1. Astronomers

2. Reflecting Telescope

3. Reflecting Telescope: uses a single or
combination of curved mirrors that reflect 
light and form an image.

4. Percival
Lowell

5. Percival Lowell: built his observatory in
Flagstaff because of its –
High altitude
Lack of cloudy
weather
Distance away
from city lights

6. Percival Lowell: very
interested in Mars and
its geographic landforms

7. He was determined to
prove that what
appeared to be canals
were not naturally
formed

8. His theory died in the 1960’s
with the Mars mariner
missions
Found surface markings to
be optical illusions

9. Discovery of:

10. Lowell spent the last 10 years of his life
observing the orbits of Uranus and Neptune

11. He predicted that Neptune and Uranus’ orbit
were displaced due the gravitational pull of
Planet X’s orbit

12. About 15 years after Lowell’s death Pluto was
discovered by an astronomer at Lowell’s
observatory

14. Edwin
Hubble

15. Hubble was the first to discover that the
universe stretches beyond the Milky Way
Galaxy

16. He found some stars to be much to far to
be a part of the Milky Way
These stars were thought to be located in
various Nebulas within the Milky Way

17. Nebula: is an interstellar cloud of dust, 
hydrogen, helium and other ionized gases

20. His work in astrophysics went a long way
in helping contribute to a support the
Big Bang Theory: the idea that the
universe is expanding

21. Hubble’s 2 HUGE contributions:
There are other galaxies out there
Made observations that supported the
Big Bang Theory

22. What do Copernicus, Galileo, Lowell and
Hubble have in common?