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The Researchers reconstructed the face of the organism which might be one of our earliest ancestors. Meanwhile, two researchers from Harvard announced that they have created solid metallic hydrogen.

Hosted by: Hank Green

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Hank: The fact that we exist at all is kind of amazing. Like, somehow, a bunch of primordial goop became everything living on Earth today.

To figure out how that happened, scientists turn to the fossil record, and in a paper published this week in the journal Nature, a team of researchers reconstructed the face of one of our earliest ancestors, found in some 540-million-year-old limestone that’s in what is now central China. And it looks like something straight out of a B monster movie, or a Alien, but this thing is tiny — only a millimeter or so big, so don’t be too afraid.

Scientists call it Saccorhytus coronarius. The genus name comes from the Latin for “sack” or “bag,” which is basically the animal’s body shape, plus the Greek word for “wrinkled.” So it’s like “wrinkly sack”. And the species name is a nod to its crown-like mouth.

S. coronarius is basically a worm, but it’s not just any worm. It might be the common ancestor of all vertebrates, from humans to dogs, and even some invertebrates like sea stars. We’re all what biologists call deuterostomes, a classification that has to do with how we develop as embryos. The most widely-used definition of deuterostome has to do with how our mouths and — the SciShow commentors’ favorite term — anuses develop.

We start out as a hollow blob of cells, which forms a tube that becomes our digestive system. When animals called protostomes, like insects, crabs, or earthworms, develop that tube, the first opening they make becomes their mouth. But in deuterostomes, the first opening becomes the anus, and the second opening becomes the mouth. So, these scientists think S. coronarius could be one of the earliest deuterostomes, based on comparisons of more than 60 features to other living creatures and fossils.

The weird thing is: even though S. coronarius has a big ol’ mouth, it doesn’t seem to have a clear anus. But the lack of an anus doesn’t disqualify S. coronarius from being a deuterostome. Because while “anus first, mouth second” development is a pretty good rule of thumb, it’s not perfect. Taxonomy is messy, and after scientists learned more about biology and genetics, they found exceptions to the rule.

In fact, the earliest deuterostomes might share common traits like openings that they used to help with filter feeding. And S. coronarius has a bunch of those, which it might also have used to dump its waste. So, hey, we might all be related to this wrinkled sack with a crown for a mouth.

And while some scientists are looking for our earliest ancestors, others are looking for ways to make weird, but super useful forms of matter. In a paper published last week in the journal Science, two researchers from Harvard University announced that they’ve done what physicists have been trying to do for 80 years: they’ve created solid metallic hydrogen.

Metallic hydrogen would be a huge deal. It could be used for all kinds of new technologies, from really efficient electronics to rocket fuels. But this experiment is turning out to be super controversial. A lot of experts are questioning how conclusive their results are, and pointing out flaws. If you’ve learned anything about chemistry, you know that hydrogen isn’t normally a metal.

Metals are reflective and conduct electricity, and plain-old hydrogen doesn’t do either of those things. But back in 1935, physicists predicted that the right conditions — specifically, very high pressures — could force hydrogen into becoming a metal. And if we could figure out how to make this stuff, it would be incredibly useful: It’s thought that metallic hydrogen would be a superconductor at room temperature, meaning that it would be perfectly conduct electricity.

All the other superconductors we’ve discovered only work at very low temperatures, but one that works at room temperature would revolutionize the power industry by making it way more efficient to transfer electricity. And with it’s super-strong bonds, solid metallic hydrogen would also be a great way to store energy, which would make it a better rocket fuel than the fuels we use now, like liquid hydrogen and oxygen. Teams of researchers all over the world have been trying and failing to make metallic hydrogen for decades. But now, these Harvard University physicists say they’ve done it.

They squeezed some hydrogen gas in a vise made of two tiny, carefully-engineered diamonds at a temperature just above absolute zero. As the pressure between the diamonds increased, they saw their sample turn dark, which meant it was turning into a black, solid form of hydrogen.

Then, when the pressure hit 5 million times the standard pressure you’d experience at sea level, the sample turned shiny. It reflected about 90% of the light that hit it, just like a metal. So the researchers announced these results in the paper published last week: they’d created solid metallic hydrogen.

But other physicists were skeptical. Which I probably would be too if lots of brilliant people had been trying and failing to do thing for decades. See, the team coated their diamonds in aluminum oxide to keep them from breaking, and it’s possible that the shiny stuff they saw was metallic aluminum oxide, not metallic hydrogen.

Another issue is that they couldn’t monitor the pressure the entire time because the lasers used to precisely measure pressure tend to weaken the diamonds. They also haven’t checked if the material is conductive, or even if it’s actually solid — which are pretty important tests if you think you’ve made a solid metallic superconductor. The researchers say they’ve held off on doing more tests because they’re worried they might ruin their sample.

They wanted to publish these results first. But their next step is to analyze how the hydrogen atoms are arranged, based on the way they scatter laser and X-ray light. Eventually, they plan to release the vise and see if the hydrogen stays solid and metallic — which theoretically, it should. And of course, they want to make more samples. If all these tests are successful, the results of their experiment will be a lot more convincing.

In the meantime, we can’t say for sure that they’ve created metallic hydrogen. But if they have, it is a big step for the future of technology.

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