This comic strip has been making its way around the internet: [![Carl and Steve dinosaur comic][1]][1] The final panel (which was added later) is clearly implying that Steve is watching the asteroid or comet that would eventually create the [Chicxulub crater][2] and cause the [K-T extinction event][3]. Obviously it's just a joke, but I'm curious about the astronomy involved. Wikipedia says the [Chicxulub impactor][4] is thought to have been a 10-15 km diameter object. Would it have been visible to a (human) naked eye before impact? And if so, would it have appeared like a star that grew brighter and brighter each night? [1]: https://i.sstatic.net/UKN93.jpg [2]: https://en.wikipedia.org/wiki/Chicxulub_crater [3]: https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event [4]: https://en.wikipedia.org/wiki/Chicxulub_impactor