Page 16: Subsonic speed? That's incredibly slow for something moving through space. For example, the speed of something in low Earth orbit is 7.8 km/sec or over 20 times the speed of sound. Plus it doesn't make sense to define speed in terms of sound in space, where sound can't be transmitted (well, kind of:
https://physics.stackexchange.com/questions/162184/what-is-the-speed-of-sound-in-space).
I was thinking the same thing
If the object is close to Saturn (going off pg 15) at the time of the image being taken, and we assume they're using the speed of sound on Earth when they say subsonic, then it would take at least 100 years to arrive
1,200,000,000 km is the distance to Saturn when it is closest to Earth
The speed of sound is ~343 m / s
1.2*10^9km=1.2*10^12m
So 1.2*10^12 m/3.43*10^2 m/s ≈ (1/3)*10^10 seconds ≈ 106 years