Is Dark Energy Getting Stronger?

PBS Space Time

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    The power of Dark Energy may be increasing as the universe ages. Subtle clues are emerging that the accepted model for the nature of dark energy and dark matter may not be all that. We saw the first such clue recently in our recent episode on the Crisis in Cosmology. Today we’re doing a Space Time Journal Club to reveal another clue. We’re looking at a new paper in Nature Astronomy, “Cosmological constraints from the Hubble diagram of quasars at high redshifts” by Risaliti and Lusso. It hints that the cosmological constant may not be so constant after all. In fact it may be increasing. If this is true, then our prediction for the future of our universe looks VERY different, and may involve the entire universe tearing itself to shreds at the subatomic level in the Big Rip.
    On this edition of Space Time Journal Club we look at:
    Risaliti & Lusso (2019) "Cosmological Constraints from the Hubble Diagram of Quasars at High Redshifts"
    #darkenergy #darkmatter #spacetime
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    سلطان الخليفي

    Am Vor Monat


    1. ofsinope

      That moment when he says "spacetime" at the end

    2. Jesse Mai

      show me the math, intuitively I disagree on both experimental and theoretical platforms... show me the math for corrected theoretical measurements and the math for the theory behind it

    3. Sandy

      i feel intelligent after clicking this video...even though I don't understand what he says

    4. Jay Antani

      Cool Video!

    5. James Alexander

      maybe the entropy of the universe is increasing which would explain it's expansion just like a piece of metal or being that this may only be a short period of rapid expansion; somewhat like an oven that may sit at say 350F for several seconds or more before actually reaching the next digit in temperature. Of course in reality, this may be a period of chaos, destruction & growth in the universe. People often misinterpret current events because they perceive reality to be steady without considering acceleration/deceleration

    6. Ne, oder?

      12:33 says all about spacetime

    7. Sami Saieed

      Totally, An epic episode

    8. John Foyer

      So this is the cosmic error He spoke of. Hm...well let's say I had a...conversation with a...deity that claimed he was the...creator. he spoke of this miscalculation that was originating from the effects black holes were having on the space time weave of the fabrics within the universe. The miscalculation was the gravitational effect of the first moments when particles first formed. The excess build up of particle formation led to the formation of black holes and the model of creation was a constant spherical shape that would expand and then retract. However o proposed a new algorithm to the model that would redistribute the excess particle energy to instead imbed themselves into the cosmic microwave background and using the energy generated by the particles and motion into and along the CMB to fill in the inconsistencies due to gravitational effects, then using the energy remainder to interweave itself with the fabric of particles stretching the borders of the universe infinitely outward, reinforcing the newly formed particles and allowing them to settle into the formation of matter without the gravitational build up the less to black hole formation. It was about thay time I woke up spitting up the lung fluid that had built up in my lungs while I was sleeping that night...

    9. Luke Tyas

      E Lusso is my next door neighbour, and one of the most wonderful humans in the Universe.

    10. Walt F.

      Could dark energy have a waveform? Could the expansion of space come in waves? An unaccelerated phase followed by an accelerated phase, followed again by an unaccelerated phase, and so on ad infinitum?

    11. SketchyJay o.o

      Could dark energy be caused by a layer of matter/charge which surrounds the universe. During the big bang this "shell" would have been expanded, possibly increasing the "space" between it and all other matter within the universe - reducing interactive forces. This could initially slow the expansion of the universe, however it's ability to expand without fracture could suggest 'elasticity' and would therefore recoil. Eventually this recoil would provide an inward pressure, while increasing the strength of interactive forces - increasing its pull on everything internal. This could therefore create the "illusion" that the expansion is accelerating when in actual fact space is in recession.

    12. kaczan3

      I love the music during the 14:41 anyone got a link for that?

    13. Blair Macdonald


    14. Mr Temporal

      Nice thumbnail

    15. Kickin Rocks

      Starting a band... Tommy Terror and the Big Rip Quantum Physic and the Maths Bonaparte and the Big Bang White Hole and the Dark Matter Particle and the Waves Entry Lovell and the 101's Tyson Swarm and the Suns 10 Billion Days to Die The Eight Planets Celestial Hot Bodies When Iron Collides Lifeless XO's

    16. Gsup7s

      Of course it's getting stronger. It's an unlimited free energy source. According to you.

