Science

A history-changing space mission is one that opens a new capability, returns evidence nobody had before, or changes how later missions are designed. By that standard, Apollo and Voyager sit at the center of space history, but they are part of a longer chain that also includes Mars landers, space telescopes, orbital laboratories, and frontier probes that pushed the map outward. Why These Missions Still… Space Missions That Changed History: From Apollo to Voyager

Comets and asteroids are small bodies that orbit the Sun, but they are not the same kind of object. In simple terms, asteroids are usually more rock-heavy, while comets contain more ice and can release gas and dust when sunlight warms them. Both preserve very old material from the early solar system, so they help explain what the solar system was made of before the… What Are Comets and Asteroids? Differences and Key Facts

The Milky Way is a barred spiral galaxy that contains the Solar System. Its bright disk stretches a little over 100,000 light-years, holds a few hundred billion stars, and places the Sun in the Orion Spur rather than near the center.[a][c] The Picture That Matters First The Milky Way is not just the pale band seen in the night sky. That band is the inside… The Milky Way Galaxy: Structure, Size, and Our Place in It

Neutron stars are collapsed stellar remnants left behind after certain massive stars explode, and they pack more than the Sun’s mass into a body only about 20–25 kilometers across. That makes them the densest stable objects astronomers can study directly. A pulsar is not a different material or a separate cosmic species; it is a neutron star whose radiation beam sweeps across Earth with such… Neutron Stars and Pulsars: The Densest Objects in the Universe

Dark matter and dark energy are umbrella names for two big unknowns in modern cosmology: one that acts like extra gravity (dark matter) and one that is tied to the Universe’s accelerating expansion (dark energy). In today’s standard picture, together they account for roughly 95% of the Universe’s total “energy budget,” while the atoms that make stars, planets, and people are the small remainder.[a]🔗 This… Dark Matter and Dark Energy: The Invisible 95% of the Universe

An exoplanet is a planet beyond our Solar System, orbiting another star. The search for Earth-like exoplanets is really a search for measurable “Earth-ish” clues—size, orbit, starlight, and sometimes atmosphere—without pretending we already know what the surface is like. [a] ⓘ A Clear Starting Point Most “Earth-like” headlines boil down to three things: small (likely rocky), temperate (not too hot or cold from starlight), and… Exoplanets: Searching for Earth-like Planets Beyond Our Solar System