An asteroid recently made the second closest pass to Earth ever observed on October 1st. And astronomers only found it after it had already completed its closest approach. That offers another lesson in how difficult it is to find small objects coming close to our planet in the vast dark ocean of space.

To be clear, the asteroid, now known as Asteroid 2025 TF, didn’t pose any sort of danger. It is likely only 1-3m across, and would have created a pretty spectacular fireball if it had entered Earth’s atmosphere - but most likely no one would have been there to see it as it flew over Antarctica in the beginning of their spring. There was a possibility it would have burnt down to a meteorite that could have one day been discovered though.

Alas, that didn’t happen as the asteroid made a pass around 428 km above the southern continent at around 1 AM UTC on October 1st. For comparison, that’s around the same height as the international space station’s orbit, which can vary from between 370 and 460 km. It would have been a very bad day if those two had found each other, but luckily the orbital space that far above the planet is vast, and even something as large as the ISS is easy to miss in that vastness.