UNIT 7.5STARS, CONSTELLATIONS AND GALAXIES

Stars

• Spherical body.• Generates light and heat through nuclear

reactions.• Most of them consist of gases, hydrogen

and helium.

Stars

Characteristics:

•Colour: depending on the temperature they can be red, yellow, orange, white or blue.

•Size: all stars are enormous, but some are bigger than others.

•Luminosity: depends on the amount of light from the star that reaches the Earth. Obviously it also depends on how far it is from us and how big it is.

Constellations

•Stars are divided into eighty-eight groups.

•Their names come from classical mythology,

animals and objects because of the shapes

they form in a bi-dimensional point of view.

•Ursa Major: a constellation that can be seen

all year round.

•Orion. Can only be seen in winter.

•Hercules can only be seen in summer.

Nebulae

Clouds of dust and gas

Some are illuminated by stars. That’s why we can see them.

This gas and dust can join and form a new star.

Nebulae: la tarántula

Nebulae: la gaviota.

Nebulae: la hélice La Nebulosa de la Hélice es uno de los ejemplos más brillantes y próximos de nebulosa planetaria, una nube de gas creada al final de la vida de una estrella similar al Sol. Los gases más externos de la estrella expulsados al espacio asemejan, desde nuestro privilegiado punto de vista, como si estuviésemos mirando a través de una hélice . El núcleo estelar resultante, destinado a convertirse en una estrella enana blanca

Galaxies

•Enormous groups of rotating stars, gases

and dust.

•There are three types according to their

shape. Elliptical, spiral and irregular.

•Milky way, our galaxy. We are placed on the

edge of one of its arms