In 1977, NASA launched two 12-inch gold-plated copper disks filled with the sounds of children's laughter, heartbeats, and bird calls. Is their time in space running out?

In 1977, NASA launched two 12-inch gold-plated copper disks filled with the sounds of children's laughter, heartbeats, and bird calls. Is their time in space running out?

Find Planet Earth Day Night stock video, 4K footage, and other HD footage from iStock. Get higher quality Planet Earth Day Night content, for less—All of our 4K video clips are the same price as HD.