It is 100% true that you’ll not find any explicit statement in the Bible saying there are no aliens.
My argument is based on the silence of Scripture and the exclusivity of Scripture.
Silence as in the complete absence of anything of the sort and exclusivity in the sense that the Bible is the entire story of God and His relationship with man, no one else.
Some will say that’s thin. After all, absence of something does not disprove its existence. That’s fine. It’s my opinion but I think it’s the Scriptural way to look at it.
You have the entire story of creation of the entire universe at the beginning, the fall and redemption of man through a perfect sacrifice and then the end of all things. Culminating in a new heaven and a new earth in which God will dwell with His people. No mention of anything else.
If there were anyone else you think He would’ve mentioned it in His Word. All this stuff serves to deceive, confuse, distract and sow doubt. Nothing more.
The angles one could argue against mine are myriad so it’s hard to address them more specifically without them being brought up.
The crisis of Faith if there will be one is nested in three issues on how Christians can deal with aliens.
1.) Ezekiel appeared to mention them overtly, but elsewhere in the Torah there are just minor footnotes that could be interpreted as such. The New Testament we know today does quote from apocraphal books that most Christians do not read or know existed, but the Book of Enoch is loaded with mention of crafts and beings. It's weird and its ancient. Christians are not oriented through the current 66 book canon to think of their smallness in the grand scheme of the universe.
2.) I have a minority opinion on the reading of Genesis, but most take it as a literalist interpretation and the idea of aliens absolutely crumbles the Fall of Man and Original Sin using mainstream interpretations.
3.) Jesus as savior and part of the Trinity.
If anyone cares about my fringe interpretation of Genesis, it does stand up better to a larger universe than current mainstream interpretations. The point of Genesis is to explain what we are, why we are here, and our relationship to a creator. Adam was the first "Man", not the first "Human". It wasn't a scientific text, it was a moral text. What power did the first man gain from eating the forbidden fruit? "The Knowledge of Good and Evil". That's what made him a man, not an ape. Before then, humans were like animals, governed by natural impulse responses like animals. It's why we don't judge a lion for murdering an impala...it's just natural. The "Fall of Man" sets humans on a path of accountability for actions and a knowledge they are not God, they are immoral, and they have an obligation to be better.
You can imagine my interpretation of Genesis creates zero issues when we discover there are countless worlds with innumerable sentient beings existing in the future. Genesis didn't tell me about them, it told a story of my orientation on earth in relationship to my behavior, purpose, and agency.
Regarding Jesus and the Trinity, this will also be a crushing and confusing blow to some people of Faith when faced with other sentient lifeforms. It's because of weak understanding of scripture. We know of the unity of God and plurality of persons going all the way back to Genesis. We don't affirm there is only a Trinity, we affirm that is what was revealed to humanity. Even in Calvin's institutes he postulated as much. Alien's may not have Jesus, but they may have a 4th or 58th "person" of the Almighty that has dominion over other universes, multiverses, things beyond space and time, etc. This isn't heresy, its simply speculation that we know what we need to know to live within the confines of what we are and where we are. For some Christians, the idea of other beings with other revelation would be a massive crisis of Faith.
All of these crisis of Faith are from small minds and an improper orientation of what scripture was supposed to instruct for humans on earth.
Both that professor and his wife are still kicking and are both in emeritus status now having retired several years ago. 
