The "Southern Cross" is a constellation also known as the Crux Constellation that can be viewed from most of the Southern hemisphere. The 4 brightest stars within the constellation form a cross pattern. Sailors have relied on the "Southern Cross" to help in navigating their boats. The national flags of Australia and New Zealand have versions of the Southern Cross on them.
This was written by Stephen Stills with help from Richard Curtis and Michael Curtis. In the CSN Boxed Set, Stills explained: "The Curtis Brothers brought a wonderful song called 'Seven League Boots,' but it drifted around too much. I rewrote a new set of words and added a different chorus, a story about a long boat trip I took after my divorce. It's about using the power of the universe to heal your wounds. Once again, I was given somebody's gem and cut and polished it."
Jimmy Buffett covered this on his 1999 album Buffett Live: Tuesdays, Thursdays, Saturdays. (thanks, Amy - Chicago, IL, for all above)
There is a vocal mistake in the line "But it's as big as the promise, the promise of a coming day." One of the vocalists says "coming" on the first "promise." (thanks, Dave - Leesburg, VA)
Since this song is based on a song called "Seven League Boots," it bears mentioning that seven-league boots are a common magical artifact which crops up repeatedly in many European folk and fairy tales. They're a pair of boots which allow the wearer to take strides that are seven leagues (21 miles, 33.8 kilometers) long. The same concept of footwear that greatly increases one's traveling speed or stride is adapted into many role-playing and video games.
This same year that "Southern Cross" came out also saw David Crosby arrested on drug-related charges. He would be in and out of court on them numerous times until he finally turned himself in for an 8-month sentence.
The video for this song, with a ship a-sail, saw heavy rotation in the early MTV years, providing a soft rock respite from the European pop acts that dominated the network at the time.
The cover art for the Daylight Again album features an enigmatic domed structure on a rocky hilltop, flanked by three glowing blue flying saucers. The US was in the midst of a resurgence in UFO popularity in the late-'70s and early-'80s, bolstered by the writings of Chariots of the Gods author Erich von Daniken and renewed interest in Area 51.