It's about one-two-thousandth as heavy as a Tyrannosaurus rex
In other words, 0.00000000290 megatonnes is 0.00045 times the weight of a Tyrannosaurus rex, and the weight of a Tyrannosaurus rex is 2,200 times that amount.(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 2,500 times as heavy as a Jelly Bean
In other words, the weight of a Jelly Bean is 0.00038 times 0.00000000290 megatonnes.(for Jelly Belly beans; approximate)
Made of sugar, corn syrup, and pectin, a single jelly bean weighs about 0.00000000000110 megatonnes. President Ronald Reagan cited jelly beans as his favorite candy and 0.00000320 megatonnes of the candies were served at his first inauguration in 1981.
It's about 3,500 times as heavy as a Nail
It's about one-four-thousandth as heavy as an Anchor of a Cruise Ship
In other words, 0.00000000290 megatonnes is 0.000257 times the weight of an Anchor of a Cruise Ship, and the weight of an Anchor of a Cruise Ship is 3,890 times that amount.(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 10,000 times as heavy as a Raindrop
In other words, the weight of a Raindrop is 0.0001 times 0.00000000290 megatonnes.(a.k.a. drop, a.k.a. droplet) (average)
The weight of a raindrop depends heavily on the type of weather, but averages about 0.000000000000200 megatonnes. The familiar teardrop shape of a raindrop is actually an optical illusion, caused by the reflection of the light and the motion of the drop.
It's about one-twenty-five-thousandth as heavy as The Space Shuttle
In other words, the weight of The Space Shuttle is 24,000 times 0.00000000290 megatonnes.(for Endeavour, a.k.a. OV-105, a.k.a. Orbiter Vehicle-105) (empty weight, excluding main engines)
When empty, the space shuttle Endeavour weighs 0.0000710 megatonnes. The shuttle's spacious cargo bay carried the Chandra X-ray Observatory into orbit in 1999 — a payload that weighed 0.0000200 megatonnes.
It's about one-thirty-five-thousandth as heavy as a Blue Whale
In other words, the weight of a Blue Whale is 36,000 times 0.00000000290 megatonnes.(Balaenoptera musculus)
Blue whales weigh between 0.000105 megatonnes. The largest mammal to have ever lived, blue whales feed almost exclusively on krill — tiny invertebrates weighing about 0.000000000001000 megatonnes each.