Author Topic: EEVblog #846 - Solar Panel Micrometeorite Impact!  (Read 48435 times)

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Online Fungus

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #50 on: January 28, 2016, 08:58:38 pm »
Looks very much like a golfball. I have a hard time reconciling either the small mass of a micrometeorite vs terminal velocity or the mass of a larger one vs the lack of puncture. The size of the coronal ring in that impact suggests something the size of a baseball. Unlikely in OZ. central pierce points like that are common in impacts of round blunt objects. I suggest a object of more mass moving at a lower velocity. Perhaps with a launch vehicle of perhaps 5 to 15 years of age.

"Coronal ring"?

That's just the way glass breaks.

eg. https://encrypted.google.com/search?q=bullet+hole+in+glass&tbm=isch
« Last Edit: January 28, 2016, 09:00:42 pm by Fungus »
 

Offline ozwolf

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #51 on: January 28, 2016, 09:26:07 pm »
Lot's of interesting ideas and theories, however, usually the answer will be the simplest scenario.

I think most likely a cricket ball (about the right size), followed closely by stone from lawn mower (hmm, big impact area for that), and then remotely a ball bearing from slingshot (too small I think).  I should probably also suggest a golf ball.

Try Googling "cricket ball damage" and "golf ball damage".  I believe one of these is the most likely scenario.

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Offline ozwolf

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #52 on: January 28, 2016, 10:30:02 pm »
Having seen those microscope images I am now of the opinion that it was a cricket ball. I think it hit seam first and that it was an old one which had picked up grit which had become embedded in to the leather outer thus giving the sharp penetrating point. Also it was travelling upwards towards the roof hit the panel and continued onwards over the ridge and would have landed somewhere on the other side of the house from that on which the panel was mounted which is why when Dave looked in the gutter and on the ground underneath he did not find ant thing the seam depressing the glass and silicon would make the dent and the outer of the ball would be the ring in the break pattern. The brown bits in the glass would be leather particles.

I was thinking more about this as I drove to work this morning.  I like the scenario of a cricket ball/golf ball impacting and bouncing over the ridge.  Dave, have you considered speaking to your neighbours to see if they have picked up any random items in their yards?  I would start with the neighbour "over the ridge" side of your home.

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Offline calexanian

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #53 on: January 28, 2016, 10:50:15 pm »
Looks very much like a golfball. I have a hard time reconciling either the small mass of a micrometeorite vs terminal velocity or the mass of a larger one vs the lack of puncture. The size of the coronal ring in that impact suggests something the size of a baseball. Unlikely in OZ. central pierce points like that are common in impacts of round blunt objects. I suggest a object of more mass moving at a lower velocity. Perhaps with a launch vehicle of perhaps 5 to 15 years of age.

"Coronal ring"?

That's just the way glass breaks.

eg. https://encrypted.google.com/search?q=bullet+hole+in+glass&tbm=isch

Tough crowd. Try to use a high voltage reference and they jump all over you.
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Offline pickle9000

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #54 on: January 28, 2016, 10:59:07 pm »
Throw a ball at another panel. Maybe LG has one you could use, good excuse to make a cricket cannon.

 

Offline Barny

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #55 on: January 28, 2016, 11:03:12 pm »
Hey, you have all forgotten the marks at the back site.
The object which hit the panel had enough energy to smash the hardened glass, the solar cell itself ans leaves a small, sharp pointed dent in the back site.

If it was something like a cricket ball or golf ball, the dent wouldn't look like this.

The object was small (<5mm / < 0.2inch) and was impacting with high speed.

Possible objects:
small meteorite -> improbable but not impossible
a gun bullet -> in Australia even more improbable then a small meteorite
crossbow bolt -> the bolt wout probably bounced of but its not impossible
plane part -> the part would not be fast enough to make this type of damage
.
.
.

In the end, no one knews the type of object.
(Except the part gets discovered.)
 

Offline EEVblog

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #56 on: January 28, 2016, 11:14:21 pm »
Hey, you have all forgotten the marks at the back site.
The object which hit the panel had enough energy to smash the hardened glass, the solar cell itself ans leaves a small, sharp pointed dent in the back site.
If it was something like a cricket ball or golf ball, the dent wouldn't look like this.
The object was small (<5mm / < 0.2inch) and was impacting with high speed.

