You're listening to Shortwave from NPR.
Hey, Shortwavers.
Regina Barber here.
And Angela Zeng.
With our biweekly science news roundup featuring Juana Summers of All Things Considered.
You're super fun.
I'm glad you're back.
Glad to be back with y'all.
Okay, so this week we've got a few mysteries unraveling.
First up an object in space that might be a planet or might be a failed star, and what new observations about its clouds can reveal about it?
Juana, Angela, if you could have a cloud made of anything, what would it be?
I mean, I feel like my brain automatically goes to marshmallows, which I feel like might be a cop-out, but I'm also really hungry, so that might have something to do with this.
Marshmallows will not quench that hunger, though.
But they taste really good.
Yeah, that's true.
Oh, man.
I had something a little bit more.
You wouldn't want to be in it, but I'm kind of tired this morning.
Yeah.
And I was like, some coffee sounds great in a cloud, you know?
Coffee clouds.
That sounds awesome, actually.
And it like raining down and just open your mouth.
Exactly.
And then you're caffeinated.
Only if it's iced coffee.
That's otherwise might be a little painful.
It'll be a cold storm.
It's fine.
A cold front.
I personally think instantly like cotton candy.
Perfect.
Cotton candy is the first thing.
But these clouds are none of those things.
Yeah, stay tuned.
Our second and third topics are a lot closer to home the exciting possibility of a sex-specific burial site of ancient human relatives, and what great apes' laughter can tell us about the evolution for human communication.
I don't have a fun question for this, though.
And yet I'm still intrigued.
We'll laugh a lot.
That's all I can say.
So today on the show, we've got mysteries across space and time.
You're listening to Shortwave, the science podcast from NPR.
All right, Gina and Juana, we've got a lot to get into.
I would love it if we could start in space.
Tell me about the weather on another planet.
Yeah, this might not even be a planet that we're talking about here.
There's a debate over this object, GJ504b.
It's roughly 25 times larger than Jupiter.
And astronomers are uncertain how to define it.
Is it a planet like Jupiter or is it a failed star?
What do you mean by that?
Like they look the same to us from a telescope, but they're actually different things?
Yeah, huge Jupiter-like planets and a failed star, they do look super similar.
But how they get there is different.
Stars need a lot of mass to ignite fusion and turn on.
And without enough mass, the star doesn't turn on, basically.
It failed.
And whichever one this object is, we know that it's really dim and couldn't be fully studied from ground telescopes until a study out this month in the Astronomical Journal about GJ504b.
Astronomers were finally able to analyze the light using the James Webb Space Telescope, and they got some information on what chemicals are in its atmosphere.
So what can scientists say about it?
They could say something about the kind of clouds that were in the atmosphere.
So this may be, maybe not planet.
It's about 550 degrees Fahrenheit.
That's probably how hot your oven gets at home.
And that might seem hot to us, but that's actually pretty cool for other worlds like this.
Yeah, and that temperature affects what kind of weather it has.
Like there are exoplanets that are so hot, the clouds are made up of gemstones.
Yeah, and our Jupiter is so cold that the clouds are ammonia ice and beneath that, water vapor.
So what are these clouds made of?
And how does knowing that help our understanding of space?
So the study modeling and this temperature all pointed towards, get this, salt clouds.
And there actually aren't a lot of objects in space like this one.
Yeah, there's still a lot of questions.
Astronomers like the lead author, Anish Babaraj, have like We still don't know how big planets can get.
So uncovering as much as possible can help astronomers make better models for how planets and stars are born.
All right.
Up next, we've got a story about ancient human relatives.
What did scientists find out that's so interesting?
So in 2013, archaeologists discovered more than a thousand human-like fossils so like bones and teeth in the Rising Star cave system in South Africa.
And one big thing jumped out.
All the reconstructed skeletons looked oddly the same size, which surprised scientists, because in most primate species there's a clear difference in size between the sexes.
And this species, called Homo naledi, they lived a few hundred thousand years ago.
They walked upright and they had human-like hands and feet, but their brains were much smaller than those of ancient humans.
