Earth’s atmosphere shields life from harmful radiation through absorption, scattering, and magnetic interactions.

A clear look at the evidence behind the Big Bang model, from cosmic microwave background radiation to galaxy expansion and light-element abundance.

Explore the universe’s main ingredients, from ordinary matter to dark energy, and how scientists measure what makes up everything.

Explore the leading scientific ideas behind cosmic infinity, including geometry, expansion, and what current observations actually allow.

GPS depends on relativity to keep satellite clocks synchronized enough for accurate navigation.

Learn how weightlessness happens, why astronauts float, and what microgravity really means in orbit.

Relativity explains how gravity, time, and motion shape space travel, GPS, and our view of the universe.

Discover what space-time is, how Einstein changed our view of reality, and why gravity, light, and time all depend on it.

Explore why modern cosmology says the universe has no center, how expansion works, and what the cosmic microwave background reveals.