Key facts
- Category
- Atoms
- Object class
- Atom
- Scale fact
- 100 pmdiameter
- Composition
- 1 proton, 1 electron
Hydrogen Atom
100 pmdiameter
Visual creditscaleofspace.org / CC BY-NC 4.0
Details
Hydrogen is the universe’s simplest and most common atom. Most hydrogen nuclei were forged in the first minutes after the Big Bang, and neutral hydrogen atoms emerged only after the universe cooled enough for electrons and protons to combine about 380,000 years later.
Hydrogen nuclei formed within the first few minutes after the Big Bang, but neutral atoms could not persist in the hot plasma. About 380,000 years later, the expanding universe had cooled enough for electrons to remain bound to protons. With far fewer free electrons to scatter photons, the universe also became transparent to the light now observed as the cosmic microwave background.
Links
- Editorial guides
- Wikipedia
- Hydrogen Atom on Wikipedia
- Preset views
Size neighbors
Objects near Hydrogen Atom on the scale
On the logarithmic size axis, Hydrogen Atom falls between Plutonium-244 Nucleus and Water Molecule. The band uses nearby Atom records.
Shared physical scale
398pm
Sources
References for Hydrogen Atom
Measurements and descriptive context are compiled by the Scale of Space team from the references below. If you find an error, please let us know.
- Hydrogen Atom — Wikipedia
- Visual: scaleofspace.org / CC BY-NC 4.0
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About
Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.
Guides explain selected parts of that range, while focused views filter the objects by subject.