IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, we’re going to look at 50 years of the Endangered Species Act, how it’s helped preserve plant and animal species that were on the brink of extinction, and the status of the act now.

But first, put on your sunglasses because 2024 is the sun’s time to shine. Vox staff writer Umair Irfan is here to talk sun science and other big stories of the week. Welcome back, Umair.

UMAIR IRFAN: Hi, Ira. Thanks for having me.

IRA FLATOW: Nice to have you. So 2024 is going to be a big year for the sun. And we’re going to have a solar eclipse. Let’s get into that. But first, let’s talk about perihelion day, January 2, because it’s sort of a teaching moment for me. It illustrates a point about why it’s hotter in the summer than in the winter.

UMAIR IRFAN: That’s right. The perihelion day is the point in which Earth’s orbit is closest to the sun. And even though it’s winter here in the northern hemisphere, that’s actually– on January 2 was the point where we were actually the closest to the sun. So that indicates that our seasons don’t actually have to do with how close we are to the sun but rather how the hemispheres are oriented or tilted in the orbit.

IRA FLATOW: Yeah, tilt of the Earth. All right, let’s get into the big solar news that’s coming up later– a total solar eclipse on April 8?

UMAIR IRFAN: Yeah, that’s right. I mean, I think a lot of people are really excited about this. And scientists are excited about it too because it’s an opportunity to study a lot of solar phenomena without the sun’s big, bright disk blocking the way. So this year, scientists are raring to go with a lot of experiments. They’re going to be chasing the eclipse with aircraft that can observe it above a lot of atmospheric distortion.

But also, they are going to be recruiting scientists on the ground. There’s an initiative called the Citizen Continental America Telescopic Eclipse Experiment. And that’s going to have 40 identical setups along the path of the eclipse here in the United States. And crucially, they’re going to be training ordinary people, community scientists, and citizen scientists to be doing these observations. And the idea is if we can follow the eclipse, taking a lot of snapshots from the ground from different angles at different points along the path, we can gain a lot more sharper of a picture of what’s going on with the sun.

And the National Science Foundation and NASA are teaming up to provide them with training and resources as well. And you can still apply if you look up and go to their website.

IRA FLATOW: That is cool. And the sun is expected to get a lot more active this year, right?

UMAIR IRFAN: Right. The sun has already been pretty active. Just on New Year’s Eve, we saw a coronal mass ejection. This is basically a big bubble of plasma that sends a burst of solar wind towards the Earth. The sun is actually heading towards the peak of its 11-year cycle, the solar maximum. And that leads to more sunspots and more events like flares and coronal mass ejections.

For us here on Earth, the consequences typically are very spectacular– auroras. But if these events can get severe enough, they can cause geomagnetic storms, which can lead to interference with electrical systems and communication satellites.

IRA FLATOW: And then we also have NASA’s Parker Solar Probe, which has been orbiting and studying the sun, what, for five years? It’s going to make its closest approach to the sun.

UMAIR IRFAN: That’s right. In December, the year is going to end with the Parker Solar Probe basically getting the closest any human-made object has gotten from the surface of the sun. And it’s also going to be one of the fastest human-made objects because the sun’s gravity is going to be pulling it very fast.

This probe is meant to try to answer the question of why the sun’s corona is actually hotter than its surface. This is the solar heating problem. And by getting really close and getting a close-up snapshot, scientists hope that they can actually figure out what the mechanism is.

IRA FLATOW: And just how close to the sun will it get?

UMAIR IRFAN: We’re talking about 4 million miles or less from the sun’s surface. The Earth is about 93 million miles away from the sun. And so that should give you a sense of just how close it’s going to be.

IRA FLATOW: So that’s about as close as you can get without landing on the sun.

UMAIR IRFAN: Right, exactly. Yeah. Otherwise, you’d have to just go there at night.

IRA FLATOW: Good point, good point. All right, let’s transition to a heat-related story, speaking about the sun. Researchers are expecting that 2024 is going to be the hottest year on record. Didn’t we just come from the hottest year on record?

UMAIR IRFAN: Yeah, it sounds like a broken record. Yes, 2023 was established to be one of the hottest years humans have measured in at least 175 years, possibly in hundreds of thousands of years. But a lot of the same factors that made 2023 so hot are still in play this year, the big one being the El Niño. This is the warming pattern in the Pacific Ocean. And that tends to drive up global temperatures.

And right now, it’s still flexing in the southern hemisphere. We’re seeing intense heat waves in Africa and Australia and in South America. But also, the other things like the temperature cycles in the oceans, those are also amplified this year. And of course, humans are continuing to emit heat-trapping gases, which are heating up the planet and raising average temperatures.

IRA FLATOW: And I know that you’ve talked to several scientists studying these climate changes, who say they feel a little bit of optimism and urgency on this issue. Tell me about that.

UMAIR IRFAN: Right. I was at the American Geophysical Union Conference in San Francisco last month. And that conference was just at the tail end of that big COP28 climate meeting. And I was kind of surprised to see a lot of scientists were taking some of these observations personally, that it was starting to have an effect on them. And that raised the urgency for trying to figure out exactly what’s going to happen with the planet as temperatures go up.

But I was also kind of surprised to hear a lot of them were very optimistic. Some of them told me about some of their–

IRA FLATOW: Really?

UMAIR IRFAN: Yeah, exactly. Some of them were telling me about how they have new tools that they can use to observe the Earth. They have a better analysis of models and a lot of the trajectories that they can anticipate for the planet. And they think that these tools can help us get a better handle on the problem and then work towards solving problems like greenhouse gas emissions and methane pollution and so on.

IRA FLATOW: And that’s one bright spot to this story, right, that greenhouse gas emissions might even fall this year.

