This is Science Friday. I am I Refledo. If you've done nothing else this summer, I'm betting,

you've been sweating a lot. And as we all know, sweat helps us cool off as it evaporates.

But what do animals that don't sweat? What do they do to cool off? Some unexpected things,

as we'll find out, as we talk about the science of sweat a little bit later. But first,

what do embryos, a moon landing, and arm joints? All have in common. Well, they're all part of our

news roundup this week. Here with her selected short subjects in science is Casey Crownheart,

Climate and Energy Reporter at MIT Technology Review reporting from New York City.

Casey, welcome back.

Thanks so much for having me back, Ira.

You're quite welcome.

Big news this week in the world of stem cell research scientists at the Wiseman Institute in Israel

have successfully created a 14-day-old human embryo model without sperm or eggs. The findings were published in the

prestigious journal Nature. Casey, why is this such a big deal? Yeah, so these, you know,

kind of synthetic embryos or embryo models, as we may call them, could be a really big deal for

understanding the earliest stages of our development,

creating new drugs and treatments. And it's kind of a wild bit of science that these researchers

had to do to make it happen. You know, like you said, instead of a sperm and an egg,

this embryo model is made with stem cells, those cells in your body that can turn into a lot of

different kinds of things. And by reprogramming

them, scientists were able to make a small fraction of them kind of spontaneously come together

and assemble into something that looks a lot like a human embryo. Okay, tell us why it's like a human

embryo. It's a model and not an embryo itself, which could become a person. Yeah, so a natural embryo really means

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