Underground Knowledge — A discussion group discussion

Hello, I am Francis Flanders, and I have just published the book Bridging the Cosmos: Ancient Myths, Modern UFO Narratives, and the Pursuit of Science. In this book, I made a calculation on the energy needed to reach 99% of the speed of light. If you are curious about what it takes to achieve near-light-speed travel, here's an excerpt explaining it in more detail. You can find it by searching for Bridging the Cosmos on Amazon. I hope you find it interesting!

Energy required for propulsion
Let’s explore the feasibility of this journey in terms of energetic propulsion. Suppose we have a futuristic and sophisticated spacecraft weighing 1 ton (1000 kg), capable of reaching 99% of the speed of light (0.99c). Achieving such a velocity is far beyond our current propulsion capabilities, as we approach the speed of light, the energy required increases dramatically due to the effects of special relativity.

If you do not feel terrified by maths, you can see in Figure 1 a detailed calculation of the energy necessary (assuming brute explosions could be fully transferred to kinetic energy and expressed in TNT units). It is found that the energy needed to push our 1-ton spacecraft to 0.99c is equivalent to 2.6 million thermonuclear or hydrogen bombs (each with a yield of 50 megatons). This dramatic requirement arises because, as the spacecraft accelerates, its relativistic mass increases, making it progressively harder to push closer to the speed of light. The closer we get to c, the more energy is required— not linearly, but exponentially.

This example highlights why light-speed travel remains firmly in the realm of theoretical physics for now.

I look forward to hearing your thoughts, questions, or comments!