Correct.
Everyone keeps harping on about kids with rocks, slingshots etc. It's definitely not that.

Someone now says they have spoken to several experts in meteorites and they both say it's very likely a meteorite, golf ball size or even a bit larger, hit on some pointy edge.

Quote
Possible objects:
small meteorite -> improbable but not impossible
a gun bullet -> in Australia even more improbable then a small meteorite
crossbow bolt -> the bolt wout probably bounced of but its not impossible
plane part -> the part would not be fast enough to make this type of damage

I'm not ruling out something from a plane
Crossbow bolt is even more implausible than a bullet.
 

Offline HAL-42b

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #57 on: January 28, 2016, 11:44:08 pm »
Dave, it is most likely in the rain gutter or somewhere nearby. You must put us out of this misery.
 

Offline mtdoc

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #58 on: January 29, 2016, 12:08:32 am »
Has anyone mentioned vandalism?  How easy is it to get up on your roof?  Even if improbable, it's got to be at least as plausible as a meteorite.
 

Offline Stonent

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #59 on: January 29, 2016, 01:21:01 am »
I blame Giorgio Tsoukalos.
The larger the government, the smaller the citizen.
 

Online Brumby

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #60 on: January 29, 2016, 01:55:37 am »

Someone now says they have spoken to several experts in meteorites and they both say it's very likely a meteorite, golf ball size or even a bit larger, hit on some pointy edge.


That's where my thinking is heading as well.  Terminal velocity considerations mean there would have to be a larger mass involved than that of a micrometeorite.  The penetration and dimple out the back suggests to me that the impact velocity was significant - and that tends to make the idea of a terrestrially launched object somewhat improbable.

The other thing that, to me at least, excludes the possibility of a cricket ball (unless it had a sharp piece of something like blue metal (gravel) embedded into it) is the actual damage to the glass itself.  By looking closely at the centre, we see an area less than 1mm across where the glass is all white.  To me, this is where the glass has been crushed - by direct and intense pressure from the initial point of contact of the object.  All other fracturing radiates out with increasing size of the glass pieces, indicating less intense forces (if any) and the fundamental radial fracture pattern of tempered glass.


The final thing which gives me more confidence in the meteorite idea is that, if you don't know what to look for, the offending object will just be another rock in the back yard.
 

Offline TheCharels

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #61 on: January 29, 2016, 03:22:40 am »
How about Australian ninjas?

Dave have you checked for ninjas recently?
 

Offline Razor512

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #62 on: January 29, 2016, 03:34:32 am »
It has to be a pigeon's high velocity poop attack. They like to poop on cars, and anything else shiny. The issue is that they have noticed that people don't often look at their solar panels, thus they have to work harder on the way they deliver the poop to the surface of those panels.

Pigeons have found that it is effective to accelerate to high speeds, and then poop on the panels.


 

Offline rrinker

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #63 on: January 29, 2016, 03:38:04 am »
 Pigeons in America just leave unsightly droppings, usually on your freshly washed and waxed car. But those Australian pigeons - like the Australian version of most animals, they are 100x as deadly......


 

Offline miguelvp

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #64 on: January 29, 2016, 03:48:18 am »
There is no reason to believe that if it was a ball it would have left residue.

The outer broken rings are consistent with a ball. The inner point is just due to the concentrated pressure transferred through the glass of the point of impact, the reason it looks that small is because it was broken by the upper glass layers, nothing to do with the object other that the object being round has a small point of impact.

The even more outer cracked rings increment at almost equidistant rates half the diameter of the impact.

Not a micrometeorite but a baseball or something like that.
 

Offline EEVblog

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #65 on: January 29, 2016, 03:57:57 am »
This mob reckon it's not a meteorite:
http://fireballsinthesky.com.au/2016/01/has-this-solar-panel-been-hit-by-a-meteorite/

Although they do only say micrometeorite which I agree with.
 

Offline miguelvp

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #66 on: January 29, 2016, 04:08:08 am »
This mob reckon it's not a meteorite:
http://fireballsinthesky.com.au/2016/01/has-this-solar-panel-been-hit-by-a-meteorite/

Although they do only say micrometeorite which I agree with.

