Space & Particles

Question 1

Big Bang -

Answer 1

Happened around 13.7 billion years ago
Generated a massive explosion of energy and matter that, over time, cooled to form the
elements
It is supported by the fact that the universe is still expanding (Hubble)
Hydrogen and helium came very soon after big bang (earliest elements)

Question 2

Universe -

Answer 2

The Universe is, literally “all things”
that exist, including the Earth and
everything else in space.

Question 3

Galaxy -

Answer 3

Galaxies are smaller than the
Universe, but are vast anyway. They
can have anything from 107 stars
(dwarf galaxies) up to 1013 stars.

Question 4

Planet -

Answer 4

A very large, spherical object made
mostly of rock and orbits a star. A
true “planet” has moons or other
satellites and has cleared the area
of small debris.

Question 5

Star -

Answer 5

A star is a large ball of gas and dust
that, due to gravity and pressure, is
undergoing nuclear fusion to release
vast quantities of energy. The sun is a
star.

Question 6

Orbit -

Answer 6

The orbit of an object is the path
around another object in space. A
moon orbits a planet. A planet orbits a
larger object like a star. An orbit can be
circular or elliptical.

Question 7

Satellite -

Answer 7

A satellite is an object that orbits
another object. A moon is an example
of a natural satellite. The Hubble
telescope is an example of a human-
made satellite.

Question 8

Moon -

Answer 8

Moons are huge objects that orbit
around other planets, typically they are
rocky formations and don’t have a
molten core. They are natural satellites
of planets.

Question 9

Speed of light -

Answer 9

This is how fast a wave of light (a

photon) will travel in one second in
space. The speed is 300 000 000 m / s.

Question 10

Comets -

Answer 10

Comets are rocky and icy lumps,
held together by frozen gases and
water, that orbits the sun.

Question 11

Ellipse / Elliptical -

Answer 11

An elliptical orbit is one that is not quite
a circle, but is slightly stretched. It has
an outline like the outside of a hens’
egg. This affects the speed of the
object.