What would happen if you moved at the speed of light?

If you leave Earth at 15 years old and travel at the speed of light for 5 years, several effects and implications arise:

a) Time dilation effects: According to the theory of relativity, time slows down for an object moving at high speeds relative to another object at rest. This means that if you travel close to the speed of light for 5 years, time would pass more slowly for you compared to someone on Earth. When you return, you would find that more time has passed on Earth than for you.

b) Twin paradox implications: The twin paradox is a thought experiment where one twin travels at a high speed while the other stays on Earth. When they reunite, the traveling twin would be younger than the twin who stayed on Earth. In this case, if you left Earth at 15 years old and traveled at the speed of light for 5 years, you would still be 15 years old when you return, while your peers on Earth would have aged more.

c) Relativistic considerations: Relativity theory states that the laws of physics are the same for all observers in uniform motion. This means that the laws of physics would apply to you during your journey, even though you are traveling at the speed of light. For example, the principle of conservation of energy and momentum would still hold true.

d) Space-time distortion aspects: As you approach the speed of light, space and time become distorted. This means that distances and durations of events can appear differently for observers in different reference frames. For example, objects in the direction of your motion would appear contracted in length, and time intervals would be dilated.

To summarize, if you leave Earth at 15 years old and travel at the speed of light for 5 years, you would experience time dilation effects, the twin paradox implications, relativistic considerations, and space-time distortion aspects. These concepts arise from the theory of relativity and show how our understanding of time, space, and motion change at high speeds.

What would happen if you moved at the speed of light?

In science fiction, traveling at the speed of light often seems like a thrilling possibility. But have you ever wondered, could your body actually handle moving that fast? What would happen to you if it were possible?

To start, let’s imagine a hypothetical scenario where traveling at the speed of light is achievable. Light travels at an incredible 299,792,458 meters per second (about 186,000 miles per second), or nearly 983 million feet per second. If you were moving at this constant speed, your body wouldn’t necessarily feel anything unusual. That’s because humans don’t sense constant motion—we only notice changes in velocity, like acceleration or deceleration.

The real challenge isn’t moving at the speed of light but getting to that speed. Accelerating to such an extreme velocity would be incredibly dangerous. The force of acceleration exerts intense pressure on the human body, and too much of it can cause serious harm or even be fatal.

“At high accelerations, your blood will have a hard time pumping to your extremities,” explained Michael Pravica, a physics professor at the University of Nevada, Las Vegas. Essentially, your circulatory system wouldn’t be able to keep up with the intense forces, which could lead to a host of life-threatening complications.

So, while traveling at the speed of light makes for great science fiction, the realities of human biology and physics make it an impossible dream—for now.

Most humans can handle acceleration forces of about 4 to 6 times the force of gravity (4 to 6 g) for short durations. However, as g-forces increase, your body’s ability to pump blood from your feet to your head becomes severely limited. When blood starts pooling in your lower body, your brain doesn’t get enough oxygen, leading to unconsciousness. If the force doesn’t let up, it could ultimately be fatal as your organs are deprived of the oxygen needed to function.

Fighter pilots, who regularly endure high g-forces, are trained to prevent blackouts by using techniques like tensing their muscles and wearing specialized g-suits. These suits help them tolerate up to 9 g for brief periods. However, if you were to accelerate to the speed of light in just a few seconds—like in Star Wars—the outcome would be catastrophic. The extreme force, over 6,000 g according to Omni Calculator’s g-force tool, would crush you instantly, turning you into a human pancake.

In short, the physics of such rapid acceleration is far beyond what the human body can withstand, making light-speed travel an unattainable fantasy for now.

Unfortunately, reaching this lofty speed turns out to be impossible. “You cannot go at the speed of light, given that you have a finite mass,” Pravica said.

Einstein’s theory of special relativity shows that as an object with mass gets closer to the speed of light, the mass starts to increase as it nears the speed of light, Pravica said. If an object could reach the speed of light, it would become infinitely massive and would require infinite energy to maintain that speed.

Humans have managed to make some “things” go incredibly fast—though these “things” are subatomic particles. In particle accelerators, scientists can push particles like electrons to speeds exceeding 99.9% of the speed of light, according to physicist Michael Pravica. However, getting an electron to move that fast is vastly different from propelling a human. Launching a person at such speeds would require an unimaginable amount of energy, making it highly improbable—even if it didn’t violate the laws of physics.

If you could travel at speeds approaching the speed of light, the effects of Einstein’s theory of relativity would come into play. Time would slow down for you compared to people moving at normal speeds, though your personal experience of time would remain the same. From your perspective, people moving at everyday speeds would appear to be in slow motion. This phenomenon is known as time dilation.

Interestingly, in a way, we already experience relative movement at high speeds. Our planet is constantly rotating and orbiting the sun, and our entire galaxy is also in motion. If Earth were moving away from a distant galaxy at a high enough speed—and that galaxy was also moving away from us—our relative velocity could approach the speed of light. In fact, it’s possible we’re already moving at such speeds relative to some far-off part of the universe.

As Pravica explains, “That’s what Einstein showed: everything is relative.”