If a spaceship were to attempt to reach speeds near the speed of light using our current fuel technology, several significant challenges would arise. These challenges are rooted in the fundamental principles of physics, particularly Einstein's theory of relativity.
Increasing Mass: As an object with mass accelerates, its mass increases according to the theory of relativity. As the spaceship approaches the speed of light, its mass would progressively increase, requiring a tremendous amount of energy to continue accelerating. This effect is known as relativistic mass increase or mass dilation. Consequently, it would be increasingly difficult to supply sufficient fuel to overcome this massive increase in mass.
Energy Requirements: As the spaceship's mass increases, the energy required to further accelerate also increases exponentially. Approaching the speed of light would demand an enormous amount of energy. Our current fuel technologies are inadequate to provide the necessary energy density for such high speeds.
Time Dilation: According to time dilation, as an object moves closer to the speed of light, time appears to slow down for that object relative to an observer at rest. This means that time onboard the spaceship would pass more slowly compared to an observer on Earth. The closer the spaceship approaches the speed of light, the more pronounced this effect becomes. Consequently, while the crew on the spaceship might experience a relatively short journey, much more time would have elapsed on Earth.
Relativistic Effects: When an object moves at high speeds, relativistic effects become significant. For example, lengths contract in the direction of motion, and the passage of time is different for observers in different reference frames. These effects can introduce complications and distortions in various systems on the spaceship.
Given these challenges, it is currently beyond our technological capabilities to achieve speeds near the speed of light using conventional fuel technology. It would require revolutionary advancements in propulsion systems, energy sources, and our understanding of physics to overcome these limitations.