History of Universe & Solar System

Question 1

3 ideas important in framing universal context:

Answer 1

1. Universe is vast & old
2. Elements of life are widespread
3. Same physical laws that operate on Earth operate throughout universe

Question 2

Primary lesson of Copernican revolution?

Answer 2

We are not the center of the universe.

Question 3

Definition of galaxy?

Answer 3

Great island of stars in space, all held together by gravity and orbiting a common centor.

Question 4

Local gropu?

Answer 4

Groups of galaxies. Our local gropu is lcoated in the outskirts of the Local Supercluster, called Laniakea

Question 5

Superclusters?

Answer 5

The regions in which galaxies & galaxy clusters are most tightly packed.

Question 6

Universe?

Answer 6

Sum of all matter and energy.

Question 7

What key points doe sthe voyage model teach us?

Answer 7

• Sun is larger than any of planets
• Planets vary a lot in size
• Emptiness in our solar system

Question 8

Star?

Answer 8

Large glowing ball of gas that generates heat and light through nuclear fusion in its core.

Question 9

When can an object be considered a planet?

Answer 9

• It orbits a star
• It is large enough for its own gravity to make it round
• Has cleared most objects from its orbital path.

Question 10

What is 1 light year?

Answer 10

9.46 trillion kilometers.

Question 11

How do you calculate how fast something can travel / what distance?

Answer 11

Distance = speed x time

Question 12

Nearest star system?

Answer 12

Alpha Centauri

Question 13

What two types of evidence are there for the big bang?

Answer 13

1. Universe must have been hotter and denser when it was smaller, with high temperature and density. As it cooled down it left a faint glow of radiation called cosmic microwave background which is detected and studied.
2. Calculations that run backward allows scientists to predict when chemical elements should have been born. First soup contained 3/4 hydrogen and 1/4 helium.

Question 14

How is a star born?

Answer 14

Gravity compresses material dense enough to generate energy by nucleaur fusion.

Question 15

What is nucleur fusion?

Answer 15

A process in which lightweight atomic nuclei smash together and stick/fuse together to make much heavier nuclei.

Question 16

How are planets/is a galaxy born?

Answer 16

Planets may be born at the same time as stars. The natural spin of an interstellar cloud keeps some of its gas spread away from its center while shaping it into a flattened disk.

Question 17

What happens after a star is born?

Answer 17

It shines with energy. During most of it’s life nucleur fusion combines hydrogen nuclei to make helium nuclei (4 hydrogen for 1 helium because helium nucleus has slightly less mass). A small amount of energy has disappeared and becomes energy in accordance with E = mc^2.

Question 18

How does a star die?

Answer 18

It lives until it has burned through all fuel. When everything has been exhausted, a star blows much of its content back into space. Massive stars die in huge explosions called supernovas. Returned matter become part of new clouds of gas and dust from which new stars can be born.

Question 19

What are 4 features of our solar system?

Answer 19

1. Patterns of motion
2. Two types of planets
3. Asteroids & Comets
4. Exceptions to the trend.

Question 20

Two types of planets?

Answer 20

Terrestrial & Jovian.

Question 21

What are asteroids?

Answer 21

Chunks of rock & metal that orbit the Sun in much smaller size than planets.

Question 22

Comets?

Answer 22

Like asteroids but contain large amounts of ice and are found much further than the Sun.

Question 23

Two places where comets come from in our solar system?

Answer 23

Kuiper belt; donut shaped region beyond Neptune
Oord cloud; spherical region that extends to thens of thousands of times Earth’s distance from the Sun.

Question 24

What type of patterns of motion are there?

Answer 24

• All planets orbit the Sun in nearly same plane and same direction.
• All have nearly circular orbits

Question 25

What are exceptions to the trends?

Answer 25

• Uranus rotates nearly on its side
• Venus rotates backwards
• Many small moons have backward or inclined orbits

Question 26

What is the Nebular theory?

Answer 26

A scientific theory for formation of solar system.

Question 27

What is the solar nebula?

Answer 27

A cloud that gave birth to our own solar system about 4,5bln years ago.

Question 28

3 processes that altered solar nebula’s density, temperature & shape - so that it changed from a large spread-out cloud to much smallr spinning disk?

Answer 28

1. Heating
2. Spinning
3. Flattening

Question 29

How did heating influence solar nebula?

Answer 29

The temperature increased as it collapsed, and the gravitational potential energy was converted to kinetic energy of individual gas particles falling inward - these crashed into each other, converting it to thermal energy.

Question 30

How did spinning altered solar nebula?

Answer 30

Conservation of angular momentum: the total amount of circling motion of an object must be conserved. The solar nebula rotated faster and faster as its own gravity made it shrink in radius.

Question 31

How did flattening alter solar nebula?

Answer 31

The collisions between particles in a spinning cloud flattened the solar nebula into a disk. Different clumps collide and merge as the cloud collapses, keeping average of motion, which tends to force all particles in a flattened, spining disk.

Question 32

What are seeds in planet formation?

Answer 32

Solid bits of matter around which gravity could build planets.

Question 33

Condensation?

Answer 33

Process in which solid or liquid particles form in a gas.

Question 34

What are materials in solar nebula?

Answer 34

Hydrogen& helium gas (98%)
Hydrogen compounds (1.4%)
Rock (0.4%)
Metals (0.2%)

Question 35

What is the Frost line in our solar system?

Answer 35

Location from Sun (2.7AU) where water ice can only condense.

Question 36

Acretion?

Answer 36

General process by which particles stick together and grow larger.

Question 37

What are planetismals?

Answer 37

Growing objects.

Question 38

Close encounter model?

Answer 38

Planets formed from blobs of gas that had been gravitationally pulled out of the Sun during the near-collision.

Question 39

Fall & Rise of Nebular model?

Answer 39

Early 20th century: scientists found aspects of solar system that model did not seem to eplain.
Mid-20th century: calculations show close encounter model could not account for a few things (orbital motion of planets & neat division of planets into two categories).
Modifications were made to nebular theory.
Nebular theory gained acceptance.

Question 40

Questions that competed nebular theory?

Answer 40

Discoveries of hot Jupiter-type gian textrasolar planets - but planetary migration has been invoked as a mechanism that explains.

Question 41

Who proposed Nebular theory?

Answer 41

Kant.

Question 42

Evidence for nebular theory?

Answer 42

• High resolution images of new stars being born out of gasses contracting gravity
• High res images of disks spinning bc of nebular theory
• Actual detection of planets around other stars.