New research based on data from the Kepler space telescope's observations indicates that an Earth-like planet maybe right on our doorstep . . . astronomically speaking.
Keep in mind, the galaxy is huge. It's 100,000 light years across. And a light year is 5,878,499,814,276 miles. So that's . . . a very big number. Just call it 5.88 x 10^17 miles across the galaxy. That's absolutely unfathomably huge.
So when scientist say an Earth-like planet could as close as 13 light years away, that's, well, right on our doorstep. Only problem is getting there. If you could (you can't) go the speed of light, it'd take 13 years to get there. If you could fly a 737 there (you can't), it would take about 17.5 million years. That's a long time in a coach seat. If you could build a spaceship capable of going a million miles per hour it would take about 8,700 years.
Still, 13 light years away is, on the scale of the galaxy, right next door.