UMAIR IRFAN: Yeah, that’s right. There’s a German think tank called Climate Analytics. And according to their estimates, if everybody on Earth continues to follow their pledges on climate change, the things that they’ve already promised to do, we could potentially see 2024 as the first year where emissions level off and perhaps even decline, which is the first step we need in order to start keeping climate change in check.

IRA FLATOW: Yeah, we’re going to be needing steep reductions in the years to come if we’re going to get to net-zero by mid-century.

UMAIR IRFAN: Yes, we’re doing more than ever. But right now, still not enough in order to keep in line with our targets.

IRA FLATOW: Let’s talk about a story that everybody loves to talk about. I’m talking dinosaurs. There’s a T. rex debate in the dinosaur world. Is that right?

UMAIR IRFAN: Yeah, that’s right. When you find a dinosaur skeleton, how do you know it’s a new species? Or how do you know it’s a different version of an existing species? That’s been a big debate with a lot of skeletons. But there’s been one in particular that’s been really riling up scientists for a long time.

There was a Tyrannosaurus skull that was found in Montana in the 1940s. And initially, scientists thought that this was actually a separate species. And they dubbed this Nanotyrannosaurus lancensis. And later, though, other scientists looked at that and said, well, that’s not a new species. Maybe it’s just a smaller version of the existing T. rex that we know and love. And scientists have been going back and forth for years afterwards.

And this year, there was another entry in this front. There was a paper that came out this week where a research team said they analyzed the anatomy of these smaller Tyrannosaurus fossils and found that there were about 150 anatomical differences that they couldn’t reconcile with the full size T. rex. And according to them, that means that this is actually a separate and distinct species.

IRA FLATOW: Yeah, that is cool. Your next story is a potential treatment for antibiotic-resistant bacteria. We know that this is a really big issue because the bacteria can be very dangerous, especially if we don’t have any– we’re running out of effective antibiotics.

UMAIR IRFAN: Right. One of the biggest public health concerns is that the rise of antibiotic-resistant bacterial infections– more than a million people a year die from these infections. And if they’re left unchecked, the CDC estimated that 10 million people a year could die by 2050. So we need all the tools that we can get.

And this week, scientists reported that they developed a new drug that can target this bacterial infection. Hang on. It has a very long name– Carbapenem-Resistant Acinetobacter Baumannii. Fortunately, it’s abbreviated as CRAB. But this is an infection that’s found oftentimes in hospitals that affects vulnerable people on immunosuppressant drugs, like people on ventilators or people who just received organ transplants. This is a priority one infection for the World Health Organization.

But this new drug is called zosurabalpin. And it actually uses a mechanism that scientists have never really used before when it comes to treating bacteria. Rather than interfering with the bacteria’s genetic reproduction, with how it replicates DNA, it actually interferes with how it transports a molecule called the lipopolysaccharide. And by using this category of mechanism, they think that this could actually be a whole new class of antibiotics that could be powerful at addressing these historically resistant infections.

IRA FLATOW: Well, not just for this one infection but a whole bunch of them.

UMAIR IRFAN: Exactly. So this is going to be a whole new category that we can actually try leveraging to try with other infections and maybe some of the other ones that the bacteria that are resistant to some of the existing drugs that we have now.

IRA FLATOW: I’m still waiting for phage to be the rage again– so those phage therapies. Well, we’ll see what happens. Here’s an interesting story you have about researchers learning that apes can recognize each other after decades. Who knew?

UMAIR IRFAN: Well, yeah. Just like us, apes have friends. And they can actually keep track of them over a long time. There was a study in the proceedings of the National Academy of Sciences that just came out last month. Researchers looked at 26 captive chimpanzees and bonobos at zoos around the world. And they showed them pictures of apes that they previously interacted with versus strangers. And they monitored their eyes using an infrared laser tracker.

And basically, what they did was try to see which apes that they looked at longer. The scientists found that the apes looked at the pictures of apes that they recognized– so basically, apes that they shared enclosures with or that they were actually related to. In one case, there was a bonobo that recognized her sister, who she hadn’t seen in more than 26 years.

IRA FLATOW: Wow.

UMAIR IRFAN: And so that shows that there’s this powerful mechanism in apes that has devoted a lot of mental real estate towards memory of other apes. And it shows that social cues are actually something that’s a very ancient evolutionary mechanism that a lot of organisms, including hominids, are using for our survival.

IRA FLATOW: That is interesting. I have to stick with biology one more moment because we have a really– this is a Science Friday-only story, I’m kind of figuring. Scientists have finally figured out one of the great mysteries of life. And that is, why is our pee yellow? I’ll leave it there for you to pick up.

UMAIR IRFAN: Sure. So the chemical that generally turns yellow is called urolibin. But scientists, for a long time, weren’t exactly sure how it was produced. They know it’s a byproduct of how red blood cells get broken down. Our red blood cells basically cycle through every six months.

But what it turned out was– what scientists realized is that it’s not actually being converted to this byproduct by our own cells but rather with our gut microbiome. Basically, there are bacteria that live in our urinary tract that are doing this conversion for us and then turning this into a molecule that turns our urine yellow. Now, beyond just revealing something that maybe all kids are wondering, this is actually something that could be potentially used to treat illnesses.

We’ve been hearing a lot about the gut microbiome being used to treat digestive illnesses. Potentially, learning more about the urinary tract microbiome could lead to cures and treatments for problems that we have with our urinary tracts.

IRA FLATOW: We love the microbiome on this program. Thank you, Umair. Great stuff as always.

UMAIR IRFAN: My pleasure, Ira. Thanks for having me back.

IRA FLATOW: Umair Irfan, staff writer at Vox.

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