When fourth-year physics and math major Justin Dowd takes an airplane flight, he places his bare feet on the cabin floor “to feel the engines go from nothing to that deep rumble,” he said. But that’s nothing compared to Mach 3.

For as long as he can remember, Dowd has been obsessed with outer space and space travel. So it’s no wonder he’s having a hard time wrapping his mind around the news that in 2014 he’ll travel into space at three times the speed of sound, becoming one of the world’s first civilian astronauts.

On Wednesday, Dowd learned that his video “Einstein’s Discovery” won him first place in the international Metro Race for Space competition. Dowd beat out thousands of readers of the free, daily, global newspaper for a seat on the XCOR Lynx, a rocket-powered spaceplane currently being built by the space-flight company SXC.

“I’ve been explaining that same 20-minute lecture, that light-bulb moment from the video, since I was in 8th grade,” Dowd said. He drew 3,000 chalk murals and filmed them with a time-lapse camera to describe Einstein’s theory of relativity, the concept that got him into physics in the first place. “It lit the fire,” he said.

Using Boston’s MBTA Orange Line train as a backdrop, he explains how time slows down when you travel extremely fast. “That is Einstein’s daydream that he discovered by looking out the window,” says Dowd in the video.

He has always been interested in learning new things. For the video, he recommenced a 10-years-gone piano practice, composed a song and played it. He taught himself chalk drawing while waiting around as a food runner at a restaurant in the Back Bay.

But he’s always known he wanted to study physics. “I’ve been falling asleep to the same glow in the dark globe since I was three years old,” he said. Still, the recent news is a game changer. “My life just took a fork in the road, and it’s not going to be the same again. … They say that when you see the earth from space it changes your life.”

Murray Gibson, dean of the College of Science, said, “Northeastern is very proud of Justin. All of our students aim for the stars, and some students actually reach them. We’ve had students represent our university on all seven continents, but this is the first one to reach the final frontier.”