ESCI 1001 Midterm (Lecture 1-2)

What is cosmology?

The study of the universe; origin, evolution, nature of the universe

What is a solar system?

A sun, planets, moons, and other objects

What is the Milky Way?

The galaxy in which Earth resides

What is stellar nucleosynthesis?

Elements H, O, C, N, Ca, P, K, S and all other elements from Be towards Fe are created by fusion reactions in stars

What is the nebular theory?

Elements are being produced, stars are being born and dying, we now have 'matter' in the universe

What is a protoplanetary disk?

The region on the outside of an accretion disk

What are planetesimals?

A body that could or did come together with many others under gravitation to form a planet - Bodies that exceed ~1 km in size

What is accretion?

The process of which a planetesimal, or planet is formed; coming together and cohesion of matter under the influence of gravitation

What are protoplanets?

Large bodies of matter in orbit around the sun and thought to be developing into a planet

What is differentiation?

The process by which planets begin to melt and materials in them begin to separate from one another

What is Helios?

Greek term for the sun

What is Kentrikos?

Greek term for the center

What is Logia?

Greek term for the study of [___]

What is Kosmos?

Greek term for the world or universe as a structured system

Who is Claudius Ptolemy?

Egyptian mathematician who proved that the Earth was at the center of the universe; 'I am the center of the Universe'

Who is Nicolaus Copernicus?

Polish astronomer/mathematician who proposed the heliocentric theory ~ 1514-1543 CE; explained that the heliocentric view could easily explain the motion of celestial bodies than the geocentric view

Galileo Galili

Italian astronomer/mathematician who believed in the heliocentric theory. He surveyed the heavens as an Italian astronomer and mathematician.

Johannes Kepler

German astronomer/mathematician who developed Kepler's First Law

Isaac Newton

English astronomer/mathematician who explained gravity

Law of Universal Gravitation

Every object attracts every other object with a force proportional to their masses

Via Lactea

Latin term for Milky Way

Terrestrial

Small, dense, and rocky planets

Jovian

Large, low density, and gaseous planets

Cosmology

The study of the origin, evolution, and nature of the universe

Geocentric

The theory that the Earth is at the center of the universe

Heliocentric

The theory that the Sun is at the center of the universe

Middle Ages

The period from ~476-1400 CE

What did Copernicus believe about the motion of celestial bodies?

The heliocentric view could more easily explain their motion.

What is unique about Mercury and Venus?

They have phases similar to the Moon.

What orbits Jupiter?

Moons.

What is unique about moons?

They have unique features.

According to Kepler's first law, what is one focus of the elliptical path followed by each planet?

The Sun.

What did Newton observe that led him to explain gravity?

An apple falling from a tree and the Moon's orbit around the Earth.

What governs natural events in predictable ways?

Natural laws, such as gravity.

What is the generally-accepted paradigm?

Heliocentricity.

How many planets are in our solar system?

7.

What is a planet?

A large body orbiting a star, with a nearly spherical shape, and has cleared its neighborhood of other objects.

What is a moon?

A sizeable body locked in orbit around a planet.

What are the two types of planets?

Terrestrial (small, dense, rocky) and Jovian (large, low density, gaseous).

What are stars?

Balls of incandescent gas

What produces heat and light in stars?

Nuclear reactions (fusion)

What holds stars together in groups?

Gravity

What is our solar system on?

An arm of the Milky Way Galaxy

How many stars are there in the Milky Way?

Approximately 300 billion

What is our nearest neighbor galaxy?

Andromeda (aka Andromeda Nebula)

How far away is Andromeda galaxy?

2.2 million light years

How far away is the moon from Earth?

1.3 light seconds

How far away is the Sun from Earth?

8.3 light minutes

How many galaxies are there in the Universe?

More than 100 billion (probably closer to 2 trillion)

What is the Doppler Effect?

The change in frequency or wavelength of a wave due to the motion of the source or observer

What are two important characteristics of waves?

Wavelength and frequency

How does sound move?

