Science isn't as reliable as you might think. Many spurious scientific claims and discoveries are and can be proven false.

For example, Cold Fusion—the 1989 claim of two scientists that energy could be produced via electrolysis of heavy water—could not be replicated nor verified by other scientists.

Recently, the claim of parallel universes being a possibility is making a comeback of sorts on the internet. The operative word is possibility. Since it can't be proven or disproven, people can hold onto this as some hope for life beyond our planet.