Category Archives: History

History, Imaging, Science, Space, Technology, Travel

Spotting ancient walls at 17,000 MPH

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Great Wall of China
Photo by Tianxiaozhang.

“You know, you can see it for miles – goes on for miles, over the hills and everything. But, so does the M6. Do you know what I mean? You can see that for miles. And you go, ‘Great. And that does a job. You can drive on that.’” Thus did an unimpressed Karl Pilkington of An Idiot Abroad describe the Great Wall of China, allegedly the only manmade object visible from space.

Which raises and interesting question: Why can’t you see the British M6 motorway from space? Or can you? For that matter, can you actually see the Great Wall?

Great Wall of China: Only Manmade Object Visible from Space?

History, Science

We’re going to need a bigger island

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Crowd at hockey game
Photo by Sreejith K.

Sometime around Halloween 2011, the global population topped seven billion. That’s a staggering number of people. In fact, linked arm to arm, a human chain would wrap around the equator roughly 175 times or extend to the moon and back about nine times, according to CBC/Radio-Canada.

Bearing this image in mind, we can be forgiven for believing that there are more humans roaming the Earth today than during all of history and prehistory combined. But is it true?

Are There More People Alive Today than Ever Lived?

Consumer, Culture, Engineering, Gadgets, History, Technology

Wristwatches: Is it time to disband?

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Wristwatches at a store in London
Image courtesy David Castor

Every few years, someone writes an article about how kids today don’t know what a rotary phone is, or have never heard of a cassette tape, or are losing the ability to spell or write cursive. I still remember, years ago, when one study revealed that not only did today’s youth not know how to wind a watch – they didn’t know what the phrase meant.

As someone who was required to be able to understand references to technology, art and entertainment dating back to my grandmother’s time, I take these articles with a grain of salt. That includes the recent spate of pieces in blogs and news outlets declaring the death of the wristwatch. Sure, we all have cellphone, and there are as many clocks in my kitchen as appliances, but – as I point out in this misleadingly named article – the watch has yet to tick its last tock.

Why don’t we wear wristwatches anymore?

Computing, Consumer, Electromagnetism, Engineering, History, How To, Internet, Physics, Science, Technology

You don’t know jack about optical audio

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Photo by Hustvedt, via Wikimedia Commons

If the back of your entertainment system looks like a cross between mission control and a 1960s Manhattan switchboard, you could probably use a little help separating your composite from your component video. In this article, I’ll explain the oxymoronic mystery that is optical audio, with stops along the way to explore the evolution of inputs, outputs, standards and jacks that led to it. I’ll also tell you how this fiberoptic system stacks up against HDMI.

What is Optical Audio?

Art, Astronomy, Biochemistry, Consumer, Electromagnetism, Engineering, Gadgets, History, How To, Imaging, Photography, Physics, Science, Space, Technology

Starlight, star bright, first shot I snap tonight

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Infrared photo of Webster's Falls
Photo: Marcus Qwertyus/Wiki Commons

Photography is all about light; it’s right there in the name: photo (“light”) + graph (“means of recording”). So how do you shoot in the gloom between the golden hours? Well, you have a few options. You can pop in a flashbulb. You can try your hand at painting with light – that is, fiddling with f-stops and shutter speeds to let more light in over a longer period. Unfortunately, flashbulbs tend to wash out photos, and setting up longer exposures tends to limit your photographic freedom.

Night-vision cameras and attachments get around these problems, either by amplifying existing light or working with a different kind of ambient “light” – aka infrared radiation, either from body heat (thermal IR) or from an active IR illuminator attached to the camera. Today, infrared and ultraviolet cameras also make useful tools for inspections and field work. But how do they work, and what is their history?

How Night-vision Cameras Work