From The Desk of...The Chief Scientist

"But Can We Eat It?"

Written by Paul Sutter on Tuesday, 04 April 2017. Posted in From The Desk of...The Chief Scientist

Tyler Fox, one of COSI's Floor Faculty Managers, was working in the Planetarium the other day and encountered a difficult question. What if someday we discover alien life - say, in the subsurface oceans of Europa or living on a distant exoplanet around another star - and it's as complex as life here on Earth. Not just single-celled critters that we only get to gawk at through a microscope, but large organisms with thriving ecosystems.

Of course we would first celebrate a major triumph of scientific inquiry and human philosophy, answering one of the most important questions of our species: "Are we alone?"

But Tyler's gang didn't care about that question. They cared about the second most important question of our species: "Could we eat it?"

That's actually a pretty challenging question. On one hand, complex molecules like sugars and amino acids are built from (literally) universal ingredients. We've even detected glycine, the simplest amino acid, on comets and identified glycolaldehyde, a simple sugar, in interstellar nebulae. So presumably alien life would be built from the same basic blocks as their Earth-born cousins, rendering them eatable.

But digestible is another matter. There are many, many things just on the Earth that are either too tough, too poisonous, or too poor in nutrients to eat. Humans are omnivorous, but not that omnivorous. There are many steps to go from "contains nutrients" to "we can acquire those nutrients" to "we can enjoy doing so."

Could we eat alien life? I guess there's only one way to find out.

"The Constant Eclipse"

Written by Paul Sutter on Monday, 20 March 2017. Posted in From The Desk of...The Chief Scientist

When the total solar eclipse visits the US this August 21st, the whole experience will last about three hours. Here in Columbus the party starts around 1pm, when the disk of the moon begins to cover up the face of the sun. An hour and a half later, at 2:30pm, we will reach maximum coverage. That maximum ends at...2:32pm. It will be another hour and a half until the moon fully exits the sun, but for some that maximum simply isn't enough.

Hence the anonymous question posted on my COSI whiteboard recently. The eclipse is covering the whole country, entering the US on the Oregon coast near the town of Newport and exiting the Atlantic side via Charleston, South Carolina. Any one spot along the path connecting those two cities will experience totality for around two minutes tops.

But what if we could drive - or better yet, fly - along that path, "catching" the totality in Oregon and riding it all the way to South Carolina? How fast would we have to go to really get the greatness of the Great American Eclipse?

Newport goes dark around 10:20am PDT, and Charleston doesn't follow suit until around 2:50pm EDT, so the most you're going to get for this eclipse is an hour and a half. Due to the moon's orbit the eclipse path doesn't take a direct line between the two cities, but we can take the great circle distance of 2,500 miles as good enough approximation, leading to a speed of 1,600 mph.

That's twice the speed of sound.

"ELI5: Angular Momentum"

Written by Paul Sutter on Monday, 13 March 2017. Posted in From The Desk of...The Chief Scientist

Jarod Smith, a member of the COSI on Wheels team, asked me for help in crafting a quick-and-easy way to explain conservation of angular momentum to young kids, and more importantly sometimes to their parents.

The topic comes up in a fun and simple demo. Sit on a chair that can rotate, and hold a spinning bicycle wheel in your hands. Flip the wheel over and presto-chango you start spinning in your chair. Magic! I mean, science!

I like to think of momentum as the amount of "oomph" an object has - how much it can pack a punch if it were to hit you. A small object (like a bullet) traveling fast enough can hurt, and a big object (like a truck) can be a pain pretty much no matter how fast it's going.

Angular momentum is then oomph going in a circle. It's conserved, which means the total amount of oomph must be the same.

For very young kids, I just refer to it as spin. The bicycle wheel in your hands is spinning really fast in one direction. That's the total amount of spin that you+wheel can have. When you flip the wheel over, you're taking away the spin in that direction, so some has to be added: you yourself start spinning to compensate.

Ultimately, while we can explain what's going on as best we can, I think in some cases it's sufficient to let the demo do the talking. Kids are developing an intuitive sense of angular momentum conservation, and that's something we can build on when they're older.

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