I'm John Batson. This is Hotel Mars Episode N. I'm joined by my colleague and co-pilot David Livingston, Dr. Space of the Space Show.

And we're looking for guidance on cosmology, and we welcome Assistant Professor Kishelay Day.

He is in the Department of Astronomy at Columbia University.

He's also a research scientist at the Flatiron

Institute. Most recently, he is the lead researcher on a revelation about supernovas and what

becomes of them, why they're important, and how does this relate to the black holes that may be

the mystery of the universe and may have an explanation for where we came from?

Professor, a very good evening to you. Thank you for this.

What is important to understand is a failed star turns into a failed supernova.

I had learned in the 20th century in my cursory education about

cosmology that when stars collapse, they turn into something like a density that you cannot

escape from. And that that turns into a singularity. This is science fiction talk, and that turns into a black hole.

You've discovered another fate for some stars that are as much as eight times the size of our sun.

What is it you've discovered and what does it mean in terms of the cosmologists' assumptions about our universe?

Good evening to you. Good evening. Thank you for having me. Like you said,

we've known that black holes exist. They were first theorized from Einstein's theory of relativity,

and we've since discovered many, many black holes in our own galaxy. And today we detect black holes

through observations in light. We detect them through gravitational waves. But what has been missing so far is a clear understanding of how stars turn into black holes. Black holes are fairly massive objects. So we've always suspected that really massive stars, stars that are more than 10 times the mass of the sun might produce black holes.

And the expectation is that massive stars at the end of their lives, when they essentially run out of the fuel that they have, they might collapse into very, very dense objects.

In many cases, this collapse actually produces a supernova explosion shortly after it, so that briefly an individual star can become as bright as a full galaxy.

And today we find hundreds of them every year.

But what we've been missing for the longest time is an

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