just how big?

Hydrogen atom vs DNA double helix

The helix diameter of DNA double helix is about 18.9 times the characteristic size of Hydrogen atom.

Characteristic scale
ENLARGED ×13.5
01
Hydrogen atom105.8 pmCharacteristic size
02
DNA double helix2 nmHelix diameter
Inset ×13.5Hydrogen atom is too small to see clearly at this scale. The ring marks its position; only the inset is enlarged.