius A's black hole needs to be considered.

The strongest force is magnetic which is electrical.

couldn't the cosmic background scientists look at the waves (that are analogous to the CMB waves) at every stage of the universe were we have data (from light) and show where the ladder is off?

Ok map out all the mass clumps/dark matter and then calculate the "de blooping" or calculate the corrections for all of that einsteinian lensing that shows very distant objects taking in many cases a much longer time to reach us because of all the twists and turns that the mass made it do then you're hubble tensions will be in finer agreements?

The best way to resolve the Hubble Tension is to light some incense and play a little smooth jazz.

What's wrong with staying on X?

We don't understand red shift as much as we think we do. Halton Arp wasn't all wrong...

What Will happen when the expansion rate Will exceed the Speed of light?

1:23 - where is that animation from? - how do we know the gravity is in that shape?

Dear.. Atom.. Now you know distance.. Univers diameter. Size not 97 - 98 bly.. 7000 +- BLY.. Imagine.. Jago Baramand.. Arun Jagoji JaMBhuLKaR.. 15/5/1969..DhaRMapUR Bhiwapur Nagpur MaharAshtra

Twitter is number one ☝️

What if there is no red-shift drift at all?

FRAZIER IM UR BIGGEST FAN BROWSKI

IT'S MUCH HARDER THAN YOU THINK 😋

Brightness is NOT a conclusive measure of distance.

❤️ Journalism. ^.^

If everything is expanding away from each other. Please explain why the the Andromeda galaxy is heading our direction? To eventually join with our galaxy.

Frasier Cain's first words: "A lot of our understanding of the Universe depends on our ability to measure distances..." And for that we have depended on our present interpretation of cosmic redshift. Last year when the James Webb Space Telescope produced the deep field images, we discovered that the 'Dark Ages', an epoch consisting primarily of primordial particles right after a supposed Big Bang, does not exist. Instead, that cosmic volume turns out to be full of galaxies. If the Dark Ages - a realm predicted by cosmic redshift - was wrong, then our interpretation of said phenomenon is not fully understood. Sadly, that doesn't seem to bother the majority of cosmologists. Instead of tackling this obvious problem, they devise unprovable handwaving explanations that cannot be verified.

If everything is flying away from everything else at the speed of light, htf do galaxies collide?

And, is there really no "wear & tear" on photons? It can "fly" trough space for billions of years and be as fresh it was on the day it escaped an atom when it arrives to us? If we could measure somehow some deterioration of photons that will be like a "time-tag" telling us when it was created?

So at 1:1:35, you say that your mother was surprisingly good at technology for someone of the previous generation, but I feel like you're falling into this trap of thinking that old people somehow don't understand technology, when in fact they have far more experience with it than you do. What's actually happening is that we younger folks have been exposed to newer technology more than the older generation have and whenever an older person doesn't know how to deal with a new tech, it's because they have no experience with it. This is exacerbated by the fact that many older people don't wanna put in the work to learn something new, for a variety of reasons, but that does not mean they don't understand technology. Most of the time, those older people will have a very strong understanding of the technology that is now ubiquitous, but was novel in their time or was commonplace in their time and is now on its way out. A perfect example of this is that episode of Star Trek: The New Generation where they visit a Starfleet space station and Captain Kirk asks Wesley Crusher to come with him to visit the Admiral. Now Wesley has never left the Enterprise, as he was born there part of the way through their multi year mission. When they come to the Admiral's office he walks right into the door, because growing up on the Enterprise that has automatic sliding doors everywhere, he has literally never seen a door that wouldn't just open up for him and Captain Picard is forced to show him how a door knob works. If you've been around long enough, you have seen multiple examples of this, where young people are completely clueless about a piece of tech that predates them, but older people are experts in it. For instance, my mother couldn't install an operating system to save her life, but she can take apart and service any type of sewing machine you put in front of her, from hobby machines to industrial and highly specialized models. I can get into Unreal Engine and put together a video game, but I see an overlook machine and I'm completely lost. She has the opposite reaction, due to, of course, life experience, which I feel we tend to downplay when looking at older people. The truth is that our world has been "high tech" and evolving rapidly faster than a human generation since the 19th century. The vast majority of people alive today have personal experience with high technology, its just that i might not be the type or generation of technology that YOU have experience with.

So dark matter is everything we can’t measure or justify in anyway 🤔

Uh, thats what he… oh never mind.

Webb telescope reveals BB cosmology is likely not correct.

The high redshift of CMB is supposedly because the assumed denser gas clouds in early universe that we have no proof of?

Didn't a probe at edge if soler system measured the darkness outside and it didn't match the prediction? Sounds like it says something about how much light we see.

We are about to have UAP disclosure so it's a bit of a moot point to aspire to be a chimney sweeper but that aside, if we trust parallax to a significant extent, how about yeeting a few very light 7 meter mirror telescope out with a vasimr engine to whatever max speed we can get. 100AU in 10 years. Comparing to Gaia measurements out to 20kLY, such a scope should be able to range out to 10MLY which is perhaps a pretty good baseline. Still subject to new physics but should be so information rich as to rule a lot out. Since it's enough to span our galaxy it might shed a lot of light on the galactic spin anomaly, maybe rule out dark matter.

Every video dust potentially a source of error. Every video gravitational lensing gives us the answer 😂

Hi Fraser, what is this agest thing about your Mum? She was probably around when there were mainframes only, and punched tape or cards, things were more difficult then. No RU-vid videos to show you how, you needed a good understanding of the maths structure of a problem and a keen understanding of how numbers work (factors etc). I think you need to buy her a really good birthday or christmas present (which ever next) !!! Great video though, thanks.

A lot of circular pontification, nothing new introduced…

time we stopped thinking so small, and instead start to speculate on the forces at play on our universe from outside, we might be in a universe acted upon by external sucking forces more relevant than internal pushing forces, this could also replace the problems associated with the goldilocks theory and the ludicrous solutions posited to solve them by dealing with all these issues simultaneously we might begin to get some idea of what our reality really consistes of and so start to understand a much bigger picture universe