[hoagy62]

Although this thread gave me the giggles, I agree. It does look (like someone already said) like a comet or something with many pieces hit Uranus.

If it was a comet, wouldn’t we have seen it beforehand?

A mystery indeed.

[GonzoGOP]

If it was a comet, wouldn’t we have seen it beforehand?

That far from the sun a comet doesn't have a tail. A small probably black or gray rock in a highly elliptical orbit. No chance we would have picked that up other than by absolute dumb luck. The outer solar system is very cold and dark. The sun isn't much brighter than any other star. (Insert the joke about Uranus being the place where the sun don't shine here). It makes spotting small objects by either visible or infrared very hard. And to plot a highly elliptical orbit you need multiple observations.