Will Interstellar Travel ever become a reality?

Credits : wallup.net

Right from the time humanity evolved, about 300,000 years ago, human beings have dispersed far and wide, to every corner of the planet. The curiosity and the desire to explore new lands have been fundamental to human kind. So much so, that the aspect of interstellar travels seems like a genuine scientific possibility in the recent times! 

The quest to conquer and explore new places have led to the emergence of the era of space exploration in the present times. In the past years, human beings have achieved significant milestones of space exploration from setting foot on the moon to sending probes to the outer edge of the solar system. The recent developments towards the exploration and possible colonisation of Mars is no exception.

But what happens after we have explored each and every part of our solar system? Do we still have something to explore?

The answer is yes - absolutely! Keeping in mind the vastness of our universe, you can be pretty sure that there will always be a new place for humanity to explore! But, what do we expect in the near future? Interstellar exploration could be a thing, right? But will it  ever be possible? Believe it or not, its probably only a matter of time before interstellar travel becomes a reality!

Curious? You might be wondering if interstellar travel is possible with present day technology? Or if it is possible when are our going to board our spaceships to explore the vastness of the universe that lies beyond our solar system? Where should we go in our first ever interstellar mission?

Don't worry, this article will help you find the answers to all the questions you might presently be wondering about! Let's get started!

Is Interstellar space travel possible? 

Though the very thought of interstellar Travel seems to be a scene from a far-fetched science fiction movie, recent discoveries have showed that interstellar explorations should indeed be possible someday in the future.

Several crazy and interesting ideas and theories have been proposed by scientists for deep space exploration in the recent times,  from Fusion rockets to wormholes, antimatter drives and, of course, the Futuristic "Alcubierre Wrap Drive".

Yeah, the last one is extra interesting! But, we will get to that after sometime.

Now that we know that interstellar travel may not be a thing too distant in the future, you may ask, where do we go in our First ever interstellar space mission? Let's check out.

What Would be Humanity's First Interstellar Travel Destination?

There are 59 known stellar systems within 40 light years of the Sun, containing 81 visible stars. In some of these systems, certain planets have been found to be located in the habitable zone of its star which could be the prime destination for future interstellar space missions.

Proxima Centauri - B
Credits : futurism

But, the destination for humanity's very First Interstellar Space Mission would probably be the Planet - Proxima Centauri B, an exoplanet located in the habitable zone of its star - Proxima Centauri, in the Alpha Centauri System about 4.3 light years away. 

Now that we have chosen our destination, let us find out what are the challenges that we would need to overcome before we think of ways to make interstellar space flight a reality!

Present Challenges to an Interstellar Mission :

• ‌Even though the aspect of interstellar explorations have been speculated to be possible in a near future, it cannot be denied that even our nearest star system is at an abominally large distance to scale in a human lifetime. The fastest outward-bound spacecraft yet sent, Voyager 1, has covered 1/600 of a light-year in 30 years and is currently moving at 1/18,000 the speed of light. At this rate, a journey to Proxima Centauri would take 80,000 years.

• ‌A second factor in this aspect is the efficiency of the fuel. Propellent is a big limiting challenge in space travel. If we want to reach proxima Centauri in our lifetime, it is calculated that we would need a speed of about 10% the speec of light. And to achieve that with traditional rocket fuel, we would need a fuel tank larger than the observable universe. Not too efficient! So we would need a fuel with maximum energy density and almost 100% efficiency.

• ‌The key to interstellar travel would be to find the correct balance between the speed of the starship and the time it takes for us to develop the starship. No point in launching a starship in 20 years, if a starship launched in 50 years overtake it. This factor, known as the Wait Calculation is a huge issue to address .

• ‌Severe possible biological hazards to the crew is also a big problem. The crew of an interstellar ship would face several significant hazards, including the psychological effects of long-term isolation, the effects of exposure to ionizing radiation, and the physiological effects of weightlessness to the muscles, joints, bones, immune system, and eyes.

After looking at the challenges that we would need to overcome, Let us now finally explore the different ways we could possibly overcome these challenges using technologies of the present time or of the near future.

Some proposed Interesting Methods for interstellar explorations :

• ‌ Fusion Rockets :

The orion project.
It was a project based on the use of fusion engines
Credits : Wikipedia 

Since we need high energy density of the fuel for our interstellar space flight, using fusion as a fuel source, as in the sun, could be a good option. We already have the tech. We would just need to scale up our production of nukes!

According to a calculation, we would have to launch with about 300000 of 1 megaton hydrogen bombs, nuke them behind our spaceship one by one and we woulid end up at 10% speed of light in 1 month. A trip to Alpha Centauri would theoretically take us 45 years. But since we would need to slow down our speed when we are near our destination, this would lead to half the fuel efficiency and we would take about 90 years to reach Alpha Centauri.

Although it would probably mean, we would need three generations of human beings on board, it is by far the most achieveable Method using present day technologies.

