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.”