While the world speeds ahead into the digital information age, two Alaskas have come to exist in the far north. One is the Alaska of long, cold, dark, depressing winters and short, wonderful, midnight-sunned-blessed summers. This is the Alaska known to most of its residents, who for eight or nine months of the year struggle between their homes and offices in the modern world, with a stop at Starbucks to properly caffeinate in the morning and a pause at Wal-Mart or Safeway to resupply the kitchen with groceries in the evening.

The other Alaska is the land of year-round myth and mystery, the land of the great escape, the Great Land, the Last Frontier. This is the Alaska that is what the rest of the globe was -- until man conquered so much.

Fifty people on foot, on bicycles or on skis set off to challenge this Alaska Sunday. The bulk of them are from Europe or the Lower 48. A handful of them harbor thoughts of winning a competition called the Iditarod Trail Invitational, which boasts neither trophies nor prize money: Most of them will be competing solely with themselves.

Once, humankind considered the wilderness home. We were part of it. Now it is considered a challenge to our very survival.

Race away from evolution

The Iditarod Invitational runs 350 to 900 miles along the Iditarod Trail from the abandoned port of Knik to McGrath and then Nome. Most people opt for the 350-mile version of the trip. A few, however, do keep going. Less than four dozen have made it all the way to Nome at the north end of the trail in the past decade. More people annually complete the Iditarod Trail Sled Dog Race.

The Iditarod, "The Last Great Race,'' is considered one of the world's toughest sporting competitions. It is extremely difficult because of a musher's dependence on the dogs.

The Invitational is extremely difficult for another reason -- simple, human frailty. A journey of even 350 miles along the Iditarod is an easy adventure to abandon. There are so many convenient excuses to quit. Some are ordinary: blisters, twisted ankles, aching joints, a little frostbite. Others are extraordinary: A couple years ago, competitors had to wade through waist-deep snow for tens of miles through the Alaska Range. The bikers in the race carried their bikes for much of that way. Sometimes, though, they couldn't carry them.

They had to pitch them onto the snow ahead, drag themselves to them, and then pitch them forward again.

A few years before the great snow slog, the problem was different. Temperatures plunged to a life-threatening 50 degrees below zero on the north side of the range. Of those temperatures, turn-of-the-century Alaskan Hudson Stuck, the author of "Ten Thousands Miles with a Dog Sled," observed, "the old-timers in Alaska have a saying that 'traveling at 50 degrees below is all right as long as it's all right.'''

(Stuck's book is an Alaska classic and a must-read for those in Alaska or intrigued by the Alaska mystique. And you can now find it free online.)

At 50 degrees below, things can go badly wrong and quickly. At 50 degrees below, it can quickly become difficult to survive.

Suffice to say, there are sensible reasons to avoid travel on the Iditarod Trail in February and March. But most people avoid this journey simply because it is in large part everything modern day America is not. Modern day America is easy and comfortable. The Iditarod is about difficulty -- and no matter how one travels -- becomes at times a little uncomfortable.

"Tomorrow I head out on the Iditarod Trail,'' Invitational organizer Bill Merchant posted on the race website Wednesday. "Whether on skis, foot, bike or breaking trail with a machine it is the trail and culture that comes alive this time of year that has pulled me back out there for the past 13 years. In all that time the trail has never been the same twice."