It was recently reported by a number of online news outlets, including the Daily Star, Mirror, Irish Mirror, Bristol Live and Edinburgh Live that an asteroid bigger than Big Ben is set to “crash into the Earth’s atmosphere” on 11 January.
In reality, the asteroid, named 2013 YD48, will not crash into the Earth’s atmosphere. According to NASA, the closest it will come to Earth is 3,480,000 miles away. At the time of writing, the Mirror had changed its headline to reflect this.
There are five layers to the Earth’s atmosphere. The furthest from Earth’s surface is the exosphere, which extends between 440 miles and 6,200 miles.
In 2019 a study using data produced by NASA and the European Space Agency (ESA) found evidence that the Earth’s outermost atmosphere reaches almost 391,000 miles from Earth’s surface. Even using this definition, 2013 YD48 is not expected to reach Earth’s atmosphere.
The articles all state that while almost 3.5 million miles may sound like an extremely far distance, this is relatively close in terms of outer space. They then proceed to say that NASA defines anything passing within 120 million miles of Earth as a Near Earth Object (NEO).
This is inaccurate. NASA classifies objects as NEO’s, not based on their distance from Earth, but from the Sun. NEO’s are objects that pass within 120 million miles of the Sun, which means they can “circulate through the Earth’s orbital neighborhood”.