Here's a breakdown of its abundance in different places:

* Universe: As mentioned, hydrogen makes up the vast majority of the universe's mass. It is the primary component of stars and other celestial bodies.

* Earth: On Earth, hydrogen is relatively rare in its elemental form due to its lightness and reactivity. It exists primarily as part of compounds, such as water (H₂O), hydrocarbons (like methane), and organic molecules.

* Atmosphere: Hydrogen makes up only about 0.00005% of Earth's atmosphere.

* Oceans: Hydrogen is the most abundant element in oceans, being a major constituent of water.

However, even though it is rare in its elemental form, hydrogen is still the most abundant element by *number of atoms* on Earth. This is because water is so prevalent.

So, while hydrogen is the most abundant element in the universe, it is relatively rare on Earth in its elemental form.