If you’re a fan of science fiction, chances are you encountered a few franchises where humanity has spread throughout the known Universe. The ships that allow them to do this, maybe they use a warp drive, maybe they “fold space,” maybe have a faster-than-light (FTL) or “jump” drive.
It’s a cool idea, the thought of “going interstellar!” Unfortunately, the immutable laws of physics tell us that this is simply not possible.
However, the physics that govern our Universe do allow for travel that is close to the speed of light, even though getting to that speed would require a tremendous amount of energy.
Those same laws, however, also tell us that near-light-speed travel comes with all sorts of challenges. Luckily for all of us, NASA addresses these in a recently-released animated video that covers all the basics of interstellar travel!
To summarize, according to the immutable laws of physics (specifically, Einstein’s Theory of Special Relativity), there’s no way to reach or exceed the speed of light.
This means that if you’re going to attempt interstellar travel, your best bet is to either settle in for the long haul (i.e. a Generation Ship) or find a means of propulsion that can allow for constant acceleration until a fraction of the speed of light (relativistic speed) is attained.
For the sake of this video, titled “NASA’s Guide to Near-light-speed Travel” (shown above), it is assumed that the interstellar traveler (who appears to be an alien creature) has built a spacecraft that is capable at traveling at 90 percent the speed of light (0.9 c).
The video is presented as an information video for an interstellar traveler. It is introduced with the following message:
“So, you’ve just put the finishing touches on upgrades to your spaceship, and now it can fly at almost the speed of light. We’re not quite sure how you pulled it off, but congratulations! Before you fly off on your next vacation, however, watch this handy video to learn more about near-light-speed safety considerations, travel times, and distances between some popular destinations around the universe.”
Putting aside the question of how the spacecraft is able to reach this kind of speed, the video then moves directly to tackle the big issues that come with traveling around in a relativistic Universe.
These include time dilation, the need for shielding in the interstellar medium, and how long it would take to travel to even the nearest destinations, like the nearest star (Proxima Centauri) the nearest galaxy (Andromeda), or the farthest one (GN-z11).
Admittedly, these challenges are pretty tough and the greatest scientific minds in the world are still looking for a work-around. A good example is Breakthrough Starshot, an initiative that hopes to send a laser-powered lightsail to Alpha Centauri in the coming years. Relying on directed-energy propulsion, the proposed spacecraft would reach 20 percent the speed of light (0.2 c) and make the trip in just 20 years.
Naturally, this plan involved considerable research into the hazards of interstellar travel and led to some creative solutions of how to deal with them.
These include (but are not limited to) shielding, communications, the types of cameras and instruments that would yield the best scientific returns, the type of sail employed, and the shape of the sail itself, and how the spacecraft would slow down once it gets there.
In the meantime, it is good to have educational resources that let people know the scientific realities that underlie (or in many cases, undermine) our favorite franchises!
It’s also helpful when it comes to aspiring physicists and scientists who hope to see interstellar travel happen within their lifetimes. You have to know what the challenges are if you’re planning on beating them!
The video was the work of scientists and media experts from the NASA Goddard Space Flight Center’s (GSFC) Goddard Media Studios (GMS). The effort was led Chris Smith, a multimedia producer and member of the Universities Space Research Association (USRA) within Goddard’s Astrophysics division. He was joined by fellow-USRA member Krystofer Kim, who was the video’s lead animator.
NASA Goddard has also made shorter clips of the video and printable postcards available for download here: https://svs.gsfc.nasa.gov/13653