Destroying a Continent
Now let’s give the Death Star an upgrade, and target a continent.
During the formation of the Himalayas around 40 million years ago, the mass of a rather large continent was completely consumed by the mantle and destroyed. A recent study calculated this mass to be 450 quadrillion kilograms (about 500 trillion tons) of rock.
Let’s assume the continent is made of granite. At the surface, it’s about 15°C (59°F). We want to cause it to melt, which happens at 1,260°C (2,300°F). How much energy would the Death Star’s superlaser need to melt an entire continent? Fortunately, there’s an equation for this.
Multiplying the temperature change, the mass, and a value known as a material’s specific heat capacity together, scientists can calculate how much energy is required to make the temperature change take place. In this case, that would be 4.4 x 1023 joules.
That’s not a very relatable number, so we can phrase it another way – this is roughly the same energy released in the dinosaur-killing asteroid impact that took place 66 million years ago.
Destroying an Ocean
Now we're talking. Harvepino/Shutterstock
What if the Death Star wanted to root out an aquatic species by destroying an entire ocean? Well, fortunately, we can use the same equation to calculate the required superlaser energy too. Thanks, science!
The Pacific Ocean contains about 714 million cubic kilometers (171 million cubic miles) of seawater. At a density of 1,029 kilograms per cubic meter, that means that there's about 735 quintillion kilograms of seawater waiting to be evaporated.
The average surface temperature is about 17°C (62.6°F), and to get seawater to boil, we need to raise it to 102°C (215.6°F). Using the same equation as before, this means the Death Star would need to find 2.4 x 1026 joules of energy to completely evaporate the Pacific Ocean.
That’s about 548 dinosaur-killing asteroid impacts. As it turns out, it takes a lot more energy to evaporate water than to melt a continent, so if the Death Star is coming your way, best go take a long dive underwater.