Every scientist dreams of making a discovery that fundamentally changes our understanding of the universe.

My guest today, Nobel Prize winning astrophysicist Adam Reese, did exactly that.

What's even more remarkable, he may just be in the process of completely upending cosmology

for a second time. In the laws of physics, things really should match. It's not okay for things

to be off by five times the margin of error of your experiment. In fact, it's not just not okay,

we get very excited.

Welcome to people I mostly admire with Steve Levitt.

To understand Adam reached his contributions to cosmology, one needs to know what scientists believed prior to his findings.

So I began our conversation today by asking Adam to describe the accepted scientific consensus on the expansion and contraction of the universe

back in 1992, the year he started his PhD.

Well, I would say for the better part of 100 years, this goes back to Edwin Hubble and others of his time, cosmologists, astronomers had measured that the universe was expanding just by measuring objects around us, the distance to galaxies and the apparent speed at which they were moving away from us, something called the red shift.

In the 1960s, cosmologists had discovered the radiation left over from the Big Bang, so it became

even more clear that the universe was expanding after

what we call the Hot Big Bang. Of course, the big question then was, what is going to happen next?

What is the fate of this expanding universe? And so it really comes down to the question of how

much matter and gravity from that matter is there that can be slowing the expansion.

Like if you launched a rocket off the surface of the earth, you would wonder, is that rocket

going to escape the Earth's gravitational pull or will it fall back?

And it's really a question at that point of velocity and mass.

By the 1990s, the big question was,

is there enough matter in the universe to stop the expansion in the future? And they were finding

not enough matter to stop the expansion. So essentially, the way cosmologists were thinking

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