Our Planet and Solar System
description
Transcript of Our Planet and Solar System
![Page 1: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/1.jpg)
Our Planet and Solar System
![Page 2: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/2.jpg)
Ancient and Pre-Modern Theories of the Universe/Solar System
• Aristotle’s theory of four elements• Astronomy and Astrology exist• But Heavens are considered to be a separate
realm from earthly objects
![Page 3: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/3.jpg)
![Page 4: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/4.jpg)
![Page 5: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/5.jpg)
Geocentric vs. Heliocentric Models
• Geocentric Model– Places Earth at the center of the universe– Objects in Heavens (planets, Sun, stars) are
fixed crystalline “spheres,” nested around Earth– Big achievement: it explained the motion of the
Sun, moon, planets, and stars.• Established c. 500 B.C.
![Page 6: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/6.jpg)
![Page 7: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/7.jpg)
– Based on:• Observations• Belief that the heavens must be geometrically
“perfect.”
– Ptolemy c. A.D. 100-170• Combined others’ work to create a quantitative
model• Used circles within circles• Was fairly accurate for the time
![Page 8: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/8.jpg)
Problems with Geocentrism
• Circles within circles inelegant (or imperfect)
• Didn’t explain phases of the moon• These problems not considered big enough
to push alternative theory
![Page 9: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/9.jpg)
Nicholas Copernicus (1473-1543)
• Used a heliocentric model of the solar system• Proposed by a Greek
astronomer Aristarchus in 260 B.C.
• Copernicus applied math to the data (which wasn’t all that good)
• Even though more correct, still assumed perfect circles
• predictions weren’t much better than the geocentric model.
![Page 10: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/10.jpg)
Tycho Brahe (1546-1601)• Took really good data
and tons of it.
![Page 11: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/11.jpg)
Tycho Brahe (1546-1601)
• Was funded by the king of Denmark and then the
German emperor.• Had an island observing station• Died without knowing whether
he had made any breakthroughs.
![Page 12: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/12.jpg)
• Brahe was convinced other planets orbited the Sun, but concluded (b/c he couldn’t detect stellar parallax) that Earth must remain stationary.
![Page 13: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/13.jpg)
Johannes Kepler (1571-1630)
• Worked for Tycho• Approached the data
mathematically, assuming circular orbits.
• After 8 years, found a mathematical model for a circular orbit of Mars that almost matched Tycho’s observations. There was a difference of 8 minutes of arc.
![Page 14: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/14.jpg)
His “aha” moment:
“If I had believed that we could ignore these eight minutes [of arc], I would have patched up my hypothesis accordingly. But, since it was not permissible to ignore, those eight minutes pointed the road to a complete reformation in astronomy.”• This decision to trust the data over his
preconceived beliefs marked an important transition point in the history of science.
![Page 15: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/15.jpg)
• Kepler discovered that the planets did not orbit in circles, but rather ellipses.
• Even through Kepler’s model made much better predictions, many scientists still believed in the geocentric model.– Earth couldn’t be moving, otherwise birds and
thrown rocks would be left behind.– Non-circular orbits meant heavens weren’t
perfect
![Page 16: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/16.jpg)
Galileo Galilei (1564-1642)• Demonstrated Newton’s 1st law
before Newton was even born (in 1642…)
• Firm believer in scientific inquiry– Remember our pendulum experiment?
![Page 17: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/17.jpg)
Galileo Galilei (1564-1642)
• Demonstrated Newton’s 1st law before Newton was even born (in 1642…)
• Saw sunspots on the sun – so now the Sun isn’t perfect
• Saw topography (mountains) on the moon– So the Moon isn’t perfect either
• Discovered that Jupiter has moons that orbit it– Clearly don’t revolve around the Earth
• Aristotle’s doctrines considered part of Catholic Church doctrine.
• Galileo persecuted by church for publishing his results late in life
![Page 18: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/18.jpg)
![Page 19: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/19.jpg)
The imperfections just pile up. . .
![Page 20: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/20.jpg)
Phases of the Moon
![Page 21: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/21.jpg)
Retrograde Motion – Planets switch directions in their paths in the sky
![Page 22: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/22.jpg)
![Page 23: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/23.jpg)
![Page 24: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/24.jpg)
Phases of the Moon• Key ideas– ½ the Moon is always lit.– The Moon reflects the Sun’s light.– We aren’t seeing different sides of the Moon,
what is changing is what is lit.• There is no one “dark side of the Moon.”
– Period of about 27 days.– Phases are due to Moons orbit around the Earth– Moon rises and sets due to the rotation of the
Earth.
![Page 25: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/25.jpg)
Eclipses• Two types– Lunar eclipse• Earth is directly between the
Sun and Moon– Earth’s shadow falls on the
Moon
• Can only be seen at night
– Solar eclipse• Moon is directly between Sun
and Earth– Moon’s shadow falls on the
Earth
• Can only be seen during the day
![Page 26: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/26.jpg)
![Page 27: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/27.jpg)
![Page 28: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/28.jpg)
![Page 29: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/29.jpg)
![Page 30: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/30.jpg)
Seasons
![Page 31: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/31.jpg)
Our Solar System
• What was evidence for Geocentrism?
• What was evidence for Heliocentrism?
![Page 32: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/32.jpg)
Comets and Minor Planets
![Page 33: Our Planet and Solar System](https://reader035.fdocuments.in/reader035/viewer/2022062411/5681668a550346895dda4883/html5/thumbnails/33.jpg)
Extra-solar Planets