"What's the scariest thing you've ever done?"

Former astronaut Chris Hadfield begins his riveting TED talk about overcoming fear with this simple question. In his case, the answer is rather dramatic. While on his first space walk outside the International Space Station, he completely lost vision in both his eyes.

That kind of thing can put the risks associated with starting your own business into perspective. But whether what's frightening you is actually life-threatening, economically threatening, or merely a threat of embarrassment or failure, coping with fear is one of the most challenging things we all have to do. How do you do it? Here's some of Hadfield's wisdom:

1. Compare the fear with the actual danger.

"Maybe you're afraid of spiders," he says. Well, spiders are pretty scary. But, as he notes, of the 50,000 spider species on this planet, only a couple of dozen are venomous. And in Canada, where Hadfield is from and where TED talks take place, there's only one venomous spider species, the black widow, which is easy to spot because of its bright red markings.

Spiders are only one example of the mismatch between danger and fear. Take air travel: Most people are more afraid to fly than to drive even though statistics suggest it should be the other way around.

2. Practice.

The more often you do something scary, the less scary it becomes. This is why Hadfield suggests that the next time you encounter a spider web you should deliberately walk right through it (after a quick check to make sure there isn't a black widow in residence). Do that 100 times, he says, and you can change your natural human reaction and start seeing spiders and spider webs as no big deal. "You'll be able to walk in the park in the morning without worrying about that spider web, or into your grandma's attic, or into your own basement."

This makes perfect sense because it's part of human nature to fear the unfamiliar more than the familiar whatever the actual danger might be. The inverse is also true: The less you do something, even something ordinary, the scarier it can become. When I lived in Manhattan and flew for business often but almost never drove, I had no fear of air travel. But I was terrified to get in a car and drive. So practice doing the things you're afraid of or they'll just get even more frightening.

3. Prepare.

Something frightening becomes much less so if you know what to do at every moment. That even applies to going blind in space. Though Hadfield had never done a space walk before, he'd practiced underwater thousands of times, and also in virtual reality labs that closely simulated the experience. He and his fellow astronauts knew everything there was to know about space suits and space walks. They had even practiced "incapacitated crew rescue," so Hadfield knew his partner on the space walk could have floated him back to the air lock and stuffed him inside if necessary.

And so Hadfield remained calm and his vision eventually cleared. The problem turned out to be the anti-fog substance, a mixture of oil and soap, they were using inside their helmets. Some of it had gotten in his eyes. "Now we use Johnson's No More Tears," he adds.

4. Weigh risk against reward.

What about times when something frightens you because it truly is very risky? The recent Virgin Galactic accident is a stark reminder that even in 2014 space travel remains a highly uncertain undertaking. At the time Hadfield climbed into the space shuttle, he says, the odds of a catastrophic failure on any given flight were about 1 in 38. I doubt most of us would ever step onto an airplane if 1 out of every 38 flights ended in a crash. Why did Hadfield get into that shuttle?

Because it was the fulfillment of a dream, he says. From the age of nine, he'd longed to travel into space. You get a view of the world that you can't get any other way. And then he mesmerized the audience with shot after shot of our gorgeous planet from the unique viewpoint of orbital space. "You have taken the dreams of that nine-year-old which were impossible, and dauntingly scary, and put them into practice."

What dangers would you be willing to face in order to live out your dreams--if you were not afraid?