
20220817: What If Dark Energy is a New Quantum Field?
 06:25: ... over the past several billion years, we get one number for that expansion rate. But if we calculate the current expansion rate based on observations of ...
 13:27: ... James Webb Space Telescope will help by pushing our measurements of the expansion rate back billions of years from the current supernova measurements. There ...


20210818: How Vacuum Decay Would Destroy The Universe
 00:21: ... is how it is. Its just the right size, has just the right expansion rate, and has just the right particle properties to allow stars ...


20210323: Zeno's Paradox & The Quantum Zeno Effect
 13:22: ... gave you an update on the crisis in cosmology  the tension between the expansion rate of the universe measured at the beginning of the universe with the ...
 14:04: We then use our cosmological models to predict what the expansion rate should be today.


20210316: The NEW Crisis in Cosmology
 01:16: ... the redshifts and distances of many, many galaxies and you have the expansion rate of the universe, typically expressed as Hubble’s constant ...
 03:55: ... VERY important to perfect our measurements of the expansion rate  both to confirm dark energy’s existence and to learn of its ...
 04:42: ... map of the CMB using the Planck satellite can give us the expansion rate. The Planck team calculated a Hubble constant of 67.6 km/s/Mpc  ...
 10:40: ... measurement of cosmic distances, and with that a measurement of the expansion rate that’s independent of the cosmic distance ladder. So ...


20200511: How Luminiferous Aether Led to Relativity
 14:23: ... let's pretend that the expansion rate is constant. And for an infinite universe the "size" is just the average ...


20200504: How We Know The Universe is Ancient
 06:06: ... there’s the fact that the expansion rate has changed over time. You can’t just assume that the galaxies were ...
 09:39: ... continued to revise those estimates. He eventually concluded that the expansion rate of the universe – the Hubble constant – was about 75 kilometers per ...
 12:21: from assuming the expansion rate hasn't changed at all.
 12:25: ... is to get the matter content, and the dark energy content, and the expansion rate, and more all from the one source  the cosmic microwave background ...


20191202: Is The Universe Finite?
 02:06: ... about this socalled crisis in cosmology  the Planck team calculate an expansion rate for the universe that does not match the expansion rate observed today  ...
 07:14: ... created a model that included all of the relevant parameters  the expansion rate, details of inflation, the amount and behavior of all different types of ...
 10:46: In the case of the discrepancy in the expansion rate, hidden physics is the great hope of many physicists.
 10:59: ... example, if the expansion rate of the universe really has evolved it may mean that the behavior of dark ...
 11:09: In fact, if the universe really is curved and closed, the discrepancy between the early universe and modern expansion rates becomes even stronger.


20191111: Does Life Need a Multiverse to Exist?
 08:45: ... energy was discovered in the 90s as astronomers tried to measure the expansion rate of the universe, only to find that expansion was ...


20190819: What Happened Before the Big Bang?
 12:15: ... Bang Theory doesn't explain the initial expansion at all, it includes an expansion rate in its initial conditions and then tries to explain everything that ...
 12:29: ... a physical reason for the universe to have started with a rapid outward expansion rate in terms of pretty well understood ...


20190328: Could the Universe End by Tearing Apart Every Atom?
 03:05: ... the whole universe describing the acceleration or deceleration of the expansion rate which depends on how much stuff there is in the universe because this is ...
 05:32: ... positive which means dark energy is pushing outwards to increase the expansion rate. In fact, any equation of state parameter less than 1/3 would cause that ...


20190220: Secrets of the Cosmic Microwave Background
 12:34: ... and clusters and the dark energy based on measuring the accelerating expansion rate of the Universe So that's how you lay bare the secrets of the cosmic ...
 14:23: ... would have in the modern Universe But to do that you have to assume an expansion rate for the Universe the Hubble constant The power spectrum I showed is from ...


20190207: Sound Waves from the Beginning of Time
 11:08: Those observations revealed that the expansion rate is accelerating due to an unknown influence what we call dark energy.
 12:02: They allow us to track the expansion rate of the universe.


20190124: The Crisis in Cosmology
 06:12: So it's a more or less direct measurement of the CURRENT expansion rate.
 06:19: What if we could measure the expansion rate of the universe at the very beginning?
 06:23: Then, we could figure out what its current expansion rate should be, given our best understanding...
 09:05: ...as well as the expansion rate of the universe in that early epoch.
 09:09: So, how do you get the Hubble constant, i.e., the current expansion rate, from all of this?
 09:26: ...as well as the initial expansion rate.
 12:50: The near centennial quest to measure the expansion rate of the universe will be concluded.


20190109: Are Dark Matter And Dark Energy The Same?
 11:00: ... straight part in the rise in the sine curve, which is almost a constant expansion rate. ...
 11:19: We already know that a constant expansion rate happens to give a similar age to the standard dark energy age.
 11:25: But a constant or nearconstant expansion rate definitely does not fit the supernova data.


20161109: Did Dark Energy Just Disappear?
 00:52: They expected to see that this expansion rate was slowing down due to the gravitational effect of all of the matter in the universe.
 01:00: Instead, they found the expansion rate has been accelerating for half of the age of the universe.


20160511: The Cosmic Conspiracy of Dark Energy Challenge Question
 03:55: Assuming a constant expansion rate, a constant increase in the scale factor, that means it was only two to three billion years ago.


20160504: Will Starshot's Insterstellar Journey Succeed?
 09:01: Dark energy does drive the expansion rate, causing a sort of antigravity effect.


20160427: What Does Dark Energy Really Do?
 01:01: See, measuring the density of the universe is one way to determine its fate because the future expansion rate does depend on density.
 06:41: That means the expansion rate of the universe has actually sped up, accelerated, while that supernova light was traveling to us.
 08:25: See, it's not the expansion rate the Adot that's constant in this equation.
 09:04: Currently, there's still enough matter in the universe to influence the expansion rate, but we're already at the point where dark energy dominates.


20160413: Will the Universe Expand Forever?
 03:53: ... there's some current expansion speed that would allow the future expansion rate of the universe to slowly grind to a halt over infinite ...
 06:48: And if the lefthand side is negative, in that case there was never a highenough expansion rate to reach that extreme size.
 07:18: The expansion rate now is what we call the "Hubble constant." It's around 70 kilometers per second per megaparsec.


20160302: What’s Wrong With the Big Bang Theory?
 08:09: So 100 trillion trillion to something like our grain of sand size at which point it slowed down to its regular expansion rate.
