Is interstellar travel possible? To answer this question, let’s have a look at the word interstellar. It basically means traveling to different stars in our Milky Way. Movies and TV shows like Star Wars and Star Trek have shown us that if we want to travel to the stars, all we have to do is activate the “warp drive” or the “hyperdrive,” but is that really possible with our current technology and understanding of physics?
Well, the short answer is yes, it is possible, but there are some kinks that need to be worked out (more on that later). While there is some possibility that humans will be able to travel to other stars someday (if we survive that long as a species), we have to keep ourselves grounded in order to understand the situation a bit better.
Let’s analyze whether interstellar travel is possible.
Is Interstellar Travel Possible?
As mentioned earlier, interstellar travel is definitely a real possibility for humans. However, according to experts, the best option would be to keep it local. Why should we stay within our local area? Well, that has a little something to do with the speed of light.
The nearest star to us is Alpha Centauri, and that’s 4 lightyears away. We won’t get into the specifics of lightyears here, but just know that a lightyear is basically how far light can travel in a year. If you want a number, light travels about 6 trillion miles in one year!
Before we get sidetracked with all this physics talk, there’s something you should know about Alpha Centauri. In 2016, a planet name Proxima Centauri b was discovered in the star system that is in Alpha Centauri’s habitable zone and is similar in size to Earth. This gives us a good reason to want to visit the star system.
Now, back to interstellar travel. If you’re able to travel at the speed of light (which is impossible for any object with mass, by the way), you’ll be able to reach the star system in 4 years. Now, that’s still a fair bit of time, but where interstellar travel is concerned, it’s like a 10-minute drive from your house to the nearest convenience store. At speeds slower than that, it is still too far. The Voyager 1 Spacecraft (which is one of the fastest traveling human-made objects ever made) was launched in the year 1977. If had been sent in Alpha Centauri’s direction, it still wouldn’t have made it for another 75,000 years.
Interstellar Travel Concepts
In 1998, NASA funded an interstellar concept by Landis. The proposal suggested the use of lasers as a means to push a craft that’s made entirely of light sails. But no progress was ever made on the project. The concept was picked again in 2016 by the Breakthrough Starshot Group, whose main purpose was to send a small light sail to Alpha Centauri.
Landis suggested that that the idea could possibly be used to carry people. However, the spacecraft needs to be extremely small, or else it will not get to the star system. This is why the project was just modified to send a small probe to the system. The probe could take readings (and maybe even photos). The benefit of this concept is that it can travel really fast – fast enough to reach Pluto in 5 years.
The NIAC program by NASA has been the primary funder of many interstellar travel studies. One study in 2017 by Heidi Fearn shows that a kind of interstellar travel vessel based on ‘Mach effects’ can be used to travel to the stars. ‘Mach effects’ refers to how the mass of various objects can vary in rest and acceleration. This occurs due to the changes in the internal energies of the objects.
More Interstellar Travel Ideas
Lasers aren’t the only way to get somewhere fast. In 1958, the Project Orion was launched by Ted Taylor and Freeman Dyson. They designed a spacecraft that would be propelled by nuclear explosions. However, it was estimated that around 300,000 to 30 million of the most powerful bombs ever made – the hydrogen bomb – would be needed for that kind of force.
In the era of the 1950s, the Nuclear Engine for Rocket Vehicle Application (NERVA) examined the possibility of using nuclear fission to travel in space. Recently, the Kilopower Reactor Using Stirling Technology (KRUSTY) was also completed. This reaction demonstrated what is necessary for ships powered by fission – that it can be used as a possible fuel source for ships that can then be used to explore our solar system.
Nuclear fusion is also being looked into as a possible solution for interstellar travel. In 2012, NAIC proposed the possibility of using a rocket powered by nuclear fusion to travel through space. The British Interplanetary Society (BIS) launched Project Daedalus in the 1970s. This was then revived by Icarus Interstellar, an organization that aims to launch a starship based on fusion technology in 2100. The only problem is that the energy needed to fuse atoms is more than the output we get.
Other possibilities to ensure Interstellar travel are through ion propulsion. The Dawn spacecraft used electricity to accelerate nuclear ions. Nuclear electric thrusters can also be used as a fuel-efficient source.
An antimatter engine can also be used to propel the ship at high speeds. While this is an effective solution, the problem is that antimatter generation in large quantities is something we haven’t figured out as of yet. Another issue is ensuring that an explosion doesn’t happen unless we want it to.
The thing we should keep in mind is that when matter and antimatter touch, they tend to destroy each other upon impact. The energy of this explosion needs to be harnessed but in a safe way so that we can use it to launch the spacecraft instead of hurting someone or the environment in the process.
A chemical rocket can also be used to propel a rocket through basic brute force. These rockets use a mix of liquid oxygen and hydrogen to launch the rocket into space from Earth. However, this type of rocket can only propel a spacecraft into space at a fraction of the speed of the other rockets mentioned above. It is enough to get the spacecraft moving at a sensible pace, but not enough for interstellar travel.
For chemical rockets, it is an unrealistic option to expect speed-of-light travel. Dr. Richard Obousy remarks that one spacecraft would require more mass in fuel than is available in the universe to travel at the speed of light. This is why we cannot expect interstellar travel from our available rockets right now.
Dr. Richard Obousy suggests that we shouldn’t underestimate the power of a simple picture of another planet in another solar system. There are also plenty of astrobiological studies that can be quite exciting. He suggests that the information we have till now hasn’t given us any that life can exist on other planets. But, due to the vastness of the universe, it is quite possible that life on other planets exists, which is why people continue to be interested in space travel and interstellar travel in particular.
Landis has also remarked that there are many lessons that we should take from our space exploration endeavors. The most important and noticeable one perhaps is that space is definitely weirder than a lot of people expect. For example, the Kepler Space Telescope observed other exo-planets in our galaxy. It revealed that other solar systems are wildly different than the one we live in. All of them have different chemical makeups that may or may not be hospitable to life as we know it.
For example, some solar systems have a ‘hot Jupiter,’ which is basically a giant gas planet that orbits close to the parent star in the middle. Others may also have a ‘Super-Earth’; these are planets that are more massive than the Earth but less massive than the ice planets in their solar system. Others may have a rocky planet that is somewhere in size between Earth and Neptune. This is why it can be so hard to predict what astronauts or probes may encounter when they enter faraway planets, stars, and solar systems.
There are so many things that we have not yet imagined or considered. When we try to answer the question, “is interstellar travel is possible,” we need to account for the fact that exploring the universe in a decent timeframe poses a LOT of different problems. Once we have solutions for the problems with space travel, we can begin to find out how weird and vast this universe really is.