Since creationist believe the earth is 6000 years , how do they explain human remains dating back 40,000 years?

The oldest directly dated human remains have turned up in a Bulgarian cave. The tooth and six bone fragments are more than 40,000 years old. The new discoveries came from Bulgaria's Bacho Kiro Cave. They support a scenario in which Homo sapiens from Africa reached the Middle East some 50,000 years ago.Jun , 2020

The oldest Neanderthal remains (to date) were found in a cave near Rome and is estimated to be 90 to 100,000 years old