Download 80.BrainPopLifeCycleStars

Brain Pop – Life Cycle of Stars
1. Stars __________ throughout their lives just like we do; only they live for
___________ of years.
2. They start out as clouds of gas and dust called __________ nurseries. The force
of __________ within these clouds slowly pulls the particles together, causing
dense clumps to form.
3. If the clump becomes large enough, the ____________ caused by gravity forms
a __________, and it begins to give off heat.
4. The heat and pressure build until nuclear _______ begins. Gravity pulls two
hydrogen atoms together, ________ them to a single heavier helium atom.
5. Nuclear fusion produces huge amounts of energy, causing the star to ________.
6. This is the longest part of the star’s life, called its _____________________.
7. Our sun is at this stage now; about 4.6 billion years into its main sequence cycle
of ________ billion years.
8. What happens to a star after its main sequence depends on its _________.
Astronomers do not know what happens to _______ mass stars, those with less
than half the mass of our sun. They may actually have a main sequence that
lasts for a __________ years, longer than the current age of the universe.
9. Mid-size suns like ours become ________________. These are super dense
objects as massive as the sun itself, but only a fraction of the size – about the
size of the Earth.
10. Before the sun becomes a white dwarf, it will begin to die as it uses up the
____________ in its core. At that time, the sun will begin to _________to many
times its original size. Stars in this stage of their lives are called
________________, because their surfaces cool down to a red glow.
11.The sun will begin to burn ______________ at this stage, forming even heavier
elements. Eventually it will get so big, it will ____________ the Earth.
12.After a __________ years as a red giant, the sun will begin to ___________
under the pressure of gravity. _____________, it will begin to expand and
contract, shedding its outer layers in the process. The remains of those out
layers form a big cloud of gas and dust, called a ____________________.
13.At the center of a planetary nebula is a core of ___________, which after
cooling becomes a white dwarf.
14.Stars much bigger than ours (super red giants) collapse so quickly that they
explode into a _____________, scattering stellar material far and wide. A
supernova explosion can last for a _____________ or longer, and is bright as a
galaxy with a billion stars.
15.The clouds of gas and dust from a supernova are where the heavier elements are
found, and they lead to the formation of new ___________.
16.The left over core of a supernova can go one of _________ ways depending on
the mass of the original star. If the star is about ___________ times as massive
as our sun, protons and electrons in the core are crushed into neutrons and
forms a ____________ star.
17.Some neutron stars spin rapidly and emit pulses of radio waves. These are
known as ________________.
18.If the original star was ______________ than ten times as massive as our sun,
the supernova core will collapse in on itself and become so dense it will form a
______________ called a _______________. Its gravity is so powerful that
nothing in its area can escape it, not even ____________.