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From The Desk of...The Chief Scientist

"How do astronauts scratch their noses?"

Written by Paul Sutter on Monday, 18 July 2016. Posted in From The Desk of...The Chief Scientist

You're three hours into your spacewalk. Suspended 250 miles above the surface of the Earth, you can see the night-day terminator line creeping its way across the Sahara. You focus on your tasks, trying not to think too much about your circumstances. Just a few layers of synthetic fabrics separate you and the relentlessly overwhelming vacuum. Tethers that looks a lot thinner than you remember are your only connection to the space station. You can hear your own breathing inside your helmet; the warmth of the suit has begun to fog up your faceplate.

And it happens. You have an itch on your nose.

Instinctively, you bring your hand up to scratch, but succeed only in uselessly thumping your helmet. The movement unbalances you, nudging yourself into a slight backwards roll. Sigh.

Thankfully, you're not the first astronaut to experience such issues, and over the years your predecessors have come up with a few solutions. There are all sorts of things inside your helmet, like a microphone, a device to pinch your nose so you can readjust pressure in your ears, and a few controls.

But what gets the job done is a little patch of velcro, situated in just the right spot for scratching.

"Seeing in the dark"

Written by Paul Sutter on Monday, 11 July 2016. Posted in From The Desk of...The Chief Scientist

I got a great little email from Elizabeth Moody, an Outreach Educator for COSI on Wheels, a couple weeks ago, regarding astronomy and the non-visible parts of the electromagnetic spectrum (which is, you know, most of it). Our eyes are only sensitive to a small sliver of frequencies of light, so when we operate an x-ray or infrared telescope, how do they work and how do they make images that we can...see?

First it's important to note that no matter what kind of light it's observing, a telescope has two important jobs: it's a bucket to soak up as much light as possible, and a focuser to dump that light onto a sensor. The "sensor" is your eyeball if you're an old-timey professional astronomer or a modern-timey amateur astronomer. Usually nowadays the pros have gone all digital.

Think about what your eyeball does: it collects light - the iris - and dumps it onto a sensor - the retina. What gets sent to your brain is raw "data": how much of what frequencies of light and where that light came from. Lots of reds from the barnside, a good bit of blue above it, green below, etc. Your brain turns all that data into an "image", giving you a visual map of an idyllic farm scene.

So what if we have a telescope that collects x-rays? The sensor reads how much of what frequencies of light came from where, and tell it to a computer. It's just a bunch of numbers, and to make a picture some creativity is required. Maybe the high-energy x-rays should be colored purple-bluish, and the lower-energy ones we captured should be given a gentle soft red.

In the end, a computer paints a picture for us, but giving us the same kind of information our brains do with visible light. We can play the same game at any frequency, from radio to gamma-rays. In effect, modern telescopes make us all a Superman.

"Whether Weather is Climate"

Written by Paul Sutter on Tuesday, 05 July 2016. Posted in From The Desk of...The Chief Scientist

This great question popped up on my whiteboard a few weeks ago: what's the difference between weather and climate? These two words are often jumbled together, or tossed into places they don't belong, so it's not surprising there's some confusion.

Here's a short version for the impatient: weather is short, climate is long.

Here's a long metaphor for the patient: weather is like watching your day-to-day activities. What time did you leave for work? What did you eat for lunch? You picked those shoes? Specifics, not trends.

Climate is watching your habits every day for thirty years, and using statistics to draw broad conclusions. You leave for work within the same 15-minute window. You generally like sandwiches. You have poor taste in footwear. Trends, rather than specifics.

What's fascinating about weather systems is how frenetically chaotic they are: a tiny change in an unexpected corner can build up to alter the course of an entire storm. This is the so-called "butterfly effect" and makes weather prediction so dang difficult. Sure, we know where a thunderstorm is today, but a billion zillion factors can influence its future movement, so it's hard to say where it's going to be tomorrow.

But despite that complexity it's also fantastically regular. Summers are miserably hot. Winters are unbearably cold. The weather may be unpredictable a few days into the future, but the climate moves (relatively) slowly, making predictions (relatively) easier.

Predicting both the weather and climate is a humongous job, requiring heaps of computing power crunching the numbers day-in and day-out, but that's a story for another memo...

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