Can Humans Ever Travel at the Speed of Light?

“I feel the need….. the need for speed!” as quoted by Maverick in the hit movie “Top Gun”. And as many speed records documented, humans are obsessed with speed. There’s the fastest accelerating electric car, fastest car through salt flats, the fastest bicycle, the fastest passenger jet, the fastest motorcycle and so on. Also, the United States air force are planning to develop hypersonic jets that would travel at more than five times the speed of sound. That’s about 3,790 mph or 6,100 km/h.

At present, the fastest human speed record is shared by the three astronauts who flew NASA’s Apollo 10 mission in 1969. The astronauts’ space capsule hit a peak speed of 24,790 mph or 39,879km/relative to planet Earth on their way back from a lap around the Moon.

The fastest man-made, unmanned, robotic spacecraft title is held by NASA’s Juno space probe when it arrived at Jupiter on July 4, 2016. Jupiter’s intense gravity accelerated the probe to about 165,000 mph or 265,000 km/h relative to Earth. This made the Juno space probe the fastest-moving human-made object in history so far.

Now, humans have made many advances in many fields of science, specifically in physics and astronomy. For many people interested in these fields or those who are into science fiction, you have surely heard talk of “warp speed” or “the speed of light” and if you’re a fan of Star Wars or Star Trek, you have an idea of what we’re talking about. Have you ever asked yourself, “Can humans travel at the speed of light?” Or can humans ever develop warp drives and use it in spaceships to make interstellar travel? Will humans ever develop the technology to make it real?

The Numbers

Let’s start with the speed of sound. Sound travels at sea level in dry air at temperatures of 20C or 68F at 767 mph or 1,235 km/h or 1 km in 2.91 seconds or 1 mile in 4.69 seconds. Many modern jets have broken the speed of sound. One fine example is the experimental jet plane the Bell X-1 piloted by Chuck Yeager on October 14, 1947. It’s the first man-made aircraft that broke the sound barrier.

On the other hand, light travels at a constant and finite speed of 186,000 miles/second or 1080 million km/h or 671 million mph. Say a traveler or an aircraft would circumnavigate the world, it would go around 7.5 times in one second. From the Earth to the moon, about .3 second; from Earth to the Sun about 8.3 minutes. To go across the Milky Way Galaxy about 100,000 years and from Earth to the Andromeda Galaxy is 2.5 million years. Just imagine the scale of it.

In Theory, Warp Speed is Possible

At present, there is no technology available for humans to travel the speed of light, but according to Einstein’s Theory of Relativity, warp speed space travel is a possibility in the next 100 or 1,000 years, according to astrophysicist, Professor Geraint Lewis of the University of Sydney. He said that the idea of warp speed is part of Einstein’s theory of relativity because the said theory can be bent and warped. But whether or not humans will able to get the materials and the technology to build such a machine is another question.

He stated that Einstein’s theory shows it’s possible to bend and warp space thus, a human using a spaceship can travel at any speed in the universe. He also said that they have hints that the kind of materials needed to build a warp drive exists in the universe, but whether or not we could get them and build a machine possessing such a powerful engine is still out of the equation.

The professor argued that humans need materials with negative density energy to make warp travel possible as part of Einstein’s equations, which scientists have yet to discover. He also added that science fiction writers have given many images of interstellar travel but traveling at the speed of light is simply not possible at present.

He said that the big problem that humans have now is the speed of light, while it is very fast, the distances involved are too great. So even traveling at the speed of light, it would take 4 years to reach the nearest star and 2 million years to go to the nearest galaxy.

Nature put strict constraints on the magnitude and duration of negative energy, and the construction of warp drives is highly unlikely. It would also possibly produce gravitational fields that would rip everything to shreds.

Crossing these great distances would possibly allow humans to colonise the universe. We still need to find a material way to break the speed limit.

But What If?

Let’s assume that humans have overcome the technical obstacles and have built a fast aircraft capable of traveling at the speed of light. What will happen to the human body and to the spacecraft itself? The fragile human body which is mostly water will have to contend with many significant new hazards. There will also be speculative dangers if humans achieve faster-than-light travel, either by paradigm-shattering discoveries or exploiting loopholes known in physics.

Rapid acceleration and deceleration can be very dangerous to the human body. Just imagine the trauma of a human body in a car crash. This is due to inertia and gravitational forces. 1 G is equal to the pull of Earth’s gravity towards the planet’s centre at 9.8 m/second squared.

The average person can withstand a sustained force of about 5 Gs from head to toe before going unconscious. The human record for momentary Gs is 82.6 Gs held by Eli Beeding on a rocket-powered sled in 1958 at about 34mph or 55 km/h in 1/10 of a second.

In space, G forces will not be felt as much, astronauts at a cruising speed of 16,150 mph or 26,000 km/h in orbit feels like passengers do on a commercial plane. The problem will be the small space rocks or micrometeoroids. A grain-sized rock can be devastating at speeds nearly 186,000 mph or at 300,000 km/h.

According to Eric Davis, a senior research physicist at the Institute for Advanced Studies at Austin and contributor to NASA’s Breakthrough Propulsion Physics Programme, considering conventional physics for getting humans up to reasonable interplanetary space travel – they are fission, fusion and the antimatter annihilation.

Different propulsion systems based on fission and fusion could theoretically accelerate a vessel up to 10% of the speed of light or about 62,000,000 mph of 100,000,000 km/h.

The best case for powering a fast spacecraft far and away is antimatter. When matter and antimatter make contact, they obliterate each other as pure energy. Technologies that will generate and store minuscule amounts of antimatter exist at present, but production of useful amounts would require next generation facilities

With antimatter-fuelled engines, it can accelerate over periods of months or years to very high percentages of the speed of light with Gs having tolerable level for occupants.

And at hundreds of millions of kilometres per hour, every rock will become a high-powered bullet into the hull of the ship. Also, the ambient hydrogen of space would result into a bombardment of intense radiation.

Hydrogen will break into subatomic particles that will pass through the ship that will irradiate the ship, the equipment and the crew. Reaching at speeds around 95% will be instant death. The ship will heat up to melting temperatures, while water in the human body will boil and then explode.

Now, let’s say man has reached the technological advancements and has built the warp drive of Star Trek. The drive is called the Alcubierre drive, which involves compressing the normal space-time in front of the ship while expanding it behind. So the ship will be inside a warp bubble that moves faster than the speed of light. The ship inside remains at rest within the pocket of normal space-time, which avoids any violation of the universal limit of light speed. The concept needs an exotic form of matter that possesses a negative mass to contract and expand space-time.

But a 2012 paper by the University of Sydney researchers suggests that the warp bubble would collect high-energy cosmic particles. Some particles would leak into the bubble and bombard the ship with immense radiation destroying everything, which would suck big time.

If physics and future scientists find out that the technology is possible, it would also give them new and unforeseen possibilities for protecting the ship and the crew.

Speed. What a rush!



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