Is the Universe TWICE as OLD As We Thought?!

like pretty much every other astrophysicist and cosmologist I know I've always answered the question of how old is the universe with the answer about 13.8 billion years now though there's a lot of attention and publicity being given to a paper and a claim that the universe is actually twice as old as that 26.7 billion years this would be a huge change to our understanding of the universe so what's new let's talk about why this new paper claims a new age how it seemingly discovered this while the rest of us all missed it why is it getting so much attention and should we believe it foreign [Music] this is the paper in question it's called jwst early Universe observations and Lambda CDM cosmology and of course it's making a bold claim so where does all this come from it all starts from jwst and the fact that this 10 billion telescope has imaged a surprising amount of very massive galaxies in the early Universe we've been seeing galaxies that are as bright and massive as nearby galaxies but they appear to have existed within three four or five hundred thousand years of the Big Bang even compared to the current age of 13.8 billion years that's incredibly early in the universe's history nearby galaxies that are bright and massive aren't a problem that's because they've had the entire lifetime of the universe to grow and evolve and we have very good models and explanations for how they grow the confusing thing is that these methods for growing galaxies take quite a lot of time meaning that when we see galaxies just as big and bright in the early Universe we don't have a explanation yet for how they grew so quickly there are a few ideas we have that might work but they haven't been proven or confirmed yet these might include massive primordial black holes that form just a few seconds after the big bang and they can act as a huge seed to start galaxies off or maybe there could be some way that galaxies can collect matter and form Stars much faster than we think at the moment these sorts of things are the way that most cosmologists are approaching the surprise of these massive early galaxies by rethinking some aspects of how we thought galaxies formed those galaxies haven't broken cosmology they're just teaching us more and getting us to tweak our best theories to explain them a little bit better this new paper however takes a different approach instead of trying to explain how galaxies can grow to be so massive so soon after the big bang it asks what if those galaxies are as old as we think but in fact the Big Bang actually happened way earlier than we thought and so they've had plenty of time to grow and evolve in all of the usual ways that actually sounds like a good question so let's look at how they go about this we'll have to start with the rest of the title of the paper we've covered the jwst early observations but what is Lambda CDM cosmology we call Lambda CDM the standard model for cosmology and it's our best almost complete model for what's in the universe and how it behaves it's the culmination of all of our best work in cosmology and it starts from the standard model of particle physics we assume that these are the particles and forces that make up most of the normal matter in the universe but we need more than that for a complete picture first of all we need to add in gravity and we assume that it behaves exactly as Einstein's general theory of relativity tells us we also need to add in Dark Matter that's the CDM in Lambda CDM cold Dark Matter cold here means slowly moving our best evidence for Dark Matter tells us that it doesn't move anywhere close to the speed of light which we would call Hot Dark Matter instead but rather that it seems to be some sort of massive particle or object that moves around normally under Gravity just like the other heavy particles we already know about for Lambda CDM we also need to add in dark energy that's represented by the Greek letter Lambda Dark Energy was discovered in 1998 and it's what we call whatever is accelerating the expansion of the universe we don't know what it is but we know it must be there based on our observations of the universe so we need to include that too all of that together is Lambda CDN our best model of the universe we know it's not complete or perfect but it's the best one we have at the moment now there are actually a few little assumptions we need to make alongside this model the important one for this discussion is that the so-called fundamental constants of nature really are truly constant these are important numbers like the speed of light Planck's constant the gravitational constant and so on here it doesn't really matter exactly the details of those numbers if you haven't heard of them before and it doesn't matter what they represent too much but they appear in lots of equations that explain the physics of the universe and in Lambda CDM we truly believe them to be constant they don't change over time the new paper though claims an older Universe by ditching a couple of the key assumptions of Lambda CDN the author first of all abandons the assumption that the fundamental constants are constant they assume that the numbers like the speed of light Big G and h-bar Vary over time on the face of it this doesn't sound like an unrealistic idea to me things change over time a lot in physics so why not these numbers too the problem is that they need to assume that they change in very particular ways and change all together so that they don't break any of the physics that we do observe in the universe for example they would need all of the numbers to change in sync so that Atomic transitions are just as likely to happen at the same energies in order to be consistent with things like 21 centimeter maps of the universe that we can make they also need to add in another bit of slightly Contour virtual physics to get all of this to work it's called tired light and it relates to how light travels