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by minota 2773 days ago
Transcribing the interesting bits from 18:15

Man A (ATC?): There's nothing showing on either primary or secondary

Woman A: Ok, it was moving so fast. [Inaudible]

Man A: Alongside you?

Woman A: Yes, it was rapidly [inaudible] bright light and then it just disappeared at a very high speed. I am still wondering. Didn't think it was likely collision course. Wondering what sort it could be.

Man B: Meteor or another object. Some kind of re-entry. Seem to be multiple objects following the same sort of trajectory. Very bright where we were

Woman B (ATC?): Ok, that's copy, so what's the direction it was going in.

Man B: Virgin 76 [inaudible] saw that NRS 11-o'clock position two bright lights.

Woman B: Roger that's copy, thank you.

Man C: So that wasn't just me?

Man B: No. Yeah, very interesting, that one.

Man B: Virgin 76. I saw two bright lights 11 o'clock. Seem to bank over to the right and then climb away. Speed at least Mach [inaudible]

Woman B: Okay, we're passing that on, thank you.

Man D (or is it Man A?): [inaudible] 94 Shannon.

Man D: Just to let you know that other aircrafts in the area have also reported the same thing. So we're going to have a look and see.

Man E: Speed was astronomical. It was like Mach 2.

Man D: Roger, OK. Thank you.

3 comments

I know meteors seems to be a common theory, but do they normally travel that fast?
I don’t think you can trust their assessment of its speed. There’s no way to reliably determine the speed of an unknown object of unknown size and distance.
I was watching a meteor shower once, and after a few hours, the angle seemed to change. Instead of streaking across the sky, they appeared as a circle that got brighter and bigger before winking out....they were coming right at me. This could explain the light in this video if it were a fairly large meteorite, maybe.
Mach 2? Yes. Far in excess of it.
They enter at orbital velocity or higher, so yes. Mach 20 or 30 would be on the low end. Of course depending on their shape and mass they lose a lot of it on the way down...
And all the light the aircrews reported was kinetic energy before hitting the atmosphere.
https://en.wikipedia.org/wiki/Hypersonic_speed

The relevant regime for astronomical entities is in above the 'high-hypersonic' and into 're-entry speeds' (uber-sonic?). These are above Mach 25.

At these speeds, not only is the air no-longer considered an ideal gas, nor a two-temperature ideal gas, nor a dissociated gas (O2 and N2 become O and N along the wings), nor an ionized gas (electron temperature must now be considered), but rather a radiation dominated gas. Modeling these radiation dominant gases is very hard. As you increase the number of volumes to model, the computation load grows exponentially.

What I want to know is, do they tend to "bank and climb away"
Far more likely that the observer interpreted it the wrong way, happens all the time.
If they go straight thru the atmosphere and out then yes, that is exactly as they would appear.
Do meteors ever dip into the atmosphere, light up, and skip away? Like a skipping stone?
It's very unlikely but definitely possible. If the meteor is fast enough and targets outer earth atmosphere, it an enter outer atmosphere, slow down, light up due to friction, then escape earth atmosphere vertically. The only problem with this scenario is that meteor has to be much faster than Mach 2, unlike what pilots reported. But it's easily possible they saw a Mach 12 meteor and thought it's Mach 2.
If the meteor has a shape that could generate lift in some way, I can definitely imagine this happening.
Earth moves at ~100,000 kph around the Sun.
would be interesting to know the relative trajectory – would help determine if it was a known satellite reentry or on a typical orbit of debris (lots of periodic comets have well known debris trails, they form most of the "meteor showers" that happen yearly.)
The transcript above refers to the object banking and climbing. That sounds a lot more like a secret military vehicle than falling space debris.
Could be one skipping off the atmosphere. Aero breaking (https://en.wikipedia.org/wiki/Aerobraking) if you want to stick with the spacecraft theory.
I'm not an astronomer but it seems unlikely to me a meteor skipping off atmosphere would be as slow as Mach 2 and not hot enough to shine red.
What if it was perceptually at Mach 2 / distance X yet really was at Mach 20 / distance 10 * X ? (Bullshitting numbers here, but you get the point)

Angular speed across FoV is a function of distance from the object and the only thing that makes us understand that high altitude airplanes are nowhere close to a standstill is that we can infer distance from the intrinsic knowledge of the airplane size.

If all observers are close enough together we'd be unable to uncover the illusion, as that would require a widespread enough configuration.

Additionally, I question the "astronomical" attribute, especially with planes cruising at ~800kph, Mach 2 is at most 2.5 their typical speed. Concorde is hardly astronomical, and although jet fighters are not chasing for top speed anymore some of them are still able to go to such Mach factors. Now, Mach 12, that would be closing in to being astronomical (entering the order of magnitude of an ICBM descent speed).

I believe they call such a thing a 'bolide'
Could be outgassing.
Or plain lift. If the object is flat when it hits the atmosphere, it may get some lift and bounce back to space.
Maybe it's something from the recent Rocket Lab launch?
Seems extremely unlikely air traffic control wouldn't know of it, since it's potentially a >200-casualty mistake if it hits a commercial airline.
The rocket lab launch was south from New Zealand - and there aren't many planes flying around down there as far as I know.

I'm guessing only the final stage would still be airborne/in space once it orbited around to populated areas. And the second/final stage should be deliberately de-orbited for exactly this reason, right?

It was either Swamp Gas or Weather balloons. Everyone knows that.