Unit 7: Discoveries About Our Solar System

What was the identity of the person that built the largest telescope of the 18th century?

William Herschel

What was the identity of William Herschel’s assistant, and the 1st paid European female scientist?

Caroline Herschel

What was William Herschel’s career background?

music

What were William Herschel’s reasons for building massive telescopes?

• large primary mirror = more light collection

• long tube = large image

• stellar parallax search

What is the identity of the 1st person to discover a planet, in 1781?

William Herschel

What were the reasons for finding stellar parallax?

• prove Earth moves

• calculate star distance

True or False: William Herschel detected stellar parallax.

False: William Herschel did not detect stellar parallax.

What happened to William Herschel after the discovery of Uranus?

composer → King George III private astronomer

What was William Herschel’s method of discovering Uranus?

• non-point star

• moved across sky over a week

True or False: Galileo Galilei saw Neptune, though he didn’t know it was a planet.

True.

What was the identity of the King’s Astronomer Royal that confirmed Herschel’s report?

Nevil Maskelyne

What was concluded about Uranus in 1783?

nearly circular orbit → another planet

What is Saturn’s orbital period?

84 years

True or False: Uranus is over 2x further away than Saturn.

True.

What was William Herschel’s suggestion for Uranus’ name?

George’s Star

What were the word origins of “Uranus?”

• Greek sky god

  • Saturn’s father

  • Jupiter’s grandfather

What is the identity of the Greek earth god?

Gaia

What is Uranus’ mythology?

• ruled universe with 12 Titans

• Jupiter formed 12 Olympians

• Olympians overthrew Titans

What did the Herschels discover in conjunction with Uranus?

• Titania

  • brightest moon

• Oberon

  • 2nd brightest moon

What were the word origins of Uranus’ moons?

• William Shakespeare

• Alexander Pope

What were the word origins of Jupiter’s & Saturn’s moons?

• Greek & Roman mythology

What are some examples of Uranus’ larger moons?

• Puck

• Miranda

• Ariel

• Umbriel

What did NASA do in the 1980s?

sent Voyager II to outer Solar System

What is the largest moon compared to its planet?

Earth’s Moon

What is Uranus’ mass in M_Earth?

15 M_Earth

What is Jupiter’s mass in M_Earth?

300 M_Earth

What is Saturn’s mass in M_Earth?

100 M_Earth

What was the method of estimating Uranus’ mass?

• determine Titania’s orbital period

  • by Uranus’ gravity

    • by Uranus’ mass

What was the method of estimating Uranus’ physical size?

• angular size

• distance

  • by Kepler’s 3rd Law

True or False: Uranus is about 2x-3x wider than Earth.

False: Uranus is about 4x-5x wider than Earth.

What were the Herschels’ reason for classifying Uranus as a gas giant?

• low density

  • by mass

True or False: People are sure about the gas giants’ core materials.

False: People are not sure about the gas giants’ core materials, but they’re probably made of rock & ice.

What surrounds Jupiter's & Saturn’s cores?

metallic hydrogen → molecular hydrogen

What surrounds Uranus' core?

frozen hydrogen & water & ammonia & methane mantle → hydrogen & helium & methane

What was discovered about Uranus in the late 1970s?

rings

What was the method of discovering Uranus’ rings?

• waited to occult star

• star unexpectedly dimmed

What was the Cassini spacecraft’s significance?

• launched in 1997

• flew to Saturn in 7 years

• orbited for 13 years

What material mostly comprises Saturn’s rings?

ice

What are the possibilities for Saturn’s ice in its rings?

• ice formed while Saturn formed at Solar System beginning

• icy moon tore apart by gravity through tidal stress

What material mostly comprises Jupiter’s rings?

rocks

True or False: Uranus orbits the Sun upright.

False: Uranus orbits the Sun on side, on an approximate 97.8° axial tilt.

What is a possibility for Uranus’ axial tilt?

past collision

What is Mercury’s approximate axial tilt?

0°

What is Venus’ approximate axial tilt?

177.3°

What is Mars’ approximate axial tilt?

25.2°

What is Jupiter’s approximate axial tilt?

3.1°

What is Saturn’s approximate axial tilt?

26.7°

What will happen to Uranus in 2028?

Northern winter solstice

What will happen to Uranus in 2049?

vernal equinox

What will happen to Uranus in 2070?

