What the science says about that moment in ‘The Last Jedi’
It's been well over six months since Star Wars: The Last Jedi came out and audiences have gone through the full cycle of liking it on opening night and disliking it the longer they spend thinking about it. Now, it's been released for viewing in homes across America and leaking potential spoilers is no longer a crime punishable by death.
That being said, this is your official spoiler alert. We are going to talk about Star Wars: The Last Jedi ahead.
And my personal question: If that was such an effective tactic, why not just attach hyperspace drives onto asteroids and use them to bombard enemies?
Still with us? Okay, here we go.
In the second act of the film, the First Order has the Resistance cornered. Vice Admiral Haldo orders her people to board the transport ships and evacuate to the nearby planet, Crait. She then pilots the Raddus and aims it right at the First Order fleet and their flagship, the Supremacy.
She floors the Raddus into near hyperspeed and smacks right into the bad guys in what was one of the coolest moments of the film. Pieces of the shattered Supremacy then domino-effect outward, into the other ships, destroying them as well.
As awesome as this moment was, it opens up many questions for the fans that could be better understood with some science. Like, is that even possible? What kind of force (not that kind) would be required to pull that off?
Everything always comes back to science.
The filmmakers behind the Star Wars universe have taken many creative liberties with the franchise, telling elaborate storiesat the expense of scientific reasoning— and that's fine.The series is literally about magical space samurai that befriend countless alien species without translators and everyone seems to be just fine walking on random planets without wearing space suits.
In this one particular instance — the hyperspace Kamikaze move — everything seems to be perfectly in order. This all comes down to Albert Einstein's famous mass-energy equivalency formula, otherwise known as E = mc2.
Even though many people see that formula and think it's just some smart guy's way of proving he's smart, it's actually the fundamentals of energy. It means, in basic terms, that energy and mass are interchangeable.
Cut the movie some slack. It's far more interesting than reading science textbooks.
With a little algebra, however, this same formula can be rearranged to explain that achieving the speed of light would be nearly impossible because everything within the universe with mass would require a incalculable amount of energy to achieve such a speed. It's challenging to send even a single atom at a fraction of light speed, let alone a massive frigate.
In the real world, achieving hyperspeed is near impossible for anything other than massless photons. But this is the universe with tiny green muppets teaching farmboys how to move rocks with their minds. Let's pretend that the hyper-drives hand wave that all away and moving faster than the speed of light is possible and it can be achieved by things with mass.
It's basically the idea behind the "Rod from God" that never happened.
Thankfully for the audience, the next scientific laws that apply to this scene are also very well-known: Newton's First and Second Laws of Motion. The first says that every object in a state of uniform motion will remain in that state of motion unless an external force is applied to it. The second states that the rate of change of momentum of a body is directly proportional to the force applied, and this change in momentum takes place in the direction of the applied force.
In normal-people words, this means that since the Raddus was extremely massive and was working up to light speed (which meant that it still had mass at that point), it had an unfathomable amount of energy behind it's punch that could, theoretically, shred through anything with ease.
This is a magnified version of a rail gun on planet Earth. You take something heavy, use magnets to send it extremely high speeds, and crash it into something. Boom. No more enemy.
Then again, this could also explain why two missiles could destroy a Death Star and a couple of laser blasts destroy the second one.
The real question is why don't they use it more often in the Star Wars universe? We've accepted that, for the sake of storytelling, that hyper-drives really work, but this Kamikaze strategy hinges on how the fictional hyper-drive works. If achieves immense speeds by reducing a spacecraft's mass to zero — similar to that of a photon — then the spacecraft couldn't destroy something unless it was in the process of picking up speed. This version is more in line with the destruction we saw in the film.
The problem with this option is that if the ship doesn't have enough speed, it'll simply bump off the target's shields. If it has too little mass, it'll simply squash like a fly on a windshield. The conditions would have to be near perfect to make a serious impact.
The other way a hyper-drive could work is if it creates the insane amount of energy required to bring an object past light speed. If that's the case, then the hyper-drive would be destroyed with the collision. For scale, the energy needed to send a Ford Mustang into hyper-speed would be more than a star going supernova. When a spacecraft containing an entire military crashes and the hyper-drive that powers it blows it, it'd let off enough energy to snuff out the entire galaxy in an instant. So, it probably wasn't that.