If Langford's team could reach Heliopolis by stargate in 1945, why was Abydos the only planet SGC could dial before discovering the Abydos Cartouche?

Question

In SG1 Children of Gods (episode 1.01/02), Samantha Carter concludes that, without accounting for stellar drift using a map such as the Abydos Cartouche, the only planet reachable by Stargate is Abydos because it is in some sense the most local relative to Earth.

In 1945, Paul Langford, Ernest Littlefield and their team successfully dialled Heliopolis, (SG1 The Torment of Tantalus, episode 1.11) implying that Heliopolis, too, is local enough for the Earth gate to reach it without adjustments in the 20th century.

Why then was Heliopolis not found when SGC were trying to find alternative destinations to Abydos in the aftermath of Stargate (the film)?

Answer 1

Because besides Abydos, they would have to dial randomly to find other gates, and they didn't find any other gates via that method. As of the first episode, Carter was stating that with the knowledge that they only had one good Stargate address that worked (i.e. Abydos). At the end of that first episode (well, the 2-parter), they had the cartouche addresses, which provided many more valid addresses.

It wasn't until they dialed Heliopolis that they knew there was a Stargate on that planet, meaning at that point they knew that Abydos and Heliopolis were both close enough to Earth to contradict Carter's earlier statement.

Answer 2

AFAIK, the movie states that Abydos was the only planet they were able to get to, because of celestial drift. The first 2 episodes of stargate confirm that, and then show that with the list of addresses on Abydos and taking into account the drift they could then reach other worlds. Later they reach Heliopolis which we had already gone to. However, all information regarding that initial gate travel had been wiped/kept secret. Therefore it doesn't actually contradict anything else in series, because since they were dialing randomly, they just hadn't gotten to the Heliopolis combo yet. While it was in fact close enough to reach, since after thousands of other tries and only being able to reach Abydos it appeared to them that Abydos was the only reachable gate.

Answer 3

The existing answers only seem to partially address the problem. (Disclaimer: this is my understanding based on somewhat rusty recollection; it's been a while since I watched either the movie or the show.)

As noted, there are a LOT of possible addresses. The chances of finding a working gate dialing randomly are slim. A fair bit was said throughout the course of the show with respect to the need to find valid addresses; in particular, most of the addresses they had came from somewhere (I forget where), but only the Abydos address worked without drift compensation. Once they learned how to compensate for drift, they were able to get other, known addresses to work. Dialing randomly, however, was unlikely to establish a connection. Unlikely, but not impossible.

Another potential problem is just how the gates actually perform addressing. DHDs were said to have some ability to compensate for stellar drift. This may or may not correspond to translation of the symbols into other symbols, or to somehow directing the gate itself to make adjustments.

Heliopolis was a random dialing. It worked "by accident", and the address they dialed may or may not correspond to the "proper" address. If the drift correction worked by translating a known address into the appropriate symbols for a gate's current location, then obviously no "old" address would work, because they are wrong. If it works by altering the gate's targeting, then only (known) addresses whose gate was "close enough" to unchanged would work.

In either case, however, Heliopolis was a case of simply stumbling upon an address that worked... and note particularly that in both cases, the address that was actually dialed would not match the "proper" address for Heliopolis, had it been known.

In theory, we might be able to tell by comparing original dialing sequence circa 1945 to the "present day" sequence. If they're different, that would suggest that the correction happens in the gate itself, and (knowing now how to do it) the team back-computed the original, "proper" address for Heliopolis. If they're the same, however, it's inconclusive, because they might have just disabled the correction to dial Heliopolis. A more conclusive test would be if we ever see a "known" address appear somewhere outside a dialing sequence, and a different address dialed on the Earth gate for that same destination.

Answer 4

I believe it has been stated that Capt. Carter’s original theory was correct and that it applied to Heliopolis as well as Abydos. They’re both close enough to Earth that the stellar drift didn’t need to be accounted for(which I believe was at some point stated to be within 25 light years of Earth.) Which is interesting as the Icarus planet is said to be 12 light years from Earth. Which goes to prove the statement the amount of difficulty in randomly dialing a gate is in finding a working gate you would be able to reach,of which there is only one other example of this happening and that was with a functioning DHD that was receiving regular correlative updates from the gate network and it still took I believe it was said years before he succeeded in reaching another address that worked which was the planet of thee Unas,which would make doing so with out corrections for stellar drift at least a order of magnitude higher.