Is interstallar space travel possible?
What do real scientists say?

Adapted from Daniel O'Connor's book "Only Man Bears his Image" with permission

We opened our article on UFO movements on earth with the fact that all technologies that operate in the universe are subject the same laws of physics, regardless of any innovation by hypothetical "aliens".

“An object in motion stays in motion with the same speed and direction unless acted upon by a force. The rate of change of momentum of an object is equal to the force applied to that object. For every action there is an opposite and equal reaction.” —Cf. Sir Isaac Newton

Now to a modern day scientist:

“Those of us who were raised on science fiction became accustomed to thinking of travel to the distant stars as part of our birthright. It is a powerful dream. Giving up any dream is sad, and there are many who refuse to give up this one. But as with many other fantasies, faster-than-light travel is and always was a pseudoscientific concept. It was never part of science.” —Dr. Rothman, Physicist & Sci-Fi Pioneer

Cannot travel faster than the speed of light

“Canis Major Irregular Dwarf Galaxy” is a full 25,000 light years away.[170] This means that a ship travelling at the speed of light would take 25,000 years to reach our solar system from the nearest galaxy. For perspective, the manmade object that is farthest from earth is the Voyager 1 craft, launched in the year 1977. As of 2023, it is almost 15 billion miles from earth, having left the solar system in the year 2012 travelling a dizzying 40,000 miles per hour. If it were perfectly aimed at the aforementioned “galaxy,” it would take almost a billion years to arrive. The next closest galaxy after Canis is 75,000 light years away, and the distances continue expanding dramatically for other galaxies.

Clearly, any hope of meeting aliens on earth must be placed in their ability to travel faster than the speed of light. But this is absolutely impossible. If any object with a “rest mass”—a category including electrons, protons, neutrons, all atoms, all molecules, etc. (everything that is not a photon or a neutrino)—were to travel at the speed of light, then its own mass would have increased infinitely. As noted in an explainer from the U.S. Department of Energy: ... as an object moves faster, its observed mass increases. This increase is negligible at everyday speeds. But as an object approaches the speed of light, its observed mass becomes infinitely large.[171] If, however, the mass of any object anywhere in the universe were to have increased infinitely, then so too would the force of its gravitational pull. An infinite gravitational pull would have caused the entire universe to collapse into itself.

As we can be somewhat confident that the entire universe has not yet thus collapsed, we can be equally confident that nothing whatsoever (other than light)—anywhere in the universe—has ever travelled at light speed, much less beyond it. Other paradoxes arise from the counterfactual scenario above; not only would it entail a situation we can be certain has not happened, but the very generation of the situation in the first place would also be impossible. An infinite amount of energy—i.e., more than is contained in the entire universe—would be required to propel so much as a single atom to the speed of light; therefore it goes without saying that no spacecraft has ever, anywhere, achieved this feat. It is irrelevant whatever technology, from whatever galaxy, one may posit. We are not dealing with technological limitations, but bedrock scientific ones.

Many other demonstrations can prove that the speed of light can never be surpassed. One such argument is presented by Dr. Rothman, who explained:

The well-known consequences of relativity include the impossibility of any matter, energy, or information traveling faster than the speed of light. ...if a message could be sent faster than light from earth to a space ship traveling faster than a certain velocity (but less than the speed of light), the ship could transmit a reply that would arrive at the earth before the original message was transmitted. [note: this is counterintuitive—and, indeed, impossible, hence Rothman choosing it to highlight the absurdity of proposing faster than light travel—but it derives from the physics of relativity theory as applied to time dilation and the absolute constancy of the speed of light]... This circumstance would violate the principle of causality (the idea that a cause must always come before its effect) and allow the occurrence of typical time-travel paradoxes. For example, a scenario could be created in which a catastrophe takes place on earth, after which a warning is relayed from earth to a moving spaceship and then back to earth. If the ship is moving fast enough, the warning would arrive on earth at a time prior to the catastrophe. The catastrophe could thus be halted before it happened. Has the catastrophe taken place? If not, then why was the warning sent? Rather than deal with such implausible paradoxes, we say that the thing that causes them faster-than-light travel—is impossible.[172]

Now, this absolute barrier does not prevent Ufologists from proposing all manner of alternative theories. Some conjecture teleportation via “wormholes,” or describe the phenomena with other newly invented terms. All of this is pure pseudoscience without the slightest evidential basis. The moment such explanations as these are brought into the discussion, a Ufologist has demonstrated he has no desire to be scientific in his views, and has thereby again implicitly transferred the discussion into the domain of spiritual discernment. UFO proponents argue that aliens would have devised ways to circumscribe laws that only appear to be immutable to earthbound scientists. Some scientists have speculated that objects entering “wormholes” in space could travel immense distances instantaneously. This assumes that one could first find a conveniently located wormhole, that one’s vehicle could withstand its tremendous gravitational and tidal forces, and that one could know in advance where in the universe one would emerge.

