What is this anomaly that Superman's spacecraft passes on his way to Earth?

Question

Because it is a flame, it almost looks alive as Superman's craft passes it. As if it is observing him. Time code 22:00 in Superman: The Movie.

Update: There is likely no canonical answer. I'm wondering if maybe somewhere on a audio commentary or something maybe the special effects guys explained what they did or why it was included.

Answer 1

In the Silver Age Superman stories, there was a cloud of crimson energy that Superman's spaceship either passed near or through on his way to Earth.

• This crimson energy was supposed to be the source of what would become Red Kryptonite, whose effects while temporary were always unpredictable to Superman.
• Radioactive Green Kryptonite was transformed into Red and continued onward toward Earth.
• Though the movie never used it, I suspect they may have wanted to consider it an option at some future time and included it.

"How the Super-Family came to Earth from Krypton" from Superboy #100 (1962)

Answer 2

It always seemed to me to be (a) yellow sun, which is what grants him his powers (in some continuities).
It looks an odd shape because of time lapses, and the spaceship's relative speed.