Could the Universe be TWICE as old as we thought?

it's not every day you wake up to find out the universe is twice as old as it was the night before but a new paper by rajendra Gupta at the University of Ottawa suggests the universe is really 26.7 billion years and not 13.8 billion years as we thought that's pretty remarkable because over the last 25 years we've developed a fairly robust model of the universe it explains everything from the cosmic microwave background to the accelerating expansion due to Dark Energy in fact I can remember when astronomers estimated the universe's age at anywhere from 9 to 20 billion years so narrowing it down to 13.8 billion years was kind of a big deal bagupta's paper was motivated by what he calls The Impossible early Galaxy problem it started when the James Webb Space Telescope found galaxies that were surprisingly massive even though the universe was just 300 to 500 million year years old at the time to the best of our understanding that's not nearly enough time for Galaxies to have gotten so big and that probably means there's something wrong with our understanding of how galaxies formed however Gupta is taking a different approach and asks well what if the universe is really just older than we thought so the paper got a lot of press which I guess is understandable because it's good for the clicks but for all of the public attention astronomers are skeptical and it's not because we are determined to cling to our long hell dogmatic beliefs about the universe rather the paper just doesn't seem to match up with the observations So today we're going to take a look at our current understanding of the universe and then we'll talk about this new model for its age our best understanding of how the universe works is called Lambda CDM Lambda refers to the cosmological constant that's been driving and accelerating the expansion ever since the Big Bang that expansion causes galaxies to move away from us faster with increasing distance the faster the Galaxy is carried away from us the more its light is stretched to longer and therefore redder wavelengths we call this effect cosmological redshift CDM refers to cold dark matter it's cold in the sense that it's moving slow enough to Clump together and that allows it to attract normal matter to form the Stars galaxies and the large-scale structure we see today Lambda CDM tells us the universe is made of five percent normal matter that makes up the stuff we see 27 percent dark matter and 68 Dark Energy it also tells us that the universe is 13.8 billion years old it's a good model in fact it's our best model but we also know it's incomplete for example Lambda CDM predicts the universe should have something like three to four times more lithium than it does dark matter doesn't explain all of the gravitational interactions we observe and the age as measured from distance measurements to the furthest galaxies converges on an age of 13.3 billion years instead of 13.8 billion years at first it was assumed that the two methods would be reconciled with better data but as measurements improved the discrepancy has only become more apparent this problem is called the Hubble tension or the crisis in cosmology and I should really save that for another video but the short version is that our measurements to distant galaxies are based off of distance measurements to nearby galaxies it's thought that those nearby measurements are probably being thrown off by dust in the Milky Way and in the galaxies themselves if that's true then jwst should be able to see through the dust and improve those measurements and hopefully that will bring the age of the universe as measured from galaxies back in line from the age as measured from the cosmic microwave background we'll see but until then we take the 13.8 billion year age as the canonical age of the universe because it's measured against the cosmic microwave background and microwave radiation is even less disturbed by dust so from CMB measurements we get things like the expansion rate of the universe and the overall density of the universe you can then use these values to work out for how long light with a given redshift must have been traveling through the universe to reach us and from there determine how old the universe was when we are looking at a given object for example a galaxy with a redshift of 10 means we're seeing it 13.3 billion years ago that means we're seeing the Galaxy when the universe was just 500 million years old but this particular Galaxy appears to be too massive for a 500 million year old to give the Galaxy more time to come together Gupta introduces a version of Lambda CDM that includes some critical modifications the first modification is an idea called tired light it was proposed by Fritz Wiki back in 1929 as a reaction to Edwin Hubble's discovery that Galaxy's redshifts increased with their distance today we understand this as the discovery of the expanding Universe which led to the Big Bang model which led to the discovery of dark energy which led to Lambda CDM that we know and love today but at the time it contradicted the widely held belief that the Universe was static and eternal in order to maintain a steady