Battlestar Galactica (creative & TV franchise): What are the major differences between the 1979 seri

Originally written in answer to a question on Quora.

There are many differences between the 1979 and 2003 versions of Battlestar Galactica. Beginning with the backstory, in the 1979 version the human race evolved on a planet on the other side of the universe called Kobol, where they lived in thirteen tribes and were ruled over by a group of Lords. At some point in their history, the tribes of Kobol left their home world, twelve of them heading off in one direction and settling a local system while the thirteenth set off in another direction and were never heard from again. The 2003 version is almost the same, although where the thirteenth tribe in the original were also human, the thirteenth tribe here were made up of a race of sentient machines known as Cylons.

The next major difference between the two versions is the background of the main antagonists, the Cylons. In the 1979 version, the Cylons were originally alien reptilians who built themselves a race of robotic servants. By the time the series begins the reptilian species has long since died out, but their race of machines have lived on, gained sentience, and continued to be known as Cylons. In the 2003 version, the Cylons were created by man and rebelled against their creators. A long war is fought between the two races until the Cylons mysteriously declare a ceasefire and an armistice is signed. Whereas the Cylons remain mechanical robots throughout the original 1979 series, the Cylons of the 2003 re-imagined series evolve to a level where they are indistinguishable from humans.

Both the original and re-imagined series of Battlestar Galactica begin with the almost total annihilation of the human race by the Cylons, although the details of the attack differ significantly. In the 1979 version, the humans and Cylons are still at war, but are on the brink of signing a peace treaty. The governor of one of the colonies, Count Baltar, has somehow managed to convince the Cylons to cease hostilities and begin negotiations. In actual fact, it is a plot between Baltar and the Cylons to wipe out the majority of the colonies, while sparing Baltar's colony for subjugation under him. In the 2003 version, Gaius Baltar is a scientist involved with the planetary defence systems of the colonies. He is tricked by one of the humanoid Cylons into supplying the planetary defence codes that allow their nuclear weapons to penetrate the shields. In addition, the Cylons have also developed a computer virus that allows them to disable the computer systems of all nearby human ships. The Baltar of the original version spends the rest of the series hunting down the fleeing humans on behalf of the Cylons, while his counterpart in the re-imagined series joins the Galactica crew and spends his time trying to cover up his mistake.

Another significant difference between the two series is the characters. The main characters of the original 1979 version are the bridge crew of the Galactica and the elite blue fighter squadron. The bridge officers are Commander Adama, Colonel Tigh, Flight Officer Omega and Commander Adama's daughter, Athena. All the bridge officers except Omega have a counterpart in the 2004 re-imagining, although their characters are somewhat different. Commander Adama is a peaceful man, who views aggression only as a last resort. His primary concern is the safety and protection of the colonial fleet. In the pilot episode, following the Cylon attack, he returns to his home world of Caprica to assess the damage. While there, he and his military escort are beset upon by an angry mob demanding to know where the military were while the colonies were being destroyed. While the people are eager for retaliation against the Cylons, it is Adama's decision that they should retreat. In contrast, Commander William Adama of the re-imagined series is more interested in launching an immediate counteroffensive against the Cylons. It is only the intervention of newly appointed President Laura Roslin, a character not in the original, that prevents him from doing so. The Adama of the original series has faith in the existence of the thirteenth tribe, and it is his decision that the survivors head out in search of Earth. The Adama of the re-imagined series believes that Earth is nothing but a myth. It is President Roslin's idea that the fleet go in search of the lost tribe, a plan the commander only supports as a method of instilling hope in the last survivors of mankind.

Colonel Tigh of the 1979 series is a respected man, who the officers and crew of the Galactica look up to. The Colonel Tigh of the re-imagined series is an older man on the brink of retirement. He is an alcoholic and a gambler, who is disliked by most of the crew. It is also established later in the series that he is one of the Cylons of the lost thirteenth tribe.

Lieutenant Athena is the daughter of Commander Adama in the original series. She is a bridge officer and shuttle pilot. Although the character herself does not appear in the re-imagining, the name is given to another character.

In the original version, Blue squadron is the elite Viper squadron aboard the Battlestar Galactica and is commanded by Adama's son, Captain Apollo. The group includes Lieutenant Starbuck, Lieutenant Boomer, and later Lieutenant Sheba. All these characters have a counterpart within the 2004 re-imagining, apart from Sheba. In the original, these are the characters full names. The naming tradition of the tribes/colonies seems to be that individuals have only a single given name with no family suffix. For example, Adama and Apollo, although father and son, have no shared family name. In the re-imagining 'Adama' becomes the family name, with the Commander being William Adama and the Captain becoming Lee Adama. 'Apollo' becomes Lee Adama's call sign, a protocol followed across the other squadron members. Starbuck and Boomer become Lieutenant Kara “Starbuck” Thrace and Lieutenant Sharon “Boomer” Valerii. In contrast to the original series, where both Starbuck and Boomer were male characters, in the re-imagining they are both women. In addition, the Boomer of the re-imagined series is a Cylon sleeper agent, of the same model, and therefore appearance, as Sharon "Athena" Agathon. Although Lieutenant Sheba does not appear in the re-imagined series her father, Commander Cain, does have a counterpart. In the 1979 version, Cain was Commander of the Battlestar Pegasus, although seemingly of a lower level than Adama as the Galactica commander appeared to outrank him. In the re-imagined version Cain is a female Admiral, and commands the Battlestar flagship Pegasus.

The final, most significant difference between the two versions is the period setting. When Galactica finally reaches Earth, the crew of the re-imagined Battlestar Galactica find themselves at the dawn of the evolution of prehistoric man, implying that they are the ancestors of modern humans. In the original version their arrival time is contemporary to the original broadcast time of the series, the early 1980s.