Interstellar Travel - Is it possible?

Universe has always been a topic of huge interest. And why shouldn’t it be. It has brightest stars and spinning galaxies. Bright supernovas, dusty nebula, mysterious black holes and the list goes on. There are some things which are not even discovered yet. One’s lifetime is not enough to study and understand them. Many scientists have dedicated their lives for it. They make theories on how life would be in far part of the universe. Or even in the neighboring galaxy. Or could life even exist in other galaxies. Human technology is not that advanced YET to figure these things out. So unfortunately, such theories just remain theories.

This makes us wonder; wouldn’t it be cool to just travel all the way from our galaxy to the nearby galaxy and see for ourselves? Travelling from one galaxy to another like the Guardians of the Galaxy and visiting different planets, meeting different beings, knowing their way of life! Who knows, we might bump into Thanos and punch him in face for snapping his finger.  Or meet Tony Stark and bring him back home.

IS IT REALLY POSSIBLE?

But seriously, is interstellar travel really possible? Can humans actually travel long distances through space? We could but to achieve that we have to solve lots of problems. The first obvious concern is health issues. Living in micro gravity for long time tends to weaken human body over time.  Next thing is time. Even if we decide to travel to the nearest stars which we see at night, it will take 50 to 100 light years because that’s how far they are.  The nearest galaxy is two million light years away from us.  So can humans even survive such long distance for such a long time is a questionable.

Next thing is resources. Let’s say we can survive the travel. We might need lot of food, water and fuel to keep the spacecraft going. It is difficult to sustain resources for such a long time. Unless we speed up and travel at the speed of light. But here’s the problem to travel at the speed of light. Accelerating a spaceship with pure energy would take a lot of propulsion. And not to forget that we would eventually run into speed limit. According to General Theory of Relativity, as an object approaches speed of light, its mass reaches infinity and its length zero, which is practically impossible. Thus no one can actually travel at the speed of light.

Another possibility is to travel through worm holes (like in the movie Interstellar!). But this solution has its own issues. We have to figure out how to get enough mass at one place to create a worm hole. Then there are problems like how to keep them open and safely traverse through them. Black holes could be one of the solutions here but we still know very little about them.  

And even if choose the solution of travelling at the speed of light or travel through worm hole, there is this another phenomenon we run into is Time Dilation. As one approaches the speed of light, he/she would age at slower rate compared to people on Earth.  So people on such long voyages may return home to find their loved ones greatly aged or dead.

REALITY:

So is interstellar travel still possible? Yes but if we keep it local. The nearest star system to us is Alpha Centauri .  We could reach there in just four years, if we travel at the speed of light. But below that speed, it is still far. If the Voyager2 spacecraft, which was launched in 1977 and breached the interstellar in 2012, had gone in that direction, it would reach Alpha Centauri in another 75,000 years!

OTHER OPTIONS:

 NASA's Innovative Advanced Concepts (NIAC) program ; NIAC examines far-out ideas for space exploration. One of the solutions examined by them is use of lasers to push the spacecraft.  But for this we have to build the spacecraft very small to reach Alpha Centauri quickly.

Of course lasers aren’t the only solution. Back in 1958, General Atomics' Ted Taylor and physicist Freeman Dyson of Princeton University worked on an initiative called Project Orion, which would use atomic bomb explosions to propel a spacecraft. But NASA’s Landis cautioned that the Orion proposal would need between 300,000 and 30 million hydrogen bombs. "That's a pretty hard ship to do," he remarked.

Nuclear power still is popular option for interstellar travel.  In 1950s, NERVA examined nuclear fission to generate energy to travel around the solar system. Nuclear fusion is another possibility. In 2012 NIAC proposed a fusion rocket to get to Mars.  Other possibilities include accelerating nuclear ions with electricity or nuclear electric thrusters which are more efficient in fuel usage.

To conclude, many doubt interstellar travel because the light barrier is so difficult to break.  But hey, we also thought travelling to space is impossible yet humans marked their first journey to Moon 50 years ago. Therefore we cannot rule out the possibility that our civilization will advance to come up with more realistic, possible solutions.