An upgrade to this method could be the contained thermonuclear reactions, but the tech still in the infant stages and could be a viable option in the near future.

• ‌Antimatter Drives :

The meeting of Matter and Antimatter results in the annihilation of both particles liberating huge amounts of enery with an efficiency of almost 100% ! It would take probably only a few kilograms of anti protons to take us to Alpha Century in just a few years !! 

Seems like a solid plan to scale the universe? Well, Don't start packing too early for this method too comes with some major drawbacks! 

We can create antimatter in a particle accelerator, but the catch here is that it is enormously time consuming and hugely expensive. We would need to increase our production to more than trillion trillion times to produce the kilograms of antimatter required for our expedition.

But, considering how fast technology is developing, it is only a matter of time before this becomes a plausible option.

The pion rocket
Credits : wikipedia

Pion rockets could very well be a possibility. The annihilation of a proton and an antiproton releases pions, which on channelising with a suitable electric field, could be an extremely efficiency fuel in the future. Using such rockets, it is possible to reach 50% of speed of light meaning a trip to Alpha Centauri would take only 9 years.

With slight modifications, 80% of the speed of light could be possible cutting short fhe time taken to reach Alpha Centauri to only 3.3 years from the astronauts' perspective as a direct consequence of time-dilation! Fascinating!

• ‌The interstellar light sail :

The light sail 

What if we didn't want to carry any fuel at all? Is Interstellar travel possible without any fuel?

In theory, yes, it is possible! Joking? No! It is actually possible to sail in a "highway" of powerful laser in space as you would in a sea using a sailboat! 

For the purpose of interstellar voyages, this is actually a pretty plausible method even in present days. Giant lasers have to set up, harnessing power from the sun or through Helium - 3 Reactors from the moon which would drive gigantic sapphire sails of over a kilometer in diameter. As for speed, 10% lightspeed can be easily achieved using modern day materials. But with a laser light effective for over a large distance, it could even be possible to achieve furthur more speed.

The lightsail 2 project. 

The only drawback to this technology is that it would be absolutely difficult to slow down at the destination star. Also the factor of wait calculation needs to be taken into account before this can be seen a s a viable option.

But the best part? This technology is not even a theory anymore. This is actually a technology being currently under testing for unmanned space missions! This is probably the only technique, other than the fusion engine, which is plausible in our lifetime.

• ‌The Black Hole Drive :

The Schwarzschild Kugelblitz
Credits : space.com 

Another interesting way of creating a spacecraft for the interstellar expeditions, could be the "Schwarzschild Kugelblitz" , Kugelblitz is German for "Ball Lighting", or the blackhole drive! A black hole of the right size would be able to radiate enough hawking radiations, which when channelised properly could be used as a highly efficient source of energy.

The Kugelblitz black hole is not formed out of mass but out of light. A high powered beam of light focus on a single point would lead to the formation of the singularity. The optimal size of the black hole would be about the size of a proton with a mass of 600 Billion tons. It would radiate an energy equivalent of 160 Petawatts and would have a life of about 3.5 years.

The Kugelblitz
Credits : space.com

This technology could take us to 10% the speed of light in only about 20 days! It could be possible to even reach more than 90% the speed of light. It is indeed one of the fastest methods for interstellar space missions.

The drawback to this method is that the lasers producing the black hole would have to be more powerful than the blackhole itself! This is possible but only with the technology of the distant future. It would probably be a few thousand years before the right technology would allow us board blackhole powered star ships!

• ‌The Alcubierre Wrap drive :

The wrap field.
Credits : researchgate

This is probably the craziest and the most phenomenal theory for reaching to speeds beyond our imagination.

Inspired by science fiction, the idea was first introduced by physicist Miguel Alcubierre. He used the theory of special relativitiy to derive a mathematical form of a "wrap field" or "wrap bubble", which is a region of extreme curvature in space time in the form of a bubble. The fundamental idea was that a starship placed inside a wrap bubble would have space time bending inward in front of it and bending outward at its back. This would allow the starship to travel at speeds faster than the speed of light while effectively remaining steady in its local frame. So the ship itself doesn't move, but the bubble of spactime around it does and takes the ship with it.

The Alcubierre Wrap Drive concept
Credits : popsicle.com

And no, this theory doesn't break the laws of physics as the cosmic speed limit applies to things, such as mass, energy, information etc but the relative velocity between two points in space could be many times greater than the cosmic speed limit.

There are massive drawbacks and challenges in this idea which could quite possibly make the existence of wrap fields impossible.

There are many other interesting facts about this idea discussing which would unfortunately lead to this post getting too long, but we promise, we would bring a dedicated post to the Alcubierre wrap drive shortly.

• Conclusion :

From everything we have discussed, it is clear that humanity is not only bound to the solar system and there are immense possibilities of interstellar travels in the near future.

Humanity, could indeed possibly become an interstellar civilisation in a few million years!!

Don't know what an interstellar civilisation is? Check out our blog about the different types of civilisations here.