As an astronomer, I spend a great deal of time outside at night looking up. I have seen many wonderful things in the night sky. And I am often asked if I have ever seen a UFO. Before I answer that question, it is always helpful to define our terms. What is a UFO?
The label UFO is the abbreviation for an “unidentified flying object.” Namely, if you see an object that appears to be flying, and you cannot identify it, then it is a UFO. At least, it is a UFO to you. Someone else may be able to identify the object; to that person it is an IFO (an identified flying object). I have seen many things in the night sky that other people would classify as a UFO. But in all cases, I have a pretty good idea what they are. So, for me, they are IFOs.
With a little knowledge of astronomy and meteorology, many UFOs become IFOs. The most commonly reported UFO is the planet Venus. Depending on where it is in its orbit, Venus can appear in the western sky shortly after sunset, or in the eastern sky shortly before sunrise. People are often surprised by how bright this planet can appear, particularly as twilight fades into night. Furthermore, when Venus is very close to the horizon, atmospheric effects can make Venus appear to rapidly change color, and even move about slightly.
Atmospheric refractive phenomena are sometimes reported as UFOs. For example, a bright, diffuse spot of light sometimes appears 22 degrees to the left or right (or both) of the moon or the sun. When associated with the moon, these are called paraselenae, moon dogs, or mock moons. When associated with the sun, they are called parhelia, sun dogs, or mock suns. Both phenomena are caused by the refraction of light through ice crystals in the atmosphere. Sometimes, they occur in conjunction with a large halo surrounding the sun or moon with a radius of 22 degrees. Parhelia are usually colorful like a rainbow, but less saturated. The colors are not as obvious with paraselenae due to their lower luminosity. There are several other kinds of similar meteorological phenomena.
Satellites are sometimes reported as UFOs. These appear as (usually) faint, slowly moving stars. They are visible to the unaided eye because they reflect sunlight. They seem to fade into nothing when they pass into earth’s shadow. A few are remarkably bright, such as the international space station. Starlink satellites are also very bright shortly after they have been launched, and occur in a long string of bright points. Occasionally a satellite will catch sunlight at just the right angle and will briefly appear very bright – a sun glint. In particular, “Iridium flares” were a very common phenomenon years ago in which Iridium communication satellites would briefly flare up, often much brighter than Venus! These events were predictable to the second. But these particular satellites have all been replaced as of December 2019. Still, less predictable sun glints from other satellites continue to occur from time to time. Occasionally, a spinning satellite such as a spent rocket casing will produce a series of semi-regular, rapid pulses in brightness due to sun glints.
Balloons are a common source of reported UFOs. These can be anything from high-altitude weather balloons to the common helium balloons used at parties. The mylar surface of certain party balloons is highly reflective, making them easy to spot even from large distances. These are sometimes reported by pilots over the ocean – generally very near where a cruise ship has passed.
Drones are commonly reported as UFOs. These days, drones are relatively inexpensive, and so more people are buying them. Some drones are equipped with lights which can be seen at night. There are even companies like SkyMagic that perform computer-controlled night shows with drones.
Temperature inversions can cause all sorts of interesting visual effects. Many of these have contributed to UFO reports. Normally, the air temperature decreases with altitude. But occasional local weather conditions will reverse this, such that air temperature increases with altitude for some distance. This causes light to refract, particularly light travelling nearly parallel to the surface of earth. Inversions allow us to see farther than the normal horizon because the light curves in the same direction as earth. The effect can cause distant car headlight to appear to move in unusual ways.
Lens flares are a common source of UFO reports. These are due to internal reflections within a camera, particularly when taking a picture or video of something very bright. In fact, internal reflections of various kinds are quite common when looking through glass or some other transparent surface. The brain can mistake a reflection of something behind the observer as actually being far away in the sky. Observations made through glass are notoriously unreliable.
Rocket launches are occasionally reported as UFOs. This is particularly the case when a launch goes wrong and the rocket spins out of control in the atmosphere. The exhaust can create a spectacular spiral pattern. I recall seeing one of these when I was very young. It was really something to see!