    17. Two super gamer girls

      You know I don't really understand because I'm only 8 years old.

    18. JorDef

      I´m dumb, the earth is flat, there´s no cosmos there´s only god. We´re the center of all. No Jesus in this video. Because of all that I´m giving this video a dislike. Better go to church and spend money on crucifixes. You all will burn in hell!

    19. FalconPunch827

      Dark energy is a perfect metaphor for my father. Permeates through all existence but no one has a clue where it is.

    20. Sledcat

      Supernov eh!

    21. nolan412

      Big phase change?

    22. Chris Ritchie

      I discovered The Big Rip in my pants

    23. Mike Price

      I think part of the problem is we are using Euclid's yardstick instead of Mandelbrot yardstick

    24. Gold161803

      Take a shot every time the CMB graphic shows up in a Spacetime video

    25. Deep Recce

      Question..How do we know the Universe expansion is not slowing down? We know its accelerating only because the further we see the greater the red shift right? But how does it measure up over time, as in maybe in a 1000 years time we see minute change in the expansion vs the current measurement? Also the further we see, meant that we are looking nearer to the beginning of the Universe where acceleration and expansion is greater nearer to the Big Bang..isnt it only natural to read a greater red shift as we see further away or rather further back in time??

    26. GateMessenger

      The theory is a quasar is a black hole consuming matter at a continuous rate but that is not so. Quasars are actually old galaxies which contain a large amount of stars, plentiful and extremely close together. The older the galaxy is the brighter it shines. Black holes cannot devour matter because of the action that is causing gravity, mentioned in a previous comment. There was no big bang but a slow continuous growth. There is more gravity, matter, energy and space in the universe today than there was yesterday. There is more now than there was in the beginning when the universe did not contain gravity, matter, energy and space. Back then the universe only contained potential gravity, energy, matter and space in time.

    27. GateMessenger

      The cosmic microwave background radiation map is the result of a manipulation in data, thus unreliable for any study.

    28. GateMessenger

      No, a big rip will never happen because as new matter is made in space, see pair production and virtual particle theories, space increases in volume (dark energy). It is not being torn apart but increasing in volume like a balloon being filled with air. New particles are made when energy comes to a rest, i.e., m=E/c^2. This is why virtual particles appear to pop into existence in the sun's corona. See the newest ring discovered by astrophysicists orbiting Saturn. When new particle pop into existence in the sun's corona they make light, heat and pairs of particles (plasma). It explains why the sun's corona is millions of degrees hotter than it's surface. This is why stars grow in mass and size over time. Stars cannot 'burn up' over time because mass is constantly added to them. Yes, I know this is conjecture for now. Let's wait and see what the Parker probe discovers.

    29. GateMessenger

      The lambda CDM 'cold dark matter' model is incorrect and incomplete. The cosmological constant was zero, not accelerating nor decelerating, i.e., a plus one or negative one thus it does not describe the expansion of the universe. Anyone who thinks otherwise needs to go back to school and study it some more.

    30. GateMessenger

      To answer your question, yes. The energy potential of the universe increases ever so slowly everywhere there is mass. See mass, in order to produce gravity has to have an equal opposite counterpart. When energy is produced inside of mass it escapes, quantum tunneling through matter, and produces a reaction to cold space, causing it to warp or bend, i.e., move in an opposite direction to the energy escaping mass. This was actually measured by the GRACE satellites. Gravity is stronger in the locations where energy is escaping the planet the most and gravity is weaker in the areas where energy escaping the surface is hindered by denser mass. Thus the same action responsible for gravity is also responsible for the expansion or addition of energy that occurs to space, i.e., dark energy. So yes, as long as mass is able to produce gravity it will continue to add new energy (dark) to space. This is why the Hubble constant, Ho is never the same when measured. Astrophysicists continue to come up with different rates to the universe's expansion with every measurement. This can even explain why stars move faster than what Einstein's field equations predicted, i.e., dark matter.

