PBS Space Time
03/08/2025
PBS Space Time
03/08/2025
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Every astronomy textbook tells us that soon after the Big Bang, there was a period of exponentially accelerating expansion called cosmic inflation. In a tiny fraction of a second, inflationary expansion multiplied the size of the universe by a larger factor than in the following 13 and a half billion years of regular expansion. This story seems like a bit of a … stretch. Is there really any mechanism that could cause something like this to happen? What what we’re covering today – the real physics of cosmic inflation.
Hosted by Matt O’Dowd
Written by Matt O’Dowd
Graphics by Leonardo Scholzer
Directed by Andrew Kornhaber
Produced By: Kornhaber Brown
Dark Energy Playlist:
The Quantum Vacuum and Hawking Radiation Playlist
Most cosmologists buy some variation of the inflation hypothesis. It seems to very neatly solve some of the biggest questions in cosmology. Those being: why is matter and energy so smoothly spread out across the entire observable universe? And why is the geometry of the universe so flat? Neither should be expected unless the universe expanded much more rapidly early on. We explored these problems in an earlier video – worth a look if you really want to get inflation. Another problem fixed by inflation is the absence of magnetic monopoles – strange particles predicted to have been produced in the early universe. We’ll come back to those another time.
Big Bang Supporters:
Anton Lifshits
David Nicklas
Fabrice Eap
Juan Benet
Justin Lloyd
Morgan Hough
Quasar Supporters:
Mark Heising
Mark Rosenthal
Tambe Barsbay
Vinnie Falco
Hypernova Supporters:
Chuck Zegar
Danton Spivey
Donal Botkin
Edmund Fokschaner
Hank S
John Hofmann
John R. Slavik
Jordan Young
Joseph Salomone
kkm
Mark Heising
Matthew
Matthew O’Connor
Syed Ansar
Gamma Ray Burst Supporters:
Adrien Hatch
Alexey Eromenko
Andreas Nautsch
Bradley Jenkins
Brandon Labonte
Carlo Mogavero
Daniel Lyons
David Behtala
DFaulk
Dustan Jones
Geoffrey Short
James Flowers
James Quintero
John Funai
John Pollock
Jonah
Jonathan Nesfeder
Joseph Dillman
Joseph Emison
Josh Thomas
Kevin Warne
Kyle Hofer
Malte Ubl
Mark Vasile
Nathan Hitchings
Nick Virtue
Paul Rose
Ryan Jones
Scott Gossett
Sigurd Ruud Frivik
Tim Jones
Tim Stephani
Tommy Mogensen
Yurii Konovaliuk
سلطان الخليفي
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27 Comments
@lioneart19
03/08/2025 - 9:30 PMStupid question, certainly, but why do we believe the universe is expanding instead of simply believing that things (galaxies etc) are moving inside the universe? Why them getting further apart can't simply mean they are moving at different speeds? Like they were thrown away and in space never stop moving. Why must space itself be expanding?
@Spootiful
03/08/2025 - 9:30 PMConsidering the weakness of gravitation, is it any wonder that the universe expanded? Perhaps gravitation is what held the universe in a compact form (maybe not even a singularity) and with just a little cooling it lost the balance, and the energy of spacetime became too great (even in those conditions).
@MargeErin
03/08/2025 - 9:30 PMI'm a layman. Every explanation I've ever heard for the Inflaton field sounds like a mathematical version of "God just made it happen". It's like String Theory; answers questions by positing something that can't be observed in the real world or modern universe. I would love to hear it explained in a way that doesn't sound like "a miracle happened". Einstein said it well: "If you can't explain something simply, then you don't really understand it." It's not just the host; he does a fine job. It's EVERY explanation of Inflation for laymen I've ever heard.
@user-gs4oi1fm4l
03/08/2025 - 9:30 PMSo the way I'm understanding this is that the primordial "universe" measuring less than 1 planck volume (so a mere handful of possible quantum fluctuations at any time) mustered enough potential energy on its own to finally trip over into a "singularity" of near infinite mass and energy that we identify with the Big Bang, where the conditions finally are made possible for a inflaton field to come into existence. So virtual particles in the smallest scale possible generated enough energy on their own absent any external field or any observer present to establish the collapse of their wave function from probable values to definitive values to create all space/time/matter/energy inherent to our universe in the form of plasma, and that the spatial expansion attributed to this energy field continued past its collapse gave the particles also created by the collapse room to cool and coalesce over time into what we see today.
@georgerevell5643
03/08/2025 - 9:30 PMI always wondered how the collapsethe inflaton field that created matter from the big bang, of was translated throughout ourt universe, wow!
@Demobius
03/08/2025 - 9:30 PMI would guess it was the mutual annihilation of a matter singularity and an antimatter singularity.
