The Personal Website of Mark W. Dawson


Containing His Articles, Observations, Thoughts, Meanderings,
and some would say Wisdom (and some would say not).

Is Interstellar Travel Possible?

Overview

We often look up at the night sky, convinced that in a universe this vast, someone must be looking back. We also wonder and hope that we can visit them or that they have visited us. But what if the laws of nature themselves prevent contact? From the absolute limit of the Speed of Light, impacts of relativistic mass, to Time Dilation in Einstein’s theory of Special Relativity, to the curvature and the nature of spacetime in Einstein’s theory of General Relativity, and the Laws of Thermodynamics, interstellar travel is likely impossible, which explains why we are truly alone in the universe and why we have not been visited by alien civilizations. The Cosmic Haystack Problem also explains why SETI (Search for Extraterrestrial Intelligence) has not succeeded in detecting signals from alien civilizations. From the tyranny of the Rocket Equation to the Lorentz factor, the impossibility of interstellar travel isn't about technology; it's about the fundamental structure of reality. The Fermi Paradox also explains why UFOs are likely not what you think they are and why the silence of the universe is actually a beautiful thing.

In the original Star Trek, Chief Engineer Montgomery Scott would often exclaim, “I cannot violate the laws of Physics”. The physics of distance, time, and energy required for interstellar travel makes it impossible, and understanding that physics reminds us that we cannot violate the laws of physics. A video by Richard Feynman (one of the great physicists of the 20th century) explains the physics, “The Laws of Physics That Make Interstellar Travel IMPOSSIBLE ”, and reveals why aliens cannot reach Earth and why we are incapable of interstellar travel to other stars. Another video, by another great scientist, Brian Greene, titled “The Physics That Makes Interstellar Travel IMPOSSIBLE”, further elaborates on this impossibility. In these videos, the science fiction and Hollywood myths are stripped away to confront the brutal reality of space exploration. This is not just a theory; it is a deep dive into the hard science of Special and General Relativity, Thermodynamics, and Evolutionary Biology.

The Dream of Reaching the Stars

As the distinguished (and now deceased) American physicist Richard Feynman has said of the impossibility of interstellar travel:

    • The Dream of Reaching the Stars
    • How Far Is the Nearest Star?
    • The Speed of Light Barrier
    • The Rocket Equation Problem
    • Energy Requirements Beyond Imagination
    • Time Dilation & Relativity
    • Radiation & Interstellar Hazards
    • Generation Ships & Human Limits
    • Why Physics Sets the Final Boundary

Boundaries Written Into the Fabric of Reality

As Brian Greene stated at the beginning of his video:

“The universe is not indifferent to your ambitions; it is not neutral. It does not simply ignore the desire to cross the space between stars. It actively and mathematically and with absolute geometric precision makes it impossible. That is not a poetic exaggeration. That is a statement derived from the most precisely tested equations in the history of science.”

And, as he further elaborated a few moments later:

“The stars are ... separated from us by a barrier that is not made by distance alone. The barrier is woven into the very structure of space, time, mass, and energy. It is not an engineering problem. It is not a funding problem. It is a problem written into the mathematical foundation of physical reality itself.”

He ends his video by stating:

“Physics does not lie to you. It does not offer false promises. It tells you with extraordinary precision exactly what is and is not possible within the boundaries of this universe. And one of the things it tells you with the quiet certainty of an equation that has never once been proven wrong is that the distance between stars is not a challenge to be overcome. It is a boundary written into the fabric of reality itself.”

The chapters of this video reveal the problems of interstellar travel:

    • The Barrier to the Stars
    • Relativistic Mass Limits
    • The Energy of Space Travel
    • Hazards of Interstellar Space
    • Time Dilation and Logistics
    • Laser Sail Limitations
    • The Geometry of Reality

Key Concepts that Limit Interstellar Travel

The key physics concepts explained in these videos are:

    • The Cosmic Haystack Problem: This problem refers to the significant challenges in finding extraterrestrial intelligence due to the vastness of space and the numerous variables involved, making it akin to searching for a needle in a haystack. Factors such as signal frequency, transmission power, and directionality complicate the detection of potential extraterrestrial signals. This concept highlights the difficulties in detecting potential signals from alien civilizations amid the immense scale of the universe, and thus in determining which star should be targeted for visitation.
    • The Fermi Paradox: If aliens exist, why haven't they arrived? This paradox highlights the contradiction between the high probability of extraterrestrial life in the universe and the lack of evidence for or contact with another intelligent civilization. It is named after physicist Enrico Fermi, who famously asked, "Where is everybody?" during a discussion about the existence of aliens. One answer lies in the scientific, technological, and engineering challenges of interstellar travel, and another in the low probability that another technologically intelligent life form would evolve within the same timeframe as human technological evolution.
    • The Lorenz Factor: A mathematical expression in Special Relativity that describes how time, length, and other physical properties change for an object moving at a significant fraction of the speed of light.In Einstein’s Theory of Special Relativity, inertial mass increases as an object moves faster; thus, more and more force is required as an object moves faster and faster, and the Lorentz factor is the mathematical expression of these changes.
    • The Rocket Equation: How the velocity of a rocket changes as it expels propellant. It highlights the relationship between the rocket's mass, the effective exhaust velocity of the propellant, and the change in velocity (delta-v) that the rocket can achieve.
    • Time Dilation: Time dilation is the phenomenon where time passes at different rates for observers in different frames of reference, particularly due to relative velocity or differences in gravitational potential. This effect is a key aspect of Einstein's theory of relativity, indicating that a moving clock ticks more slowly compared to a stationary clock. This dilation, when moving near light speed, slows time for the traveler, but it limits any chance of meeting a civilization that is still alive.