    31. Bradley Carter

      If all galaxies emit light and electromagnetic radiation in all directions simultaneously all the time, wouldn't the fields from the surrounding galaxies eventually meet and cause some sort or reflection thus pushing the galaxies further apart and explain dark energy?

    32. POSH MARK

      I hope not!

    33. Derek Currie

      *_"light_*_ noun_ *_1_*_ the natural agent that stimulates sight and makes things _*_visible:_*_ the light of the sun | [in singular] : the lamps in the street shed a faint light into the room._

    34. Marcin Skrobański

      have you ever tried gluon-free diet?

    35. Ryan Flores

      I have been talking and hearing a lot about the correlation of this and tachyon particles. Supposedly faster than the speed of light. Any potential videos on this?

    36. Aby havent considered that ark energy travels at least twice as fast as light can?! and that light speed depends on dark energy speed....not ot mention that thos light partciles that ae at teh edge of he big bang hypothesys need space to travel in for them to move out, menaing that dark matte rmust preceed light in its journey and create space time

    37. Hydra

      My fucking brain

    38. Zbigniew Modrzejewski

      Dark Energy canNOT be Getting Stronger, because it does not exist.

    39. Morbid Angel

      Love the channel , love the science , still have no idea what dark energy is... hate my life....

    40. Jeremy Castle

      Pieter van Dokkum (Yale University) allegedly discovered galaxies completely or nearly devoid of dark matter.

    41. Abraham Mekonnen

      Out of curiosity is there any chance that dark energy is just space itself?

    42. Vesa Kankkunen

      What if theres a huge black hole all ower the known universum acting like event horizont and phantom energy?

    43. Narendra kumar

      Sir please give a video for quantum spin....

    44. Schlomo Finkelstein

      13:56 xD

    45. Korhanne

      does my accretion disk make my butt look big?

    46. Ibnul Hussaini

      That's fucken lit my dude! What's the value of the Hubble constant using this method vs the other standard candles & the CMB?

    47. mR iOuS

      If the CMB gets shorter under the Rip Theory, the distance, just feels like to me, should have constant fluctuation.

    48. ChrisBrengel

      So quasars are a hot mess...literally. LOL!

    49. Bruce Liu

      The rate of exploding stars? Might be dark energy.

    50. Marvels fan club

      Dark energy could be hidden energy which is multiplying constantly

    51. Dudealus

      After the Big Rip, would particles still be able to interact with the Higgs Field? Or would they all become massless, experience no internal evolution, and never bump into another particle, making the events before the Big Rip the last events ever to happen. Time would cease to exist.

    52. Guillaume P

      Hey! Why don't you do a video on the recent discovery of CP Violation in the charm sector by the LHCb Experiment?

    53. Dimitrios Thanos

    54. gh hj

      That black stuff is surely laughing... black stuff: "MUAHA!... All of these stars, planets, tiny things and beings ALL IN ME, ALL OF THEM! MUAHA... HA... HAAA! How great am I? I can't even go anywhere, I am everywhere! MUAHAHAAAaaaa. The star prays to me and the tiny being prays to the star... huhuhuhu... MUAHAHAHAAaaa!".

    55. The Wise Wizard

    56. John Farris

      When I think of Entanglement I keep seeing hard and massless. Waves need time. Hard isn't real anyway even though it kinda is.

    57. Corey Patterson

      I’m very curious how Matt feels about the Janus Model. I know he mentioned it, but I wonder how far he dug into it. It’s hard to overstate how elegantly the notion of two conjugated manifolds ties dark energy/matter into a neat little bow to be explained. The math is perhaps not so elegant, but the explanation for why dark matter/energy behaves like it does is so exceedingly intuitive that everything else feels highly convoluted and improbable. After spending enough time with the JCM, using the concordance model feels like being a blind man groping in the dark.