state universe zviki suggested that as light travels through space it scatters off particles along the way and loses energy that energy loss caused is the light to stretch out to longer wavelengths so the light we detect is redshifted because it was tired from the journey it was an interesting idea but it was quickly abandoned for a couple of reasons zwiki himself understood this kind of scattering would cause the photons to kind of spread out and blur the images of distant galaxies Not only was no such blurring detected in zviki's time but modern deep images reveal distant galaxies that are just as well focused as their nearby counterparts tired light also predicts that if the universe is static then the amount of light coming off a Galaxy surface should be the same no matter its distance the idea is that if the Galaxy is further away the less light we're going to receive from it due to its distance but its angular size is smaller as well so the amount of light coming off a unit angular surface area should be the same that's not what we detect either when we look at the most distant galaxies the amount of light per unit surface area is much less than for nearby galaxies another problem is that tired light doesn't account for cosmological time dilation this is a really cool effect that can only happen if the universe is expanding the more redshifted a Galaxy's light is the more time it takes for the same number of emitted waves to be received so a photon at redshift of one would be twice its rest wavelength but because the waves are twice as long they arrive half as frequently than they would if they were coming from a source at rest so we have to wait twice as long to receive the same number of waves meanwhile the source of that light is moving away from us so the time required to receive that light gets longer and longer as a practical matter events coming from high redshift sources seem to take longer to transpire this effect was demonstrated with highly red-shifted supernovae that take longer to fade out than those in nearby galaxies on the other hand in a static Universe with tired light distance supernovae would appear more red than their nearby counterparts but they'd still take the same amount of time to fade cosmological time dilation was recently demonstrated with high redshift quasars that appear to vary their light output at slower rates as compared to quasars at lower redshift in fact astronomers who study quasars must apply Corrections for cosmological time dilation or else their measurements would be thrown off finally tired light doesn't explain the cosmic microwave background the cmb's redshift is a whopping 1089 according to Lambda CDM it originated just 380 000 years after the big bang tired light says that the cmb's radiation will lose energy and increase its overall wavelength as it travels so its black Body Curve would shift from the blue line to the red line but Lambda CDM says that because the universe is expanding not only does its light lose energy but the intensity of that light should diminish as well as represented by the black line that's exactly what was measured by the Kobe mission in the early 1990s in fact the cosmic microwave background is the most perfect black body Spectrum ever measured now goop does not suggesting replacing Lambda CDM with a steady state universe and tired light rather he's combining the two ideas together to create Lambda CDM plus TL but in order to do so he invokes a second modification that states the fundamental constants of nature aren't constant at all but rather varied over time and that means things like the speed of light Planck's Constant and the gravitational constant were different in the past than they are today however Atomic transitions are governed by two of the fundamental constants so if one of them were to change or if they both changed at different times then the Spectra from high redshift quasars would be unrecognizable to address that problem Gupta invokes a mechanism where all of the constants change together so the atomic Transitions and spectral lines still work correctly across all redshifts he calls this idea co-varying coupling constants the good news is that when these modifications are added to Lambda CDM it actually fits some of the data even better than Lambda CDM does on its own but the bad news is that no Laboratory test has ever confirmed that constants vary on the one hand yes it's kind of hard to wait billions of years for a lab experiment to finish but we don't need to wait a billion years because we can look at the products of radioactive decay here on Earth Decay Isotopes have been accumulating since Earth formed four and a half billion years ago the rate of Decay is governed by the fine structure constant which in turn depends on the electron charge the speed of light and Planck's constant in order to produce the abundance of Decay Isotopes we have today this constant couldn't have changed by more than 0.3 part in 10 to the 16 per year that's billions of times smaller than what gupta's variable constant explanation would require if the universe were really twice as old as we thought then there should be Stars around today much older than 14 