Bounding the whole thing may not be a problem, but you’d run into inaccuracies in combining extents long before you get to that size. For example, even for the number 1 billion represented in IEEE 32 bit encoding, the next closest representable number is 100 units away, and the distance grows bigger as the exponent climbs from 9 upwards. Gemini tells me Jupiter’s radius is 7e10 millimeters, so depending on your needs for extents, there’d be noticeable imprecision in bounding even single (small on the scale of stars!) celestial objects, if you needed to measure in millimeters (is that common?).