23 space-related words you need to know

Here’s our third and final instalment of key terms used in discussing space.:

Hemisphere: half of a sphere; the Earth has two hemispheres, the Northern hemisphere and Southern hemisphere, divided by the equator.

Infrared: a type of invisible light. The human body has a temperature that gives off infrared light, permitting the invention of infrared night-vision cameras that detect human presence.

International Space Station: a space laboratory where astronauts live and run science experiments, the ISS is the biggest man-made object orbiting Earth.

Light Year: the distance that light can travel in a year — about 9.4 trillion kilometres.

Magnetic Field: the area around a magnet where its attractive or repulsive force is felt.

Meteor: When a meteoroid (a small rock travelling through space, much smaller than an asteroid) enters Earth’s atmosphere, it creates a streak of light. This is known as a meteor or simply a ‘shooting star’. If a meteoroid, comet or asteroid lands on Earth, it’s called a meteorite. (Around 50,000 tonnes of meteoroids and other kinds of space dust enter our atmosphere every year).

Milky Way: the name of our galaxy. Our planet, Earth, orbits the Sun, which is one of 100 billion stars in the Milky Way.

Molecule: a particle containing two or more atoms (thus water is a molecule made up of two atoms of hydrogen and one atom of oxygen).

Nebula: a cloud of gas and dust in space.

Neutron Star: when a huge star reaches the end of its life, it explodes. The tiny compact core of the star that survives the explosion is called a neutron star.

Orbit: the path along which cosmic objects, satellites and spacecraft travel.

Pulsars: extremely compact stars that spin around hundreds of times a second, emitting radio waves that shine towards Earth in pulses.

Quasar: a supermassive black hole sucking in material, which, when it falls into the black hole, gives off a flare of extremely bright energy.

Radio waves: a type of invisible light used in communications to send signals from one place to another (mobile phones and TVs use radio waves).

Satellites: there are two types of satellites —natural and man-made. Natural satellites are cosmic objects that orbit around other objects in space, like the Moon that the Indian rover just landed on. (A moon is a natural satellite that orbits a planet. Most of the planets in our Solar System have at least one moon, like Earth; some planets have dozens.) A number of man-made satellites have been launched into orbit to collect information, help us communicate, navigate or anticipate the weather.

Solar System: the Sun and everything that moves around it — eight planets, five dwarf planets and countless moons, comets, asteroids and meteoroids. Without the Sun’s light and heat, life could not survive on Earth.

Star: A massive ball of luminous hot gas held together by gravity, like the Sun, our nearest star. A Star Cluster is a huge group of stars that can contain a few hundred stars or many millions.

Supernova: The explosive death of a massive star — amongst the most energetic events in the Universe, so bright it can outshine an entire galaxy!

Terrestrial Planets: Mercury, Venus, Earth and Mars are called the terrestrial planets. They are all similar to Earth in size and are made of rock.

Ultraviolet rays: Often shortened to UV, are an invisible type of light. UV waves have high energy. UV rays from the Sun cause sunburn and are capable of damaging cells in our skin.

Visible Light: the only type of light that our eyes can detect. Visible light contains all the colours of the rainbow. (Another mnemonic from my childhood is VIBGYOR: the name of an ice-cream shop in Bombay, it also stood for Violet, Indigo, Blue, Green, Yellow, Orange and Red, the colours of the rainbow in the right order.)

White Dwarf: when a Sun-like star has burned up all its fuel, it begins to collapse inwards and the material in the star’s core ends up squashed into a compact white dwarf.

X-rays: a type of invisible light that can travel through soft tissue like skin and muscle, and are, therefore, used to take pictures of broken bones.

wknd@khaleejtimes.com

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