IRA FLATOW: This is Science Friday. I’m Ira Flatow. This Earth Day, President Biden kicked off a two-day international summit on climate change, which he called “the existential crisis of our time.” And like many of us, the summit was conducted virtually, online, with 40 world leaders in attendance. Each country discussed how they would commit to decreasing emissions.

Sophie Bushwick is here to fill us in on that story and other science headlines from the week. She’s technology editor for Scientific American, based in New York. Welcome back, Sophie. Always good to have you.

SOPHIE BUSHWICK: Thanks, Ira.

IRA FLATOW: Well, let’s get right into this. There were 40 different countries. Give us some brief highlights of how some of these countries intend to cut emissions.

SOPHIE BUSHWICK: Well, one of the announcements was Biden saying that he wants to cut US emissions by about half by the end of 2030, which is a relatively short-term goal.

IRA FLATOW: Well, I was just wondering if you had any other information on what the other countries were pledging.

SOPHIE BUSHWICK: So China said they’re going to move to carbon neutrality in a much faster timeline, so they’re committing to– it’s sort of vague. They’ve committed to move from carbon peak to carbon neutrality in a much shorter time span. A lot of the stuff that they’re claiming to do isn’t quanti– for example, China has committed to moving to carbon neutrality. Brazil just moved up their goal for carbon neutrality, so now they want to reach carbon neutrality by 2050.

IRA FLATOW: Yeah, we’re going to be digging deeply into those numbers later, so I’m glad you brought that up. Let’s move on to the CDC reporting that 27% of the US population is fully vaccinated. But some areas are seeing surges in cases, and one of those is Michigan. What is happening there?

SOPHIE BUSHWICK: So Michigan is being hit by a surge. They’ve been reporting thousands of new infections per day. And it’s starting to fill up hospitals. The issues with Michigan aren’t limited to the state. There are other states that are also experiencing their own increases in cases, including Minnesota and Pennsylvania. But in Michigan, it just seems to be particularly severe. And the governor actually requested more doses of vaccine from the federal government, from the Biden administration, but they were turned down because the claim was that increasing the number of vaccines going to the state isn’t going to directly fight an acute surge like this one.

IRA FLATOW: Yeah, you may have more vaccine, but if people are not taking the vaccine, what’s the sense?

SOPHIE BUSHWICK: Right. And the other thing is that a lot of the people who are now being seen in hospitals are people who just either haven’t been vaccinated yet. So we’re talking younger populations. Whereas in many earlier surges, it was people who were over the age of 65 or over the age of 75, now they’re seeing more people in their 30s, 40s, and 50s relative to the total number of cases.

IRA FLATOW: And there are other states that are seeing an increase in cases as well.

SOPHIE BUSHWICK: Absolutely. Yes, this is a trend we’re seeing across the country. And there could be a couple different factors going into it. One of them could be the spread of the more contagious variant in the US. Another could be what people are calling pandemic fatigue. People have been being careful for so long, and now there’s positive news and the vaccines are front and center in the news, so some people might be letting their precautions slip at a time when it’s not quite safe to do so yet.

IRA FLATOW: Very interesting. Let’s go on to news about what’s happening on Mars. NASA has a helicopter, sort of, a drone on Mars that we’ve been watching all week. Fill us in on– it’s been able to actually lift off the surface for the first time.

SOPHIE BUSHWICK: That’s right. This is the first powered flight on another planet. This is particularly exciting because the Ingenuity helicopter actually has a piece of the Wright brothers’ original plane contained with it. It’s got a little postage-size stamp of the cloth from the body of that plane with it as it creates another first in the history of aviation.

IRA FLATOW: And what is it supposed to be doing there? Does it have any instruments on board for taking measurements?

SOPHIE BUSHWICK: So far, the goal of this helicopter is to just take images and to test out how powered flight on another planet works. So on Mars, the atmosphere is much thinner than on Earth. So for example, this particular helicopter has about a 4-foot wingspan, but it weighs about 4 pounds. It’s just a very light, very large-wingspan craft. And it needs to have that size, and it needs to have its blades spin faster because of the atmosphere. So its success or the things that it struggles with will help NASA researchers design more efficient aircraft for flying on Mars, for taking pictures in places that would be hard for a ground-based rover to reach and for doing sort of reconnaissance for people or robots who are limited to the ground.

IRA FLATOW: Well, Perseverance had a very busy week. It also made oxygen for the first time on Mars out of the thin atmosphere there.

SOPHIE BUSHWICK: That’s right. So Perseverance has an instrument with the very cool name of MOXIE, which takes carbon dioxide and breaks it down to produce oxygen. And in this first test, it created enough oxygen to sustain a human being for about 10 minutes. The great thing about making oxygen on Mars is that that way, astronauts or humans who are coming from Earth wouldn’t need to bring all of their supplies with them. They could create some of the oxygen that they need, not only for breathing, but also for fuel, right on the planet.

IRA FLATOW: Yeah, this is a really interesting first step, because we’ve talked about this for years, but we’ve never actually seen it done on Mars.

SOPHIE BUSHWICK: It’s a very exciting first step, and it’ll be interesting to see how they scale this up. And maybe future versions of this instrument will be bigger and able to produce a larger volume of oxygen.

IRA FLATOW: Let’s talk about other space news. China is launching its own space station?

