EEVblog #846 - Solar Panel Micrometeorite Impact!

[EEVblog]

Have you searched the area with a metal detector?

I don't have one.

[pickle9000]

A BB or pellet would not do this damage.

Not a normal one anyway, there are some very large caliber variants (try "pellet gun pig hunting" on youtube).

In any case lead is long lasting and should be present in the case of an air rifle.

The feature I like on the panel is the wave on the back just like a drop of water hitting a still pond. I can't ever remember seeing a projectile cause that kind of shape. Puckers and holes sure but the wave is pretty cool.

[TheSteve]

Have you searched the area with a metal detector?

I don't have one.

Time for a metal detector build video...

[ozwolf]

A BB or pellet would not do this damage.

At close range, I would think they could. I've seen first hand what they can do to a tempered glass door and to metal siding.

But no matter if they're not present in Australia

Believe me, BB guns and pellet rifles are all around, don't kid yourself.

However, I don't think this pattern is from those impacts.

Ozwolf

[ozwolf]

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.

This scenario gets my vote.

 

Ozwolf

[EEVblog]

Believe me, BB guns and pellet rifles are all around, don't kid yourself.

There are a grand total of 3 houses who have site access to my rooftop array, nothing visible from the road. They have to shoot from their top floor window, or be a random lob shot over the houses and down the gully. The odds round down to zero.
There is a grand total of one house that has yard access that could potentially have kids with balls, lawn mower throwing a rock etc (of which I have never seen nor heard of kids playing ball or other games there). People love to come up with all sorts of simple theories like these, which is fine, but sorry, they do not cut the mustard. My array is quite physically isolated from such things.

[Fungus]

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.

This scenario gets my vote.

It's a 1mm hole, right through to the back of the panel. There's NO WAY you could get that dent on the back with a larger object.


This thread is starting to make my brain hurt. I don't think I can take any more.

[Barny]

Let them believe what they want.
There are enough people which think the world is a disc.
Because there is no new stuff in the Butteriser section, people need to search new playground.
And if there isn't one, they have to make one.
Even if they have to stick to impossible theories.

[mikeselectricstuff]

It's a 1mm hole, right through to the back of the panel. There's NO WAY you could get that dent on the back with a larger object.

Bear in mind that the glass turns to small fragments very rapidly - I think it's plausible that a large blunt object could cause rapid fragmentation on initial contact, and one of those fragments then gets pushed through the rear as the object continues moving.
 

[RogerRowland]

If the panel were still under tension in some place, maybe you could lob a cricket ball at it to try to recreate the same effect. Who knows? It might give useful info even so .....

[Brumby]

I don't see glass 'fragments' at the centre of the impact area - I see powdered glass.

There might be a larger object involved - but the high pressure impact zone clearly indicates a hard, pointy object (~ 1mm diameter at the very tip) has made the initial, impulse contact.

[rrinker]

 OK, here's my crazy option - I stress crazy. Are there any raptors that hang around the area (the bird kind)? So suppose one was flying over, looking for a mouse or small rodent, whatever happens to live in the area - and maybe one was running across Dave's roof, or maybe the bird just saw its own reflection in the glass of the panel and thought it was an intruder - and dove on the panel. Bang, sharp beak, right into the panel. Bird is only stunned, not dead, so by the time anyone bothers to look, the bird has recovered and sheepishly flown away.
 Like I said - crazy, I don't really believe this - much.

[Brumby]

We do have a couple of birds of prey around Sydney - but they're not exactly common.

Also, they aren't known for dive-bombing solar panels.

[Dinsdale]

The best evidence is probably going to be in the depression in the back panel.
It's possible that whatever caused that dent is still there.
I'd try to get someone who has experience to examine your panel.
Mythbusters can test the effects of various objects impacting your model of solar panel. Who you gonna call?

[Brumby]

Funny that...

I was wondering about throwing this one to the Mythbusters as well.

[AndreasF]

Funny that...

I was wondering about throwing this one to the Mythbusters as well.

Too late for that. Final season finished filming some months ago.

[Brumby]

 

[Muttley Snickers]

We do have a couple of birds of prey around Sydney - but they're not exactly common.

Also, they aren't known for dive-bombing solar panels.

This reminds me of a TV show whereby one of those khaki shorts wearing people was showing off a big hairy funnel web spider on an outside table to the presenter and a kookaburra swooped down out of nowhere, grabbed it and took off and the dude in shorts didn't have a spare, I forget how it ended but it was a good laugh.

[Dinsdale]

]
Quote from: Brumby on Today at 12:47:38 AM

    Funny that...

    I was wondering about throwing this one to the Mythbusters as well.


Too late for that. Final season finished filming some months ago.

Sh*t! Maybe they like to do it for Tested?

[Yansi]

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!

[Jacko]

For small meteorites, it seems that the atmospheric drag strips away the cosmic velocity while it is still several miles above the earth and you are left with the simple terminal velocity like any other object dropped from a height.

A steel BB shot up into the air has a terminal velocity of 111.8 mi/hr (or 179.9 km.hr) when it falls back to earth.  That could make a good dent in anything that it encounters. I'm guessing that a 4.5mm meteorite would have similar performance.

[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?

[Lightages]

WRONG!  Just because something is at the same level of an astronaut does not mean it is in orbit. I can be going a delta of anything from 0 kph to over 100s of kilometers per second. It could be a piece of rock passing by the Earth, or something in orbit around the Earth that was further than the moon at its furthest. Please, stop talking about space and astronomy if you don't know about it.

Yes, but we are talking about space junk in orbit around the earth. Always happy to be corrected, I'm not expert on it, that's why I said "I believe". Relax.

Yup I should relax. Sorry I posted such a grumpy response.

[cdev]

My money would be on it having been caused by a chunk of so called "blue ice" falling from an airliner.

Example:

Why is human waste falling from India's skies?

http://www.bbc.com/news/world-asia-india-35255102

here are the first few paragraphs of the story.

"In India, as in many other countries around the world, it is considered good luck when a bird poos on you.

But as an unfortunate Indian woman has discovered, there is nothing lucky about being hit by other kinds of falling excrement.

The Times of India reports that Rajrani Gaud from Madhya Pradesh suffered a severe shoulder injury when she was hit by a football-sized chunk of ice last month.

Her injuries could have been much worse, according to eyewitnesses. They say she only avoided being killed because the icy ball crashed into the roof of a house before hitting her.

And the strong suspicion now is that this chilly projectile was composed of more than just frozen water.

The newspaper claims that aviation scientists believe she may well have had the misfortune to become one of an incredibly rare group: people who have been hit by what the airline industry coyly calls "blue ice".

That's its euphemism for the frozen human waste that very occasionally forms around the overflow outlets for aeroplane toilets, and then falls to earth. "Blue" because of the chemicals added to the toilets in planes to reduce odour and break down the waste.

Blue ice falls are unusual, but not unheard of.

Plane toilets store human waste in special tanks. These are normally disposed of by ground crews once the plane has landed, but international aviation authorities acknowledge that lavatory leaks can occur in the air."

Truncated..

Source: http://www.bbc.com/news/world-asia-india-35255102

[Wytnucls]

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. Waste water from the basins and galley sinks is drained overboard through heated masts, helped by differential pressure at altitude.