EEVblog #846 - Solar Panel Micrometeorite Impact!

[EEVblog]

Blue ice is a thing of the past. Modern airliners (Airbus and Boeing) have closed vacuum systems with clean flush water draining into waste tanks.

That's seems to be the consensus on that, so I think that can be ruled out.
Someone mentioned actual ice forming on the plane by the time it gets to my place (30km out or so) it might have enough height for that 

[HAL-42b]

Someone mentioned actual ice forming on the plane by the time it gets to my place (30km out or so) it might have enough height for that 

That is possible but unlikely to do any damage.

[JazzHarper]

It's estimated, based on meteorite finds in desert areas, that meteorites larger than 10g reach the surface of the earth at a rate of 1 per million km² per year.  Dave's solar panel installation has an area of 1.93e10^-5 km2, so the probability of an impact on the array in any given year would be 1.93e10^-11.  That's 1 in 52 billion, if my math is correct.  Meteorites smaller than 10g comprise the vast majority of mass that falls to earth, but have very little kinetic energy when they reach the surface; they are essentially dust.

[Fungus]

It's estimated, based on meteorite finds in desert areas, that meteorites larger than 10g reach the surface of the earth at a rate of 1 per million km² per year.  Dave's solar panel installation has an area of 1.93e10^-5 km2, so the probability of an impact on the array in any given year would be 1.93e10^-11.  That's 1 in 52 billion, if my math is correct.

Dave's a lucky guy!

[jnissen]

It has to be a rock or hard ball. I don't buy the micro-metorite or even a larger meteorite theory. Way to low of probability. Much more likely to have a rock thrown up from a lawn mower. I have panels in my back yard and I have to be very careful when mowing as I was warned by the installer that rocks from mowing are a common cause of panel damage. I use a lawn tractor with a 22 HP motor and three blade deck. When it gets hold of a rock it can toss it an amazing distance and terrific force. I know this as I have had to change the mower blades a time or two. The impact ring seems to show it may have even been a ball that may have been launched by a mower. I unfortunately find balls in the grass all too often as my dog will carry these things into the yard. Tennis balls get ripped to shreds but a baseball or hard ball turns into a dangerous projectile.

Perhaps these guys live near you Dave? https://youtu.be/dRS5mBt6J-o

[Brumby]

The small pointy dent on the back doesn't seem to be in the centre of the two bigger circles if you know what I mean. So I wonder if the centre of the crater on the front lines up with this small dent, or with the big circles?

I noticed that as well - and I find your question an interesting one.  I suspect the ding out the back will line up with the fine point of impact at the front, but I am interested in how the ripple impact pattern on the back lines up with the front face.



Dave - if you have a moment, can you check that?


I'm thinking the pointy bit of an object hits first, causing the crushed point of intrusion - but that this was a bit off centre with the bulk of the object's mass then impacting the glass with more of a blunt force trauma.  The pointy bit causes the ding out the back and the bulk mass the ripple impact pattern.

Object could be a rock with a pointy bit - or a cricket ball with a nail stuck in it.

[Dinsdale]

I think you can draw a straight line between any two points.

[SL4P]

I'm still in - for a 12mm (1/2-inch) nut or such falling from a plane at 25,000 feet.  It would hit and bounce maybe 10-20m at that speed/angle/distance.

[Brumby]

Don't forget - Sydney is a waypoint for air traffic passing through.  It's not uncommon for flights from New Zealand to pass overhead at 30,000ft or more on their way to Asia, for example..

[PeterL]

Blue ice is a thing of the past. Modern airliners (Airbus and Boeing) have closed vacuum systems with clean flush water draining into waste tanks.

That's seems to be the consensus on that, so I think that can be ruled out.
Someone mentioned actual ice forming on the plane by the time it gets to my place (30km out or so) it might have enough height for that 

You could check on flightradar24.com or similar sites at which height the big birds pass over your house.

[Brumby]

You could check on flightradar24.com or similar sites at which height the big birds pass over your house.

I have the App on my phone - and I often check when I hear something overhead.  That's how I know about the NZ flights to Asia...

[PeterL]

The small pointy dent on the back doesn't seem to be in the centre of the two bigger circles if you know what I mean. So I wonder if the centre of the crater on the front lines up with this small dent, or with the big circles?

