The Philippine island of Luzon was in the line of fire and there was nothing they could do but watch. Sure enough, at 5.39 pm GMT, just as predicted, the space rock collided with our world and burst into flames.
If you're wondering why you're still around to read this, it's because this meteor was only a meter long. Too insignificant to cause any damage, the asteroid instead harmlessly ignited in the upper atmosphere, temporarily painting the sky in a blue-green streak of light. As it turns out, small asteroids hit the planet all the time. They're nothing to worry about, but it doesn't take a huge jump in size to turn them into a threat. An asteroid just 20 meters long exploding in the sky can blow out windows and knock people to the ground. A 50-meter space rock can wreck a city, causing major infrastructure damage, injuries, and death many miles from the site of the mid-air explosion. And a 140-meter-long asteroid would blast its way to earth, blow a hole in the face of the planet, and instantly destroy a megalopolis.
For billions of years, Earth has been at the mercy of such cosmic threats - but we now live in much more changed times. Today, there is a field of applied science known as planetary defence, which is exactly what it sounds like: scientists and engineers working around the clock to protect the world from apocalyptic space rocks. One way they do this is by spying on the sky, scanning the night sky for asteroids that might be heading our way. In the next few years, two next-generation telescopes will be commissioned, and they will detect almost all the space rocks that elude even the most keen-eyed astronomers. And if these missions deliver on their generous promise, all 8 billion of us will be considerably safer than we are now.
Planetary protection falls into two categories. The first is more offensive, using technology to deflect or destroy an approaching asteroid of those 140-foot sizes that kill cities or megacities. In 2022. NASA conducted the first planetary defense experiment in history. As part of the Double Asteroid Redirection Test, or the Dart mission, it smashed an unmanned spacecraft into a (harmless) asteroid to see if it could deflect it. Dart passed this test - a dress rehearsal for a real global emergency - with flying colors, suggesting that an asteroid big enough to vaporize a megalopolis could be knocked out of Earth's path if we met it with force and precision.
There is, however, a huge caveat to this technique: we can't deflect asteroids if we don't know where they are. That's why planetary defense is a team effort. While space agencies are building spacecraft and developing technologies to deflect (or destroy) incoming asteroids, others are fixed on the skies, searching for near-Earth asteroids that could threaten us.
Right now, Earth's ongoing safety relies on optical astronomy: telescopes looking for sunlight glinting off space rocks that have yet to be discovered. Many observatories conduct all sorts of astronomical searches; finding asteroids is something that happens opportunistically during these surveys. Some telescopes, including several funded by NASA, are dedicated solely to finding asteroids. This method of searching for space rocks has proven quite effective, especially for the heavier asteroids. NASA estimates that most of the planet killers - asteroids a kilometer or more in length approaching Earth's orbit around the Sun - have been found. (The asteroid that quickly ended the age of the dinosaurs 66 million years ago was 10 kilometers long and easily fits into the planet killer category.
But this crop of asteroid-hunting surveys is insufficient to protect the planet. There are about 14,000 near-Earth asteroids with the potential to destroy a major city that can still be found. And only a handful of near-Earth asteroids 50 meters long have been identified; NASA estimates that hundreds of thousands of space rocks are hiding nearby and remain undiscovered. Astronomers are pushing for a better star-scanning tool to find these asteroids before they find us. Fortunately, they're on track to get the two ultramodern telescopes very soon. | BGNES
