I paused and watched from 1:06 to 1:27 at 0.25x speed, and it condenses a massive amount of messages. I am not going to talk about everything on the screen, just the parts I thought were important. I treated it as a hint to interpret the music video, and after looking into it, I think my intuition was right. Since I watched it carefully, I will try to explain this 20-second section in my own way.

Oh, before that, I wondered why she was talking about things she usually does not mention, like parallel universe theory or another world, in the shooting star content on IU's channel at first. But I think it turned out to be a kind of spoiler for the title track 'Unknown Planet (From the Breakup)'. If you plan to dig into the first 20 seconds like I did, I definitely recommend watching it.

Let us get started.
The phrase 'Cheolsu and Younghee, who started at different times, meet...' appears, and I thought this was a hint in the form of a math problem as well as a clue that pierces through the entire music video.

Also, at the 50,000km mark, the initials of the male lead, Chilean actor Jorge Lopez Astorga, are JLA, but they are written in the order of ALJ in the text, like horizontal A and vertical B, with circles drawn around them. This is also the format of a math problem.

Since it only shows a part of the problem and not the whole, it is difficult to say for sure. This is strictly a guess, but it seems to be a problem asking to calculate how many years it takes for the two main characters, who started at different timeframes, to meet.

Since this is the 9th generation of UAENA currently active, there is a deep connection to the number 9. Perhaps because it is a story about 'Unknown Planet' but also 'From the Breakup', a webpage comes up stating that on September 16, 2006, Pluto, which was the 9th planet of the solar system, was demoted.

The actual date of Pluto's expulsion is August 24th, but the music video screen intentionally displays September 16th, the release date of the music video. If you write September 16th only in numbers, it becomes 916, and even if you turn it 180 degrees upside down, it still looks like 916. The numbers 9 and 6 switch places but maintain their shape, creating a rotational symmetry within the number itself, like an endlessly connected Mobius strip. Just as the two meanings 'From this star' and 'From the breakup' coexist in a single pronunciation, the number 916 shows the same form regardless of the viewing direction. Ultimately, releasing the music video on September 16th and writing this date as the day Pluto was expelled seems to be a directing choice meant to connect the 9th generation Uaena, the 9th planet, and their symbolism together through the rotationally symmetrical number 916. Then the setting that the music video reappears after 20 years fits perfectly. So the answer to the problem is simply 20 years. Easy, right? Please just accept it and move on.

A news article screen is shown, and it says that when Pluto was stripped of its 9th planet status, articles were found in various regions reporting that an unidentified light appeared and disappeared. Then on the screen, texts saying that the light is 'not a shooting star', 'fake', and 'disappeared from observation' mix with the news screen and pass by very quickly frame by frame in multiple languages. And you can see a phrase that says 1892 X and Adalberta, which is a concept that overlaps with the actual asteroid Adalberta incident and 1892 X. It was reported to have been discovered in 1892, but it was not observed again for about 90 years. In other words, the Adalberta incident is a story where, after re-investigating the asteroid given the provisional name '1892 X' decades later, the conclusion in 1982 was that 'it never existed in the first place'. The original two observation records were actually a mistake, mistaking unrelated background stars for a single moving asteroid. Personally, I think this explains the entire music video.
Later in the video, the male lead stays on Earth while IU moves farther away from Earth in a breakup-like scene.
Could it be about breaking up from a love that never existed and where they never even met... that what was thought to be love was actually an illusion, just like the Adalberta incident?

Then the screen transitions to an old flip phone text message UX showing the line: 'If I knew summer would end this quickly, I should have left with you.' I am confused whether this is about her comeback or something she is saying to a past lover. Well, since it is just my imagination, it is probably nonsense.
Then another text screen appears with illegible text that quickly disappears, moving to a Planet screen showing the solar system. That is all for the first part.

Since non-Koreans might find it tricky to understand, let me explain starting from the MV teaser.
In the teaser, selecting a planet matches people up for 1-on-1 video calls, showing several groups chatting. Then all connections temporarily cut out, leaving people in panic. At this moment, IU, matched with the male lead studying astronomy, mentions "My hair got shorter," followed by "Hair..." while using hand gestures to show cutting hair. In reality, IU cut her long hair into a short bob, but in the actual music video, time flows showing her short hair turning back into long hair. In Korea, cutting one's hair after a breakup carries the cultural and symbolic meaning of cutting off the past and making a fresh start. Considering this, we can tell the lyrics are about accepting a breakup. Seeing long hair change to short hair on screen made it natural to connect it to the title, but the official MV shows her going from short hair to long hair as time passes, showing the passage of time.

The song title is also a brilliant wordplay. Although they sound identical when spoken, changing the spacing alters the Korean meaning completely from '이 별로부터' (Unknown Planet) to '이별로부터' (From the Breakup). In Korean, the word for star (byeol 별) is conventionally used to refer to both stars and planets, which is why the official English title became Unknown Planet. Just as planets are lonely beings that know of each other's existence but can never touch, I think this MV and teaser use that exact metaphor for unreachable relationships between people. It made me feel so sad reading the lyrics...
That is the explanation for the teaser.

To briefly summarize the music video as well, it seems to tell the story of an asteroid (Planet Nine) heading toward Earth, using a gravitational assist (swing-by maneuver) like a spacecraft saving energy to quickly alter its orbit and escape the solar system's influence.

It seems to be a story where the male lead, Jorge López Astorga, falls in love alone while attempting numerous connections with Planet Nine, the asteroid IU is riding on. They connect through video calls on a platform called Planet for 10 years, but then a signal error pops up on the PC and the connection with IU is lost. Seeing as the MV says '10 years later', the heartbroken male lead Jorge López Astorga is shown struggling for the next 10 years to become an astronomer while missing IU (starting from the part where water is leaking at home, followed by modern items like an LCD monitor, iPad, printer, etc.).

Meanwhile, IU on Planet Nine appears in the same frame as 'from this star' and is shown rapidly moving away from Earth.
After that, the Korean text 'from this star' appears, along with animation and narration showing IU's location.
Planet Nine, where IU stayed, was not an asteroid about to collide with Earth, which feels similar to the Adalberta incident explained in the first 20 seconds.
The male lead Jorge López Astorga simply grew his love from his isolated position, but in reality, they had never actually met even once. People on Earth might have thought an asteroid was approaching, but wasn't it actually just changing its orbit through a gravitational assist and escaping the solar system's influence?

The information in the first 20 seconds and the narration at the very end of the music video outro helped a lot in interpreting it.

Also, if you scan the QR code with your smartphone camera, several video call experiences with IU from each planet pop up, along with photo zones.

IU's storytelling and vocal delivery in "이 별로부터 (Unknown Planet)" are pure magic! The visuals and the emotion in her voice gave me chills from start to finish. What did you think of the music video? Let me know down below! 👇

(Also, a massive thank you to everyone supporting the channel as we aim for our new goal of 10,000 subscribers! 🦅)

Hej EagleFan,
thanks for the IU reaction as always ;-)

IU ha tenido muchas pardidas importantes y han sido así, sin aviso, perdió el contacto y ellos se fueron de este mundo. Quizas tenga esa añoranza.

아이유 리액션 잘 봤어요❤

There is her live clip performance for this song on her youtube channel.