How could Tom Riddle's diary know what happened between Tom and Hagrid?

Question

It is said that Tom Riddle's diary was made into a Horcrux via the murder of Moaning Myrtle via Basilisk.

If that was the case, the soul piece that went into the diary was split off when this happened.

Yet, the diary piece of soul, somehow, showed Harry things which happened AFTER the murder - such as conversations about school closing with Headmaster and confronting Hagrid to frame him.

How could the diary-bound soul fragment know this?

Did Tom Riddle continue writing into the diary to keep that fragment updated? (that was the only plausible explanation I can guess at, since he was the only one who knew those scenes).

Answer 1

I have 2 options, the first of which, is that horcruxes do not need to be created at the exact moment you kill a victim. We know from JKR that there is a process and a spell or 2 that need to happen to create a horcrux, and we also know that killing damages the soul, which allows a piece to be broken off.

MA: What is the process? Do you-- Is there a spell? Is there a-- What do you have to do?

JKR: I see it as a series of things you would have to do. So you would have to perform a spell. But you would also-- I don't even know if I want to say it out loud, I know that sounds funny. But I did really think it through. There are two things that I think are too horrible, actually, to go into detail about.

Slughorn says,

‘By an act of evil – the supreme act of evil. By committing murder. Killing rips the soul apart. The wizard intent upon creating a Horcrux would use the damage to his advantage: he would encase the torn portion –’

So this process seems somewhat time consuming. We also know a damaged soul can only be repaired through remorse.

Ron: "Isn't there any way of putting yourself back together?" Hermione: "Yes, but it would be excruciatingly painful."

Harry: "Why? How do you do it?"

Hermione: "Remorse. You've got to really feel what you've done. There’s a footnote. Apparently the pain of it can destroy you. I can’t see Voldemort attempting it somehow, can you?"

So given this, we again don't have an exact date that he created the diary, but I would hazard that he created it AFTER he was told he could no longer stay at Hogwarts over the summer, and decided to close the chamber, and frame Hagrid. This to me is the most logical conclusion as the Diary was intended to be used to open the chamber again.

The second option which is a very simple fix to adding memories after the fact.

We know how easy it is for memories to be extracted in Harry Potter, and in fact the memories we see through the diary have striking similar feel to memories viewed through the pensive.

Once before, Harry had found himself somewhere that nobody could see or hear him. That time, he had fallen through a page in an enchanted diary, right into somebody else’s memory . . . and unless he was very much mistaken, something of the sort had happened again. . . .

This memory is the only one that Tom chooses to show Harry, and it may simply be because it is the only memory added to the Diary in a way which can be shown like this. So creating the Diary immediately after killing Murtle and then added the memory of catching Hagrid after the fact is a simple feat.

Answer 2

There is not one shred of evidence to say that Riddle wrote the diary straight after Myrtle was killed. I'm not sure where you're picking this up from.

Because it was no longer safe to open the Chamber of Secrets, Tom created a diary to preserve a part of his soul, the very first of seven Horcruxes hoping it would one day lead someone to finish Salazar Slytherin's "noble work."

-From harrypotter.wikia

Myrtle doesn't count as a murder, seeing as it was the basilisk that killed her, not Riddle.

I have edited this comment with a breakdown of Voldemort's timeline.

• December 31st, 1926: Tom Riddle born
• December 31st, 1937: Tom Riddle turns 11 years old
• Some time 1938: Dumbledore visits Tom Riddle in the orphanage, and tell's Tom he is a wizard. Tom is still 11 years old.
• September 1st 1938: Tom start's his first year of Hogwarts.
• '38-'39: First year
• '39-'40: Second year
• '40-'41: Third year
• '41-'42: Fourth Year
• '42-'43: Fifth Year. Tom opens the chamber in 1943, and Myrtle is killed by the basilisk SOURCE:The Chamber of Secrets. Tom is 15 years old as of December 31st 1942.
• Summer of '43, between Fifth and Sixth years. Tom goes to Little Hangleton, tracing his Grandfathers name. He meet's Morfin, learns his parentage, stuns Morfin and takes Morfin's wand, and kill's the Riddles with it. Murder of the Riddle Family
• '43-'44: Sixth year. Tom creates his first horcrux, the diary, when he is 16 Tom Riddle

So when he put his piece of the soul into the diary (a full year after the Chamber was opened + closed), the piece of soul in the diary would 100% know what had happened.

Answer 3

It's probably one of those things the writer thought about two ways to do something at once and mixed them up by accident. As a writer, I can say it is easy to do. It may have just slipped by unnoticed in the editing and all that. As far as story goes, I haven't read the books and only seen the movies once, but it could be that since Voldemort himself had some seemingly psychic powers, the diary could have too. It could just be that as Tom Riddle learned and became more, so did the diary (as Thom Brannan said above one part of the soul doesn't necessarily have to be connected to stay part of the person). Without any deleted facts from the author or looking for specific "clues" throughout the story in excruciating detail that may have been missed, there is really no way of knowing how or why a lot of things happened the way they did. That is part of the allure to the whole Harry Potter fan base is that not everything needs to be described to make sense, it's a whole different world with different rules that can be one thing one minute and the opposite the next. I wouldn't think too hard into the story's mysteries or it may just become too much to be enjoyable anymore.

Answer 4

It's possible that horcruxes don't have to be created at the moment of the murder.

When Tom Riddle is asking Slughorn about Horcruxes, he is wearing the Gaunt ring, showing that he had already been and taken the ring, and already killed his father.

We also find out that he no longer wanted to wear the ring once it was a Horcrux. This basically means that Tom's conversation with Slughorn occurred between him murdering his father, and the ring being made into a Horcrux. And THAT means that there can probably be a time gap between the splitting of a soul, and when a Horcrux is created.

Answer 5

The first thing I thought of was quantum entanglement. With something as indefinable of a soul, I would think that something affecting one part of it (like creating new memories) would affect the rest of it, "physically" attached or not.

Also: magic.