through the universe usually when light moves through space there are three main ways that it can lose energy or be shifted to a different wavelength of light the first is cosmological redshift the wavelength of light being stretched by the expanding Universe there's then gravitational redshift which is where light loses or gains energy due to passing by Massive objects for this one I like the very simplified picture of a wavelength of light moving away from something massive like a Galaxy and as it tries to climb out of the gravitational well it feels the Galaxy sort of pulling on it causing it to stretch to a longer wavelength and lose energy but just remember that is a very simplified view of it finally there's also Doppler shift where relative motion causes wavelengths to Bunch up or spread apart this is exactly the same effect that causes Sirens to sound different when they're moving towards you compared to when they're moving away from you me tired light though which is used in this new age of the universe picture assumes there is some other inherent way that light loses energy as it traverses the universe it's not really clear to me what that mechanism is or if it can be different in different versions of tired light theories but in those theories light loses energy simply by traveling it becomes tired due to the journey itself hence the name when both tired light and varying constants of nature are added to Lambda CDM it can change things in quite a few ways the important one here of course is the estimated age of the universe it means that while our original calculation for how old and distant the puzzling jwst galaxies are is still pretty much correct the time they formed after the big bang changes dramatically what I mean is that it pushes the Big Bang back by an additional 13 billion years giving the age of the universe to be an approximate 26.7 billion years and therefore giving these galaxies plenty of time to form in the usual way then question then becomes can we believe this idea does it stand up to all of the other observations we have of the universe unfortunately if you ask me it seems like the answer to that is no it's much more likely that we just don't understand some process that allows galaxies to either start off more massive than we thought or some process to grow and merge them much faster than we currently think they aren't incompatible with Lambda CDM our formation picture just isn't perfect yet that is much simpler than changing all of these things to move the starting point of the universe but that is just me talking so let's look at some actual reasons that these new modifications probably don't check out tired light was first proposed at the end of the 1920s by a famous astronomer called Fritz Wiki but even back then it was pretty quickly abandoned even by zviki himself due to its incompatibility with the actual Universe the compelling evidence against it back then was the fact that if light gets tired images of the more distant you Universe would be blurrier than we actually see them the longer the wavelength of light is the harder it is to take high resolution images in that wavelength so by adding an additional way for distant light to lose energy you add an additional way for distant objects to look blurrier and they would be noticeably more blurry than the images we take of them nowadays we have even more evidence we know about the cosmic microwave background too and this also provides evidence against tired light I don't want to go into huge detail here but if light gets tired then it would change the emission spectrum of the CMB and it wouldn't look like a blackbody spectrum unfortunately if your theory can't reproduce the CMB Spectrum then it's hard to trust the theory and I'm afraid the CMB here is a real sticking point for me similarly varying the contents of nature is also something that's been considered before and it has problems too there are lab-based tests that we can do to test how these constants vary and none of those tests have ever seen any evidence for it even more problematically for the theory is that we can look at how radioactive elements have decayed over billions of years here on Earth and that process depends on a number called the fine structure constant which in turn depends on the speed of light and Planck's constant the rate of Decay over the last couple billion years tells us that that number isn't really changing or if it is it's doing so billions of times slower than would be required to change the age of the universe by double to conclude I don't really think we should be rewriting textbooks with a new age just yet although briefly Google did change its answer when you asked it the age of the universe answer now I don't know having radical new theories I think I think worthwhile to consider ideas like this but to also understand why they might not work and how hard it is to improve on Lambda CDM I'm not sure why this one in particular got so much press and attention but I did think it would be fun to talk about it here please leave me any other questions you have in the comments below I know I didn't have time to go super in-depth here but hopefully this tells you enough to understand the big picture of the paper and if you want to read the whole thing you can do so with a link in the description until next time stay safe team I'll see you soon bye foreign

Channel: Chris Pattison

Views: 2,576

Keywords: cosmology, quantum, chris pattison, PhD, inflation, cosmic, cosmological, big bang, big bang theory, physics, early universe, icg, phdlife, einstein, dark matter, universe, age, age of universe, twice as old, double, doubled, jwst, james webb space telescope, earliest galaxies, early galaxies, galaxies, massive, bright, LCDM, standard model, break cosmology, broken, first, tired light, varying fundamental constants, gupta, claim, claimed, cmb

Id: pOE0v2CTizQ

Length: 11min 14sec (674 seconds)

Published: Thu Jul 27 2023