Hmm, to me it seems they say it's not a micrometeorite.

Gretchen says that if it was really that small it would have been slowed down a lot before impacting the solar panel if it was indeed a micrometeorite.

Martin says Cricket ball, also mentioning the outer rings as not being consistent with a micrometeorite.

Edit, or even a meteorite because of the explosive nature it wouldn't have those big outer rings.

« Last Edit: January 29, 2016, 04:09:48 am by miguelvp »
 

Offline EEVblog

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #67 on: January 29, 2016, 04:21:18 am »
Hmm, to me it seems they say it's not a micrometeorite.
Gretchen says that if it was really that small it would have been slowed down a lot before impacting the solar panel if it was indeed a micrometeorite.
Martin says Cricket ball, also mentioning the outer rings as not being consistent with a micrometeorite.
Edit, or even a meteorite because of the explosive nature it wouldn't have those big outer rings.

Cricket ball size round object surely does not explain the small crushed impact point as Brumby pointed out. It just doesn't fit.
Seem I now have competing meteorite experts, two saying it likely is, and two saying it likely isn't.
 :-//
 

Offline miguelvp

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Offline pickle9000

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #69 on: January 29, 2016, 04:24:56 am »
From my perspective the investigation is the fun part.
 

Offline miguelvp

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #70 on: January 29, 2016, 04:25:47 am »
Hmm, to me it seems they say it's not a micrometeorite.
Gretchen says that if it was really that small it would have been slowed down a lot before impacting the solar panel if it was indeed a micrometeorite.
Martin says Cricket ball, also mentioning the outer rings as not being consistent with a micrometeorite.
Edit, or even a meteorite because of the explosive nature it wouldn't have those big outer rings.

Cricket ball size round object surely does not explain the small crushed impact point as Brumby pointed out. It just doesn't fit.
Seem I now have competing meteorite experts, two saying it likely is, and two saying it likely isn't.
 :-//

On impact the upper glass will break off pushing to the lower layers concentrating the impact shard into a point on that lower layer, but the damage is done by the glass pushing down so it looks like a small point but that's the point of maximum pressure on the impact.
 

Offline ejeffrey

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #71 on: January 29, 2016, 04:31:15 am »
Not a micrometeorite but a baseball or something like that.

I actually doubt that a baseball or cricket ball would even break the glass.  It is too slow, too soft, and too blunt.  We aren't talking about a MLB player hitting a ball directly into the panel at short range, we are talking about a fly ball from some kids playing in their back yard or whatever.  Those glass panels are tough.  It would need to be something denser, harder, and faster.  Unless kids is australia use diamond studded cricket balls, I don't think that is it.

A chunk of metal from a plane (or maybe ice) seem more likely to me than a meteor, but honestly I have no idea what the even rate of either would be.  Either would at least explain the observations as far as I see.
 

Online Brumby

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #72 on: January 29, 2016, 04:36:45 am »
Space debris impacts:

4mm impact in solar cell retrieved from space:



Source: http://www.esa.int/spaceinimages/Images/2003/12/Impact_crater_size_4_mm_on_solar_cell_retrieved_from_space

Hubble solar panel impacts:


Source: https://www.quora.com/What-is-the-likelihood-of-something-like-space-debris-damaging-satellites-or-astronauts-like-shown-in-the-movie-Gravity-What-safeguards-does-NASA-provide

No atmosphere to slow down or burn up anything - so even the smallest meteoroids will still have significant velocity.
 

Offline miguelvp

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #73 on: January 29, 2016, 04:53:54 am »
This is my hypothesis:



The glass pieces on the higher energy part of the impact causes the small pinpoint damage on the lower layer, as the ball gets deeper there is more surface to slow the ball down in a logarithmic fashion, then you get the traversal wave damage across the rest of the panel.
« Last Edit: January 29, 2016, 04:56:26 am by miguelvp »
 

Offline EEVblog

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Re: EEVblog #846 - Solar Panel Micrometeorite Impact!
« Reply #74 on: January 29, 2016, 05:01:37 am »
No atmosphere to slow down or burn up anything - so even the smallest meteoroids will still have significant velocity.

11km/s apparently. Not pretty.
 


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