Various kinds of meteors may be reported as UFOs. Most people will properly identify a typical “shooting star.” This occurs when a small particle orbiting in space intersects earth’s atmosphere and is incinerated due to the heat of its high speed. Most meteors are not much larger than a grain of dust, or perhaps a pebble. But larger objects can produce a spectacular show. Especially bright meteors are called “fireballs.” They are often vividly colorful. I once saw an amazing green fireball with an orange trail and perimeter. It was easily as bright as the full moon.
Occasionally, we are treated to an artificial meteor – a satellite re-entry. When satellites have outlived their usefulness, they are de-orbited and intentionally plunged into earth’s atmosphere. But since they have far less velocity than a typical meteor, they produce an extremely slow, long-lasting “falling star.” I have seen only one satellite re-entry in my life (so far) and it was really stunning.
Rare atmospheric phenomena such as ball lightning or a green flash at the last moment of sunset are also known to occur. I have not seen either of these yet. But if a person didn’t know what these were, they could easily be interpreted as a UFO.
Aircraft are responsible for certain UFO reports. We are familiar with the way most aircraft appear most of the time. But when combined with effects of weather or illumination particularly around sunrise or sunset, either the plane itself or the vapor contrail it produces can take on an unusual appearance. Flares released from military aircraft have been reported as UFOs. Furthermore, we are not familiar with all aircraft. The military is always testing new kinds of jets, and some such projects are classified. Anyone who saw the Lockheed F-117 “Stealth Fighter” before its declassification in 1988 would have said that it looks like nothing else in this world.
And there are hoaxes too. These days, it is very easy to create fake videos that look very real. Be especially cautious when viewing supposed video footage of any UFO.
Flying Saucers from the Beyond
One option that has not been presented as yet is perhaps the first that enters many people’s mind when they hear the term UFO. Namely, could some UFOs be alien spacecraft? Given the enormous number of natural and man-made aerial phenomena, this is a really strange default option. It really isn’t the first thing we should think of when hearing the term UFO.
Consider the following. You are sitting by a pond with your friend. Out of the corner of your eye, you spot something move under the water. The water is murky, preventing a clear view. But there was definitely something moving. As you begin to contemplate the possibilities, suppose your friend blurts out, “It’s probably an alien creature from a distant planet whose ship crashed nearby, but jumped into this pond because it breathes water!” Now of all the possible explanations, is that really the one to start with? Wouldn’t we more naturally think it was a fish or a frog? Granting that we can’t absolutely disprove your friend’s conjecture, wouldn’t a more mundane explanation be infinitely more probable?
Likewise, when a person sees a flying object that he cannot identify, should he immediately assume it is due to extra-terrestrial intelligence – something that has never been observed? If a flying object is clearly an artificial machine rather than natural phenomena, wouldn’t it be more natural to think that humans made it. “But it looked like a flying saucer!” Human beings have had the capacity to build flying saucers since the VZ-9 Avrocar built in 1958.
So, there really is no logical reason to jump from UFO to “alien spacecraft” considering all the natural and manmade flying objects that now exist. Could it be that such a conclusion is motivated more by wishful thinking, perhaps influenced by science fiction books and movies?
Extra-Terrestrial Life Forms?
There are some pretty compelling reasons to conclude that extra-terrestrial life forms native to other planets do not exist. But these reasons are worldview-dependent. That is, whether we accept or reject such reasons depends greatly on our other beliefs about the world and its origin.
Those who believe in neo-Darwinian evolution tend to think that life is an accident of nature. Namely, evolutionists teach that life began when non-living chemicals happened to assemble in such a way as to produce a self-replicating cell. This cell then divided, and mutations produced slightly different versions. Those with traits less suitable to survival tended to be supplanted by those with advantageous traits, eventually resulting in the variety of life we see on earth today. If life is just something that happens given enough time and the right chemistry, it stands to reason that it probably has happened elsewhere as well. After all, it is a big universe with perhaps 100 billion times 100 billion planets. It seems nearly certain that a few of them will have the right chemistry. And if the universe really is 13.8 billion years old, then life has had plenty of time to evolve on some of those planets. Extra-terrestrial life is virtually a certainty in the evolutionary worldview.
