How a needle hitting Earth at the speed of light would have catastrophic consequences

There's a viral video going around sharing what would happen if a needle happened to hit the Earth at the speed of light.

It's purely a wonderous thought experiment as it's been marked as impossible to ever happen - but that doesn't stop the curious from dissecting the potential outcomes.

YouTuber AstroKobi unravelled the science behind it. He imagined the needle to be made of iron, weighing one gram and travelling '99.9999% the speed of light.'

To put that into perspective, a typical sewing needle is around 0.1 grams (0.035274 ounces). This is minuscule compared to the mass of the Earth, which is about 5.97 x 10^24 kilograms.

Yaorusheng/Getty

But travelling at the speed of light must do some damage, right?

'When it strikes the Earth, it will have a kinetic energy of 201 million billion joules,' the YouTuber described.

'That is the equivalent of three Tsar bombs, the largest nuclear weapon ever detonated.'

This energy would be powered by the needle’s relative mass and released upon contact with the Earth's atmosphere.

However, these same factors also mean that the needle would likely vaporise due to friction with the atmosphere long before it ever reached the Earth's surface.

Nevertheless, to carry on with the theme of the hypothetical situation, some theorise that the resulting shockwave would be felt around the world.

Whereas, others suggest that the needle would simply pass through the Earth, leaving behind just a small hole.

AstroKobi/YouTube

According to Einstein’s theory of relativity, objects moving close to the speed of light experience an increase in mass and a slowing of time.

This means the needle's mass would increase massively and would experience significant time dilation.

Overall, the impact of a needle would be catastrophic, causing a chain reaction and eventually, widespread destruction.

'It would definitely create an impact crater, significantly smaller than if it was an asteroid because the needle is just much smaller but definitely big enough to cause some damage,' the YouTuber continued.

He added that the impact would 'form a huge fireball. Much bigger than the biggest nukes.'

Thankfully, the YouTuber reassures at the end that all of this is purely theoretical and 'nothing can travel at the speed of light so you don't have to worry.'

I guess, we can't help but wonder.