Interstellar travel. our fastest current spacecraft travel away from earth at a speed of roughly 50,000 kilometers per hour. at this speed, how long would it take to travel the 4.4 light year distance to alpha centauri, the nearest star system to our own?

It will take about 21,689 years.

To start, we need to know that there are 9.5 x 10^12 kilometers in a light year. Next, lets divide that by 50,000 (or 5 x 10^4) to find the number of hours that it will take to travel that distance.

9.5 x 10^12 5 x 10^4 = 1.9 x 10^8 hours

We could further divide that be 24 to find the number of days and then by 365 to find the number of years.

1.9 x 10^8 / 24 / 365 = 21,689 years

It will take about 21,689 years.