      1. Corey Patterson

        (Continued pt 3) Think about two scenarios. In one a much greater mass of marbles is dropped on the sheet; in the other a far greater mass of balloons are released under the sheet. How do we imagine these joined systems interact? A bit of logical thinking and we can conclude that the accretion pattern of the dominant mass in any given area of the sheet will determine the pattern of curvature. That is to say, if there are more balloons we will see hills with valleys full of marbles; if there are more marbles, however, we will see pockets full of marbles depress into bowls formed by ridges of balloons. Current cosmological models insist there's more dark matter than regular matter. If visible matter takes the pattern of the former, we can assume there is more inverted mass in the area. If visible matter takes the pattern of the latter, we can assume there is more regular mass in the area. The standard model of the universe describe large galaxy clusters linked by hundred-lightyear long threads of galaxies surrounding massive empty voids. This can be pictured like bubbles from a pot full of dish soap. Planes of soap would be fairly rarified areas of matter, lines would be the galactic threads, and vertices of the bubbles would be galactic clusters. The ΛCDM model proposes "galactic filaments" which accrete around threads of dark matter. I will not emphasize problems with that, as I feel it is more productive to emphasize the very specific way this bimetric understanding of the manifold accords with reality (or at least our observations of reality). When we look at the universe on a grand scale, it seems to imply there is a greater distribution of inverted masses due to the filamentous shape. We see big voids full of “empty space” with apparent energy content, thus conclude dark matter. So on the universal scale the balloons of inverted mass matter are pushing regular matter marbles into “filaments” or valleys, but on the scale of our local group the marbles representing galaxies are held in rotation by the inverted matter surrounding them since there aren’t enough marbles to break past the balloons. My point in relation to THIS video (finally) is that if the Janus model is at all accurate, then it stands to reason that the “energy of the vacuum” could be the average energy density of all inverted mass as it slowly accretes in the massive voids between galaxies. That would explain why the expansion doesn’t happen in areas rich with positive-mass matter. Thus, if mass in the universe is somehow being inverted, perhaps in the center of a critical-mass neutron star (google “1916 Schwarzschild on the gravitational field of a sphere of incompressible fluid according to Einsteins theory”) we can assume that this inverted mass will simply increase the accretion rate of the voids, and therefore the expansion rate of the universe. Not sure I buy it, but it’s a hell of a better story than “mystery energy” and “matter we can’t find”.

      2. Corey Patterson

        (Continued pt 2) So if we want to consider it this way, we need two metrics g(+)µν and g(−)µν from which two different families of geodesics are calculated, referring to positive mass particles and negative mass particles, respectively. From these metrics, we calculate Ricci tensors R (+) µν and R (−) µν as well as Ricci scalars R(+) and R(−) . This crude 2-dimensional analogy is merely used to explain things, but it does helps illustrates what may be happening in our very own 4-dimensional universe. I prefer to refer to "negative mass" as "inverted mass" simply because, the way that this model requires you to look at it, negative mass is not an intrinsic feature of some "exotic matter", but instead stems from topological consequences; it is purely relative. The "bigravity" associated with inverted masses is an extension of general relativity describing the universe as a Riemannian manifold associated to two conjugated metrics generating their own geodesics, solutions of two coupled Einstein field equations. The second equation gives the metric and spatial curvature for the "negative sector" of the manifold. This is the equivalent to being on the balloon side of the sheet. Positive mass (marbles), viewed from the underside of the sheet, will produce a negative curvature and an anti-gravitational effect. The system of two coupled field equations involves a 4D hypersurface with two sides, each type of mass belonging to its own metric. What is important to note however, is that the two field equations are coupled, i.e. a mass always creates a positive curvature in space-time according to its own metric (where the mass appears visible), and it also always induces a negative curvature in the conjugate metric (where the mass appears invisible). To reiterate, "negative mass" is not an intrinsic feature of some exotic matter. It is nothing but the (anti)gravitational effect produced by any mass, when observed from the opposite sector. According to an observer measuring such mass in the same sector where it lays in, that mass always appears positive. This introduces the concept of apparent gravitational mass. Fundamentally, a mass is not "positive" or "negative"; it is both. Its sign depends on from "which side" we are measuring that mass. It is therefore a purely relative concept. Same thing for the "positive" and "negative" sectors: we call our sector the "positive" one simply because it is the one we live in, and we have to name both. But this is only a sign convention.

