Earth Science: The Universe and Solar System, Earth Systems

The Universe

- comprises all space and time, and all matter & energy in it
- made up of 4.6% baryonic matter, 24% cold matter, and 71.4% dark energy
- it is 13.8 billion years old

Hydrogen, helium and Lithium

The three most abundant elements in the universe

Baryonic Matter
? 4.6%

- “ordinary” matter consisting of protons, electrons and neutrons that comprises atoms, planets, stars, galaxies and other bodies
- How much of it is in the universe?

Dark Matter
? 24%

- matter that has gravity but does not emit light
- How much of it is in the universe?

Dark Energy
? 71.4%

- a source of anti-gravity; a force that counteracts gravity and causes the universe to expand
- How much of it is in the universe?

The Steady State Model

- proposed in 1948 by Bondi and Gould and by Hoyle
- pertains that new matter is created as the universe expands thereby maintaining its density
- implies that universe have NO BEGINNING and END

The Big Bang Theory

- states that one time, the entire universe was confined to a dense, hot, supermassive ball. Then, about 13.8 billion years ago, a violent EXPLOSION occurred, hurling this material in all directions

1. General Relativity
2. Cosmological principle

• what are the 2 ideas the Big Bang Theory rests on?
(1) Gravity is a distortion of space and time
(2) Assumes that the universe is homogeneous and isotropic; means every observer SHOULD see the universe with the same physical properties wherever you like and the same structure whatever direction you see it

1. Redshift
2. Abundance of hydrogen, helium & lithium
3. uniformly pervasive cosmic microwave background radiation

• The tests for expansion the Big Bang Theory has withstood

Redshift

- the shifting of absorption lines from the light spectrum towards larger wavelength(red light)
- happens when a light source is moving away(receding) towards the observer
- discovered by Edwin Hubble when he noticed that most galaxies have spectral shifts toward the red end of the spectrum

Hubble’s Law

- states that galaxies recede at speeds proportional to their distances from the observer

Cosmic Microwave Background

- a faint glow of light that fills the universe, falling on Earth from every direction with nearly uniform intensity
- can be observed as a striking uniform glow in the microwave band coming from all directions-blackbody radiation with an average temp of about 2.7 degrees above absolute zero

1. Decelerating universes
2. Coasting universe
3. Accelerating universe

• The three possible fate of Expanding Universe

Stars

- formed when gravity cause matter to accumulate into large “clumps” and “strands” of interstellar matter known as NEBULAE
- first developed approximately after 400,000 millions years after the Big Bang

All stars, regardless of their size, run out of fuel and collapse due to gravity

• How do stars die?

Hertzprung-Rusell Diagram

- a graphical representation of the relationship between the true brightness(absolute magnitude) of stars and their respective temperatures

H-R Diagram and Stellar Evolution

- useful for illustrating the changes that take place in an individual star during its life span

Galaxies

- collections of interstellar matter, stars and stellar remnants that are gravitationally bound
- the first of them were small and composed mainly of massive stars and abundant interstellar matter
- have 3 basic types

Spiral Galaxies

- flat, disk-shaped objects that range from 20,000 to about 125,000 light-years in diameter
- have a greater concentration of stars near their centers, but there are numerous variations
- makes up 30% of the universe

Milky Way

- a large SPIRAL GALAXY whose disk is about 100,000 light years wide and about 10,000 light years thick at the nucleus
- has at least 3 distinct spiral arms, with some splintering
- part of the so called Local Group of Galaxies, which in turn is part of the Virgo supercluster of galaxies

Barred Spiral Galaxy
• Andromeda Galaxy

• what kind of spiral galaxy is this?
• give an example

Elliptical Galaxy
• Cygnus A

- have an ellipsoidal shape that can be nearly spherical and they LACK SPIRAL ARMS
- some of the largest and smallest galaxies are classified as this
- makes up 60% of the universe
• give an example

Irregular Galaxy
• Small & Large Magellanic Clouds

- have no symmetry
- some were once spiral or elliptical galaxies that were subsequently distorted by the gravity of a large neighbor
• give an example

Galactic Clusters
• Fornax Galaxy Cluster

- galaxies that are grouped intro gravitationally bound clusters
• give an example

Galactic Collisions

- interactions between galaxies, often driven by one GALAXY’S GRAVITY disturbing another
- common within galactic cluster