Northern summer solstice

What happened to Uranus in 2007?

autumnal equinox

What mystery gained attention in the early 1770s?

Mars ↔ Jupiter gap

What did Bode’s Law predict?

undiscovered Mars ↔ Jupiter planet

What is Mercury’s orbital radius?

0.39 au

What is Venus’ orbital radius?

0.72 au

What is Earth’s’ orbital radius?

1 au

What is Mars’ orbital radius?

1.5 au

What is Jupiter’s orbital radius?

5.2 au

What is Saturn’s orbital radius?

9.54 au

What is the identity of the German that wrote about the mystery in the early 1770s?

Johann Bode

What is the Bode’s Law equation?

(4 + 3 × 2ⁿ) / 10

True or False: Bode was the first person to identify the Bode’s Law equation.

False: Bode was not the first person to identify the Bode’s Law equation; Bode became a popular person as a result of his astronomy textbook.

What did Bode’s Law prove about the mystery that gained attention in the early 1770s?

something representing 2.8 value between Mars & Jupiter

What is Uranus’ orbital radius?

19.2 au

What did European astronomers do as a result of Bode’s Law?

form Celestial Police

• planet hunting coalition

What was the identity of the Italian that detected a star-like object in a near-circular solar orbit between Mars & Jupiter in 1801?

Giuseppe Piazzi

What was the reason for Giuseppe Piazzi detecting a star-like object?

producing star catalogue

• looking for stellar parallax

What did Giuseppe Piazzi do to assure the star-like object was not a fixed star?

track for 3-4 days & 25-26 days

What is the name of the star-like object?

Ceres

What did Giuseppe Piazzi conclude?

star-like object has 2.7 au orbital radius

What did Giuseppe Piazzi write of his dicovery?

announced star-like object as comet

What is Ceres’ word origin?

Roman harvest god

What was the identity of the Sicilian that named the star-like object?

Giuseppe Piazzi

What was the reason for the name of the star-like object?

Sicily was large Roman Empire grain contributor

What was the reason for the star-like object’s short-lived planet status?

tiny

• star-like despite being close to Earth

What did William Herschel conclude about the star-like object?

size: Ceres < Moon

What was discovered after 1801’s star-like object?

several star-like objects between Mars & Jupiter

What term initially described the new star-like objects?

minor planet

What was the identity of the British that coined the new Solar System category?

William Herschel

What does “asteroid” mean?

star-like

What was discovered over the next century after 1801’s star-like object?

Asteroid Belt

What is the number of known asteroids in the Asteroid Belt?

> 1 000 000

What is the largest Asteroid Belt object?

Ceres

What is the 2nd largest Asteroid Belt object?

Vesta

What gives the largest Asteroid Belt object special status?

spherical

What did the Dawn spacecraft discover about Ceres?

2 bright spots

What makes up Ceres?

thick outer crust

• ice & salt & mineral

bright spot

• salt

intermediate layer

• briney liquid (saltwater)

core

• rock

What makes up asteroids?

rock & ice

What is the reason for Ceres’ bright spots?

saltwater spills on surface by cracks or volcanoes → water sublimates & salt deposits

What was discovered in the 1830s?

Uranus orbit deviates

What was the possible reason for the discovery in the 1830s?

undiscovered gravity source

What were the identities of the British & French mathematicians that used Newton’s equations to predict the gravity source?

British John Couch Adams

French Urbain Le Verrier

True or False: The British & French mathematicians attempted to predict the gravity source together.

False: John Couch Adams & Urbain Le Verrier did not attempt to predict the gravity source together.

What did John Couch Adams predict in 1845?

1. sent coordinates to England Astronomer Royal

2. asked to use Royal Greenwich Observatory telescope

What was the identity of the England Astronomer Royal that was sent John Couch Adams’ report?

George Airy

What was George Airy’s response to John Couch Adams’ report?

took a year to get to John Couch Adams’ report

What did Urbain Le Verrier publish in 1846?

gravity source prediction

What did Urbain Le Verrier write on September 18, 1846?

asked German Johann Galle to use Berlin Observatory telescope

What did Johann Galle conclude on September 23, 1846?

found celestial body in 30 minutes

What was Johann Galle’s response to his discovery on September 25, 1846?

confirmed Urbain Le Verrier’s instructions