IRA FLATOW: This is Science Friday. I’m Ira Flatow. A little bit later in the hour, a look at a new biometric technology for unlocking your phone using different parts of your body. You’re going to want to listen to that. But first, if you were listening last week, we told you about how the 1919 solar eclipse served as a check on Einstein’s ideas about gravity and helped make him a household name. Remember that? Well, this week, Einstein’s theory of general relativity gets another boost with info on how stars orbit the center of our galaxy.

Here to tell us more about that study and other selected short stories in science is Ryan Mandelbaum. He’s a science writer with Gizmodo, and he’s here in our puny studios. Welcome, first time.

RYAN MANDELBAUM: Yeah.

IRA FLATOW: First time, longtime, as they say.

RYAN MANDELBAUM: First time. I’m excited.

IRA FLATOW: So let’s talk about– what part of Einstein’s theories was this new research testing?

RYAN MANDELBAUM: Right. So essentially what’s happened is the laws of physics that you learn about in high school and Newton’s laws work pretty much up until the scale of maybe a planet or a star, in which case, corrections need to come in to account for the weirdness of gravity. Now, in the case of– one of the original proofs of general relativity was, Mercury’s orbit actually processed sort of like a spirogram around our own sun.

Now, you can think of this almost like a way bigger test of that, because they wanted to know, OK, so if Einstein’s theory of relativity fits up at this point, how big and how massive a scale does it continue to work? So what they did was they actually watched stars orbiting Sagittarius A star, which is a huge, massive thing in the center of our own galaxy, to see if their orbits actually went along with the rules of general relativity.

IRA FLATOW: And they had to mine a lot of data for this? And look through a lot of stuff?

RYAN MANDELBAUM: Oh, sure. It took about two decades’ worth of data about these three stars, including a lot of new data from the very large telescope in Chile.

IRA FLATOW: Mm. And so, I guess it all worked out right for Einstein?

RYAN MANDELBAUM: So, for now, it all works out. But the error on it was– basically, there was a pretty big level of uncertainty on the results. So as of right now, they know that it’s consistent with the theory of relativity, but more data might show up that there might need to be some new corrections.

IRA FLATOW: It’s amazing that, what, 100 years? 100 years of testing out this stuff.

RYAN MANDELBAUM: Yeah.

IRA FLATOW: They’re still doing it.

RYAN MANDELBAUM: It still works is what I think is most exciting.

IRA FLATOW: That’s the good news. Speaking of news, there’s news this week about a big salmon going on sale. Tell us about that.

RYAN MANDELBAUM: Yeah. So I wouldn’t say it’s big as much as I would say it’s fast. It’s– the first genetically engineered salmon hit the market in Canada from a company called Aqua Bounty Technologies. Now, it’s taken them 25 years to get this to the market. And really, what’s happening is that they’ve found a way to make salmon grow to be the same size as non-genetically modified salmon in about half the time. It costs about 5.3 US dollars per pound. And they didn’t say who bought it. But it is apparently on sale now in Canada.

IRA FLATOW: So is it getting any pushback because it’s a GMO? Salmon.

RYAN MANDELBAUM: I think that the place where it’s gotten the most pushback has been here in the United States. I mean, you might wonder why we didn’t get the first genetically engineered salmon. I love salmon. But what’s happened is that the FDA actually approved the salmon back in 2015. But an Alaskan senator basically said that there should be some program to tell customers that they’re buying these genetically engineered salmon. And people have really been pushing back here in the United States.

IRA FLATOW: So it’s a– has it been approved yet by any– who needs to approve it?

RYAN MANDELBAUM: The FDA did approve it. But there’s just been a lot of regulatory hurdles that have sort of prevented it from coming to market here.

IRA FLATOW: Let’s move on to some news this week that you have about colon cancer rates in the US.

RYAN MANDELBAUM: Basically, there’s just something going on with colon cancer rates right now. And we just don’t know why. What happened was that there was a study earlier this year that found that in folks younger than 50, there was an increase in the rates of colon cancer. But this new study in the Journal of the American Medical Association found that mortality from colon cancer was also increasing in this group.

And the reason that’s important is because, the original study, just increasing rates could have meant that maybe more people were getting screened, and that’s a good thing. But if more people are dying, then it actually paints sort of a bleaker picture and shows that maybe there’s some cause that we don’t quite know about.

IRA FLATOW: How young are we talking about?

RYAN MANDELBAUM: This is– the rates increased 1% between– for folks between 20 and 54 years old.

IRA FLATOW: Wow. You would not think– you’d think it would go the other direction. Older people.

RYAN MANDELBAUM: Right. And it’s not increasing in older people.

IRA FLATOW: And no one knows why?

RYAN MANDELBAUM: Got to figure it out.

IRA FLATOW: Figure it out. Finally, a huge, huge dinosaur finally gets named. This dinosaur– this dinosaur I’ve seen at the American Museum of Natural History. They have a cast of it. It’s so big, it’s head has to stick out of the door of the exhibit area. Have you been to that one?

RYAN MANDELBAUM: It’s amazing. You want to take a selfie with it, because it’s just right there.

IRA FLATOW: They called it– they dubbed it Titanosaur originally, but that’s not a scientific name. They have now given it a scientific name.

RYAN MANDELBAUM: Right. That’s correct. What happened was, way back in 2012, they found all of these bones in Argentina and obviously, the American Museum of Natural History needed to get on and get a cast of this huge Titanosaur, but now they’re actually releasing the paper on these dinosaurs to really get that analysis of what they’ve found. And they’ve named it Patagotitan mayorum. Patago is for Patagonia, where they found it. Titan is obviously for the Titans, the Greek divinities. And then, mayorum is actually named for the family, the Mayo family, who hosted the archeologist during the excavation.

IRA FLATOW: You mean the fund– the people who funded them. They host them? I mean, they actually– with their house, or somebody who paid for it?

RYAN MANDELBAUM: That’s just what it said. And I don’t remember.

IRA FLATOW: But is it the biggest dinosaur? It’s certainly one of the biggest, right? How much did it weigh?

RYAN MANDELBAUM: Right. It weighed 69 tons and it was 122 feet long. But while it is the biggest in size, it is not the heaviest animal, because we know that the blue whale has it beat at around three times heavier, 200 tons.

How Wow.

RYAN MANDELBAUM: Yeah. It’s big.

IRA FLATOW: Well, this one won’t be hanging from the ceiling like the big blue whale is.

RYAN MANDELBAUM: That’s right.

IRA FLATOW: Anytime soon. Thank you for taking the time to be with us today. Thank you, Ryan.

RYAN MANDELBAUM: Yeah, thanks so much, Ira.

IRA FLATOW: Ryan Mandelbaum. He’s a science writer with Gizmodo, and talking about the news of science this week.

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