[SunkenCiv]

Thanks DoodleBob. The 2029 pass is sufficiently close (given that the mass estimate is still likely to be wrong) that the trajectory of its pass in 2036 remains uncertain, but it wasn't going to be too close anyway (150 lunar distances, it sez here).

[DoodleBob]

You're welcome.

I'm not a physicist, but my guess is there is enough data to compute accurately the orbit of Apophis. That is, the proximity to Earth may be quite close (150 lunar distances). However, if they're pretty certain it won't deviate too far from that pathway then the x-axis value on the Torino Scale not just small, but pretty robust.

Those instances of NEOs where the orbit/pathway is erratic and the error bands around the central tendency are wide/grow over time (see below)...

...that's where we may see x-axis values further from the origin, producing Torino Scale values that are worrying.

For now, I'll keep setting my alarm clock.