It's about one-fifteenth as heavy as a Tyrannosaurus rex
In other words, the weight of a Tyrannosaurus rex is 15 times 0.000000420 megatonnes.(for FMNH PR2081, a.k.a. "Sue") (a.k.a. Tyrannosaurus, a.k.a. T-Rex) (estimated live weight)
The notable Tyrannosaurus specimen housed at the Field Museum of Natural History in Chicago, Illinois, "Sue," is estimated to have weighed about 0.00000640 megatonnes while alive. A renowned predator in popular culture, the teeth of tyrannosaurus rex were up to 33.02 cm (13 in) long.
It's about one-twenty-fifth as heavy as an Anchor of a Cruise Ship
In other words, the weight of an Anchor of a Cruise Ship is 26.90 times 0.000000420 megatonnes.(for QE2 forward anchor, a.k.a. RMS Queen Elizabeth 2)
Each of the forward anchors of the RMS Queen Elizabeth 2 weighs 0.00001130 megatonnes. The anchor of the QE2 now sits in front of the Holyrood Church in Southampton, England, United Kingdom, along a pedestrian tourist route known as "the QE2 mile."
It's about thirty times as heavy as a Gold Bar
In other words, 0.000000420 megatonnes is 33.75828390 times the weight of a Gold Bar, and the weight of a Gold Bar is 0.02962235885 times that amount.(London Good Delivery bar)
A "London Good Delivery" gold bar — the variety commonly held by Central Banks — should weigh 0.000000012441390720 megatonnes. The largest gold bar ever produced was minted by Mitsubishi Materials Corporation (a sibling company of the auto manufacturer) in 2005 and weighed 0.000000250 megatonnes.
It's about 50 times as heavy as a Dachshund
In other words, the weight of a Dachshund is 0.02 times 0.000000420 megatonnes.(a.k.a. "Wiener dog", a.k.a. Teckel, a.k.a. Dackel, a.k.a. "hot dog dog", a.k.a. "sausage dog", a.k.a. "doxie") (FCI standard; standard size)
The Fédération Cynologique Internationale (FCI) calls for dachshunds to weigh about 0.00000000900 megatonnes. Despite of their small size, a 2008 survey conducted by the University of Pennsylvania named dachshunds as the most aggressive dog breed.
It's about 60 times as heavy as a Bowling Ball
In other words, 0.000000420 megatonnes is 61.72943340 times the weight of a Bowling Ball, and the weight of a Bowling Ball is 0.0161997275 times that amount.(most common selection among male bowlers)
With an allowable range of 0.000000004989516070 megatonnes, the most-preferred bowling ball weight among adult, male bowlers is 0.000000006803885550 megatonnes. Because regulation balls measure the same diameter irrespective of their weight, ball density varies by size and balls weighing less than about 0.00000000500 megatonnes will float in water.
It's about 80 times as heavy as a Gallon of Paint
It's about 90 times as heavy as a Cat
In other words, the weight of a Cat is 0.01 times 0.000000420 megatonnes.(Felis catus) (Domestic; healthy weight)
The average domestic cat should weigh between 0.00000000500 megatonnes. Cats are known for their righting reflex, which allows them to land on their feet and survive falls from heights of 1 m (3 ft) up to about 21 m.