Other Technological and Engineering Problems of Interstellar Travel

The technological and engineering challenges of creating a spacecraft capable of interstellar travel are immense, not to mention the economics of such an effort. There are also the problems of spacecraft operations that must be maintained over the round trip. Some of these technology and engineering problems are:

  • You cannot violate the Laws of Physics.
  • You cannot ignore the Fundamental Properties and Constants of the Universe.
  • You must account for Thermodynamics and Entropy in interstellar travel.
  • The Importance of Energy is crucial, as energy is central to all forms of science, technology, and engineering:
    • Energy Storage and Generation.
    • Energy for Propulsion for both the spacecraft and fuel supply.
    • Energy for Shields to protect from collision by matter in nearly empty space.
    • Energy for Spacecraft Operations.
  • The Immensity of Space and Time:
    • Navigation must be extremely precise, and mid-course corrections require extremely precise knowledge of the spacecraft's current position.
    • Rendezvous for resupply and refueling is almost impossible due to navigation problems.
    • The travel time for crew members is very long, and they would be very old when they returned, and they would return to their home planet centuries, if not millennia, after they left due to Special Relativity.
    • General and Special Relativity have impacts on interstellar travel.
  • That Which is Seen, and That Which is Unseen:
    • Impossibilities exist, and they cannot be ignored.
    • Implausibilities are many, and it may not be possible to overcome them.
    • Logistics Provisions for Repair and Replacement during the journey are great.
    • Food, Water, and Air replenishment, as well as Waste disposal or recycling are huge.
    • The Economics of constructing a vessel for interstellar travel are vast.

These other technological and engineering problems associated with interstellar travel are examined in my Science Article “Science vs. Science-Fiction”.

Physiological and Psychological Challenges

Additionally, the Physiological and Psychological Challenges (which also apply to a Moon Base and a Martian Trip) may be so taxing that they may not be surmountable. These include:

  • Physiological Challenges:
    • Radiation Exposure.
    • Altered Gravity Impacts:
      • Cardiovascular Issues.
      • Musculoskeletal Changes.
      • Sensory Systems Changes (sight, hearing, taste, smell, touch, balance, body position, and internal body sensations).
    • Psychological Challenges :
      • Isolation has psychological effects.
      • Confinement has sociological effects.
      • Anxiety and Depression will occur.
      • Sexual Tensions will happen.
      • Crew competition and power struggles are likely.

These Physiological and Psychological Challenges are examined in my Science Article on “Human Impacts of Long-Duration Space Travel

Conclusion

Accordingly, interstellar travel is highly unlikely, if not impossible, and attributing UFOs and UAPs to alien spacecraft is nonsensical. Let us be inquisitive about the true nature of UFOs and UAPs and seek a scientific explanation for these phenomena. But let us not jump to conclusions that defy our scientific, technological, and engineering knowledge. For those who believe that interstellar travel is plausible and that UFOs are visitors from another star, viewing these videos and reading my article should raise sufficient doubt and prompt a reexamination of this belief.

As for those who claim that some unknown science could supplement or replace our current scientific knowledge to enable interstellar travel, I would respond that this is highly unlikely. This is because our current scientific knowledge of physics has been among the most rigorously tested in the history of science. While our current scientific knowledge can and will be expanded, this expansion will be insufficient to overcome the boundaries written into the fabric of reality.

I would also say that the vastness of space and the enormity of time in the universe are impossible to fully comprehend, yet must be addressed in interstellar travel. So must the physical laws and properties of the universe, the technological challenges, and the engineering problems of interstellar travel be addressed.

Disclaimer

Please note that my Science Articles disclaimer applies to this article, as it does to all of my science articles. These science articles are for the purposes of general scientific information that is understandable to a layperson, so that they can grasp the concepts of the topic being discussed. As such, they are neither as accurate nor as thorough as academics, scientists, engineers, and science writers strive to achieve. My hope is that these science articles will be informative and interesting, and that they will pique the reader's interest in exploring these topics in further detail via the hyperlinks that I have embedded into these articles.