IRA FLATOW: This is Science Friday. I’m Ira Flatow. Yeah, I know there’s a lot going on this week, so we can forgive you if you haven’t been paying close attention to the Nobel Prizes. This week the Nobel Prize in Physiology or Medicine went jointly to Harvey J Alter, Michael Houghton, and Charles M Rice for the discovery of the hepatitis C virus. In chemistry, Emmanuel Charpentier of the Max Planck Institute, and Jennifer Doudna of the University of California at Berkeley won the prize for their work on the technique known as CRISPR. Back in 2017, Dr. Doudna summarized the technique for us on Science Friday.

JENNIFER DOUDNA: You can think about it almost like a pair of scissors for DNA in the cell. And the great thing about this tool is that it’s programmable, so scientists can directly tell the scissors where to go in the cell, which piece of DNA to cut, and can do that relatively inexpensively and quickly. So, it’s become a very widespread technology for altering the DNA, and virtually all types of cells.

IRA FLATOW: But it’s not initially what the Nobel winners were going for.

JENNIFER DOUDNA: Yeah, it’s a great story of how curiosity driven research, aimed in one direction, ended up uncovering something that could be employed in a completely different way. I think that the way that bacteria can program proteins to cut viral DNA, and protect themselves from viral infection was the original work that we were doing. And this was a project of international collaboration with Emmanuel Charpentier in her laboratory. But that uncovered the mechanism that we realized could be employed in a very different way namely for gene editing.

IRA FLATOW: It’s a technique that quickly took the molecular and cellular biology research world by storm.

JENNIFER DOUDNA: There’s a very important timing aspect to technologies. I would say that’s true for gene editing. It was a tool that was, very much, that the scientific community was ready for we needed a way to manipulate DNA in cells given all of the DNA sequencing that’s going on now. And whole genomes being sequenced, and more and more information about the content of genomes. And what was missing was a way to rewrite, a way to manipulate that information. And when that tool became available as you pointed out, it was very quickly adopted globally.

IRA FLATOW: Congratulations to Emmanuel Charpentier and Jennifer Doudna. In physics, the award was split. One half went to mathematician, Roger Penrose, for the discovery that black hole formation is a robust prediction of the general theory of relativity. We talked about it on Science Friday back in 2015, about the work he and the late Steven Hawking did on black holes, matter pulled so tightly into itself by gravity that it forms what physicists call a singularity.

ROGER PENROSE: The thing we were trying to do was to show that the singularity is, first of all in the black hole, and secondly in the big bang, which people knew about already, but only in very, very special circumstances. When the situation was exactly symmetrical, and the material involved didn’t have any pressure, and so on, it is very, very special. And people didn’t necessarily believe that those singularities would be general things, which could occur under completely general circumstances. So, I started to think about these things in terms of what you will a topological argument. That means you don’t solve equations you use quite general arguments to show that in this case, the singularity had to exist somewhere. The situation that we now call a black hole, in those days, they didn’t even have a word for it. But where the matter collapses down past a point of no return was point of no return was the thing I call a trapped surface. That it doesn’t depend on any symmetry or anything like that. It’s just a point of no return that you can characterize. And when it gets to that level, you can use these topological arguments to show that somewhere in the future of that collapse, there must be a singularity.

IRA FLATOW: What does it matter to me, as an average citizen, if there are singularities out there?

ROGER PENROSE: Well, it’s not so much the singularities, because you can’t get at them, you see. At least the ones in the black holes. It’s more that the black hole is a stable thing. It doesn’t collapse down and the swish out again. You could imagine that if the matter collapsed in an irregular way, it might swirl around in some complicated way and then come swishing out again. But what these arguments show is that doesn’t happen. It collapses, and keeps on collapsing in the same way that the symmetrical situation did, and it becomes singular. Now, the singularity is not accessible to us in the black hole. The big bang is another question because, of course, that singularity is, in a sense, the origin of all the things we know about.

IRA FLATOW: And then, all of a sudden, after your papers are published, a few books were written, black holes really caught people’s imaginations. Were you surprised by the amount of public interest in your work?

ROGER PENROSE: It took quite a long time. I was surprised– well there was actually wasn’t a great deal of interest to begin with. It took– I used to go to these meetings called the Texas Meetings on Relativistic Astrophysics. I was there at the first one. That was when people were just beginning to realize that you had situations which might be something like a black hole. And it took a long time, I remember going to several of these meetings, every two years or so, and each time there was a bit more interest and a bit more interest. And it took quite a while before people really swung around and the general community believed that these objects were really likely to be there.

IRA FLATOW: Why do you think there is so– why are people so fascinated by this?

ROGER PENROSE: Well, they are pretty wild things aren’t they? And they’re also– now we know there are absolutely huge ones. There are 10,000 million times the mass of the sun. There’s some absolutely whopping ones. Our galaxy has one which is about four million times as massive as the sun, but there are now known ones that which are far, far bigger than that.

IRA FLATOW: New Nobelist, Roger Penrose. The other half of the physics prize was split between Reinhard Genzel, and Andrea Ghez for the discovery of one of those much bigger black holes, a supermassive compact object at the Center of our galaxy. We’ll be talking more about that in the weeks ahead. But, for now, congratulations everybody.

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