Explanation:
1 billion years after the big bang, the temperature is 20K and some stars and galaxies began to contract due to the gravitational contraction of the over densities of the previous universe. At about 10 billion years after the big bang, our earth and sun form
Is there a multiple choice?
Well, I think it kinda depends on how long the "extended period" is.
If the extended period is a week, a month, or a few months,
then I'd call it a 'cold wave'.
If the extended period is like 100 years or more, then you're
starting to talk 'ice age'.
Pull and motion effects :)