Learn Astronomy

The study of celestial bodies and phenomena in the universe.

The Big Bang, expansion from an initial point.

Approximately 13.8 billion years.

An immense collection of stars, gas, dust, and dark matter.

The Milky Way.

Barred spiral.

A gaseous celestial body producing energy through fusion.

The Sun.

A celestial body orbiting a star.

Jupiter.

Saturn (the most visible ones).

The distance light travels in one year.

Nicolaus Copernicus (modern).

Galileo (Galileo Galilei).

A region of spacetime with extreme gravity.

A cloud of interstellar gas and dust.

White dwarf.

A spectacular explosion of a massive star.

A small rocky body orbiting the Sun.

A small body made of ice and rock, with a bright tail.

Neil Armstrong.

Apollo 11.

Yuri Gagarin.

A change in frequency related to relative motion.

Hubble's Law.

Dark matter.

Dark energy.

A planet orbiting a star other than the Sun.

Hubble Space Telescope (HST).

James Webb Space Telescope (JWST).

Johannes Kepler.

Isaac Newton.

A very luminous and distant galactic nucleus.

Mars and Jupiter.

The average Earth-Sun distance.

Energetic particles coming from space.

Sputnik 1.

Approximately 300,000 km/s.

The Moon obscures the Sun.

The Earth obscures the Moon.

The Kuiper Belt (beyond Neptune).

Nitrogen and oxygen.

A neutron star that emits pulsations.

Nebula, protostar, main sequence, red giant, white dwarf.

Residual radiation from the Big Bang.