Voyager 2 (man's fastest space craft) is traveling 35,000 miles per hour / 60 = 583 miles per second.

187,000 miles per second equals the speed of light.

Light can travel 57,395,520,000,000 miles in one year (roughly 5.7 trillion miles).

So, in 21 years that would equal 57,395,520,000,000 miles x 21 years, or roughly 120 trillion miles.

Thus, if Voyager 2 was our space craft we'd have 583 miles per second x 60 seconds x 60 minutes x 24 hours x 365 days x 21 years to get 386,095,248,000 billion miles towards our new planet.

There is a huge gap between 386 billion and 120 trillion miles, like 311 times.

That means it would take us roughly 310 x 21 years = 6528 years to get there using current technology.

I just don't see us going there as being very practical.

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EDIT: I'm getting down voted for doing the math! Seriously?