Previous: Cherenkov Radiation : Particles Faster Than the Speed of Light?
Next: The Stardust Mission: Collecting Comet Dust in Space



View count:133,860
Last sync:2019-06-14 08:00
A bizarre lonely star grows brighter, and we investigate a study that looks at whether astronauts that leave the magnetosphere have higher incidences of heart disease.

Hosted by: Hank Green

Support SciShow by becoming a patron on Patreon:
Dooblydoo thanks go to the following Patreon supporters -- we couldn't make SciShow without them! Shout out to Kathy & Tim Philip, Kevin Bealer, Andreas Heydeck, Thomas J., Accalia Elementia, Will and Sonja Marple. James Harshaw, Justin Lentz, Chris Peters, Bader AlGhamdi, Benny, Tim Curwick, Philippe von Bergen, Patrick Merrithew, Fatima Iqbal, Mark Terrio-Cameron, Patrick D. Ashmore, and charles george.
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:
Looking for SciShow elsewhere on the internet?

Image Sources:
[SciShow intro plays]

Hank: It’s not often that we get to see astronomy happen right before our eyes. But in the issue of the Monthly Notices of the Royal Astronomical Society being published next week, a team of astronomers reported that they’ve watched a young star get hundreds of times brighter in just a couple years. That’s lightning fast, by astronomy standards -- and nobody's exactly sure how it’s happening.

Stars are generally born in stellar nurseries, which are huge clouds of gas and dust where hundreds of stars can form at a time. The stars in these nurseries usually take a really long time to sweep up all the gas around them, but every once in a while astronomers will see a young star that suddenly starts vacuuming up everything nearby. All the gas that would’ve taken thousands of years to fall onto the star gets sucked up in just a few years. And with all that gas falling onto the same place, the star’s surface heats up and gets hundreds of times brighter than it was before.

Then, after a few months or years of intense activity, the stars cool off and start to calm down. Astronomers have seen about a dozen of these sorts of stars before, but they think it’s something that most stars go through before they leave the nursery. So when they noticed a young star called CX330 rapidly getting brighter in 2009, it seemed like just another one of these super-active events.

But there are a couple of things that set CX330 apart. Not only did it start out hotter and denser than other stars — it’s over a thousand light-years from the nearest stellar nursery. So all that gas that’s been falling onto the star and heating it up? Astronomers aren’t sure how it got there. CX330 could have been thrown out of a nursery, but that wouldn’t explain all the gas. The star is only about a million years old, so it would’ve been thrown out too quickly to be able to drag all that gas along with it.

Another possibility is that there’s a lot more gas around CX330 than we’d expect, which would put the star in a kind of tiny nursery of its own. If all this extra gas is there, astronomers haven’t seen it — though they have been actively looking for it. So for now, CX330’s explosive growth is still a mystery.

But while some space researchers are studying how stars are born, others are examining how astronauts die. In a paper published last week in the journal Scientific Reports, a group of researchers announced that the Apollo astronauts who went to the Moon were 4-5 times more likely to die of heart disease than other astronauts. But don’t... like, unpack your spacesuit just yet. There are a lot of strict physical requirements to be an astronaut, which means that they tend to be much healthier than the average person.

So it was important to compare astronauts against each other instead of against just random people of the same age. The researchers started by splitting the data on 84 deceased astronauts into three groups: 7 who went to the Moon, 42 who went into low-Earth orbit, and 35 who trained as astronauts but never left Earth. Then, they looked at the difference in how the astronauts in the three groups died.

On the surface, the results look pretty grim: 43 percent of the Apollo astronauts died of heart disease, compared to only about 10 percent of both of the other groups. There’s a simple way to explain this huge difference: the Apollo astronauts were the only people to ever leave Earth’s protective magnetosphere, which blocks out most cosmic radiation long before it hits us. And mice exposed to increased radiation tend to show early signs of heart problems, so it’s possible that there’s a link between radiation and heart disease.

But it’s hard to draw too many conclusions from this study, because... most astronauts are still alive. There were only 7 Apollo astronauts in the sample, and only 3 of them died of heart problems. Yeah, that’s 43%, but it could have easily been a statistical fluke that three of them died in similar ways.

So these results aren’t exactly conclusive proof that astronauts who go far from Earth will have heart problems. But it is something for future, larger studies to look at, and for astronauts and their doctors to consider if they’re planning a mission to the Moon or Mars.

Thanks for watching this episode of SciShow Space News, and thanks especially to our patrons on Patreon who help make this episode and this entire channel possible. If you want to help us keep making videos like this, you can go to, and don’t forget to go to and subscribe!