Meteor over Croatia

[Shpaget]

This morning (9:34 UTC) there was a meteor over Croatia. It's still unclear where exactly it entered and exploded, videos are still being processed, but it caused quite some noise. Unfortunately I was in a basement at the time and didn't register the boom, but my mom heard it.

There are already quite a few videos of it, some even from shot from Italy.

This was shot in Zagreb and is the best video I was able to find:

 

[Scotius]

Very cool I'm glad we didn't get a repeat of Chelyabinsk event.

[Vanamonde]

When you compare this to the visual rate you see aircraft travelling at that altitude, the speed of this thing is dizzying. 

[magnemoe]

Looks like most meteorites blow up high up. It makes some sense as most are not very solid and if they start breaking up the surface area increase who increase drag who increase the breakups. 
And yes you want them to burn up high up.
Interesting I think I saw much smaller meteorite do something like that as an kid, it was an flaming light in the night. The weird thing was that it dimmed and then started burning again. 
Friend of mine said it was an nike anti air missile who was two stages being test fired, we all agreed on that. 
However they was never tested over populated areas, an effect like this on an smaller meteorite would explain it. 

[Zeiss Ikon]

I saw a fireball over northern Idaho back in 1980 -- greenish, bright, and traveling south to north.  We figured then it was probably a satellite burning up after its orbit decayed.

Those don't generally get bright enough to be visible in daylight, though, never mind to flare a camera sensor in daylight...

@Vanamonde Average meteoric entry speed is something like 20 km/s, as I recall -- compared to ~1 km/s for an SR-71 going all out...

[Shpaget]

Yeah, that thing really was in a hurry. Initial estimates are that it broke up at around 30 km. Local astronomy and seismological organisations are still processing data and collecting videos to triangulate.

[Guest]

I saw a bolide like that as a kid once too. Impressive stuff.

[Josh IN SPACE]

What a quickster!

[Starman4308]

I do hope nobody was hurt! It's some nice footage, even from a dashcam.

<Slight soapboxing here>

This helps illustrate why we should put more effort into detecting Earth-crossing asteroids, particularly those inside Earth's orbit (where it's hard for amateurs to detect them). Not only are some events (e.g. Cheylabinsk) dangerous and utterly preventable, but less dangerous events could easily serve as a tourist attraction; it would've been neat to have good cameras set up and ready-to-go to catch this one.

[lajoswinkler]

Preliminary analysis by Croatian astronomical union

- date and time: 2020-02-28 09:30:34 UT

- estimated energy release equivalent: 0.34 kT

- estimated speed: >20 km/s

- estimated mass: 5.5 t

- estimated size: 1.5 m

 

[Wjolcz]

On 3/3/2020 at 4:01 PM, lajoswinkler said:

- estimated mass: 5.5 t

- estimated size: 1.5 m

That's a surprisingly high mass for something that's 1.5m. I don't know much about asteroid densities but I guess either that rock was pretty dense or it was metal-rich.

Nevermind, the Chelyabinsk meteor had similar density.

Edited March 4, 2020 by Wjolcz

[cubinator]

33 minutes ago, Wjolcz said:

That's a surprisingly high mass for something that's 1.5m. I don't know much about asteroid densities but I guess either that rock was pretty dense or it was metal-rich.

Looks to be a stony-iron or some such composition, as a pure iron sphere would be about 13 tons. See page 7 of https://arxiv.org/pdf/1203.4336.pdf

[Zeiss Ikon]

Even if you figure these asteroids are only about 50% solid (i.e. similar to a pile of pebbles, lightly vacuum welded together, hence why they break up and don't produce a crater on the ground), the overall density should be close to twice that of water or solid ice -- so a 1.5 m spheroid at 5.5t is pretty reasonable.

[lajoswinkler]

First fragment found. Location: Novo mesto, Slovenia. 203 g chondrite.

https://bojanambrozic.com/2020/03/08/najden-je-bil-prvi-kos-meteorita-novo-mesto/