How much energy is required to destroy a planet like Star Wars' space fortress "Death Star"?

On December 18, 2015, the series's latest work "Star Wars / Force's AwakensStar Wars series released to the public. In the work there are multiple weapons and abilities with perfect SF elements such as "Force" and "Lightsaber", but among them the "Death Star" will appear as the final weapon of the Galactic Empire. The ultimate destructive weapon of destroying the planet is this Death Star, but if it is realized how much energy will be needed is called "How Much Power Do You Need To Destroy A Planet?"The movie that explains it.

How Much Power Do You Need To Destroy A Planet? - YouTube


In 1977, "Star Wars Episode 4 / New Hope" to be the first series in the series (the fourth in the time series within the work) was released. Then after the time of 38 years, the awakening of the Force which becomes the seventh work of the series in 2015 is released.


Among them, the space fortress "Death Star" appeared. This fortress destroys the planet · Orderan emerging in the work with a destroy weapon called "super laser". Although it is an incident in the SF work, is there a power that is strong enough to destroy the planet in the real world? Also, in the play, Super Laser has destroyed the planet Orderan, but if this super laser was completed, how much energy would you need?


A paper that actually calculated the imagination "how much energy is needed to destroy the planet" was announced in 2011.


To destroy a spherical planet, it is necessary to have a force that exceeds the gravitational binding energy of the planet. Because gravity acts on the planet, even if the planet is destroyed halfway, it is because gravity causes the substance to be attracted and immediately returns to the shape of the planet. For example, in the case of the Earth, in order to destroy the Earth and crush it to fine trees of crabs, each piece must have the initial velocity on the ground surface necessary to shatter the earth's gravityEarth escape speedIt is necessary to exceed that.

Even on planets other than the Earth it is relatively easy to calculate the speed to escape from the gravity of that planet. The equations are as follows, which represent the universal gravitational constant (G), the mass of the planet (M), and the radius (R), respectively.


In the case of the Earth, each numerical value becomes as follows and it means that energy of 2.25 × 10 ^ 32 J (Joules) is required.


The paper also calculates the energy required to destroy a gigantic planet than the Earth like Jupiter and the author of the paper says that Death Star can destroy Jupiter's planet as well.


If we destroy Jupiter, the required energy is 2 × 10 ^ 36 J.


The authors of the thesis said "Death Star of Star Wars movie can destroy the planet thanks to a gigantic power source with the same power as several main series stars, but it is a huge planet If you are a partner you will have trouble and you will not have the ability to destroy such a gigantic planet. "


Still, in the process of Star Wars, Death Star destroys the planet Orderin.



The destroyed Orderan blows away at once.



However, considering replacing this planet with the Earth, the fragments of the planet will fly at a speed of more than 10,000 km per second, so the scene of the movie will be about one second at most.


The scene where Orderan was destroyed is two to three times longer.


The gravitational binding energy is actually only a small correction, compared with the kinetic energy required for the object to obtain the escape speed of the planet. Also, if the planet is to be destroyed, Scott Manley, the author of the movie, that many substances will disappear with an explosion.


That is why if we destroy Olderan in the movie, we need 1000 kph of energy at the initial speed so that the debris of the planet will not be caught by gravity. Then, the actual energy required will be 3 x 10 ^ 36 J, which is larger than if you think only by escape speed.


In addition, the latest generation of "Force's Awakening" seems to introduce a new generation of planetary destructive weapons, and we are also considering this weapon in the movie. However, since it becomes spoiler, the person who is worried should check it after watching the awakening of the Force.