@snehashispanda4808
03/08/2025 - 9:30 PMI am an Atheist. I do not believe in the existence of God. There is no evidence to support the belief in any gods or supernatural entities. I rely on science, reason, logic, and empirical evidence to form my worldview and have not found compelling evidence or arguments to support the existence of God. The universe is governed by natural laws and forces, rather than moral, spiritual, or supernatural ones. As an atheist, I reject religious dogma, supernaturalism, and superstition as the basis of morality and decision-making. I emphasize the social and empirical nature of inquiry and prioritize scientific solutions to intellectual problems. There is an intrinsic intellectual conflict between faith and science, and that it inevitably leads to hostility. I am engaged in a continually evolving search for truth, primarily through science and philosophy.
"God of the Gaps" fallacy is a logical fallacy that assumes a lack of scientific knowledge is evidence of supernatural
@MrCampfires
03/08/2025 - 9:30 PMCan someone answer this: If space stretched during inflation, did time also stretch?
@johnbould7544
03/08/2025 - 9:30 PMWhat I'm reading in the past 5 years, is that cosmic inflation PRECEDED the "hot big bang"….it seems that science communicators have something of a hot mess on their hands in explaining the big bang and inflation.
@tristanjones5347
03/08/2025 - 9:30 PMGod did!
@GoodMan-b3j
03/08/2025 - 9:30 PMSorry I have to say this. Your accent is hard to understand, your hand gestures are random at best, the topic is complicated, so please tell us why you have to add the annoying music on the top? I really what to know!
Keep up the good work.
@GoodMan-b3j
03/08/2025 - 9:30 PMSorry I have to say this. Your accent is hard to understand, your hand gestures are random at best, the topic is complicated, so please tell us why you have to add the annoying music on the top? I really what to know!
Keep up the good work.
@doublepinger
03/08/2025 - 9:30 PMHaving an "uncertainty" implies that an inflation change didn't happen everywhere at once. I wonder if that's accounted for in the maths, and if it'd be possible to distinguish a more global / "it's all spacetime" effect from a "this part of the galaxy inflated first".
@HerveMendell
03/08/2025 - 9:30 PMI figured it out. God farted and caused the Big Bang. Problem solved, now I want my Nobel prize.
@Danger_Dee
03/08/2025 - 9:30 PMThe Big Bang is the start of a black hole where time and space swap places. The Big Bang became a moment in time instead of a point in space.
@elusiveDEVIANT
03/08/2025 - 9:30 PMI nutted
@bonelessbooks9263
03/08/2025 - 9:30 PMIn this theory would all of the universe have existed in this false vacuum, or were there different bubbles each in their own false vacuum?
@bonelessbooks9263
03/08/2025 - 9:30 PMCould inflatons have decayed to dark matter particles or do we assume they’re became the standard model particles that we currently know of?
@bonelessbooks9263
03/08/2025 - 9:30 PMCould we produce inflatons in places like particle accelerators or are the requisite energies too high?
@bonelessbooks9263
03/08/2025 - 9:30 PMIf the “bubble” expands out from the nucleation point at c, then would that not imply that there are parts of the universe past our horizon that are still experiencing exponential inflation? What kind of impact would something like this have on the fate of the universe? Does this bubble behave like a wave where the amplitude can decrease as it travels through spacetime? Could the bubble lose enough energy to the point where the distinction between the universe experiencing normal Hubble flow and exponential acceleration is such that the differential causes a big-rip or pinching off sort of fate?
Edit: got my questions answered lol
@basbas1228
03/08/2025 - 9:30 PMIs the buzzing sound on 5:27 the sound of a Wisp in Warcraft3 or am I tripping
@Sonderin
03/08/2025 - 9:30 PMI'm sure the universe will suffer the same entropy as everything else, including empires if we don't open communication and remove the class system.
@andylacza5434
03/08/2025 - 9:30 PMCan you please explain to me if there was an inflationary period with the part of 10 on the -33 second, how does Einstein statement of particles cannot travel FTL, contradicts this speed of extension. Apparently there are more articles of time 10 on the -33 second fit in one singular second then as many second passed since the Big Bang.
@bobritter9115
03/08/2025 - 9:30 PMWhile Matt O'Dowd is a great presenter, I got lost for several reasons. First, I am not a physicist and quantum theory is beyond my capacity to understand, admittedly. So inflatons and bubbes don't shed light on my understanding of the Big Bang. That aside, I didn't get a good picture of timing of the Big Bang itself, followed by cosmic inflation and then Hubble expansion. I transcribed the video and will go back over it and later watch other O'Dowd videos which will perhaps tie things together. Last, to me, the video was about post Big Bang and I was looking forward to learning what actually caused the Big Bang which wasn't discussed. So after I viewed this video, I see another by O'Dowd called "What Happened Before the Big Bang?" Perhaps that was really what I was looking for and PBS could have called this video "Post Big Bang".
@tcos918
03/08/2025 - 9:30 PMMy question is what are we inflating or expanding into in the first place?
@fraser_mr2009
03/08/2025 - 9:30 PMIf the universe never produced consciousness, did the big bang happen?
What I mean is, could the big bang have happened without producing consciousness?
@trevormcnabb868
03/08/2025 - 9:30 PMBullshit. How about the big collapse. A former universe collapsed onto itself and after it crashed we got the big bang. U cant get something from nothing