A large asteroid called 2024 YR4 has been making news lately. Scientists initially thought it had a higher chance of hitting Earth, only to revise that estimate down significantly. Now, it has about a 0.28% likelihood of colliding with our planet in 2032, compared to an earlier estimate of 3.1%. Interestingly, it’s now more likely to strike the Moon, with a 1% chance.
Since 2024 YR4 was discovered in Chile two months ago, many other space rocks have zipped by Earth closer than the Moon, indicating how busy our cosmic neighborhood is. Though many small objects probably burn up in our atmosphere unnoticed, the real intrigue lies in the asteroids that make headlines: the close calls and the possible impacts.
Most asteroids are harmless, but they can offer valuable clues about the universe. They are essentially leftovers from the birth of our solar system around 4.6 billion years ago. As they orbit the Sun, some fly near Earth, pulled by gravitational forces from other planets.
Historically, tracking these objects has been a challenge. Serious monitoring started only in the late 20th century. Before that, we didn’t realize how many massive objects were passing close by. Nowadays, we know that several large asteroids—about 40 meters wide or larger—whiz between Earth and the Moon each year. For context, a similar-sized asteroid exploded over Siberia in 1908, causing significant damage.
One notable near-miss was an asteroid named Apophis, discovered in 2004. At 375 meters wide—about the size of a cruise ship—it was once deemed a major threat. It took years of observation to confirm it wouldn’t collide with Earth. The science community learned valuable lessons from this experience, including how to respond to potential dangers.
While a large asteroid hitting Earth could lead to significant disasters, much depends on its size and location of impact. If 2024 YR4 (estimated to be around 90 meters) were to strike, it could potentially create a massive crater and cause destruction within many kilometers.
Fortunately, advancements in planetary defense have come a long way since Apophis was first observed. Organizations like NASA and the European Space Agency have developed strategies to divert asteroids if they’re on a collision course with Earth. For example, NASA’s DART mission successfully altered the path of an asteroid by crashing a spacecraft into it. However, the success of this approach on YR4 remains uncertain due to unknown factors about its composition and the limited time for intervention.
Interestingly, not all asteroid impacts are negative. If one were to hit a remote area, it could yield samples that provide insights into the early solar system. For instance, nearly 50,000 asteroids have been discovered in Antarctica, with some believed to have originated from Mars, offering clues about the planet’s wet, warm past.
As for the current situation with YR4, scientists are closely watching its trajectory. While the risk of a direct hit seems to decrease, discussions about planetary response and preparedness are ongoing. The Space Mission Planning Advisory Group will meet again in April to assess the asteroid’s path further.
In conclusion, the recent concerns surrounding 2024 YR4 highlight our planet’s vulnerability to asteroid collisions. It’s crucial to continually improve our monitoring capabilities. Later this year, the Vera Rubin Observatory in Chile will start observing the night sky with an incredible new digital camera, capable of detecting even more asteroids. The more we look, the more we can understand our dynamic cosmic environment.
