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Scientists announced a major discovery about Uranus using 34-year-old data from Voyager 2, and the Canadian telescope CHIME has detected 9 new FRB repeaters, helping us learn more about these mysterious signals.

Hosted by: Hank Green

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Sources:
https://iopscience.iop.org/article/10.3847/2041-8213/ab7208
http://www.frbcat.org/
https://www.universetoday.com/145440/even-more-repeating-fast-radio-bursts-discovered/
https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083909
https://www.nasa.gov/feature/goddard/2020/revisiting-decades-old-voyager-2-data-scientists-find-one-more-secret
https://www.lpi.usra.edu/icegiants/mission_study/

Images:
https://en.wikipedia.org/wiki/File:Canadian_Hydrogen_Intensity_Mapping_Experiment_-_overall.jpg
https://www.eso.org/public/videos/eso1915b/
https://vimeo.com/197539739
https://svs.gsfc.nasa.gov/4140
https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00035
https://commons.wikimedia.org/wiki/File:Plasmoid.jpg
https://www.nasa.gov/feature/goddard/2020/revisiting-decades-old-voyager-2-data-scientists-find-one-more-secret
https://svs.gsfc.nasa.gov/13506
https://svs.gsfc.nasa.gov/4144

Thumbnail: https://www.jpl.nasa.gov/news/news.php?feature=7587
https://voyager.jpl.nasa.gov/galleries/images-voyager-took/uranus/
[♪ INTRO].

Ever since 2007, scientists have been seeing huge, fast bursts of radio energy from mysterious sources around the universe. We still don’t know why they happen or exactly where they come from.

But astronomers keep trying to find more of these fast radio bursts, or FRBs, in the hopes of finally understanding them. Well, last month, scientists using the Canadian telescope CHIME announced nine new confirmed detections, and they’ve already helped us learn more about these mysterious signals. What’s really exciting is that these new detections are all repeaters.

Usually, FRBs look like a burst from some part of the sky that never bursts again, but sometimes, in the case of repeaters, the same source will burst multiple times. And no one quite knows what to make of that. Are repeaters totally different from FRBs that just burst once?

Are they the same type of object, just in very different environments? Are they aliens? They’re probably not aliens.

But one of the main questions astronomers are trying to answer is how these two types of FRBs are related, or not related. So in a study published in the Astrophysical Journal Letters last month, scientists took advantage of all this new data to do a statistical comparison of repeaters versus non-repeaters, to see if they could find anything to explain why only some sources repeat. One thing they looked at was the duration of the radio pulses, because if two events have totally different mechanisms, you would expect them to last different amounts of time.

They also looked at how the radio waves dispersed, or spread out, before reaching Earth, because that could tell astronomers something about the environment around the FRBs. In the end, they found that repeaters tend to have a longer duration than non-repeaters, but that the signals tend to be dispersed about the same amount. So that suggests that the sources might live in similar environments, but have different mechanisms driving the bursts.

This confirms the results of a previous paper based on CHIME data, but the conclusions of both papers rely on a small data set. Fortunately, CHIME has made hundreds of other FRB detections; they just need to be processed and confirmed. So when the CHIME team finishes sifting through all that data someday, scientists will be able to repeat this study with a much bigger sample size, and we’ll be even closer to solving the mysteries surrounding FRBs.

Next, telescopes like CHIME aren’t the only ones taking us into new territory recently. Last week, scientists announced that they’d made a major discovery about Uranus, which they made using 34-year-old data from Voyager 2. Voyager 2 passed Uranus back in 1986.

And it found all kinds of stuff right away, like two new rings and eleven moons. But it also picked up on something that no one had noticed before: a plasmoid, charged gas from the planet’s atmosphere that gets siphoned into space by the planet’s magnetic field. Magnetic fields generally help protect planetary atmospheres, because they deflect the solar wind, which is full of charged particles that can strip an atmosphere away.

But a magnetic field can also do the exact opposite and funnel particles from the atmosphere right out into space. Over time, that can change the atmosphere’s composition and eventually strip a planet of its atmosphere altogether. So astronomers generally want to know how magnetic fields and atmospheres interact, because it can say a lot about a planet’s eventual fate.

On Uranus, though, that’s complicated. The planet spins sideways, and the magnetic axis makes a 60-degree angle with the axis of rotation. That means that, as Uranus rotates, its magnetic field is wobbling all over the place.

It’s really complicated to model, and scientists still don’t understand it. So, when NASA started thinking about how feasible it would be to revisit Uranus one day, scientists at the Goddard Space Flight Center decided that, first, they needed to take another look at that planet’s magnetic field. And since the Voyager mission was the last time we gathered any magnetic data from Uranus, they started by going over all that old data.

The measurements Voyager took back in the ’80s actually had a really high resolution, but the software and processes that existed back then to analyze that data smoothed over some of the detail. Fortunately, those processes have changed a lot since the 1980s, and in the new study, published last week in the journal Geophysical Research Letters, scientists at NASA were able to use modern techniques to look at the data in much finer detail. That’s when we saw something unusual: a spike in the strength of the magnetic field.

It almost looked like a heartbeat: a spike up, followed by a spike down. And the scientists who spotted it recognized it as the signature of a plasmoid, one of those magnetic bubbles full of escaped particles from the atmosphere. When they analyzed it further, they found that the plasmoid was a cylinder of atmospheric gas trapped out in the tail of Uranus’ magnetic field.

Plasmoids with this shape tend to form as bubbles of gas that pinch off from the atmosphere and fly off the spinning planet into space, and the scientists think similar plasmoids could be responsible for anywhere between 15 and 55 percent of the leakage from Uranus’ atmosphere. That’s a wide range because this is just one data point, so we can’t make any sweeping conclusions about the whole planet, but it can help scientists decide what to keep an eye out for future missions. Which is not too shabby for 34-year-old Voyager probe data.

Thanks for watching this episode of SciShow Space News! And if you want to learn more about this odd planet, you can check out our episode on the mysteries of Uranus. [♪ OUTRO].