In astronomical terms, it won't be long: In the year 2439, residents of the Polaris star system, if there are any, will be treated to a transmission of The Beatles 1968 song, "Across the Universe," courtesy of NASA.

At 7pm EST on Feb. 4, NASA, with a little help from its friends at Spain's space agency, will beam an mp3 of the four-minute song from a giant space antenna near Madrid. From there, the transmission will begin its long and winding road to Polaris.

Monday marks the 40th anniversary of the recording of the song. It's NASA's birthday too; the transmission will commemorate the 50th anniversary of the agency's founding, as well as the 50th anniversary of Explorer 1, the first US satellite, and the founding 45 years ago of the Deep Space Network, a network of antennas around the world that transmits and receives signals from distant stars.

The song got its ticket to ride on NASA's signal when Martin Lewis, a Los Angeles-based Beatles historian, secured permission from former Beatle Paul McCartney, John Lennon's widow Yoko Ono, and the two companies that own the rights to The Beatles' music, to have NASA transmit the song into deep space. According to The Associated Press, one of those companies, Apple Records, said that it was happy to approve sending the song because it is "always looking for new markets."

But there's a good chance that NASA's transmission will be for no one. To pick up the signal, our Polaris denizen would need to have an antenna and a receiver. The alien listeners (assuming they have ears) would also need technology to decrypt the mp3 format.

Still, those involved are nothing if not optimistic. Mr. Lewis, placing his trust in the taxman, told The Guardian, "We don't know if there's life out there, but I'd like to think the US government wouldn't be spending taxpayers' money on this if there was no hope."

Mr. McCartney, for his part, dashed off a short note to NASA endorsing the project. "Amazing! Well done, NASA!" read his message. "Send my love to the aliens. All the best, Paul."

Whether or not the song will reach anyone, we can expect no reply, at least not for a long, long, long, time. Polaris, also known as the North Star, is located at the end of the handle of the little dipper, about 2.5 quadrillion miles away. Traveling at lightspeed, the signal will take 431 years to reach the star, and it'll be at least that long again before we get any response. Sending the song any faster would require exceeding the speed of light. And you can't do that.