IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, we’ll talk about how researchers are using donated brains– just like yours, yeah– to understand conditions like Alzheimer’s, Parkinson’s, and even depression.

But first, it’s orbited above us for decades. It’s a valuable tool for scientific research. And in 2031, it will crash into the sea. I’m talking about the International Space Station. The aging station, NASA reported this week, has a set expiration date and will join assorted spacecraft from history, including the Russian Space Station Mir and Skylab, in a watery ocean grave.

Here with this and other selected short subjects in science is Maggie Koerth, senior science writer for FiveThirtyEight. Welcome back, Maggie.

MAGGIE KOERTH: Hi. Thanks for having me.

IRA FLATOW: You’re welcome. So why are we losing the ISS in 2031?

MAGGIE KOERTH: Mostly because it is a 20-plus-year-old piece of spacecraft that is not going to be in good working order for a whole lot longer than that. NASA and the Biden administration have decided that they want to keep it flying until 2030, which would extend its life by an extra six years from where it’s currently set. They still need to get some sign-offs from that to make that plan happen, though, both from Congress and from Russia and from a bunch of other international partners. But it could end up meaning that the old girl is with us just a little bit longer.

IRA FLATOW: And they have a place that they’re aiming for to bring it down, right? A very famous place.

MAGGIE KOERTH: They do. It is called Point Nemo. It’s Greek for “no man,” which is very apt because it is the spot in the Pacific Ocean that’s optimized to be the furthest from land that you can get anywhere on Earth. It’s more than 1,600 miles from the nearest land. The astronauts who are currently aboard the space station are often the closest humans to Point Nemo as they pass overhead in orbit.

So over the years, like you said, this Point Nemo has turned into a popular retirement home for spacecraft. And the deal is that, like, nobody wants to have to worry about what or who craft might hit as they land. So we land them in this place where there’s nothing, really, at all, like not even that many fish.

That’s because the Point Nemo is in the middle of a gyre. So it’s this location in the ocean where currents kind of move in a circular pattern, so you don’t even get very many new nutrients flowing in. There’s not a lot of plants or fish, even, in this area, which is probably a really good thing, because there’s a lot of environmental concerns, actually, around dumping space junk into the ocean. These are things that can leak toxic hydrazine rocket fuel and also radioactive chemicals.

IRA FLATOW: Wow. Yeah. It’s interesting that you can actually pick the spot where you want it to land.

MAGGIE KOERTH: It super is. It super is. One other thing that I found about this that maybe you’ll enjoy is that the ocean may perhaps someday have its revenge. In 1928, years before anybody started dumping rockets there, HP Lovecraft had identified this general area as the location where Cthulhu lies sleeping.

IRA FLATOW: Whoa.

[BOTH LAUGH]

Whoa. Think about that for a while. Let’s go elsewhere in space. There are two black holes that may be about to merge.

MAGGIE KOERTH: Maybe. This is such a great story. I love this so much. So at the center of a galaxy 1.2 million light years from Earth, there are two gigantic black holes that are about to crash into each other. This event could release a huge burst of light, surges of gravitational waves and neutrinos, and it would give scientists a chance to witness something that’s previously only been theorized.

It could happen in as soon as just 100 days. Or it might not happen at all. And also, the black holes might not exist.

IRA FLATOW: Wait a minute. Wait a minute. That covers all the bases, doesn’t it? I mean–

MAGGIE KOERTH: It sure does. You know, welcome to the wonderful world of interstellar astronomy. You know, there’s so many things that we can’t see directly. And what scientists do when they can’t see things directly is they make assumptions based on kind of all of these things that they can measure.

And in this case, what they’ve spotted is not two supermassive black holes. It’s this galaxy with a bright shining center that dims and glows. This effect is something that some scientists have theorized would be caused by two black holes orbiting each other very closely, sucking in and heating surrounding matter in this kind of churning oscillation. And the fact that the oscillation periods are getting shorter suggests that the black holes, if they do exist, might be getting closer to each other.

There is no way to know in advance what is actually happening. The scientists who think this is going to happen think that it will happen somewhere between 100 to 300 days from now. So scientists are jockeying for telescope time in that range.

People are getting poised to be ready for it in case it does happen, because if it does, there would be a whole bunch of signals that show up, and everyone in science will go wild. Like, this will be in a really super amazing thing. Or we’ll all just spend the next year sitting around, and nothing happens, and nothing continues to happen.

IRA FLATOW: Wow. Let’s turn to something that is really very interesting and a bit more serious. And this is a story about Indigenous sovereignty, resistance to colonization in South America hundreds of years ago. Tell us about this mortuary rebellion, as it’s called.

