As the world has gotten more complex, the Federal government has undertaken efforts to take power away from the State governments and bring it to the Federal government for the purpose of centralized planning and to ensure that States are not abusing their power at the expense of minorities. They have done this by expanding commerce clause power (allow Congress to get involved in more than they once were) and by passing Civil Rights laws that let the Federal government get involved in state issues.
In recent memory, the States have utilized lobbying and lawsuits to push back against the Federal government. A number of States have filed lawsuits against the Federal government on issues like the Voting Rights Act and the Affordable Care Act.
For most of the 20th Century, this push has been led by Conservatives but since Donald Trump's election, liberal states are embracing the role of the State in a federalist system.
They learned the earth was much older than they had previously thought. Gradual processes changed the earth's surface. Fossils could tell the age they came from.
