Fill in the gaps, using the words below.
Milky way, Sun, galaxies, planets, atom, 13.8 billion, atmosphere,
star, universe, gravity
Long before time began, space itself was compressed into a tiny space smaller than an
__________________. But then, around __________________ years ago, there was an explosion of
energy, known as the BIG BANG, and the __________________ began. Time, space and matter
all began with the Big Bang. Around 2 million years later, a hot glowing ball of hydrogen gas
appeared: the first __________________! Over time, more and more of these formed, in groups
known as__________________.
Humans live in a galaxy called the __________________, and our biggest star is called the
__________________. When it was formed, dust and gases spun around it, and a force called
__________________ pulled them together to form rocks. These rocks then joined and formed
__________________, including Earth.
Over millions of years, Earth’s surface cooled, and a hard crust formed. The earth’s layer of
gases, known as the __________________, held water vapor, which condensed into rain, and
oceans began to form.