Last week, asteroid 2023 DZ2 flew by Earth at a distance of 168,300 kilometers (104,600 miles), roughly two-fifths of the distance between the Earth and the Moon. Asteroids often get close to our planet, but what was significant about this passage was its size. With a diameter between 40 and 90 meters (130 to 295 feet), 2023 DZ2 is in the “city killer” size category, and NASA estimated that an object like this gets this close to our planet only about once a decade.
There was no danger that the object would impact Earth – but a passage as rare as this was too good an opportunity for astronomers to miss. Understanding the properties and compositions of these Near-Earth objects is paramount if we want to understand how to protect ourselves in case of an impact.
Among the many observatories casting their eyes to the sky to look at this small celestial body, there were our friends at the Virtual Telescope Project which recorded a great timelapse of the asteroid while still a fair bit away from our planet, about 1.8 million kilometers (1.1 million miles), a couple of days before its closest approach.
There is no chance that asteroid 2023 DZ2 will hit our planet in the next century, so we do not have to worry about this body – but there could be similar-sized objects that pose a risk, and it's important to find them and understand them. This object was spotted three weeks before its close passage, so we would hopefully have enough time to send people affected a safe distance away from the possible impact area.