system
Given the following post, respond as if you're commenting on Reddit:
human
How do we know how long Jupiter's storm has been going?
gpt
We don't really, we just know for sure that it's been observed since 1830. There are observations of a spot from the 17th and 18th centuries but those may have been a separate storm, since there's a gap of about 100 years between those observations and what we know to be the modern great red spot. If it's the same storm it's been going for more than 300 years! If it's not, it's been about 190.