Meteors swarm, stars form, exomoons the norm?

Happy Thanksgiving to my American readers! This holiday is a fun one, though its history is somewhat, um, fraught. But it’s a holiday associated with leftovers, so take a look at what I wrote about it last year, referencing something I said about it in 2019. Hey, reuse, recycle, rejoice, or something like that. But the sentiment I express there still holds true: I’m thankful/grateful for a lot of stuff, but all of YOU are way up on the list.

So, thanks!

Pic o’ the Letter

A cool or lovely or mind-bending astronomical image/video with a description so you can grok it

Back in May 2022 I wrote about going outside to watch a meteor shower called the Tau Herculids, and how I saw three meteors in a row. I speculated that they might have come from the same rock that broke apart shortly before it hit the Earth — I hardly saw any meteors after being out a while, but these three came in quick succession and two were very close to each other in the sky.

I still don’t know if there just random rocks coincidental in time or actually from the same parent one, and I’ll never know. There’s no way to be sure.

On the other hand, the American Meteor Society recently reported that a wide-field camera in Norway caught a bunch of meteors all occurring very rapidly, and yeah, it’s very clear they WERE associated with each other. And they have the video to prove it. Watch (click the tweet to see the video larger):

WHOA. That’s very cool. You can see a bright one near the horizon, then a whole slew of them coming down on the right. They seem to be headed in slightly different directions, but that’s almost certainly due to perspective, which I describe in the Tau Herculid post linked above.

Some of the meteoroids — the solid bits of rock or metal that burn up to create the meteor — are very fragile, so it’s not a huge surprise one might break up. However, judging from the brightness these were pretty small, probably grape-sized or so, and the original rock would’ve been a few centimeters across. I’m not sure what would cause something that small to break apart. Maybe it had a little bit of ice or some other substance in it that got warmed by sunlight, turned into a gas, and that broke the rock apart.

Meteor swarms like this are rare, but with so many cameras pointed skyward we’re bound to see rare events more often. Did you know you can get a camera yourself and join a global network of meteor-watching people? Yup. I wrote about it in 2021. If you have the wherewithal it’s a pretty nifty project and it can do real science. Give it a shot if you can!

Tip o’ the Whipple Shield to Will Gater.

Search and Destroy

Googling gone wrong

As I’ve written before, I have a lot of numbers floating around in my head, but sometimes I need to double check them when I’m writing an article to make sure I have them right.

That doesn’t always go as planned.

I was writing an essay about the early Universe, specifically when stars started to form out of the gas that was just starting to coalesce into galaxies for the first time. I knew it was something like a hundred million years or so after the Big Bang, but in this case I needed to be a little more accurate.

So, I went to Google and entered “when did first stars form”. This is what I got:

Yeah. Thanks, Google. Maybe not exactly the kind of stars I meant.

News Cues

I choose a few to imbue clued views

Astronomers have found over 5,000 exoplanets, worlds orbiting other stars. But evidence for those planets having moons — exomoons — is scant. Most planets have been found using the transit method, when a planet blocks a little bit of the light from its star, so we see the star’s brightness dip a teeny tiny bit. The amount of dimming depends on the size of the planet, of course, where a bigger one blocks more light.

A moon, almost by definition, will be smaller in size than its planet, so it blocks even less light, making it much harder to detect. Unless we use a different method…

Jupiter’s moon Io is magnetically connected to the giant planet, and their complicated interaction produces a lot of energy emitted as radio waves. If exoplanets are similarly connected to their exomoons, then maybe we can find them that way.

A team of astronomers tried just that, using the Giant Metrewave Radio Telescope in India to look at three different stars with planets that might have magnetically coupled moons [link to paper]. The result? Well, unfortunately, nothing. They got no detections. But this isn’t the end of the story! There are lots of possible reasons this didn’t work: No moons, no volcanic moons, no strong magnetic field, weaker emission than predicted, and so on. Three targets is a drop in the bucket compared to what’s out there, and this is just a first attempt. A new radio array, called LOFAR, would be able to do a more sensitive search at better radio wavelengths, too, so that’s something that will hopefully be undertaken in the future.

It’s a solid bet that a huge number of exoplanets have exomoons. We just have to figure out how to find ‘em.

Tip o’ the phase switch to AstroBites — they write great articles about current research, so you should follow them. They have a nice, more in-depth explanation of this exomoon research, too.

Et alia

You can email me at [email protected] (though replies can take a while), and all my social media outlets are gathered together at about.me. Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or nine, too. Thanks!