For now, wormholes exist only in the realm of theory and so, in the absence of any actual evidence, cannot bolster the extraterrestrial hypothesis for the origins of UFOs.[173]

Here as in all other realms, anyone can do a quick internet search and immediately generate a long list of supposed experiments, from supposedly trustworthy periodicals, which in fact present only pseudoscience. “Scientists create wormhole!” is a headline that one can anticipate being repackaged more or less annually. It is always a lie, though gleefully promoted by media outlets who care only for clicks. *** Can we at least hope for aliens visiting from other solar systems within our galaxy? Although the intergalactic alien visit is even more outlandish, the answer to this question is also a resolute no. Explaining why is our next task.

Closest planet is 25 trillion miles away

The closest solar system to ours is Proxima Centauri. It is about 25 trillion miles away from earth. The Voyager 1 spacecraft hurtling through space at its phenomenal speed, would take over 70,000 years to reach it (if, by some miracle, its trajectory was perfect and it avoids destruction by collisions). Of the millions of trillions (i.e., quintillions) of planets in the universe, the closest one (only earth is inhabited in this solar system) requires more time than 10x the entire history of civilization.

As we can see, proposing the possibility of even the very easiest interstellar meeting requires positing travel at speeds coming within the relative vicinity of the speed of light. Yet this presents obstacles insurmountable not merely technologically but also scientifically. While those infatuated with science fiction rarely concede this fact, serious thinkers readily will.

Collision with fleck of space debris causes atom bomb effect

In his article, “Interstellar Travel as Delusion Fantasy” (in Scientific American), Dr. Ed Regis observed:

Collisions in space are by no means rare: by the end of the Space Shuttle program, for example, more than 100 shuttle windows had been replaced after impacts with space debris, some objects being as small as the fleck of paint that cracked the front window of STS-7 (the second Challenger mission) in 1983 ... It might be thought that the interstellar medium is “empty space,” or a vacuum. To the contrary, the space between the stars contains volumes of interstellar gas and dust, along with cosmic rays, and possibly objects of unknown composition, size, mass, and density. And so it would be difficult to believe that on a journey of at least 4.22 light-years (the distance from Earth to Proxima Centauri) an interstellar spacecraft would meet with no other object whatsoever. But for a starship traveling at relativistic speeds, a collision with even a random small particle, according to Tom W. Gingell of Science Applications International Corporation, who did a study of the subject, would have the effect upon the spacecraft of an H-bomb explosion. Since quickly diverting a massive spacecraft from its course would be impossible, it would be necessary instead to detect, deflect, or destroy the object within a matter of milliseconds before impact, by means of a system that would have to work perfectly and virtually instantaneously the first time out...

Collisions with the tiniest of particles in space is a massive problem for spacecraft. Combine this with incomprehensible speeds required for interstellar travel where collisions with the smallest pieces of interstellar dust would decimate any craft—regardless of its construction method or materials. For any spacecraft meaningfully larger than a molecule, countless such collisions would be statistically guaranteed when travelling between stars. Astrophysicist Dr. Paul Sutter put the matter in even more specific terms in a 2021 article for Discovery magazine. He accurately described the most “realistic” interstellar travel method as follows:

One proposed [method] for an interstellar spacecraft is called the Starshot Initiative, which aims to shoot a super-powerful laser on a lightsail (a giant nearly perfectly reflecting membrane), using the energy from the light to propel the spacecraft to a tenth the speed of light. That would enable it to reach Proxima [Centauri] in less than half a century. To make this work, the laser would have to use all the energy from every single nuclear reactor in the United States at once. And it would have to operate for 10 minutes, which is about a quadrillion times longer than we’ve ever operated our most powerful lasers). ... and the spacecraft could weigh no more than a paperclip.[175]

Admittedly, the two sources quoted above provide analyses based on the (absolutely best possible) human technology. Hypothetical alien civilizations would, of course, have more advanced inventions. But it only takes a small dose of intellectual honesty applied to the observations above to realize that it does not matter how much more advanced any civilization’s technological prowess becomes: interstellar travel remains ruled out. Any sober assessment of the distances and dangers involved, when combined with basic knowledge of the universal scientific laws governing the strength of materials, kinematic physics, thermodynamics, chemistry, and more (even leaving aside biology!) will quickly demonstrate that no natural, material object—much less one so sizeable as the UFOs reported today—will ever travel between stars.

Two Egyptians standing on the pyramids

Imagine two Egyptian friends, several thousand years ago, observing the recently completed tomb of the pharaoh Khufu (now known as the Great Pyramid of Giza). Suppose one says to the other:

“This was such a gargantuan undertaking; it took everything we had as a society, for decades, to complete. And standing atop it, it appears we are not even one bit closer to the moon. We really need to just admit that we will never build a structure that reaches the moon.”

His friend might be inclined to respond,

“No, you cannot say that! Who knows what abilities future people will have? We can’t even imagine what they will be able to do.”

Despite not knowing the future, the first Egyptian would still be correct to respond,

“I am sure they will build much taller structures in the future. But what we can already see clearly tells us that there is such a great distance involved here that much more fundamental constraints than mere technological or pragmatic ones dictate that a building cannot be erected that will actually reach the moon.”

