Asteroids with a diameter greater than 1 km are enough to trigger an extinction event.
REPUBLIKA.CO.ID, PERTH – A asteroid named 2022 AP7 advertised as a “planet-killer” asteroid (killer of the planet). Fortunately, according to Scott Sheppard, a scientist at the Carnegie Institution for Science, the asteroid doesn’t have the potential to hit Earth right now.
To find 2022 AP7, Sheppard and colleagues used a sunset telescope just after sunset. They had to do this because they were looking for asteroids around Venus and Earth. Venus is currently on the other side of the Sun from the Earth.
Making close observations of the sun is difficult. The sun’s glow obscures the faint light reflected from the small asteroid, creating a blind spot. However, before and after sunset, there is a small window where the sunlight no longer blocks the view.
Reported by SpaceOn Monday (11/7/2022), a team of scientists wrote that asteroid 2022 AP7 is the largest potentially dangerous asteroid (PHA) discovered in eight years. Its diameter is between 1.1 km and 2.3 km. Note that an asteroid with a diameter greater than 1 km is sufficient to trigger an event mass extinction on earth.
In addition to having a diameter of over 1 km, to be considered dangerous, asteroids also have orbits that cross the Earth. 2022 AP7 orbits the sun every five years. Currently, the asteroid is passing through Earth’s orbit when the Earth is on the other side of the sun. Eventually its motion will be synchronized with the Earth and will pass closer, but it will happen in the centuries to come.
Scientists have currently discovered about 95 percent of potentially dangerous asteroids and there are less than 1,000 of them. Sheppard and colleagues’ next job is to hunt down the other five percent of potentially dangerous asteroids.
What is a dangerous asteroid?
NASA (United States Aeronautics and Space Administration) closely follows all known objects in the solar system. However, there are times when scientists have “failed”.
In 2021, scientists recorded an asteroid called 2021 UA1 a few thousand kilometers from Earth, above Antarctica. In cosmic terms this is very close, however, 2021 UA1 is only two meters long and therefore presents no major risks.
In 2019, another asteroid with a diameter of 100 meters passed Earth about 70,000 kilometers away. It was announced to the public just hours before it flew away. While not that close, the size is far more concerning. This near-crash event reaffirms how important it is for us to accelerate our search for objects close to Earth.
There are currently only about 25 known asteroids that have defined orbits that are completely within Earth’s orbit. More will likely be discovered and this could significantly contribute to the loss of five percent of the potentially dangerous asteroid.
