The Crisis in Cosmology

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The Crisis in Cosmology 5

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The search for a single number: the hubble constant, which is the rate of expansion of our universe, has consumed astronomers for generations. Finally, two powerful and independent methods have refined its measurement to unprecedented precision. The only problem is that they don’t agree. This calls into question some of our most basic assumptions about the universe.

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Previous Episode: Why String Theory Is Wrong

Hosted by Matt O'Dowd
Written by Matt O'Dowd
Graphics by Luke Maroldi
Directing by Andrew Kornhaber

In 1929, Edwin Hubble discovered the universe. He gave us our first incontrovertible proof that there are galaxies outside the Milky Way by measuring the distances to the spiral nebulae. They were many millions of light years from us –far outside the Milky Way and so must be galaxies in their own right. Combined with the Doppler-shift velocity measurements of Vesto Slipher, Hubble revealed that the galaxies are not only receding from us, but they are receding at a rate proportional to their distance.

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سلطان الخليفي

💬 Comments on the video

we could just cut the photons in half and count the rings

Author — Antoine Roquentin


Man I'm smart.

*watches PBS video*

Man I'm stupid.

Author — Hugo Joubert


I thought that parsecs was just an average sexual encounter
between two golfers.

Author — revolutionpm


"Dark Energy = Dark matter * (Speed of Dark)^2" got me laughing for much longer than I should have

Author — Vellyxenya


*An engineer walks in*
Just take the average of the results and call it a day...

Author — Ahmed Appas


Well the answer is obvious isn't it?
Hubble Constant = 42

Author — Draeas


I get excited when there’s an argument between prediction and observation at this level — because it means we are missing something. And that means more science!


Author — Jes Ewers


It would seem that the "constant" would prefer to be a variable.

Author — Lloyd Hargrove


I think it's fair to say the calculation based off the CMBR relies on more assumptions than that of Type 1a Supernovae.

Author — Lee


Question: Does the Local equation assume it starts from a singularity?

What if it didn't? How big would the initial universe need to be to make the two equations align?

Author — Dorian Lust


"We know everything, as long as we can prove this number is constant"
"... damnit."

Author — TheBendejo


It's possible that the universe is a woman and is just lying about her age

Author — Mike O


It makes me sad that there's a universe where I'm a crackhead and my parents are crying, wondering where they went wrong

Author — Perfect Whine


Perplexed: if light from distant galaxies travels to us longer, that means they are older than the near ones. So if far away ones recede faster than near ones, doesn’t than follow that in the past they receded faster...?!

Author — bljah123


I have to wonder why we assuming that the expansion is a constant value

Author — Todd Nelson


I LOVE hearing: "This calls into question our most basic assumptions about...The

Author — Brian Crane


A decent treatment of this outstanding problem in current cosmology... not too overly detailed, clear, and thorough ! Great job !

Author — John Kelsey


Socrates: Shall we set down astronomy among the objects of study?

Glaucon: I think so, to know something about the seasons, the months and the years is of use for military purposes, as well as for agriculture and for navigation.

Socrates: It amuses me to see how afraid you are, lest the common herd of people should accuse you of recommending useless studies.
— Socrates

Author — Joseph Campbell


1:35 my wife sees the video and says, "why do they need a telescope to find a HO? They are pretty easy to find, even without glasses."

Author — Stephen Betz


negative mass fluid sounds a bit like the Dirac-Milne cosmology where antimatter has negative gravity

Author — Yancey Piens