It is theoretically possible to travel faster than light using the warp drive shown in 'Star Trek'.

Earth's closest star is Proxima Centauri. It is about 4.25 light years away, or about 25 trillion miles (40 trillion km).

The fastest spacecraft, the now-in-space Parker Solar Probe, will reach a top speed of 450,000 mph.

At that speed it would take just 20 seconds to travel from Los Angeles to New York City, but a solar probe would take about 6,633 years to reach Earth's nearest neighboring solar system.

If humanity ever wants to travel easily between the stars, people will need to go faster than light. But so far, the journey of light-to-light is possible only in science fiction.

In Issac Asimov's Foundation series, humanity can travel from star to star, planet to planet, or universe using jump drives.

As a child, I read many of those stories, as if I could get my hands on them. I am now a theoretical physicist and studying nanotechnology, but I am still thrilled with the ways in which humanity can one day travel in space.

Some characters - such as the astronauts in the films Interstellar and Thor - use the wormhole to travel between the solar systems in seconds. Another approach - familiar to Star Trek fans - is the warp drive technique.

The Warp drive is theoretically possible if still a distant technique. Two recent papers made headlines in March, when researchers claimed to have overcome one of the many challenges that stand between taunt drive and the theory of reality.

But how do these theoretical warp drives actually work? And will a human soon leap at a fast pace any time?

COMPRESSION AND EXPANSION...

COMPRESSION AND EXPANSION...

Physicists' current understanding of spacetime comes from Albert Einstein's theory of general relativity.

The General Relativity states that space and time are fused and that nothing can travel faster than the speed of light. General relativity also describes how mass and energy weave - fickle objects like stars and black holes revolve around them.

This curvature is what you feel as gravity and why many spacefare heroes worry about being "trapped in gravity" or "falling". Early science fiction writers John Campbell and Asimov saw this war as a way to reduce the speed limit.

What if a starship could compress space, increasing the space behind it? "Star Trek" took the idea and named it Tana Drive.

In 1994, the Mexican theoretical physicist, Miguel Alcubierre, showed that it was mathematically possible within the laws of general relativity to expand the space while compressing the spacetime in front of the space spacing. So what does that mean?

Imagine that the distance between two points is 10 m. If you are standing at point A and can travel one meter per second, it will take 10 seconds to reach point B.

However, let us tell you that you can somehow narrow the space between you and point B so that the gap is now just one meter.

Then, moving through spacetime at your maximum speed of one meter per second, you will be able to reach point B in about a second.

In theory, this approach does not contradict the laws of relativity because you are not moving faster than light in the space around you.

Alcubierre showed that the warp drive from Star Trek was, in fact, theoretically possible.

Proxima Centauri here we come, right? Unfortunately, there was a problem with Alcubierre's method of compressing spacetime: it requires negative energy or negative mass.

PROBLEM OF NEGATIVE ENERGY!

PROBLEM OF NEGATIVE ENERGY!

The Alcubierre's warp will work to create a bubble of flat space around the drive spaceship and shorten the distance to reduce the spacetime around that bubble.

The warp drive would require either a negative mass - a theorem type of substance - or a ring of negative energy density to work. Physicists have never seen negative mass, leaving negative energy as the only option.

To create negative energy, a warp drive will use massive amounts of mass to create an imbalance between particles and antiparticles.

For example, if an electron and an antielectron appear near the warp drive, one of the particles will be trapped by the mass and this creates an imbalance.

This imbalance results in a negative energy density. Alcubier's warp drive will use this negative energy to create a spacetime bubble.

But for a warp drive to generate enough negative energy, you'll need a much larger case. Alcubier estimated that a warp drive with a 100-meter bubble would require the mass of the entire visible universe.

In the year 1999, physicist Chris Van den Broeke showed that expanding the volume inside the bubble but keeping the surface area constant would significantly reduce energy requirements about the Sun's mass. A significant improvement, but still beyond all practical possibilities.

**FUTURE OF SCI-FI?**

Two recent papers - one by Alexei Bobrik and Gianni Martaire and the other by Eric Lentz - provide solutions that bring the taunt drive closer to reality.

Bobrick and Martaire realized that by modifying spacetime within bubbles in a certain way, they could overcome the need to use negative energy.

This solution, however, does not produce a warp drive that can go faster than light.

Independently, Lentz also proposed a solution that does not require negative energy.

He used a different geometric approach to solve the equations for general relativity and by doing so he found that a warp drive would not need to use negative energy. Lentz's solution will allow bubbles to travel faster than the speed of light.

It is necessary to point out that these exciting developments are mathematical models. As a physicist, I will not rely solely on the model until we have experimental evidence. Nevertheless, the science of taunting drives is coming into view.

As a science fiction fan, I welcome all this innovative thinking. In the words of Captain Picard, things are impossible only until they are.

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