A scientist wrote an opinion piece recently for CNN requesting proof of alien visitation before he can believe it's real. Also, another scientist writing for Scientific American points out five scientific hurdles that make is difficult to study UAP.
Link to CNN article: https://www.cnn.com/2021/06/17/opinions/pentagon-ufo-report-opinion-lincoln/index.html
Link to Scientific American article: https://www.scientificamerican.com/article/o-ufos-where-art-thou/