In waves

What happens to sound waves as an object moves towards you?

They compress

What happens to sound waves as an object moves away from you?

They are uncompressed (unless you're moving faster than the speed of sound)

How does light energy move?

In waves

What color of light has a longer frequency?

Red light

What happens to light waves as they move towards you?

They compress (blue) or expand (red) depending on whether the light is moving towards you or away from you, assuming that you're stationary

What is the Red Shift?

The Doppler shifted light observed from a moving star

What happens to approaching starlight? In other words, what shift is it when an object moves towards you?

It is compressed (blue shift)

What happens to receding starlight?

It is expanded (red)

What did Edwin Hubble recognize in 1929?

That light from galaxies is red shifted

What is the Expanding Universe Theory?

All galaxies are moving away from ours, and galaxies further away are moving away more quickly

What is the Big Bang?

The explosion of a single point that originated everything in the Universe

What is the second line of evidence for the Big Bang?

Background Radiation

What is the temperature of absolute zero?

-273 degrees C (0 K)

What is the actual temperature of the Universe?

-270.3 degrees C (2.7 K)

What is the state of matter during the very first instant of the universe?

Only energy

What happens during the few minutes after the very first instant?

Formation of protons and neutrons

When are electrons formed?

By 0.01 s

What happens after 3 minutes?

Temperature decreases from 10^32 K to 10^9 K, Hydrogen atoms fuse to form light elements (H, He, Li)

What can protons and neutrons collide to produce?

Deuterium (^2H)

What can deuterium collide with to produce helium, tritium, and lithium?

Protons and neutrons

When does the temperature of the Universe become too cool for nuclear fusion?

After 20 minutes

What happens to the Universe over time?

It expands, cools, and decreases in density

What is the process of creating elements through fusion reactions in stars called?

Stellar Nucleosynthesis

What percentage of our body weight is made up of H, O, and C?

Approximately 90%

What are some of the other elements that make up about 9% of our body weight?

N, Ca, P, K, S

How are elements up to Fe created?

Through fusion reactions in stars

What is the process of matter accumulation in areas after the Big Bang called?

Star formation

What happens within a nebula during star formation?

Clumps of matter attract more matter and produce hot balls of glowing gas

What happens when temperatures and pressures become great enough within a nebula?

Nuclear fusion occurs (H forms He)

What is the byproduct of fusion in stars?

Energy (temperature) and luminosity (brightness)

What happens when a star runs out of H?

It may use He to form C

What determines the elements that can be produced by fusion in stars?

The mass of the star (larger stars can produce heavier elements)

What process produces elements heavier than Fe?

Supernovae nucleosynthesis

What happens when a high mass star runs out of fusion fuel?

Core collapses, outer regions collapse inwards, creating outward moving wave of atoms

What happens to neutrons in the star's core?

Shot outwards, collide with existing atoms, build up larger atoms

What causes the nebula to spin around a newly formed star?

Heterogenous distribution of matter

What happens to lighter gases in the protoplanetary disk?

Carried by solar wind to outer regions

What happens to heavier elements in the protoplanetary disk?

Stay closer to the star

What is the protoplanetary disk made of?

H and He from the Big Bang, heavier elements from stellar nucleosynthesis

What happens as the protoplanetary disk gets denser, hotter, and starts to spin?

A sun is born at the center through nuclear fusion

What process forms planetesimals?

Accretion

How do protoplanets form?

Planetesimals grow at the expense of each other

When does a protoplanet become a planet?

Once it incorporates debris within its orbit

What types of planets are formed in the inner orbits of the protoplanetary disk?

Small terrestrial planets composed of rock and metal

What types of planets are formed in the outer orbits of the protoplanetary disk?

Larger protoplanets that evolve into gas-giant planets

How old are meteorites thought to be leftover planetesimals?

4.57 billion years old

What happens to the interior of a growing protoplanet?

Becomes hot and soft

What shapes a protoplanet (and planet) into a sphere?

Gravity