Obviously, the Egyptians were not intending to build a structure to reach the moon but ET promoters that what we do now would also seem impossible to men who lived thousands of years ago. But that is simply not true.

Modern technology would be a marvel to an ancient Egyptian, but their understanding of the laws of nature could still account for them. (We will consider this fact in relation to claims made about the maneuvers of “UFOs” supposedly piloted by ETs.) Their understanding of the laws of nature, however, could not account for one building a pyramid touching the moon, and they would have been entirely justified in deeming such a task fundamentally impossible.

Similarly, our understanding of the laws of nature cannot account for interstellar travel, much less intergalactic travel—precisely because both are impossible. As we can see from the analyses above, the amount of energy required for the closest interstellar travel, for even a comically tiny spacecraft, is so outlandish—even if the greatest power generation method that exists in the universe, nuclear power, is used—that no one who is genuinely assessing the situation could concede to it the slightest palatability.

Cosmic dust, steering, acceleration and deceleration

• Cosmic dust collisions that would destroy the craft, or
• Inability to steer (and thus effectively guaranteeing it will never arrive at its destination). Steering in space is not like steering a car, boat, or plane, where a sufficiently dense medium exists to push against for turning. Instead, it requires exponentially more expenditure of energy.
• Deceleration—which, in space, is just as energy-hogging as acceleration.
• Destruction of any biological entity travelling in the craft due to accelerations, cosmic radiation, etc.

Energy needed on board infeasible

It is not merely technologically infeasible to travel from one star to the next. It is impossible. If we are not dealing with a laser being shot at a craft to accelerate it from its home planet, then we must assume its own fuel is carried with it. The energy that would be required for any interstellar travel (not to mention a thousand other obstacles) render such a task essentially super (or preter-) natural.

To grasp that situation, we need only imagine a child’s small remote controlled toy car with a heavy truck battery plopped on top of it, wired into the toy car’s motor, with the intent of extending the toy car’s range. As soon as the child tries to make the car move, he would immediately discover it wouldn’t budge. The weight of this battery would be far too oppressive. Suppose the father of this child, seeing the conundrum, goes to acquire another car battery, hoping all that is needed is more capacity. Plopping that battery on top, as well, of course would be to no avail.

In accordance with the nature of the scenario itself, the father is stuck acknowledging its unresolvability. He must, instead, tell the child to remain content with a range for his toy car derived from the capacity of the battery with which it was built.

Yet, the notion of interstellar travel is much more outlandish than the suggestion of undertaking a long road trip with a small, plastic toy car by placing a heavy lead-acid truck battery atop it.

Astrophysicist Dr. Hugh Ross confirms this assessment. He explained:

At even half the velocity of light, the energy needed to propel an object is 170 million times greater than NASA’s fastest spacecraft requires. The energy problem compounds, however, because propellants and engines themselves involve mass. The higher a spacecraft’s speed, the more propellant and the bigger the engines it requires. Therefore, the higher the intended speed of the spacecraft, the (exponentially) higher the mass of the craft. An additional mass problem arises, of course, from the need to move the spacecraft’s payload (the total weight of the passengers, crew, instruments, and life support supplies).

The mass of a craft and its propulsion system rises geometrically relative to the mass of the payload. ... Computer modeling indicates that there is a large cloud of comets, estimated to contain 100 billion comets or more, surrounding the solar system. Such clouds likely surround any star in this galaxy that could possibly harbor planets. Astronomers suspect that the giant molecular clouds scattered throughout the Milky Way galaxy may contain even greater numbers of comets. To protect against damage from space debris, a spacecraft needs some kind of armor. However, armor means more mass, which means more propellant to move the added mass. More propellant means more propellant to move the extra propellant. Thus the problem escalates. ... Exposure to radiation poses yet another serious threat. The faster a craft travels through space, the greater the damage it suffers from radiation. The particles associated with radiation (for example, protons, neutrons, electrons, heavy nuclei, and even photons) cause erosion to the “skin” and components of the craft. Again, the rate of erosion rises with the square of the velocity.

However, a slower velocity means more time in space, and that extra time means more radiation exposure for the aliens on board ... . any reasonably sized spacecraft transporting intelligent physical beings can travel at velocities no greater than about 1 percent of the velocity of light. At higher velocities the risks from radiation, space debris, leaks, and wear and tear simply become too great to prevent the extinction of the space travelers before they reach their destination. A spacecraft traveling at 1 percent of the velocity of light (nearly 7 million miles per hour) would need twenty-three thousand years to travel 230 light-years.[176]

No logical, scientific grounds exist on which to posit the possibility of aliens travelling to us even from our closest neighbor, much less some other planet in the Milky Way beyond Proxima Centauri, still less from another galaxy. Whoever takes real science seriously is compelled to securely file such propositions in the science fiction box. There are many other reasons, however, that we can be scientifically certain we do not await contact with alien civilizations.