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Ask Dr. Universe aging
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Why do we age? – Ines, 17, Tunisia

Dear Ines,

I have gray fur. But sometimes I think it’s getting grayer—like my human friends’ hair does as they get older.

I asked my friend Jiyue Zhu about that. He’s a biochemist at Washington State University.

He told me it’s a mystery.

“We still don’t completely comprehend this,” Zhu said. “It’s an active area of research.”

Aging seems to be related to the way cells duplicate.

DNA is a set of instructions for making your body. You keep a copy of your DNA folded up inside each of your cells.

All those cells have different life spans. Some, like your skin cells, … » More …

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Why do we lose our hearing when we get older? – David, 10, Wisconsin

Dear David,

I love visiting with my grandcat. But sometimes I have to talk loudly so she can hear me.

I asked my friend Christine Portfors why that is. She’s a biologist at Washington State University.

She told me it’s all about the hair cells inside our ears.

They aren’t really hairs. They’re sensory cells. Hair cells have tiny, bristle-like tufts that stick out—called cilia—that look a little bit like hairs.

Those hair cells are why we can hear.

First, sounds funnel into our ears. They bonk into the ear drum and make it vibrate. Then, three itty, bitty bones make those … » More …

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