But the Bible gives us the actual recorded history of the universe, including its creation. It places the beginning a few thousand years ago, and claims that the first forms of life were created supernaturally by God according to their kinds. On day 3 of the creation week, God created plants – essentially self-replicating food for living creatures to eat. The Bible mentions the creation of life in earth’s oceans and skies on day 5. The Bible mentions the creation of land animals and humans on day 6.
But where are the creatures that live on other planets mentioned? Of course, just because something isn’t mentioned doesn’t prove it didn’t happen. But when we look at the creation week in Genesis 1, we see that the earth is very different from the other planets. The earth is made on the first day (Genesis 1:1-5), whereas all the other planets are made on day 4 (Genesis 1:14-19). God spent five of the six creation days working on earth, making it right for life. He takes only one day – day 4 – to create all the other planets. Clearly, earth is very special and different from the other worlds.
Moreover, when we look at Isaiah 45:18, we find that the Lord made the earth “to be inhabited.” And although the text does not add, “and He didn’t do that with any other planet,” that does seem to be the implication. Earth is uniquely designed for life. The celestial objects in earth’s sky were to be for signs, seasons, days, and years – to help us track the passage of time (Genesis 1:14-19). But apparently, they were not created to house life as the earth was. This line of reasoning may not conclusively prove that no life exists beyond earth. But the uniqueness of earth according to Scripture cannot be denied.
Furthermore, there are some theological difficulties that arise if a person believes in intelligent life on other planets. Suppose we take the Star Trek position that there are civilizations on other worlds, like Vulcans or Klingons, that are rational beings like ourselves. How would such beings fit into God’s plan of salvation? Or would they fit at all?
Jesus, the Son of God, took on human nature (Philippians 2:6-8). He became one of us so that He could die in our place (Hebrews 2:17; 2 Corinthians 5:21). Christ can represent us on the cross because He is our blood-relative, and His shed blood atones for our sins (Hebrews 9:22; 1 John 1:7). Thus, only a blood-relative can redeem us from our slavery to sin (Leviticus 25:47-49). Moreover, since Jesus is God, His life has infinite worth. So, His death can pay for all the sins of His people. His resurrection then proved that He was and is God.
But what about the Vulcans and Klingons? They have no divine blood-relative to redeem them. After all, Jesus became a man, not a Vulcan or Klingon. Some might speculate, “Perhaps Jesus then went to the Klingon home world and became a Klingon to die for their sins.” But that contradicts Scripture; Jesus died once for all (1 Peter 3:18) and will never die again (Romans 6:9). Some might speculate, “Perhaps the Klingons never sinned and therefore need no Savior.” But all creation suffers the effects of Adam’s sin (Romans 8:20-22). Biological life forms now die because through one man death entered the world (Romans 5:12; 1 Corinthians 15:21). Even animals die since Adam was given dominion over them (Genesis 1:26-28). But Adam was never given dominion over life on other planets, so how could his sin affect them? It cannot, and yet it must according to Romans 8:20-22. So, this option leads to a contradiction and must therefore be false.
Such theological problems only arise if there are sentient, rational creatures on other worlds. Yet, the Bible mentions no such creatures and uniquely specifies the earth as designed to be inhabited (Isaiah 45:18). Could it be that theological problems only arise because we are taking an inherently secular concept and trying to work it into a Christian worldview?
The earth really is special. It is the planet where God placed the only creatures that are said to be made in His own image (Genesis 1:26-27). Of all the billions upon billions of planets in the universe, it is this pale blue dot where God Himself walked. It is earth alone where God became man and paid the penalty for our sin on the cross. And He offers salvation and forgiveness of sin for all who will trust in Him (Romans 10:9-10, 13).
 The Hebrew word “star” (kocab) would include planets as well (except earth) in the ancient system.