      3. Corey Patterson

        (Continued) Consider the classic rubber sheet example used in the perpetual motion episode of PBS Spacetime. The analogy is of space-time to a sheet, and when masses like bowling balls are introduced it warps to create curvature. A marble shot in a straight line past a bowling ball on this sheet would follow an apparently straight path on a curved plane, a geodesic. According to the most theories, negative (or inverted) masses follow the same geodesics as positive masses since there is only one metric tensor. However negative masses imply a negative curvature, which gives rise to an "anti-gravitational" effect. So the negative-mass-marbles slide along the sheet, but "pull" the sheet as they move. This poses obvious problems when they begin rolling towards a bowling ball. Because the sheet is continually pulled towards them, the warped state of space stays constant and the motion continues perpetually. This was addressed in both videos concerning negative masses, and is commonly known as the "runaway motion". This definitely violates the crackpot conjecture, so we need to find an explanation that works more reasonably. Let's change the situation slightly; think about how we might get the same anti-gravitational effect without invoking strange counter-intuitive "negative mass marbles". Perhaps we could use similarly sized spherical balloons filled with various lifting gasses to represent different negative masses of different densities? Immediately we can see the behavior is not so strange as long as the marbles and balloons are on opposite sides of the sheet. Then it becomes intuitive that the balloons, who want to ascend, will push away the marbles, who want to descend, as they both respectively warp the sheet. We can see that the balloons will aggregate as they all "fall" up towards the steepest hill, and marbles will aggregate as they fall into the deepest wells. And because they are on opposite sides of the sheet, they can roll right past each other as they attempt to find their spot. In essence, like attracts like and opposites repel. In order to get something that works like this, the marbles and balloons must be on opposite sides, meaning they're following different geodesics.

      4. Corey Patterson

        For the future readers too lazy to google, here’s a brief argument: The issue begins with the Poincare group. According to dynamical group theory, the action of elements of this group on movements in space-time result in some movements which follow a time reversal, they appear to be going "backwards through time". Modern physicists use the restricted Poincare group, limited to only orthocronous movements, and therefore ignore this issue. In group theory, however, the T operator is real and we can explore retrochronic movements. Smarter people than me (namely Jean-Marie Souriau) have shown, using maths I can only begin to understand, that using the full Poincare group, time reversal goes with mass and energy inversion. In quantum field theory, the T operator acting on Hilbert spaces is complex, and can be either linear and unitary, or anti-linear and anti-unitary; but is arbitrarily chosen anti-linear and anti-unitary in order to prevent inversion of energy, as the vacuum state of the Zero-point energy must have the lowest possible ground state and can not have negative values. But when this axiom was formulated, the accelerating expansion of the universe, which implies a negative pressure, was not known yet. As pressure is a volumetric energy density, it seems sensible to reconsider how we view negative energy states. So at least the idea of mass inversion is not entirely without precedent. There is at least some mathematical precedent for negative masses...

    58. SrmthfgRockLee

      01:12 who else noticed the stars moving in backgruond

    59. dddduuuuuhhhhhhhh

      Could the red shift of an EM wave be reversed? Allowing us to see the original wave before the red shift. Then using filters like we do in space to get rid of noise, could we use this to better scan the universe for life? Maybe finding radio waves of a civilization in a far off galaxy?

    60. Kranimal Hobbies

      I have a question that maybe you can answer. I have been watching your videos and something came to mind, now I haven't watched all of your vids, but none the less, I am gonna ask. It is about stars, or, to be more specific, about our sun. If our sun is constantly burning different gases and such, creating DNA changing radiation and burning different fuels, where is it getting all the particles, elements or whatever it is doing to keep going. It would have to run out at some point right? Relatively fast as well, considering it is getting all these elements from somewhere. Considering it has nothing but space around it, where is it getting the fuel to keep burning from?

