____________________
____________________
after
the
Big
Bang
,
the
universe
was
as
hot
as
10^27°c
.
____________________
____________________
after
the
Big
Bang
,
the
universe
cooled
to
1
billion
degrees
.
Charged
____________________
and
____________________
began
to
form
along
with
____________________
neuclei
.
370
,
000
years
after
the
Big
Bang
,
the
universe
cooled
to
____________________
,
____________________
.
____________________
and
____________________
began
to
form
.
1
billion
years
after
the
Big
Bang
,
hydrogen
and
helium
clouds
began
to
collapse
onto
themselves
,
creating
____________________
and
the
universe's
first
____________________
.
10
billion
years
after
the
Big
Bang
,
stars
began
to
____________________
,
spilling
____________________
elements
into
space
.
These
elements
formed
____________________
systems
.
The
universe
cooled
to
-
270°c
.