billion years our galaxy is surrounded by a Halo of globular clusters the biggest stars to form in those clusters evolved and when Supernova long ago but they're smaller less massive members still remain to this day among them are m-type red dwarfs which should live for up to trillions of years but when we look at for the oldest stars and globular clusters we find that they're around 13 billion years at most there was one star dub Methuselah that got some press many years ago because its age was initially estimated at 14.46 plus or minus 0.8 billion years the error bars alone allow the star to still exist in a 13.8 billion year old universe but since then our understanding of Stellar Evolution has improved and that ended up revising Methuselah's age downward to 12 plus or minus 0.05 billion years if the universe was 26 billion years old there would be clusters of very old K and m-type stars still hanging around our galaxy but so far no infrared surveys have found any still gupta's theory was put forward to address the early Galaxy problem but what if the early Galaxy problem really isn't a problem at all the galaxies are thought to be massive because they'd have to be very luminous in order to be seen at such high redshift so the reasoning is that if these galaxies are as bright as they appear to be at high redshift they must have already had a lot more stars in them than we thought was possible by that time but the only galaxies whose Stellar distributions we can reasonably measure are the Milky Way and nearby galaxies when we look at the distant blob we don't resolve any individual Stellar populations so we need to assume that it has the same distribution of stars that Galaxies have today that's not a safe assumption for early galaxies the universe was a lot more dense back then and almost entirely made of hydrogen and helium so very massive luminous stars would have been able to form a relatively modest amount of massive Superstars would make the Galaxy lot brighter while still having an overall low mass something else to consider is that the galaxies we found so far are probably the brightest in the early Universe if that's the case then chances are most of the early galaxies are still too faint to have been detected yet and that would mean they are less massive as well that's why there's a jwst program to make Ultra deep images of the universe to tease out the earliest and faintest galaxies that will give us a much better idea of what the early Universe was really like and then there's the possibility that the reported redshift of these early galaxies may not be very accurate to begin with the galaxies were detected by Imaging with different filters the redder the Galaxy gets the longer the wavelength filters they show up in but you're also making an assumption that the Galaxy appears so red due to redshift and not because it's heavily Laden with dust even if you can rule out dust the filters allow a range of wavelengths to pass through so your estimate of the redshift is going to be uncertain the most robust method is to take the spectrum of the Galaxy and use well-known breakpoints to pinpoint the exact redshift a recent example was of a galaxy in the Sears survey that initially seemed to have a redshift of 16.4 but after its Spectra was analyzed it turned out to be only 4.9 you might wonder then well why bother with this Imaging Approach at all if it's going to give us wrong answers why don't we just take the Specter to begin with and be done with it well the answer is simple you need the Imaging to figure out which galaxies to take a spectrum of I suspect that as we gain more Spectra of these early galaxies we're probably going to find out that yes they're young but just not as young as previously thought none of these resolutions to The Impossible Galaxy problem would require any modifications to Lambda CDM and that's why it's risky to take galaxies whose situation we don't yet fully understand and extrapolate from there to require a fundamental change in our cosmology still there is no reward without risk and I don't think anybody is Fault in Gupta for publishing this paper he does a full breakdown of his theory and doesn't seem to be resorting to any hand waving however one theoretical study isn't going to overturn Decades of work that led to our current model but then again jwst's mission is still in its early days how cool would it be if we discover something about the universe as revolutionary is dark energy or cosmological redshift let's see what happens a huge thanks to my patreon supporters for helping to keep Launchpad astronomy going and I'd like to thank Paul Miller and Ethan Staghorn for becoming my newest supporters until next time stay curious my friend

Channel: Launch Pad Astronomy

Views: 43,374

Keywords: Could the Universe be TWICE as old as we thought, age of the universe, james webb space telescope, cosmological constant, 26.7 billion years, tired light, cosmic microwave background, big bang, rajandra gupta, coyarying coupling constants, universe age, fritz zwicky, early galaxies, dark energy, christian ready, Launch pad astronomy

Id: -PJ5Rcj0Gp8

Length: 17min 4sec (1024 seconds)

Published: Sat Aug 05 2023