Can the Infinity Stone kill Thanos

Why wasn't Ronan / Thanos interested in the other Infinity Stone that owned The Collector?

I will try to answer these as best I can.

1. Why is Thanos only interested in the sphere?

As far as we can tell is this is the only infinity stone that Thanos really knows. Even the guardians of the galaxy do not become aware of what is inside the sphere until the collector opens it and reveals it to them. Thanos uses Ronan and his adopted daughters to get the ball for him, with the promise to use it to destroy Xandar for Ronan, but Ronan takes the ball for himself and threatens to kill Thanos with it after using it to destroy Xandar and the Nova Corps. Given his unique focus on the sphere itself, we can only assume that he knows the location (however firm or loose that place may be) of that particular Infinity Stone and is simply after it for the time being.

2. Doesn't Thanos know that the collector has the ether?

Probably not. Remember, Volstagg and Sif deliver it to The Collector at the end of Thor: The Dark World. You are probably entrusting it to him with the intention that only he and various royal members of Asgard will know he has it; It is even possible to assume that Thor and Loki still think Asgard is safe. Remember: Aether was hidden for eons before Jane found it, so it was well hidden a long time before they gave it to the collector. If Thanos was unaware of his influence in Asgard's battle against a newly resurrected Malekith, we can only assume that he doesn't really know that he was brought back to the galaxy. Which leads us to point 3 ...

3. Where are the other four Infinity Stones?

Ah, you seem to have forgotten an important piece of information when you mentioned the Asgardians, who deliver the Aether to the collector at the end of "Thor: The Dark World": You discover that the Tesseract is also in Asgard and keeping two Infinity Stones so close together is dangerous . As such, we know the location of three infinity stones at the end of Guardians of the Galaxy. The Aether is with The Collector (I doubt it was destroyed with the rest of his collection), the Tesseract is in Asgard, and the sphere is now safely locked up on Xandar with the Nova Corps.

4. Will the remaining stones appear in future films?

I would say they certainly will, as Marvel has had a prop for the Infinity Gauntlet for a while, but by the time these films and their storylines are released, that would be everything , what is being said, just a guess.

UPDATE FOR # 3 AND # 4 (SPOILERS AHEAD):

As we now know, the Mind Stone resided in Loki's scepter and was used to create Ultron and ultimately vision. When you consider that Thanos gives Loki this scepter, it means that he actually does the Has given possession of an Infinity Stone to someone else in order to reveal the others and achieve his primary goal. Briefly in the hands of Hydra, it was used to create Mercury and the Scarlet Witch, the latter being able to actually destroy stones with her powers.

The soul stone was eventually discovered by Gamora, who destroyed the details of its location and tried to keep them a secret from Thanos, and even asked Star-Lord to kill her if Thanos manages to catch her. The stone is on Vormir, guarded by Red Skull, who informs Thanos that he must sacrifice someone he loves in order to preserve it. Thanos reluctantly throws Gamora to death and receives the stone.

Oliver_C

According to the post-credit scene of The avengers Thanos knows the Tesseract.

MattD

Ah, I haven't seen it since it hit theaters and just read the synopsis on Wikipedia to refresh my memory. Okay, I think it's safe to assume he knows about the Orb and the Tesseract, but probably not about the Aether, if only for no other reason than neither Thanos nor anyone else specifically states that he knows where he is?

Invalid ID

The Dark Elves knew about the Aether and weren't exactly discreet, so I'm not sure Thanos doesn't know about it, but I can't find any evidence ...

MattD

Well, his collection has been decimated to the point where it could be assumed it was a total loss before everything could be checked, which would take a while since his collection is absolutely huge. Ronan's only goal was to regain the ball for Thanos and nothing else. Once he had her, nothing else mattered to him. Even audiences can assume the collection was a complete loss by the end of the credits.

Bobson

@invalid_id - I'd guess Thanos given the overarching plot above knows all infinity stones. I would rather say that he only knew the location of the sphere.