Yeah.
And if you look them up, they look very planet of the apes.
All of the hormonality individuals that we looked at came back missing a male marker.
That's lead author and molecular scientist Palesa Madupe.
She says the chances are about one in a million that all 20 would be female.
So the team thinks this could have been an intentional sex-specific burial practice.
Oh, interesting.
So how big of a deal would that be if it's true?
It could be a big deal, because Homo naledi isn't in our direct lineage and burial practices are largely ascribed to humans, although other animals do it, like elephants and naked mole rats.
Interesting.
So how are others in the field reacting to these findings?
They're pretty excited.
Researchers have been puzzling over this for more than a decade, actually.
We talked to Charles Musiba.
He's an evolutionary anthropologist at Duke University who wasn't a part of this study, though even with his excitement, he was also a little cautious.
Could this be intentional sort of dispose of the bodies?
The answer probably is yes.
I'd like to see a little bit more evidence, but it sort of strongly suggests that way.
And the biggest question is, where are the males?
Where are the males indeed?
Hopefully we'll have you on later for an answer to this next mystery.
So let's move on here.
For our last story, let's stay with these distant relatives.
There's new research that could tell us more about how humans evolved to communicate.
And you said it's from studying primates?
Yeah, so how humans evolved to communicate is not totally clear.
I mean, we don't have recordings of our hominid ancestors, you know, talking.
But we can study some distant relatives, the great apes.
There are orangutans, gorillas, chimpanzees, empanobos.
And so how they communicate and vocalize could give us clues about our own evolution.
And what do we have in common?
We play and we laugh.
Many non-human primates love being tickled, especially when they are like babies.
That's primatologist Chiara De Gregorio from the University of Warwick.
Her team measured the tempo of laughter in great apes and human children, and they just published their results in Communications Biology.
They found that great apes like us laugh in a steady rhythm, almost like a metronome.
And they found that the laughter actually changed over time.
We go from orangutans that are solitary animals.
And then you have gorillas, which have more a family kind of group.
Then you have chimpanzees and bonobos which start to have a really complex social life, going towards more complex society.
Then a laughter becomes more variable, more flexible.
It's so cool hearing all of those together.
I mean, you can really hear how the chimpanzees and bonobos the last two that we heard do sort of sound like human laughter.
Yeah.
Yeah, they basically made us laugh, right?
And we're actually more closely related to bonobos and chimpanzees out of all the great apes.
And our laughter is the most similar to theirs, like you said.
So this study shows us that, as a species becomes more social, maybe laughter gradually evolves as well.
And what can that tell us about humans?
Well, as you heard, the great apes have a pretty cute laugh.
They do.
But it's also pretty regular, that metronome, and they can't really change it, as you also heard.
But humans can.
The human children in the study were the only ones who could actually modulate or change how they laughed.
And that laughter conveys really important information.
We can have a polite, small laugh in front of, I don't know, an important person.
But then maybe you're at the pub with friends and we laugh in a totally different way.
You can totally imagine those scenarios, right?
Oh, yeah, for sure.
Totally.
And laughing like this requires a lot of vocal control, which is also how you learn to speak.
Which, of course, also sets us apart from the great apes.
So, Anna, with all this laughing in mind, we have a joke for you.
What is a monkey's favorite month?
Oh, gosh.
I don't know.
April.
Get it?
How's that for a polite small laugh, y'all?
You're like, yeah, that was rough.
I liked it, though.
Dad jokes abound.
Please come back anytime.
Only if you bring me more jokes.
And marshmallows.
You got it.
You can hear more of Juana Summers on Consider This NPR's afternoon podcast about what the news means for you.
And for more science stories just like this one, follow Shortwave on whatever app you're listening to.
This episode was produced by Burleigh McCoy and Jordan Marie Smith.
It was edited by Rebecca Ramirez and Mallory Yu.
Josephine Neonai and Jimmy Keeley were the audio engineers.
I'm Regina Barber.
And I'm Angela Zhang.
Thanks for listening to Shortwave, the science podcast from NPR.
