One-Punch Man: How Powerful Is Boros’s Collapsing Star Roaring Cannon?

One Punch Man  episode 12

 
Collapsing Star Roaring Cannon is Boros’s most powerful attack while using Meteoric Burst. According to Boros’s own statements, it has enough power to destroy a planet’s surface in the manga, and in the anime it is implied to be capable of destroying Earth entirely.

What we can say with certainty is that we never see the attack’s direct results, which makes determining its exact yield difficult. However, we can still make reasonable estimates based on the statements provided.

One Punch Man Manga chapter 36

Extinction-Level Event

The lowest plausible estimate corresponds to an attack capable of wiping out life on a planet. This requires energy levels similar to the Chicxulub impact, the event that caused the extinction of the dinosaurs and much of Earth’s plant life.

This event is estimated at around 4.18 × 10²³ joules, or 100 teratons of TNT (100 million megatons). It created a crater roughly 180 km in diameter and 30 km deep, and triggered earthquakes of approximately magnitude 11 on the Richter scale.

Some analyses place the energy even higher, in the range of 1.3 × 10²⁴ to 5.8 × 10²⁵ joules (1.3 to 13 billion megatons), which would more than suffice for planetary surface devastation.

 Vaporizing All Water Sources

Earth contains roughly 1.4 × 10²¹ kg of water in all its states (liquid, solid, and gas), which represents about 0.02% of the planet’s total mass.

An explosion capable of vaporizing all of Earth’s water and turning it into a sterile world would effectively destroy the planet’s surface.

How much energy would this require?

To vaporize 1 kg of water at room temperature (20 °C), about 2,592,000 joules per kilogram are needed.

$$E = 1.4 \times 10^{21} \times 2{,}592{,}000 \approx 3.62 \times 10^{27}\ \text{joules}$$

This is equivalent to roughly 865 petatons of TNT (865 billion megatons).

This value is far higher than the previous extinction-level estimate. For comparison, if the entire output of the Sun (~3.8 × 10²⁶ joules per second) were focused into a laser aimed at Earth, it would take about 9.5 seconds to reach this energy.

This places Boros’s attack at a level several times greater than the Sun’s total power output, reinforcing its classification as a true planet-devastating technique.

Melting Earth’s Crust

This represents the highest reasonable interpretation of what “destroying a planet’s surface” could mean. Earth’s crust has an average thickness of about 40 km and a mass of roughly 2.7 × 10²² kg, which is about 0.5% of Earth’s total mass.

How much energy would be required to melt it?

• Mass: 2.7 × 10²² kg

• Average specific heat: ~1,100 J/kg·°C (accounting for metals and different rock types)

• Melting temperature: ~1,200 °C

• Initial average temperature: ~20 °C

• Temperature change: 1,180 °C

• Latent heat of fusion (average): ~400,000 J/kg

First, the energy needed to raise the temperature:

$$Q_1 = 2.7 \times 10^{22} \cdot 1{,}100 \cdot 1{,}180 \approx 3.5 \times 10^{28}\ \text{joules}$$

Next, the energy required for the phase change from solid to liquid:

$$Q_2 = 2.7 \times 10^{22} \cdot 400{,}000 \approx 1.0 \times 10^{28}\ \text{joules}$$

Total energy:

$$Q = Q_1 + Q_2 \approx 4.5 \times 10^{28}\ \text{joules}$$

This corresponds to roughly 10 exatons of TNT (10 trillion megatons).

For perspective, this is far greater than the Sun’s total power output. The Sun would need about 118 seconds of continuous energy output to match this amount, placing Boros’s attack firmly in the extreme planetary-scale range.

One-Punch Man: Hero Encyclopedia. Where it is claimed that it can destroy the planet 

Depending on interpretation, the Collapsing Star Roaring Cannon ranges from extinction-level to extreme planetary-surface destruction. Even the lowest estimates place it far beyond anything shown earlier, while the upper bounds reach energies rivaling or surpassing the Sun’s output—fully justifying Boros’s claim as a planet-ending threat.