100 Points PLEASE
The Universe is believed to have been formed from a very dense fireball of years ago. As the fireball
expanded and cooled stars and galaxies formed. The fireball explosion is often called the ___ . The explosion
threw all the material outwards; that is why scientists believe the universe is getting bigger or . Scientists
have confirmed that the Universe is expanding by examining the light given off by stars. Astronomers now know that the
distance to the furthest galaxies is becoming greater as these galaxies are moving away the . Stars are
produced from gas clouds or , which contain mainly the element . The type of star produced
depends on the mass of the star. Red are stars formed which have a mass than that of our
.
Hydrogen is the of all stars. During nuclear fusion the hydrogen molecules combine producing
, releasing lots of in the process. How quickly the hydrogen is used up depends on the size
of the star. Massive stars burn hydrogen very quickly. Additional nuclear fusion reactions can convert helium into
elements with larger atoms, for example lithium. However the elements with the largest atoms only form when a star
explodes as a
The amount of energy given out by a star, its luminosity, varies considerably. dwarfs are stars that have a
very low luminosity, about one hundredth of the Sun. Super giant stars which are very large red giant stars, can give out
as much energy as 1,000,000 Suns. Some scientists believe that our Solar System was once a binary star system. The Sun
was the of the two stars and burnt its fuel slowly, lasting millions of years. The larger star used up all its fuel
and destroyed itself in a supernova explosion, leaving the Sun behind.
The Sun is a very stable star. In a few billion years from now the Sun will use up its fuel supply and start to change. It will
probably expand and form a red giant. Finally, it may form a white dwarf or a star. When this happens
there will no longer be life on the Earth, but by then we should have found new around other stars.
Your answer choices are fuel, nebula, expanding, less, hydrogen, smaller, energy, Sun, quickest, supernova, homes, white, neutron, giants,
helium, Big Bang, billions