Interstellar time travel explanation [closed]

Question

1)How does time travel in Interstellar work? I understand the whole plot of the movie and that Cooper was Murphy's ghost. But if Cooper had to be her ghost, he should have gone to NASA, gone to Miller's planet then go to the black hole to come back as Murphy's daughter. So doesn't this create some form of infinite time loop? Miller had to somehow go to NASA to become her ghost. Thus the event of him visiting NASA precedes all the Morse code communications from within the black hole.

So how would he have gone to NASA the very first time? Even before his ghost is yet to be formed?

2) How is Cooper, from the black hole able to simultaneously send information to the teenage Murphy and adult Murphy at the same time? And what is the collapsing of the black hole before cooper passes out signify?

3) While reaching Miller's planet, Cooper proposes a method to land on Miller's planet yet escape the time shift. But Cooper mentions to Brand and Doyle that 1hr = 7yrs. So why does the time shift occur anyway?

4)It's evident that out of the three prospects, some of them are either too close to a black hole or some do not even sustain life. What mission does Mann keep saying that he has to complete

Answer 1

1)How does time travel in Interstellar work? ... Thus the event of him visiting NASA precedes all the Morse code communications from within the black hole.

This scene hinges on the idea that we don't know what happens inside a black hole (by "inside" I mean beyond the event horizon, which isn't really "inside" anything - it's just beyond the point that any information can escape to the outside universe.) Someone - some unknown agents from the distant future - sent this time machine back to rescue Cooper and allow him to communicate with his daughter in the past, because "they" figured out that this sequence of events needs to happen for humanity to escape the dying Earth.

COOPER (frustrated): Who’s ’They’? And why would they help us?

TARS (over radio): I don’t know, but they constructed this three-dimensional space inside their five-dimensional reality to allow you to understand it ...

COOPER: It isn’t working -!

TARS (over radio): Yes, it is. You’ve seen that time is represented here as a physical dimension - you even worked out that you can exert a force across spacetime -

COOPER (realizing): Gravity. To send a message ...

How this time machine works is not explained beyond the above, we just have to accept that it does and it allows him to send messages into the past from within the black hole.

As for Cooper's visit to NASA preceding the communications - it does, from Cooper's perspective. From Murphy's perspective, the communications come first, but she wasn't inside the black hole.

So how would he have gone to NASA the very first time? Even before his ghost is yet to be formed?

I know this is a little mind-bendy, as time travel tends to be, but you have to understand that Cooper's actions inside the black hole happen after he went to NASA, for him. They happen before he went to NASA for Murphy. The two time periods are being connected, like a piece of paper folded back on itself.

2) How is Cooper, from the black hole able to simultaneously send information to the teenage Murphy and adult Murphy at the same time? And what is the collapsing of the black hole before cooper passes out signify?

He wasn't sending information to present day Murphy. Present day Murphy was just remembering the messages from the past and finally connecting the dots. The scenes are interspersed to make the reveal that much more dramatic.

Scene 1: Murph's past

INT. MURPH’S BEDROOM - MORNING

Murph (ten) stands there, startled, STARING at the bookshelves. At the book on the floor, a broken toy beside it ...

Scene 2: Murph's present

INT. MURPH’S BEDROOM - TWILIGHT

Murph (forty) looks at the bookshelves, REMEMBERING ...

Scene 3: Cooper inside the tesseract (the time machine)

INT. THE TESSERACT - CONTINUOUS

Cooper watches Murph (ten) cautiously approach - she CROUCHES. Picks something up -

---

3) While reaching Miller's planet, Cooper proposes a method to land on Miller's planet yet escape the time shift. But Cooper mentions to Brand and Doyle that 1hr = 7yrs. So why does the time shift occur anyway?

Cooper's plan wasn't to escape the effects of the time dilation entirely, just to find a place to park the Endeavour where it wouldn't be affected - so that those who remained behind could continue the mission, without losing time to the dilation effect, if the Ranger shuttle never came back.

However, the Ranger and those aboard would always have been affected by the dilation. It's not possible to enter that planet's vicinity without being affected.

4)It's evident that out of the three prospects, some of them are either too close to a black hole or some do not even sustain life. What mission does Mann keep saying that he has to complete

There are a few different "missions" Dr Mann refers to throughout his scenes in the movie. One is the mission to save humanity (which he intends to continue doing primarily by escaping this icy world by any means necessary,) another is the "mission" to survive, himself. He goes on a lot about instinct and the will to survive as individuals vs as a species.

There's also some discussion in the middle about how Plan A (to find a new home and evacuate Earth) was a decoy all along and the real mission was always Plan B (to find a suitable colony world and leave Earth behind.)

Answer 2

1) It was Murphy who realised they need to create "extra dimension" to help Cooper be her ghost and communicate with her. They needed to create that because that ghost communication already happened.
The trick of the story is that we don't watch it "as it happens" but we are looking back from the future.
2) Cooper don't send the message simultaneously. It's just a very long message. He start sending it when Murphy was young and end when she was older. Collapsing of the dimension were the future people closing it because they knew exactly how "long" it would take Cooper to finish it.
3) The time shift occur because there was a change in their plans. They didn't done "touch & go" as Cooper planned but they need to make a stop. That's why Cooper hurry them constantly when they are looking for Miller.
4) It was some time I seen the movie but Mann by mentioning his mission was suggesting Plan B giving a fake impression that his planet was suitable for life.