WHAT EXACTLY HAPPENS IF WE TRAVEL AT SPEED OF LIGHT- learn with Pradhuman

 

WHAT EXACTLY HAPPENS IF WE TRAVEL AT SPEED OF LIGHT

The Journey Begins

Welcome back to Space Tech by Pradhuman Today, we are embarking on an extraordinary journey to explore what we would see if we were to approach the speed of light. Imagine yourself aboard a spaceship, accelerating away from Earth, moving faster and faster. As we gain speed and move further away from our home planet, we will begin to witness some fascinating optical effects and delve into the mysteries of special and general relativity.

Unfazed by Speed

Contrary to what one might think, the speed itself has no direct effect on our bodies. Just like when two trains cross, it is impossible to feel whether it is our train or the other that is at rest. Similarly, inside our spaceship, we cannot feel its speed but only its acceleration, the thrust of the reactors pressing us against our seats. As long as the acceleration is reasonable, we can bear the speed without any discomfort throughout our journey, even when approaching the speed of light.

The Aberration of Light

As we accelerate, we start to notice a peculiar optical effect. The stars in front of us, which we are getting closer to, seem to gradually move away. The sky appears to contract, as if the stars' light rays are coming more and more from the front. This phenomenon is known as the aberration of light. It causes the stars' intensity to increase as they focus in front of us, while the sky behind us seems to widen and become darker.

To better understand this, let's imagine a common situation. You are in a car driving at high speed, and it starts to rain. The rain falls vertically, but as the car moves forward, the raindrops on the windshield appear to come from the front, as if their trajectory were tilted. The faster you accelerate, the more the rain seems to fall from face on. This is similar to what we experience in our spaceship, where the stars' direction appears different due to our motion.

The aberration of light also distorts the image of the sky around us. The grid representing the fabric of space seems to contract forward, and the straight lines bend. As we move quickly, objects appear to be angled in our direction, a phenomenon known as Terrell-Penrose rotation. Images of objects seem contracted in front of us, and the perspective is strongly distorted.

Peering into the Past

When we look out into space, we often hear that the further we look, the further back in time we see. This is because the light from distant stars takes time to reach us. As we move away from Earth, the planet's light takes longer and longer to reach us. If we were to zoom in with a telescope, we would see people on Earth evolving in slow motion. This phenomenon is known as the Doppler effect, where each tick of Earth's clocks takes longer to reach us, and the light rays we receive seem to weaken and shift towards the red end of the spectrum.

However, when our spaceship catches up with the light, the opposite effect occurs. The stars appear to get brighter, and their colour shifts towards blue. Their clocks seem to tick faster. These optical effects, known as the Doppler effect, are due to the relative motion between us and the light source.

Optical Illusions or Physical Effects?

Up until this point, the optical effects we have observed were mere illusions resulting from our motion and the way we receive light. However, as our spaceship continues to accelerate and approach the speed of light, we will start experiencing real physical effects with irreversible consequences.

One of the key consequences of special relativity is time dilation. Our spaceship's trajectory in space-time gradually deviates from that of Earth as we pick up speed and move further away. The axis representing time is no longer aligned with the time axis of people on Earth. If we were to turn around and come back, our clocks would measure a different time, and we would have aged less than those on Earth.

Another consequence is length contraction. When a body moves close to the speed of light, its length appears contracted in the direction of its motion. From our perspective, the entire universe appears to be moving backward. The length of our journey seems shorter than expected. This is not just an optical effect but a physical phenomenon. If we were to travel to a distant star, the journey would genuinely seem shorter to us, taking less and less time the faster we move. However, for people on Earth, several thousand years would have passed.

The Elusive Speed of Light

As our spaceship continues to accelerate, there is a certain point where we might expect to reach the speed of light. However, this is strictly impossible. The speed of light is absolute, and no matter how much we accelerate, we will never catch up to a light ray. Even if it may seem from Earth that we are approaching the speed of light, from our point of view, we are motionless, and light always escapes us at its constant speed.

When we come close to the speed of light, our field of view continues to contract. The optical effects become even more extreme. Light rays appear to come from the front, while those behind us can never reach us. The universe seems extremely contracted, and our journey becomes almost instantaneous from our perspective. However, for people on Earth, several thousand years would have passed.

A Glimpse of the Future: Warp Drive

While nothing can ever move faster than light through space, there is a fascinating concept that might allow us to circumvent this rule. According to the theory of general relativity, the fabric of space-time itself is dynamic and can bend in multiple ways. This leads to the notion of a warp drive, where we create a bubble around our spaceship and propel it faster than light by propelling the fabric of space-time itself.

Creating a warp drive is currently thought to be impossible as it would require bending space-time with massive amounts of negative mass, a form of matter that does not exist in our universe. However, through mathematics, we can still model and calculate what we would see in such a situation. From outside the warp drive, it would seem to appear out of nowhere, and the curvature of space-time would deviate the trajectory of light rays. Looking from the inside, we would witness a contracted and bright sky in front of us, while a whole patch of the universe would vanish from our view.

Conclusion

Approaching the speed of light is a journey filled with mind-bending optical effects and intriguing physical consequences. As we accelerate and explore the mysteries of special and general relativity, our perception of the universe transforms. While it is strictly impossible to reach or exceed the speed of light through space, the concept of a warp drive offers a glimpse into a potential future where we can traverse vast distances in a fraction of a second.

As we conclude our journey, we are left in awe of the wonders of the universe and the intricate laws that govern it. The exploration of approaching the speed of light opens up new frontiers of knowledge and challenges our understanding of reality. Science continues to push the boundaries of what is possible, unravelling the mysteries of our existence.

Thank you for joining us on this exhilarating adventure through the cosmos. Stay curious, and keep exploring!