Hacker News Reader

Comment by whamlastxmas | Hacker News Reader

YouTube link: https://youtu.be/c0gnYzhTL5A?si=3fS6uvL3_5LtE7La

Pro Tip: While the YouTube player is paused, the comma and period keys move back/forward by one frame. (Memory aid, < and > but without using Shift -- assuming US PC keyboard layout.)

Here's the video without any news overlay: https://drive.google.com/drive/u/0/folders/1YfVmkgXgwGVcxdqW...

1920x1080@20fps, and there's 2 frames with the meteor in it before it impacts.

I'm messing around a bit, but no matter how I turn it over, I'm getting something like 36 m/s for the meteor's (terminal) velocity, while I'm expecting it to be going at least 60 m/s

Possibly I'm making a mess of figuring out the actual scale of the image/video.

Posting here in the hope someone can do this a lot better than me!

With only two frames and no apriori calibration for that site, etc it'd be hard to constrain the error.

That said, there's entire international communities dedicated to fireball trajectory analysis.

Starting with the OG: https://fireballsinthesky.com.au/

They do set up well in advance and like to have overlapping coverage from multiple sites, of course.

Oh! The google drive link also provides the divot with a ruler next to it. Using that instead of going by a rough guesstimate based on just a couple of pixels really helps. In that case the theoretical terminal velocity should have been about 39 m/s , which is pretty close to the speed I estimated. I'll take it.

Thanks! This shows it for 2 frames instead of 1 because there is no channel overlay showing the location (Canada) on top of the meteorite

Link without tracking for the lazy btw: https://youtu.be/c0gnYzhTL5A

This is so cool. Sorry. I can't help myself.

Reply on news.ycombinator.com