      1. Sid Kapoor

        Relatively fast is a few billion years on the comsological scale. And it is running out.

    61. What if?

      Here is a stupid question. Could dark energy be causality slowing down? Here is a video explaining what I mean and how the idea came to me;

    62. Scott deMoor

      wow....... like..... wow...

    63. Egli Zotaj

      Universe was an empty giant vacuum before big bang appeared... Dark matter is a negative energy... Electrons of dark matter resonate at frequency minus megahertz... That's why it can't be controlled... But as math says minus multiple minus gives plus... That's what may have caused big bang... dark matter.... The emptiness itself ... Its electrons are Resonating at minus... More the density of negative electrons increase than more it may provoke the production of a positive charged electron.. Minus x minus = plus.. And the presence of a positive charged electron has produced magnetic field and suddenly big bang.. Negative electrons of emptiness produce a positive electron... Just iv said minus x minus gives plus... And the presence of a positive electron creates electromagnetic field, creating a reaction of explosions....triggering other negative electrons to themselves... Forming new electrons... And the presence of positive electron in different density creates chemical production as hydrogen that was one of the elements in universe creation... Look the number of electrons of hydrogen in the chemical table...

    64. Ashwin Das

      Hmm just a thought. If space expands in all directions equally then shouldn't the amplitude of light also increase upwards as the wavelength increases sideways??

    65. Jesus McBeth

      Also - dark energy changes randomly~ based on absorption rate of the black hole which is our universe on the outside of our universe

    66. Jesus McBeth

      Episode on quantum up scattering?

    67. Jesus McBeth

      Conclusively haha

    68. William Granger

      Dark energy = spiral energy Beware the spiral nemesis

    69. Sam Harper

      If it turns out that the cosmological constant isn't constant, wouldn't that mean we'd have to get another estimate of the age of the universe?

    70. Sascha Uncia

      If the fastest speed possible is the speed of light, and objects like earth, the solar system, and the local cluster are moving through space at a set speed; does this mean that you could fire a laser from a reference point to sensors moving at the same relative speed positioned around the object, and light would reach the sensors at slightly different times? Or to rephrase, if you emit light from a fast moving cosmic object along both directions of it's vector, would the light emitted forward travel at a slower relative speed while the light fired backwards would seem like it's moving away faster than the speed of light? Could you use this for example, to determine the speed and direction of the solar system relative to spacetime? :3

    71. Alling

      Hey guys, I've got a (maybe stupid) question (probably). I have recently stumbled upon my school physics book and took a second look at all the stuff I used to find boring. What struck out at me was Newton's formular for calculating the gravitational force between to objects of mass m1 and m2. F=(G*m1*m2)/r^2. After having watched quite a few videos on this channel, especially on the properties of small particles and how they are sometimes considered as being point size I thought, maybe I could try and calculate the force between a proton and a neutron in the atom with Newton's formular. ((6.67408e-11) * (1.675e-27) *(1.672621898e-27)) / (1e-15)^2. After some digging I found that at 1 femtometer the force should be 2500N, which unfortnately the calculation above didn't yield. BUT if protons and neutrons where only points in size, one could calculate assume they can get infinitely close together, so I could calculate the distance at which they had to be to get the result of 2500N. So my question would be, is the distance between proton and neutron an inaccurate model (like the model of the atom and the electrons floating around it) or is the distance between protons and neutrons in the atom well established? And if so how big is it?

    72. Brian Levine

      My kid must have a future in cosmology. He makes up crap all the time and because it fits his "model" assumes everyone should just accept it. 😁 In all seriousness, love this channel.

      1. Michael Östman

        Brian Levine Sounds like a great kid.


      I have a doubt?? Is the distance between two higgs bosson is less than or greater than Planck's constant

    74. bunklypeppz

      I would have checked this video out when it was first posted up... but I was too busy being hunted for sport on Bill Gates' private island.

    75. Mulando

      If everything started from little point (big bang), wouldn't the particles than fly faster than light while expanding because of the bending of space. Gravity would be immense strong at this little point and while everything drifts away, the gravitational force would be reduce itself while at the same time space get's "unbend" to "normal". But because space would be bend so extremely in first place, the particles should travel like through a hypothetical wormhole.