I noticed that as well - and I find your question an interesting one.  I suspect the ding out the back will line up with the fine point of impact at the front, but I am interested in how the ripple impact pattern on the back lines up with the front face.



Dave - if you have a moment, can you check that?


I'm thinking the pointy bit of an object hits first, causing the crushed point of intrusion - but that this was a bit off centre with the bulk of the object's mass then impacting the glass with more of a blunt force trauma.  The pointy bit causes the ding out the back and the bulk mass the ripple impact pattern.

Object could be a rock with a pointy bit - or a cricket ball with a nail stuck in it.

I have no idea about the construction of these pannels, but maybe the pointy bit is something between the layers, like a spacer or so. Knowing how everything lines up would certainly give a better insight in this matter.

[SeanB]

I would guess it is space debris, probably a deorbited Progress vehicle, or the remains of the launch vehicle upper stage as it deorbited and burned up on re-entry into the atmosphere on its way to final impact in the South Pacific Ocean. As it hits the upper atmosphere you get stress and compression heating, which ablates small parts off the vehicle as it descends on the final part of the orbit, taking small pieces of debris off along the way. Sydney is on the right path for the final orbit path to pass over,  and the craft will be low enough at the time that it will be experiencing significant stress and heating.



Orbital path of MIR, and you can see that the final landing site was close to Australia, while the ISS path does often pass over Sydney, especially in the summer months.

http://www.satview.org/spacejunk.php

Depending on when the damage was done, it could even be this one.

http://www.space.com/29344-falling-russian-spacecraft-reentry-tonight.html

http://earthsky.org/space/doomed-russian-spacecraft-to-fall-from-space

[FrankT]

I think it was a stone thrown by a lawn mover

I think it was a stone thrown by a Dxxkhead.

[Fungus]

It has to be a rock or hard ball. I don't buy the micro-metorite or even a larger meteorite theory. Way to low of probability.

What does probability have to do with it? 

Random shit happens all the time.

Dave didn't plan for this to happen. He wasn't sat there waiting for it. If he'd made a video last year saying, "I've just put my panels up, now let's wait for the meteorites...", then you could start calculating probabilities.

He didn't. Random shit happened. End of.

[Svuppe]

Probability or not, they do fall from time to time, and they have to land somewhere.
Here is one I have. 3 cm long, 12 grams and with 18% iron.

[Brumby]

Hey Dave!!

Looks like we've found whodunnit.... 

[Brumby]

But ... hmmmm ..... maybe not.  12g seems a bit light for the damage caused...


But the shape looks right 

[Lightages]

Here is an example of what could have caused the damage. This is a iron nickel meteorite that I have that fell in Russia in 1947. It weighs 47g.

[6581]

This thread is rapidly turning into "show us how your meteorite looks like." Does everyone here have their own meteorites?

[TeaNTronics]

i think it might be a good idea to put security camera on the roof facing the panels.
for monitoring the panels

[Tinkerer]

Have you searched the area with a metal detector?

I don't have one.

Time for a metal detector build video...

Lol, I've been thinking exactly the same!

Also my thought. If it is an actual metorite that can be recovered, you are looking at something that could be worth some serious money. Collectors and the like will pay big dollars for these things. Especially in some cases if they have an interesting story.
I would be willing to bet that if it was a meteorite, it was metallic in composition.

[Don Hills]

It might be enough height but it doesn't give much time for ice to form. For much of that 30 km the plane would be  climbing.

There was a Mythbusters episode (it's on Youtube) about "blue ice". Briefly, it forms at altitude and falls off on approach to landing. 

[VK3DRB]

I am sceptical. Your, er, "micrometeorite" is more likely from a neighbour who chucked a yonnie on your roof. A piece of bluestone with a sharp corner could hit the solar panel and bounce off, leaving little or no residue. Given the right shape and impact, the force could be huge. The particles in on the broken glass could be just ingressed dirt from the rain. You might want to check around your house for the projectile.
But I am not a complete sceptic. There is evidence there are aliens among us. The evidence is at US Immigration at airports, where there are two entry queues with signs above them, "US Citizens" and "Aliens". 

[G7PSK]

I still think it was a cricket ball that after impact went over the ridge. The shape of the dent on the under side of the panel is caused by the glass deflection on impact, fingers of glass deflected downwards.