Award-winning journalist Tim Harford explains what it means when you hear that a COVID vaccine is 95% effective. Then, learn about Sentinel Island, home to the last uncontacted people on Earth, and what we can learn from planet HD 106906 b.
Award-winning journalist Tim Harford explains what it means when you hear that a COVID vaccine is 95% effective. Then, learn about Sentinel Island, home to the last uncontacted people on Earth; and what we can learn about our solar system’s theoretical “Planet Nine” from the newly discovered planet HD 106906 b.
Additional resources from Tim Harford:
North Sentinel Island Is Home to the Last Uncontacted People on Earth by Reuben Westmaas
Scientists discovered a solar system with its own version of the theoretical "Planet Nine" by Grant Currin
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/what-a-95-effective-vaccine-actually-means
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about what it means when you hear that a COVID vaccine is 95% effective, with award-winning journalist Tim Harford. You’ll also learn about the island that’s home to the last uncontacted people on Earth; and how scientists discovered a solar system with its own version of the theoretical “Planet Nine.”
CODY: Let’s satisfy some curiosity.
Yesterday, Tim Harford showed us how to better make sense of the numbers we see in the news and on social media. And maybe the most commonly heard number right now is 95, as in "a 95% effective COVID vaccine." That's a statement a lot of people get wrong, so I asked Tim how we can figure out what it really means. Tim Harford is an award-winning journalist, economist, and broadcaster, and author of the new book "The Data Detective: Ten Easy Rules to Make Sense of Statistics." Here's a clip from our conversation.
[CLIP 1:57]
Just to be totally clear: a vaccine with 95 percent effectiveness doesn’t mean you have a 5% chance of catching the virus if you get the vaccine, and it doesn’t mean you have a 5% chance of having symptoms. It means that if you get the vaccine and you are exposed to the virus in a way that would have ordinarily made you experience symptoms, you then have a 5% chance of having symptoms instead of a 100% chance of having symptoms. I’ll put it another way: You have a certain chance of being exposed to the virus, and a certain smaller chance of that virus infecting you in a way that causes symptoms. The vaccine reduces that second chance by 95 percent. But it’s even better than that, because like Tim said, this chance is only about symptoms — the vaccine is 100% effective at preventing death, and there’s good evidence that even if you do have symptoms, they’ll be milder than they would be ordinarily.
Again, Tim Harford is an award-winning journalist, economist, and broadcaster, and author of the new book "The Data Detective: Ten Easy Rules to Make Sense of Statistics." You can find a link to pick it up in the show notes.
In our well-connected 21st-century world, it might be surprising that any society could remain isolated from other civilizations. And yet! That’s exactly the case for the people who live on North Sentinel Island in the Bay of Bengal [BEN-gull]. They’re known as the world’s last uncontacted people — yes. Today. In 2021. Uncontacted!! Not that no one’s tried. Few who have visited the island have survived to tell the tale.
The people of North Sentinel Island have kept intruders out for about 60,000 years. And that’s despite the fact they were known since the days of Marco Polo and been visited multiple times, on purpose and by accident, over the years.
One of the first deliberate encounters with the Sentinelese came in 1880, and it might explain why they've been so hostile to outsiders ever since. An expedition led by anthropologist M.V. Portman ended when the European researchers kidnapped an elderly couple and four children in order to "study" them. To make things worse, many of the victims died shortly after from disease.
But even before this happened, the Sentinelese were hostile to outsiders. Thirteen years previously, an Indian merchant ship was wrecked on the surrounding reefs and attacked from the jungle. Something similar happened in 1981 when a merchant vessel was grounded on the reef, which left the crew to keep the Sentinelese at bay with improvised weapons. They were rescued after about a week via helicopter.
The only successful contact came in 1991 when the anthropologist TN Pandit finally interacted with them after two decades of distant observation. But the Sentinelese still don't want you there. In 2006, two poachers were killed when they broke the island's quarantine and ran afoul of its residents, and in 2018, a Christian missionary was killed when he attempted to visit the island.
Today, the Indian government recognizes the island as a sovereign entity and makes efforts to ensure its people are left undisturbed. All we know about the Sentinelese is that their population numbers somewhere between 50 and 400, they live a hunter-gatherer lifestyle, and they’ve lived on the island since before the invention of agriculture.
A lot of what we know about life on North Sentinel Island can be inferred from the peoples of the surrounding islands. After all, North Sentinel Island isn't that isolated — it's only 20-odd miles from the other Andaman islands, which are now bustling with their own cities and roads. The way aboriginal societies once thrived on the other islands can offer clues as to the current lifestyle on North Sentinel Island. For now, that's how it'll stay. The Sentinelese want it that way.
There are a few objects way out in the solar system that move in mysterious ways. That has led astronomers to suggest that maybe there’s a ninth planet wayyyy out there, beyond Neptune, that we’ve never seen. This so-called Planet 9 is purely theoretical at this point, but some scientists are pondering what the planet would be like, if it did exist. Now, a team of astronomers have come across a strange exoplanet that may teach us a thing or two about that theoretical planet closer to home.
The exoplanet in question is gigantic. It’s name is HD106906 b, and it was first spotted in 2013.
The planet weights in at 13 times the mass of Jupiter, and it lives in a solar system that’s pretty different from ours. It orbits two stars that orbit each other. This is called a binary star system, and it’s actually pretty common. Astronomers think that about a third of all star systems in the Milky Way are binary.
Another important detail is that this exoplanet moves in an orbit that’s verrrrry far out from its stars. The exoplanet is about 730 times farther from its stars than Earth is from the Sun. That means its stars exert a weak gravitational pull that makes the exoplanet putter along its orbit at a...let’s say comfortable pace. One year on the exoplanet lasts about 15,000 Earth years.
All this might seem like basic info, but it was actually pretty tricky to figure out. Astronomers had to spend 14 years using the Hubble Space Telescope to get the data necessary to infer basic facts about the exoplanet’s slow journey along its massive orbit.
Here’s what the researchers think led to the exoplanet’s strange location. It probably started out a lot closer to its star. The gravity from a huge disc of gas close to its stars made the planet’s orbit decay and brought it closer and closer toward the stars. The gravitational maelstrom from those two stars orbiting each other ended up knocking the exoplanet into an off-kilter orbit that shot it outward, away from home. The astronomers think a completely different star that was just passing by stabilized the exoplanet’s orbit and kept it from leaving its solar system entirely.
If there is a ninth planet orbiting far beyond Neptune, then there’s a good chance that its origin story is very similar to this exoplanet’s. They haven’t found Planet Nine, but they might have found its doppelganger.
Let’s do a quick recap of what we learned today
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CODY: Today’s stories were written by Ashley Hamer, Reuben Westmaas, and Grant Currin, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Scriptwriting was by Cody Gough and Sonja Hodgen. Today’s episode was produced and edited by Cody Gough.
CODY: Join us again tomorrow to learn something new — with 95% effectiveness! — in just a few minutes.
ASHLEY: And until then, stay curious!