Dust Storm Question

[Rossluck]

In Sydney and Brisbane today we are copping a very severe dust storm (It may be happening in Melbourne as well, but who cares). The strange thing here in Brisbane is that the dust storm is creating an eerie atmosphere where the lights are taking on a blue hue. I was driving down the Gateway (a famous and brilliant bit of engineering for those who don't know Brisbane. Very rarely do traffic hold ups occur on our wonderful Gateway ), and I took note of the extaordinary number of oncoming vehicles with those new fangled blue headlights. Feeling left out of this new technology, I rang my brother to have my customary whinge, and noticed with surprise that the light on my mobile phone also had a strong blueish tinge. Then I looked at the sun: same story (no blue moon jokes please). The mobile phone "blue light" thing was confirmed with four more people.

Then we started wondering what was going on in the atmosphere to create this blue light. Our best guess is that the dust is absorbing the high end light frequencies, such as magenta, and with the high end frequencies "missing" under the dust, the cooler colours are predominating. Are we wrong. I wanted to ask Dr Carl, but he's never around when you want him.

[Wongo]

I have a question too.

Is this picture real?

[BobL]

In Sydney and Brisbane today we are copping a very severe dust storm (It may be happening in Melbourne as well, but who cares). The strange thing here in Brisbane is that the dust storm is creating an eerie atmosphere where the lights are taking on a blue hue. I was driving down the Gateway (a famous and brilliant bit of engineering for those who don't know Brisbane. Very rarely do traffic hold ups occur on our wonderful Gateway ), and I took note of the extaordinary number of oncoming vehicles with those new fangled blue headlights. Feeling left out of this new technology, I rang my brother to have my customary whinge, and noticed with surprise that the light on my mobile phone also had a strong blueish tinge. Then I looked at the sun: same story (no blue moon jokes please). The mobile phone "blue light" thing was confirmed with four more people.

Then we started wondering what was going on in the atmosphere to create this blue light. Our best guess is that the dust is absorbing the high end light frequencies, such as magenta, and with the high end frequencies "missing" under the dust, the cooler colours are predominating. Are we wrong. I wanted to ask Dr Carl, but he's never around when you want him.

Normally everything looks red when there is dust around due to sunlight being scattered by dust, dust scatters high frequency light (blue) and some green, more than low frequency (red) so you you end up seeing more red.

That's why sunsets look red, longer light path length through more dust = more scattering.

Now why do lights inside the dust look Blue? That is a really good question. I suspect it is because the light you see is coming direct from the light source so it has not been substantially scattered and in relation to other red coloured objects around, white lights will have appear to take on a bluish tinge - remember the red sun you are looking at during a sunset is not really the sun, it is a projected image of the sun formed by the thick atmospheric path. The real sun has already disappeared over the horizon.

It's amazing what your eye thinks its seeing in terms of colours and how much it can be fooled. When we set up our video projector at home we were for many months projecting onto a mid-pale yellow wall. After turning on the projector, after a couple of minutes the white (which was really yellow) parts of the image looked white! It was only by looking at the TV running the same video that you could really see how different the colours were, and the white on the TV looked blue!.

[Rossluck]

Yes. It's real. But your Sydney dust must be absorbing the other end of the spectrum. Looks like you're having a monstrous day down there as well (sorry, it's the best I could do). Answer the question Wongo. You should know.

[VernJ]

Nah! looked at the photo, some one's had a fiddle with "Photochop", I'm sure!. The Luna Park gates are just not in correct perspective with the Bridge. The political processes seem to be normal enough though ...

[Phil Spencer]

I thought it was Bull Dust in the air up there here the earth moved for us.

[Barry_White]

Nah! looked at the photo, some one's had a fiddle with "Photochop", I'm sure!. The Luna Park gates are just not in correct perspective with the Bridge. The political processes seem to be normal enough though ...

The gate is correct. The picture is looking at the back of the gate and it is correct in relation to the swimming pool.

I'm not so sure about that thing in the middle of the picture though. It's a bit far from Loch Ness.

[BobL]

Nah! looked at the photo, some one's had a fiddle with "Photochop", I'm sure!. The Luna Park gates are just not in correct perspective with the Bridge. The political processes seem to be normal enough though ...

Looks fine to me.
Go to google maps and look up address "3 Northcliff St, Milsons Point, NSW, Australia" - pan around and look at the bridge and gates - it's pretty darn close to where that picture was taken

[VernJ]

Looks fine to me.
Go to google maps and look up address "3 Northcliff St, Milsons Point, NSW, Australia" - pan around and look at the bridge and gates - it's pretty darn close to where that picture was taken

Wow! you are right, BobL, sorry! it all just looked a bit unreal. But I went to Google Maps and sure enough, the gate and the bridge do look right, and then on to Google Earth ... and yes if you get enough altitude and look at the screen with really squinty eyes ... even the Political Process looks in perspective,sorta!

[graemet]

The reason that lights looked blue is because the ambient lighting was red/brown and your eyes had become adapted to the background colour. Your eyes see the red but your brain subtracts the excess red so after a while, things look normal. When you then see something bright, the subtraction still occurs and the light appears to shift toward the blue end of the spectrum. The same thing happens when you wear a coloured sunglass, initially all looks (say) green but quickly colours return to normal. When you take the sunnies off, the reverse occurs momentarily.
Cheers
Graeme (who thought all the fluorescent tubes had been replaced at work yesterday when he walked in!)

[wheelinround]

Dust right through everywhere including internals of computer with fans running it was sucking it in.

Just goes to show though country people sure like to spread the bulldust around don't they keeping us tuned to their plight of drought conditions

[snowyskiesau]

Don't forget dust in the airconditioner!

Finished mopping the floor in the office (second time this week) and thought I'd turn on the AC to help it dry. Instant dust cloud!

[Waldo]

I have a question too.

Is this picture real?

Yep, Sydney finally got nuked.

[snowyskiesau]

Just found out that Sydney Water have relaxed the rules on using the hose to clean your house/car.
Time to see if the pressure washer still works, it's been a while since I was allowed to use it.

[wheelinround]

Just found out that Sydney Water have relaxed the rules on using the hose to clean your house/car.
Time to see if the pressure washer still works, it's been a while since I was allowed to use it.

Geoff pressure washers have been allowed all the time restrictions were on.