MAGGIE KOERTH: Yeah. So some 500 years ago, people living on what’s now the southwestern coast of Peru began to take human spinal columns and thread them onto reeds one vertebra at a time. The collections look a little bit like creepy rhythm instruments. But archaeologists think these spines are actually a way for people to reclaim their ancestors and rebel against Spanish imperialism.

There’s a lot of good reasons why the scientists think that. It’s kind of this accumulation of evidence over time. So here’s some of the evidence. The researchers already knew that people of the ancient Chincha kingdom venerated their dead. They made mummies, they interred them in these stone towers, and these stone towers are where many of these vertebrae on sticks are found.

Scientists also knew that when the Spanish arrived, the colonizers tried to wipe out this ancestor veneration, because they thought it was idolatry. So they were desecrating bodies, and they were robbing tombs. And there are known cases where the Native Chincha people were coming back later in the wake of the Spanish destruction and building themselves new effigies of their loved ones from scraps of hair and fingernails that had been left behind.

But the real clincher here is dates. So this new study performed radiocarbon dating on three bones and nine of the reeds. And they found that the bones were coming from people who died between 1520 and 1550, which is a time when there were just massive numbers of Chincha people being killed by starvation, disease, directly by the Spanish. And the reeds, meanwhile, were picked as much as 40 years later. So like, this just– this hit me really hard, because you can almost imagine a grown child coming back and piecing together all that remained of a parent they’d lost years before.

IRA FLATOW: So these vertebrae may have been how colonized people were resisting conquest by continuing to mourn their dead, right?

MAGGIE KOERTH: By continuing to honor their dead, and have their dead with them in ways that celebrated their dead and made their ancestors a part of their family.

IRA FLATOW: Let me just add that the image of these bones are really, really powerful. And we’ve linked to it, that image, on our website if folks are curious to see what we’re talking about. Your next story is about a volcano stirring in Oregon. Should folks be worrying, Maggie?

MAGGIE KOERTH: No. That’s the good news. You’re fine. So this is really interesting, though.

Like, even though it is not an emergency situation, I think it’s worth paying attention to because it’s really cool, because 20 years ago, scientists were watching this mountain, South Sister, an Oregon volcano, kind of changing in ways that suggested there was activity happening underground in its magma chambers. You were getting bulging on its slopes. There were tiny earthquakes.

And then in around 2001, the changes just stopped. And for two decades, South Sister sat there, silent and immobile. And now she’s moving again.

So just to give you some sense of scale, in the months before Mount St. Helens erupted in 1980, the side of that mountain bulged out hundreds of feet. And in contrast, over the span of 1995 to 2001, South Sister bulged five inches. This is a much smaller, much smaller scale of changes. And that’s actually what makes it cool, because what this represents is how much work has gone into learning how to monitor these kind of volcanoes at a– in minute detail.

We are getting data back about changes that nobody maybe even would have noticed 40 years ago. So now we have this satellite imagery, and we have these highly sensitive seismometers that can spot earthquakes that are less than, you know, less than magnitude 1. And we are learning about what it looks like when a volcano sort of mumbles in its sleep. And that helps scientists better understand what to watch for and what changes actually are concerning.

IRA FLATOW: Cool. Cool story. Our last story we have is a bit of COVID-19 news. There’s now finally a chance for those of us who have been lucky enough to escape the virus to get deliberately infected. Do it for science, right?

MAGGIE KOERTH: Do it for science. Yeah, the world’s first COVID challenge trial is seeking a new round of volunteers who would have samples of virus inserted into their noses so that scientists can learn things like how much virus it takes to trigger an infection and what kind of immune responses are necessary to fight one off. Now, these are not anything new as a kind of trial. Scientists have done this kind of study before, but just with different kinds of pathogens. This is just the first time we’re doing it with COVID.

And when they do these trials, in this case and in the past, they’re often a way of understanding infection on a much more detailed basis than you can do with a natural infection, so that you can make better vaccines. They’ve done this with cholera, flu, and dengue fever, and a whole bunch of other things.

This particular trial has had a couple of studies published already. One of them involved 36 18 to 29-year-olds who were exposed to droplets of COVID virus. 18 became infected. 16 developed cold-like symptoms. 13 temporarily lost smell and taste.

The researchers were working in that case on figuring out the lowest possible amount of COVID you could expose someone to and still infect them. And that knowledge is now going to help them better perform this next round of experiments, which are aimed at figuring out what level of antibodies and T cells are needed to prevent infection. And that information is going to help scientists design better, more effective vaccines in the future.

IRA FLATOW: Thank you, Maggie. Maggie, it was great having you on again. Great stories.

MAGGIE KOERTH: Yeah, thank you.

IRA FLATOW: Maggie Koerth, senior science writer for FiveThirtyEight. She was joining us from Minneapolis.

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