    76. Michael Reynolds

      I think we know almost zero about dark matter and dark energy and until we know what they are exactly and not just speculating, we have no idea what will happen as a fate of the universe. We know very little in the grand scheme of things.

    77. Lance Tschirhart

      13:55 Matt's mouth here cracked me up.

    78. Paul Pena

      Can someone explain why we need dark energy as a theory? If the universe can expand faster than light clearly it "follows no laws" so why do we need some mysterious energy to explain why it is accelerating?

      1. Paul Pena

        +Chris Fuller That's my point! Space itself isn't constrained by special relativity. That's just a fancier way of saying "follows no laws". If it is not constrained by special relativity why would any of Newton's laws regarding energy sources, thrust, expansion, etc. apply? Isn't it arbitrary to say "well we would need some source of energy to explain why the universe is accelerating (i.e. that is the ENTIRE universe's expansion not just 2 galaxies relative to each other)" Yet we need nothing to explain how the universe can surpass C which is so core to modern day physics. It's the equivalent of saying 'Well Newton's laws regarding mechanics are REALLY important" but "Einstein's rules regarding relativity are supplemental you can take or leave them". I don't believe that to be true. Why is the universe expanding faster and faster? IT JUST IS. It would be like saying "OK what is the ULTIMATE speed limit for an accelerating universe". There just ISN"T ONE.

      2. Chris Fuller

        It's not "not following laws". Space itself isn't constrained by special relativity, and nothing moves locally (roughly,like next to each other) greater than c. Matt's covered this more than once, probably easy to find in the inflation episodes. We need models/"laws" so we can reason about how the Universe is changing and where's its been. You can't just turn science off and on. Maybe there are gaps in understanding, but that's something else. But dark energy isn't magic. It's hypothetical in its details, but there are quantifiable constraints on its details, and it's an important part of Lambda-CDM, which is a pretty amazing critter, considering what passed for cosmological models before it.

    79. gerald finn

      What does this tell us? That astrophysicists and cosmologists need to stop living in advanced fantasy worlds and concentrate on basic science. Menstruation is fundamental. Maybe learn to walk before ye all go piloting your Millenium Falcons throughout the universe?

    80. J Mark Morris

      This video is truly ironic, but only speaking in future tense, because cosmologists and astrophysicists don't yet realize that AGN SMBH quasars are the source of the expansion of the universe. You see, in goes standard matter, energy, and graviton superfluid gas. That all heats up and reaches a plasma state where it has all deconstructed to fundamental electrino and positrino particles. That plasma gets jetted and as it reacts and cools forms new standard matter, and more importantly for expansion, new graviton superfluid gas, which outflows to permeate the universe. So a measurement technique that is based in the same portion of space as the most intense generation of new gravitons is probably not going to be accurate.

    81. J Mark Morris

      If you like this channel, try Dr. Paul M. Sutter's ask a spaceman channel.

    82. wildernesseric

      There is a new theory that sound has gravitational mass... well actually negative mass. I would LOVE for you to do an episode about this and hear your thoughts on whether this could actually be true and what the implications are. Could this be a breakthrough discovery that we are waiting for in physics? Google "sound has negative mass" for more info and here is a link (if it works here) to their official paper on it. (Please help like this comment so Matt can see it) Thank you!

    83. Petri Sirkkala

      "...just in case..." LOL

    84. Chandria Prime

      We should forget all those phlogiston ideas like dark matter and instead embrace that our current understanding of matter might be totally flawed by scientists' expectation of finding those phlogiston matter and desperately trying to include in theory as given what might not be given at all...

    85. Deep Dooper

      I love your videos and for years, it has fueled my passion in physics, however... I think you guys need to realise that the assumptions the standard model makes are not all *justified*. I feel like this is overlooked and there should be more time invested by your team in looking at the many recent papers which suggest that the universe is indeed not accelerating in its expansion. There are also other theories which do not make the same careless assumptions that LambdaCDM does. I feel like you guys, with the reach you have need to explore and make sure your audience understands that Dark energy is STILL a theory, and there are many theories that contradict it, but the standard model has gotten much of the funding as it was “first” hence why people become brainwashed. Just food for thought.

