A gigantic asteroid the size of about 770 lions is scheduled to fly past Earth on Thursday. According to NASA’s Asteroid Tracker, it is one of the largest of all near-Earth asteroids.
The asteroid in question was designated (415029) 2011 UL21, according to the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory (JPL).
According to the European Space Agency (ESA) (415029) 2011, UL21 is one of the largest of all near-Earth asteroids (NEAs), and although it will not hit Earth during the upcoming flyby, the potential impact scenario could possibly be the worst global disaster in millions of years.
Asteroid, You Forgot Me: How Big Is An Asteroid To Miss Earth?
Asteroids come in a wide variety of shapes and sizes, and when it comes to NEAs, we usually see them measured in meters. But there’s no underestimating just how big this one is. NASA JPL placed its diameter between a more conservative 1.7 kilometers and a much more colossal 3.9 kilometers. ESA averaged it slightly more at 2.31 kilometers.
That’s a lot of big numbers. But let’s use a more relatable metric, something more down to earth, something everyone recognizes: cats. Except house cats are too small for that, so let’s use their much larger cousins ​​instead: lions.
According to the Smithsonian’s National Zoo and Conservation Biology Institute, male lions grow to about three meters in length. So, according to ESA measurements, asteroid (415029) 2011 UL21 is about the size of 770 adult male lions from head to tail.
But if this asteroid is that big, surely it must be flying slowly. But no, it’s actually hurtling through space at 25.88 kilometers per second. That means it would take less than five minutes for this asteroid to fly the distance between New York and London.
It’s a big asteroid and we’re not the lions: How dangerous would this asteroid be if it hit Earth?
Make no mistake: asteroid impacts can be devastating. Asteroid (415029) 2011 is officially designated as a Potentially Hazardous Asteroid (PHA) due to its proximity to Earth and the sheer level of devastation it can cause.
To clarify, one of the criteria for PHA designation is that it must be at least 140 meters in diameter. Experts from the Davidson Institute of Science, which is part of Israel’s Weizmann Institute of Science, claim that the impact of such a large asteroid would be at least a thousand times stronger than the first nuclear bomb dropped on Hiroshima.
Something even bigger, say over 300 meters, would have the power to destroy an entire continent.
An asteroid over a kilometer wide would be a global disaster. And asteroid (415029) 2011 UL21 is more than double that.
To put this into perspective, the last major asteroid impact on Earth was the Tunguska event of 1908, when an asteroid fell over distant Russia. The result was one of the largest known explosions in recorded history, which was heard as far away as the US and Indonesia and was reportedly visible as far away as Scotland. It left a terrible level of destruction in its wake, although only a few people were actually killed because it was so far away.
While experts disagree on the size of this asteroid, estimates range from a mere 50 meters wide to around 200 meters. Compared to asteroid (415029) 2011 UL21, it’s a drop in the bucket.
Fortunately, we have nothing to fear. All projections say the asteroid will fly over six million kilometers from Earth. It’s quite close on a cosmic scale, but it’s more than 17 times farther than the Moon.
Hakuna ma-asteroid: Are we not worried about a possible asteroid impact?
Asteroids have already hit Earth this year and will do so again in the future. But they were minor impacts that did not leave any damage.
If a large impact were to occur, planetary defense scientists will be working hard to find ways to stop it. This includes increasing surveillance to keep an eye out for incoming space rocks, as well as means to try to neutralize the threat. The most promising method so far was demonstrated by NASA’s Double Asteroid Redirection Test (DART) mission, which demonstrated that it could deflect an asteroid by bumping a spacecraft into it and slightly shifting its orbital path.
But that doesn’t mean that we can do it well in practice. A recent simulated asteroid impact scenario by NASA and its partner organizations found major gaps in the global response system, even though we had 14 years to prepare.
In other words, even though we’ve made great strides in planetary defense, humanity still has a ways to go to protect Earth.