A Michigan Fireball, An Omnivorous Shark, And An Ancient Epidemic

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, we’ll be talking about the unintended consequences of Silicon Valley creativity. Is this a modern Frankenstein story? We’ll talk about it.

But first, earlier this week, people in Michigan were treated to an unusual sight in the sky– a fire ball. Why such a big deal? Joining me to talk about that, other selected short subjects in science, is Rachel Feltman, Science Editor at Popular Science. Welcome back.

RACHEL FELTMAN: Thanks for having me, Ira.

IRA FLATOW: Give us the fireball story.

RACHEL FELTMAN: Yeah. So we had a meteor over the skies in Michigan. And you know, rocks falling out of the sky is very common. And this was like a three foot six foot wide piece of meteor.

And the thing is that most of these fireballs happen where no one can see them. We don’t think about this, but most of the planet, people are just not on it–

IRA FLATOW: That’s true.

RACHEL FELTMAN: –most of the time.

IRA FLATOW: Three quarters covered in water.

RACHEL FELTMAN: Yeah. So it always seems like such a– so shocking when we see a fireball in the sky with no warning. But the truth is these are tiny rocks. We don’t have any reason to be worried about them. So they just come and go. It’s certainly a fantastic sight to see, though.

IRA FLATOW: And so the news media just picked up on this and ran with it.

RACHEL FELTMAN: And one thing that happened is that the National Weather Service in Detroit tweeted that it had caused a magnitude two earthquake, which was incorrect. It’s understandable where the confusion came from.

It had registered on seismographs like a magnitude two earthquake, though it did not–

IRA FLATOW: If you were close by.

RACHEL FELTMAN: Right. It did not cause an earthquake. And it didn’t even necessarily make the ground tremble with the force of that earthquake. Most of that vibration was probably still in the air.

It does look like some of the rock made it to Earth. There are people around Michigan who are finding little bits of meteorite. But, you know, nothing big enough hit the Earth hard enough to make it feel like there was an earthquake.

IRA FLATOW: But it was fun to look at.

RACHEL FELTMAN: Oh yeah.

IRA FLATOW: What happened?

RACHEL FELTMAN: Absolutely.

IRA FLATOW: It just streaked across the sky?

RACHEL FELTMAN: Mhm.

IRA FLATOW: Wow. Look, it’s a meteor. It’s a fireball. Let’s go on to another story about an ancient epidemic and its relationship to teeth.

RACHEL FELTMAN: Yes. So about 500 years ago in Mexico, there was a horrible epidemic– killed five to 15 million people. We know it was some kind of enteric fever– something like Ebola. It caused bleeding and diarrhea. It was probably not a good time.

But we don’t know what actually caused it. This happened you know before epidemiology existed as a field. So the kind of historical notes we have about the epidemic aren’t actually on the sorts of things that would help us diagnose it.

And researchers haven’t ever been able to find the cause in skeletons because diseases that act that quickly don’t leave signatures on your bones. You know, if you think about it, if Ebola kills you it, doesn’t–

IRA FLATOW: It’s there and gone.

RACHEL FELTMAN: –affect your– yeah. Your bones are fine. So instead, researchers took teeth from a bunch of graves that were associated with the epidemic, and they scrubbed basically for DNA and matched bits of DNA to the genomes of known bacteria.

And so they were able to find that this strain of salmonella was present in all of these teeth. Now, this isn’t to say that salmonella singlehandedly caused this huge epidemic. There were probably other microbes in play.

It was also right around the time that Spain invaded, so there was violence. There was upheaval. People were changing things about where they lived and how they farmed that would have changed their sanitation practices. There was drought. So there were probably a lot of factors that went into this.

IRA FLATOW: Was not just a case of bad food poisoning.

RACHEL FELTMAN: No. No. There were probably a lot of factors. But this is a cool use of a technique that can help us solve these cold cases.

IRA FLATOW: It’s interesting, though, you know, how long the DNA was viable.

RACHEL FELTMAN: Right. Yeah. And, you know, we’re still getting better at looking at this kind of old fragmentary DNA. But it’s a technique that’s improving all the time, which is really cool.

IRA FLATOW: And obviously an important tool now to archaeologists who are looking stuff up.

RACHEL FELTMAN: Absolutely.

IRA FLATOW: They can look for the DNA. There’s news this week about lobsters. It’s kind of– well, you–

RACHEL FELTMAN: Yeah. So Switzerland has a new law now that it’s illegal to boil lobsters alive for humane reasons, which is actually really interesting because we know basically nothing about how lobsters experience pain, if they do it all, which is a problem for us in general.

You know, pain is something that exists if you feel it. So unless we can ask an animal whether they feel pain– which unfortunately, we can’t– it’s technically for us to ever know. Now, if an animal has a brain similar to ours, we can say, you know, they exhibit these behaviors that look like pain in us– like, you know, a dog nursing a wound. We say, clearly, that dog is in pain.

Lobsters are more like bugs, in that they have these de-centralized brains. They’re just kind of clusters of brain material all over different parts of their bodies. So even though they exhibit some signs that we could interpret as pain, like avoiding hot water, we don’t know for sure that they’re feeling pain.

And the tricky bit is that– so we know that a cow feels pain.

IRA FLATOW: Right.

RACHEL FELTMAN: We also know how to instantaneously kill a cow. We know how to kill a cow humanely because you just go for the brain, and that cow’s consciousness is over.

Because a lobster has a de-centralized brain. There’s no way to end its consciousness instantaneously. So the very thing about the lobster that makes us unsure of whether or not it feels pain makes it impossible for us to know we’re killing it painlessly.

All of this is to say if you want to cook a lobster, you should put it in the freezer first because that’s our best guess about how to anesthetize them.

IRA FLATOW: Is that what they’re saying– is that what they do in Switzerland? They’re freezing them?

RACHEL FELTMAN: So it’s not clear what they recommend people do in Switzerland because again, you know, they can say, well, you have to kill it before you boil it. But there isn’t a painless– there isn’t a better way to kill a lobster than boiling it that we know of.

But again, the best evidence we have is that if you put them in a freezer, it will hopefully anaesthetize them. Or you could just not eat lobster, I guess.

IRA FLATOW: So I guess it’s just not hitting them over the head with something.

RACHEL FELTMAN: It’s a lot more complicated than I ever thought.

IRA FLATOW: I guess– what about shrimp? Let’s not get into that. Other crustaceans and things like that.

RACHEL FELTMAN: Yeah. No, it’s a good question.

IRA FLATOW: And this is really big– it’s a thing in Switzerland.

RACHEL FELTMAN: Yeah. Yeah.

IRA FLATOW: Yeah.

RACHEL FELTMAN: They’ve taken a stance.

IRA FLATOW: And finally, shark news is going on– shark?

RACHEL FELTMAN: Yes. So head bonnethead shark in the Gulf of Mexico has been known to incidentally eat seagrass. But sharks are carnivores, so I think it was kind of assumed that the sharks just kind of accidentally ate this grass while eating things that lived in it and that they just pooped it right out.

But researchers decided to put them on an almost all seagrass diet, and they found that they still gained weight and that they were actually digesting and using these nutrients. So they are now officially the only known omnivorous sharks, which is pretty weird and cool.

IRA FLATOW: So that’s half a dozen weird and cool things you brought with you today, Rachel. Thank you very much.

RACHEL FELTMAN: Yeah. Thanks.

IRA FLATOW: Rachel Feltman, Science Editor at Popular Science.

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