single player

You can do so at world creation in the settings or via Difficulty.eco config file. Note that the meteor will not simply disappear on a world that was already created with it.

The checkbox is called "Has Meteor", the last one of three directly before the advanced settings.

It is not recommended to use the mentioned setting, as it is experimental and not easy to use - hence it is not listed. A value of 0.04 is way too much and will level you to maximum level in no time.

Originally posted by 123: Without this setting, it is impossible to play solo.

That is simply not correct, the "No Collaboration" setting is intended and perfectly fine for that and can be further adjusted to personal liking with the advanced settings. I understand that the settings may not fit you, but a recommendation of an experimental setting that we explicitly don't recommend as a general reflection on everyone is still not right. Singleplayer is always a longer experience and the meteor does not progress while not playing either.