    86. TuBFMagier


    87. Jay


    88. Jay

      Can you guys make some fart videos and upload them please

    89. Wavetrap Productions

      If its all about - Distance - From small to Large - Expansion History - Then our units of measurement have also expanded at the very fundamental level over time , Haven't they?

      1. Gareth Dean

        No, otherwise we'd not be able to tell. If everything suddenly got twice as large right now, our rulers would be twice as large and thus nothing we do would be able to prove anything had changed. For us to notice a difference some things have to change while others remain the same. In this case the distance between galaxy clusters is growing, but anything within them has generally been stable. An atom now is as big as it was when Earth formed.

    90. taekun choi

      The fact that the standard model of cosmology is wrong is a fact that the general public knows except for cosmologists. The theoretical and measurement values of cosmological constants are the difference of 120 degrees of 10, and the dark energy associated with the expansion of the universe is related to warm dark matter. -----Of Theory of evrything

    91. Oside3000

      If the universe began with a bang and has been expanding and accelerating ever since then how is it that galaxies still collide?

      1. Oside3000

        Gareth Dean sounds reasonable for sure. It’s still difficult to wrap my head around 2 galaxies racing towards each other. It does seem to make more sense when I consider it a larger scale example of something like planetary formation.

      2. Gareth Dean

        Randomness and gravity. This happens on all scales, our solar system is spinning but asteroids still smash into things.Most galaxies are in clusters, bound by gravity and fated to collapse into one single mega-galaxy, much like we and andromeda are doing currently. But galaxy CLUSTERS almost never collide as they're nearly all moving apart from each other. If expansion can overcome gravity things separate, if it can't they must collide eventually.

    92. Sergio

      two questions from a listener, but who doesn't know much about physics: 1. is 'more red light' from supernovae the only/strongest evidence for dark energy? 2. if so, could it be that light works in such a way that it just gets more red on very large astronomical distances, and so there's no need for dark energy?

      1. Gareth Dean

        1.) No, we have a few other avenues now, this quasar data is one, as is the CMB result and general redshift. 2.) The actual result isn't as simple as 'Older supernovae are more red'. A good bit of the data looks like there's too much red with great distances, but at the largest scales the effect reverses slightly, a slowing apparent expansion. The basic result is here, with the red dot being the quasar results: You can see there's still a lot of 'wriggle room' when it comes to trying to fit the data, we really do need more observations before we can be sure what's going on.

    93. Glen Hoban

      Hate this dudes voice.

    94. Ian Mastin

      I love this channel and the content you produce, I do however have one small critique. The transition from the darker background to the bright white background used in the sponsor bit at the end is really harsh on the eyes, Especially when viewed in the dark.

    95. B Bates

      Love your programs... could really do without the background music

    96. catoleg

      Hey Matt, I don't know why, but in this episode you literally irradiate some kind of positive vibe, and it makes that show even more pleasant to watch. Thank you for your and your colleagues work.

    97. Doug Reed

      Branson's really missing out. Man's the most dangerous--and therefore most exciting--game there is to hunt.

    98. Reckless Roges

      Bill Gate's private island is called: Earth. If the big rip is so far away, (and there isn't anything that we could do about it anyway) then why bother studying it? Shouldn't we apply the big physics brains to increasing quality of life and reducing human suffering world wide?

      1. Gareth Dean

        We should study everything, not least because we don't know what knowledge we'll get from unexpected areas. As it is it's not like doctors are going unpaid and being forced out onto the streets as we spend billions on dark energy studies, such studies are generally piggybacking on other physics and don't even dent the million dollar mark. Meanwhile we waste a third of our global food supply and can drop bombs that cost as much as building a house to produce. There are FAR more fruitful areas for improvement than suggesting we stop learning about something.

    99. nagualdesign

      ..still laughing at that last part. 😆