What If a Marshmallow Hit the Earth at the Speed of Light?

Look out. There’s an object hurtling toward Earth at the speed of light! And no, it’s not a comet or an asteroid. Yep. It’s a marshmallow. How could a marshmallow ever go this fast? What would happen to it as it entered the atmosphere? And what kind of damage would it do to our planet?

Early versions of the marshmallow were first eaten as far back as Ancient Egypt. But in the 1950s, these sweets made from sugar, water and gelatin exploded in popularity. In the U.S. alone, about 40 million kg (90 million lb) are sold every year. And over half of all marshmallows sold during the summer months are roasted over a campfire, then squished between chocolate and graham crackers.

Well, I’d like some more of that myself. So let’s see what happens when we make the most epic s’more possible. Time to send this fluffy treat hurtling toward Earth at an impossible speed. Warning to all the althaiophobes out there. Things could get gooey. In a vacuum like outer space, the speed of light is 299,792 km/s (186, 282 mps).

That’s so fast that an object traveling at that speed could circle the Earth 7.5 times in one second. As far as we know, no object can travel faster than light. That’s because the faster an object moves, the more its mass increases. If an object moved at the speed of light, its mass would become infinite.

To move an object with infinite mass would require an infinite amount of energy. Thus, it’s impossible. Until now. If you were an astronaut on the International Space Station, who could blame you for feeling the primal call of a good s’more? It would be a perfect way to pass an idle summertime evening 420 km (260 mi) above the surface of the Earth.

But don’t worry. You wouldn’t need to light a campfire onboard the ISS. These space station oven-toasted marshmallows would be completely harmless. Except, wait. One is missing. Uh-oh. If a marshmallow escaped the pressurized environment of the ISS, it would start to expand. That’s because marshmallows have small bubbles of air trapped inside them.

On Earth, the outward pressure of these air bubbles and the inward pressure of the surrounding air reach a stability that results in a normal-looking marshmallow. In the vacuum of space, with no surrounding air pressure, the air bubbles inside the marshmallow would expand. That would make it puff up even larger.

Now our misshapen marshmallow would set its sights on Earth. And here’s where the impossible would happen. The marshmallow would begin to travel at 99.9% the speed of light, reaching the surface in less than a millisecond. How about we roll things back and follow the action in slow motion?

As the marshmallow enters our atmosphere, it would begin to slam into atmospheric particles. At this ridiculous speed, these particles would actually punch into the marshmallow and stay there. So the marshmallow would actually gain weight as hurtled toward Earth. This highly energetic scenario would most likely cause the marshmallow to rip apart.

This would be a saving grace for us down below because it would create explosions that would dissipate the energy during its trajectory. If that didn’t happen, this once-fluffy object would hit the ground with a lot of force. Take the Chelyabinsk meteorite as an example. This meteorite exploded at a height of somewhere between 19 and 24 km (12 and 15 mi) over Russia in 2013.

With a mass of 11,000 tons, the overhead explosion injured 1,000 people. Our beloved marshmallow, moving at the impossibly fast rate of 99.9% the speed of light, would slam into Earth with a force almost four times more powerful than what occurred during the Chelyabinsk event. And it wouldn’t hit the ground as a soft, sticky substance either.

If it managed to avoid completely burning up in the atmosphere, the high-temperature journey would cause the carbon in the marshmallow to darken and harden, converting it to graphite. The damage this tasty treat-turned-meteorite could inflict upon Earth would depend on where it landed. If it remained intact and smacked right down into New York City, a 2019 NASA simulation estimated it could result in the death of over 1.3 million people.

Ok. Maybe NASA didn’t actually simulate the impact of a marshmallow meteorite traveling at the speed of light. Theirs was a much larger 60 m (200 ft) sugar-free asteroid entering Earth’s atmosphere at a comparatively slow 19 km/s (12 mi/s). Our marshmallow would likely be less powerful than this asteroid. But it would grow in danger, as air atoms would be punched into it during its trajectory. With more mass comes a greater impact force.