Length scales table

The range of length scales occurring in the universe is immense! Protons and Neutrons are approximately 10-16 Meters in diameter while the observable universe is estimated to be approximately 4 x 1026 Meters in diameter.

Atoms and Molecules
Electrons Experiments suggest the hypothesis that electrons are "point-like particles" in the sense that they lack structure.
Protons/Neutrons 10-6 Angstroms (1 Angstrom = 10-10 Meter)
Atomic Nuclei 10-5 Angstroms
Atoms A few Angstroms
Smallest viruses (e.g., polio virus) 300 Angstroms
Smallest bacteria (mycoplasmas) 1,000 Angstroms
Largest Viruses (e.g., pox viruses) 2,500 to 3,000 Angstroms
Diameter of the nucleus of the human cell 2x10-6 to 10-5 Meters
Largest Bacteria 6x10-4 Meters
Largest neurons (motor) About 1 Meter
Height of adult human being A little under 2 Meters on average
The length of the DNA material occurring in a the nucleus of a single human cell, assuming the DNA material was stretched out along a straight line 2 Meters
Land, Sea, and Air
Large Hail A few Centimeters
Tornadoes ("radius") 100 to 600 Meters
Top of Troposphere (most weather phenomenon occurs with in the troposphere) 6 to 17 Kilometers
Highest Clouds 15 to 17 Kilometers
Hurricanes Several hundred Kilometers
Top of Stratosphere (the stratosphere is the layer above the troposphere in which the temperature increases) 50 Kilometers
Top of Mesosphere (the mesosphere is the layer above the stratosphere in which the temperature rapidly decreases) 85 Kilometers
Largest recorded height for a Tsunami wave upon reaching land (Lituya Bay, Alaska in 1958) 525 Meters
Deepest point in the oceans (Mariana Trench) -11,034 Meters
Lowest point on land (near the Dead Sea) More than 300 Meters below sea level
Highest point on land (Mount Everest) 8,850 Meters
Thickness of Earth's crust Oceanic crust: 10 Kilometers

Continental crust: 20 to 90 Kilometers with an average of 35 Kilometers

Radius of solid core 1,300 Kilometers
Thickness of liquid core 2,200 Kilometers
Depth of the boundary between the liquid core and the mantle 2,900 Kilometers
Size of continental plates A few thousand Kilometers
Radius of the Earth 6,378 Kilometers
Sizes of Astronomical Objects
Eros 33 Kilometers
Ceres (the largest asteroid) 933 Kilometers
Longest Comet tail ever measured 5x108 Kilometers!
Phobos (one of the two moons of Mars) 26 by 22 Kilometers
Radius of Earth's Moon 1,738 Kilometers
Radius of Ganymede (one of Jupiter's moons and the largest moon in our solar system) 2,631 Kilometers
Pluto 1,160 Kilometers
Mars 3,400 Kilometers
Earth 6,378 Kilometers
Jupiter 71,370 Kilometers
Pulsars 10 Kilometers
Our Sun 7x105 Kilometers
Largest known star (UY Scuti) 1.8 x 109 Kilometers
Milky Way (our galaxy) 100,000 light-years wide (1ly = 9.5 x 1012 Kilometers), but only 1000 light-years thick
Estimated present diameter of the observable universe (keep in mind that the Universe is still expanding!) 92 billion light-years
Distances in Astronomy
Distance from the Moon to the Earth 390,000 Kilometers = 1.3 Light Seconds
Distance from the Earth to the Sun 150,000,000 Kilometers = 8.3 Light Minutes
Distance from Jupiter to the Sun 540,000,000 Kilometers = 30 Light Minutes
Mean distance of Pluto from the Sun 5,913,520,000 Kilometers = 5.5 Light Hours
Distance traveled by light in one year 9.5x1012 Kilometers = 1 Light-Year
Distance to the nearest star (Proxima Centauri) 4.3 Light-Years
Distance to the center of the Galaxy Approximately 33,000 Light-Years
Distance to the Andromeda Galaxy (the nearest "large" galaxy to ours) 2,000,000 Light-Years