Hydrogen is the chemical element with atomic number 1
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Earth is the fifth-largest of the eight planets in the Solar System
The Union of Soviet Socialist Republics (USSR) was a constitutionally socialist state that existed in Eurasia from 1922 to 1991
The Solar System formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago
Red is the most common color in national flags
Naturally occurring elemental hydrogen is relatively rare on Earth
Earth is the third planet from the Sun
Juipter is the largest planet in the Solar System
The average diameter of the Earth is about 12,742 km
The term Universe may be used in slightly different contextual senses, denoting such concepts as the cosmos, the world, or Natur
Current interpretations of astronomical observations indicate that the age of the Universe is 13.73 (± 0.12) billion years
Hydrogen is the lightest and most abundant chemical element, constituting roughly 75 % of the Universe\'s elemental mass
The average diameter of the Earth is about 12,742 km
The Sun accounts for about 99.86% of the Solar System's mass
The Moon is the only celestial body on which human beings have made a manned landing
Hydrogen is represented by the symbol H
The Solar System consists of the Sun and those celestial objects bound to it by gravity
The Moon is Earth's only natural satellite
The planet formed 4.54 billion years ago
The Sun accounts for about 99.86% of the Solar System's mass
The Sun has a diameter of about 1,392,000 kilometers
