So how come nobody is talking about the giant extinction event that the Earth is just barely gonna avoid on Thursday? 🙂
Asteroid 1999 FN53 will be whizzing past the Earth on Thursday, May 14 and will miss us by about 3 million kilometers. While a number of asteroids have come quite a bit closer in recent years, there is one important difference: 1999 FN53 is HUGE! It is a mile across and if it were to hit, the result would be more than a mere catastrophe. With that in mind, let’s talk about some really big-ass explosions and see where 1999 FN53 fits in the scheme of things. To ease comparison, I’m adding a scale factor to each of the impacts, events, and explosions discussed below, where a “1” is energetically equivalent to the Hiroshima bomb.
Except where otherwise labeled, the images used in this post are public domain.
Operation Sailor Hat (Scale: 0.03)
One million pounds of TNT (500 tons, or 0.5 kilotons).
Hiroshima Bomb (Scale: 1.0)
A uranium-235 fission bomb (15 kiloton yield) was detonated over Hiroshima, Japan, on August 6, 1945.
Baker Shot; Operation Crossroads (Scale: 1.5)
The Baker shot was a 23 kiloton underwater nuclear test at Bikini Atoll (1946). In the high-resolution photo below (click to view full size), an enormous column of 2 million tons of water can be seen rising from the sea.
Although the Baker shot didn’t exactly do Bikini Atoll any good, we didn’t completely fuck up the place until eight years later in 1954 during Castle Bravo.
Chelyabinsk Air Burst (Scale: 30)
On February 15, 2013, a meteor with an estimated diameter of 20 meters exploded approximately 30 kilometers over Chelyabinsk Oblast with a force of approximately 500 kilotons of TNT. The Chelyabinsk event is the only meteor in recorded history to cause multiple human injuries (1,491 were injured).
Tunguska Event (Scale: 1,000)
The Tunguska event of 1908 is believed to have been a meteor air burst (6-10 km altitude), similar to, but much more energetic than, the Chelyabinsk air burst. Due to the remoteness of the location in Siberia, there were no known human injuries. Although witnessed by local villagers, a scientific team didn’t make it to the site to investigate until 1921 — 13 years after the event. The energy of the explosion is estimated at 10-15 megatons, or about 1,000 times the energy of the 15 kiloton Hiroshima bomb.
Mount Saint Helens (Scale: 1,600)
Next week marks the 35th anniversary of the day Mount Saint Helens lost its top (literally). The mountain blew on May 18, 1980 in a catastrophic explosion that vaporized lakes and lay timber flat in scenes reminiscent of the Tunguska event. The energy released in the explosion was approximately 24 megatons.
Tsar Bomba (Scale: 3,333)
With a yield of 50 megatons of TNT, the Tsar Bomba was the most powerful nuclear (hydrogen fusion) device ever detonated. The test was conducted by the Soviet Union in Siberia on Oct. 30, 1961.
La Garita Eruption (Scale: 16,000,000)
The La Garita Caldera in Colorado (US) is the remnants of the most explosive volcanic eruption known in Earth’s history. The size of the explosion was approximately 250 gigatons (250,000 megatons).
1999 FN53 [If it actually hit the Earth] (Scale: 500,000,000)
So yeah … it’s thankfully going to miss us. But if it did hit the Earth, this is where 1999 FN53 would be in terms of the energy of the impact: Right between La Garita and Chicxulub. This mile-long rock would impact the Earth with a force of several teratons of TNT, making the explosion about 500 million times as energetic as the bomb dropped on Hiroshima. The event would cause extinctions and would likely cull the human herd by 20 percent or more. Note: 1 teraton = 1,000 gigatons = 1,000,000 megatons = 1 fucking shit ton.
Chicxulub (Scale: 6,500,000,000)
What’s bigger than a hypothetical impact of 1999 FN53? There aren’t that many options here. The object that struck the Yucatán Peninsula 66 million years ago, ending the Cretaceous period, was likely around 10 km (6 miles) in diameter and energetically equivalent to about 100 teratons of TNT.
While I compared in this post the absolute energies of various events in Earth’s history, I should point out that whether or not an event causes extinctions is probably more dependent the nature and volume of material ejected into the atmosphere and things like that. Still, it helps to gauge the energies of these various events against one another in order go get a rough idea of their relative intensities.
Anyway, 1999 FN53 is probably going to miss. Probably.