Astronomy Noteform 4 - 5: The Expanding Universe (Big Bang!)
Name: ___________________________________________ Section: _______
Directions: Read pages 148 – 152. Fill in the blanks with the correct word or phrase.
1. ______________________________________________ is the most distant
object that the human eye can see. It is 3 million light-years away from Earth.
Light from this galaxy has traveled for about 3 million years through space before
reaching Earth. When that light finally reaches your eye, you are seeing how the galaxy
looked _______________ million years ago!!!
2. What is the name of the explosive event that started our Universe’s expansion?
3. As the universe expanded, it gradually _________________________________.
4. After a few hundred thousand years, ____________________________ formed.
5. The American astronomer, Edwin Hubble, discovered that with the exception of a
few nearby galaxies, all galaxies are moving:
________________________ from us and each other.
6. ________________________________ Law states that the farther away a galaxy
is, the faster it is moving away from us.
7. See Figure 22. IF the universe if like the bread dough, then the raisins in the
dough are like:
8. In 1965, two American physicists, Arno Penzial and Robert Wilson, accidentally
detected faint radiation on their radio telescope. The mysterious glow was coming from
all directions in space. This glow is the leftover thermal (heat) energy from the Big
Bang. It is called: ______________________________________________________
9. Astronomers estimate the the universe is about ______________ billion years old.
10. After the Big Bang, matter in the universe separated into galaxies. Gas and dust
spread throughout space. A giant cloud of gas and dust collapsed to form our Solar
System about ____________________ billion years ago.
11. What do you call the early building blocks of planets, which collided and grew
larger by sticking together, eventually combining to form planets?
12. The ______________________________ planets had high temperatures, so most
water and gases evaporated, leaving behind relatively small and rocky planets.
13. The cooler ______________________________ planets grew larger due to
gravity and captured hydrogen and helium gases that now surround them in space.
14. New observations lead many astronomers to conclude that the universe will
likely expand: __________________________________.
15. __________________________________________ was the astronomer who
discovered “dark matter.” Dark matter does not give off electromagnetic radiation.
BONUS: What percentage of the universe’s mass is made of dark matter? _____%