SOPHIE BUSHWICK: That’s right. The Chinese Space Station is launching its first module at the end of this month. And then over the next months and a couple years, they’re going to be launching more modules and to be sending crewed missions up. And they’re going to be putting together a new space station that will be able to operate for about 10 years.

IRA FLATOW: So is this a statement by China that we are now seriously space voyagers like you are?

SOPHIE BUSHWICK: China has actually been working on the idea of launching their own space station like this since the ’90s. And it’s not as big as the International Space Station, so it’ll be a smaller footprint, but it’s definitely a footprint. It’s definitely a presence in space that does seem to be signaling more ambitions in that space.

IRA FLATOW: Because the International Space Station is getting pretty old.

SOPHIE BUSHWICK: That’s right. The CSS, the Chinese Space Station, is going to be brand new. And the ISS is, you could say, nearing the end of its useful life. It’s an aging presence in space. So it’ll have a younger competitor now.

IRA FLATOW: Now, I understand that the Russians have also said that they might launch their own space station. And the way they said it was sort of a poke in the eye to the American Space Station.

SOPHIE BUSHWICK: So Russia and the US, astronauts from both countries, have worked together on the International Space Station for years. The Soyuz rockets from Russia are used in American launches. And there’s been a cooperative relationship for a long time. So this signals a potential strain and change with that relationship.

IRA FLATOW: What other space projects are in the works there by China, by Russia, by other countries?

SOPHIE BUSHWICK: Well, China is launching– a few years after they complete the Chinese Space Station, they’re planning to launch a telescope that will be akin to Hubble in its ability to image the sky. And the China Sky Survey Telescope is going to be fairly close in terms of spatially to the Chinese Space Station. And the idea is that if it needs repairs or to be fixed that the two could dock together and the Chinese Space Station could– people or astronauts in the Chinese Space Station could do maintenance on the China Sky Survey Telescope.

IRA FLATOW: Very forward looking. I remember we had to rely on the space shuttle to go up and fix the Hubble in its early days. So that’s a great idea. Your next story hits the Venn diagram of Science Friday favorite topics. There’s a study that looks at the microbiome of bees. Very interesting.

SOPHIE BUSHWICK: That’s right. Bees in the same beehive actually have the same smell. And they use this smell to identify each other. But in previous studies, researchers found you could bring in a bee from a different hive that’s genetically distinct, and instead of being rejected, it actually starts smelling like its new hivemates.

So they thought that what’s going on here could potentially be that the microbiome is shared and then creates a shared scent. So in this new study, they looked at bees from the same colony, from the same hive, and they gave these bees different gut microbiomes. And the bees not only smelled different, but started attacking and biting each other because they didn’t recognize each other as members of the same hive.

IRA FLATOW: Did they kick the bees out of the hive or kill them? Or what happened to those bees?

SOPHIE BUSHWICK: The researchers just observed the bees attacking each other in this particular case. And these were newly-hatched bees. They were genetically sisters. So it’s really interesting that in this case, the genome of the gut microbiome seems to have trumped the actual genome of the bees themselves. They were really relying on the gut microbiome to recognize each other, and when they couldn’t do that, they attacked.

IRA FLATOW: Wow. That is very interesting. Finally, something I know that you’ve written about– researchers read a 17th-century letter without ever opening it. Subtle little magic going on here.

SOPHIE BUSHWICK: If you look at images of what the researchers call a virtual unfolding algorithm, so they took these high-resolution images of this folded-up and sealed letter, and then they developed an algorithm that would automatically unfold it without actually unfolding it. And there is actually video of an animation of this happening. And you can see the exact manner in which this historical letter was folded that researchers might not have been able to discover, because one of the things they’re interested in using this algorithm for is studying how exactly were people folding their letters and keeping them in this self-contained little packet in the era before envelopes? And it turns out there’s a whole variety of different methods. And it’s really helpful to be able to study them without actually opening the letter, which destroys some of that evidence.

IRA FLATOW: And so this was in a time before people put stuff in an envelope. You had to fold it for security?

SOPHIE BUSHWICK: That’s right. Some of these security methods were also very intense. So you might fold your letter and then cut a slit in it, and take another piece of paper, thread it through the slit, fold it around the outside, seal it with sealing wax. And the idea is that if I want to sneak your letter and open it and then seal it back up, I can’t do that because doing so would tear the letter in the process. So this was a kind of security method in the era before digital encryption. It was used in conjunction with codes, and it was actually used by spies, historically.

IRA FLATOW: Where did the scientists get this letter from?

SOPHIE BUSHWICK: So this letter is part of a whole box of undelivered mail from the Hague.

IRA FLATOW: Wait a minute. Undelivered mail– that sounds familiar. Even back then, huh?

SOPHIE BUSHWICK: Even back then. Well, back then, instead of the person who sends the letter buying a stamp to pay for it, it’s the person who picks up the letter who has to pay for the delivery of the letter. So if you couldn’t pay to pick up your letter or if maybe you’d moved away from a place, you wouldn’t be able to have the mail delivered to you. You would have had to go to the post office to get it. And some people didn’t come to the post office. So for the people who worked there, they would throw the mail in the unpicked-up letters trunk. And we have this cache of documents that’s like a snapshot of that era.

IRA FLATOW: Fascinating. Thank you, Sophie. You always bring such great stuff to talk about.

SOPHIE BUSHWICK: Thanks, Ira.

IRA FLATOW: Sophie Bushwick, technology editor for Scientific American.

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