Solar System

- located in the Milky Way galaxy
- comprises the Sun, eight planets, dwarf planets suck as Pluto, satellites, asteroids, comets, other minor bodies suck as those in the Kuiper belt and interplanetary dust

• Orbits of the planets are ELLIPTICAL and are on the same plane
• the periods of revolution of the planets increase with increasing distance from the Sun

• the solar system in Macroscale

• Most planets rotate prograde(west to east)
• Planets fall into 2 groups based on location size and density; terrestrial and Jovian

• the solar system in Microscale

Terrestrial Planets
• Mercury, Venus, Earth, Mars

- a planet that is composed primarily of silicate rocks or metals,
• give the 4 examples in the Solar System

Jovian Planets
• Jupiter, Saturn, Uranus, Neptune

- massive gaseous planets(gas giants) that extent far from the sun
- planets that do not have solid surfaces, have many moons and rings
• give the 4 examples in the Solar System

Nebular Hypothesis

- hypothesis for the origin of the Solar System
- thought of rotating gaseous cloud that cools and contracts in the middles to form the Sun and the rest into a disc
- in this theory, the whole Solar System starts as a large cloud of gas that contracts under self gravity

Encounter Hypothesis

- hypothesis for the origin of the Solar System
- a “near miss” encounter occurs between the Sun and a passing star. Material is pulled from the stellar surfaces by tidal forces then cools and condenses to form planetary bodies
• Problems: (1)hot gas expands not contracts and would not form planets. (2) encounter between stars are extremely rare

Protoplanet Hypothesis

- hypothesis for the origin of the Solar System
- incorporates many of the components of the nebular hypothesis, but adds some new aspects from modern knowledge of fluids ands states of matter
- In the Orion arm of the Milky Way galaxy, a slowly-rotating gas and dust cloud dominated by hydrogen and helium starts to contract due to gravity
- as most of the mass move to the center to eventually become a proto-Sun, the remaining materials form a disc that will eventually become the planets and momentum is transferred outwards

Temperature
• -15ºC to 115ºC

• factors that make a planet habitable
- influences how quickly atoms and molecules move
• acceptable range in Celsius where liquid water can still exist under certain conditions

Atmosphere
• 100 miles thick

• factors that make a planet habitable
- keep the surface warm & protects it from radiation and small to medium sized meteorites
• acceptable thickness in miles

Energy

• factors that make a planet habitable
- can either be light or chemical
- with it, cells can run the chemical reactions necessary for life

Nutrients

• factors that make a planet habitable
- used to build and maintain an organism’s body

Energy from the sun

• factor on Earth that Sustains Life; Energy
- drives EXTERNAL PROCESSES such as weather, ocean, circulation and erosional processes, PHOTOSYNTHESIS

Energy from the Earth’s interior

• factor on Earth that Sustains Life; Energy
- drives INTERNAL PROCESSES including volcanoes, earthquakes and mountain building

Water

• factor on Earth that Sustains Life
- one of the most important prerequisites of life4
- important part in regulating temperature, chemical reactions to matter, to aquatic habitat

Gases

• factor on Earth that Sustains Life
- makes up the atmosphere; greenhouse gases helps maintain the heat on Earth
- essential to photosynthesis and other biochemical reactions

Resources

• factor on Earth that Sustains Life
- include water, soil, minerals and energy
- have 2 broad categories: renewable and nonrenewable

• In the ‘Habitable Zone” where you have just the right distance away from a star like the Sun
• Made of Rocks
• Big enough to have a molten core
• Have a protective atmosphere

• Characteristics of a Habitable Planet

System

- any size group of interacting parts that form a unified and complex whole

Open System

• type of system
- allows energy and matter to flow in and out of the system

Closed System

• type of system
- allows energy to flow in and out of the system while matter cannot

Atmosphere
• through atmospheric circulation

• Earth’s Subsystem
- the thin gaseous layer that envelopes the Earth
- composed of 78% nitrogen(N), 21% oxygen(O), 0.9% argon(Ar), and trace number of other gases
- along with hydrosphere, where the exchange of heat and moisture occur
• How is the heat of Earth’s surface redistributed

Geosphere

• Earth’s Subsystem
- associated with solid portion of the Earth
- includes the rocks of the crust and mantle, metallic liquid outer core and the solid metallic inner core
- the physical structure of the surface of the Earth is shaped through process of plate tectonics[a process for this subsystem]

Hydrosphere
• through ocean circulation

• Earth’s Subsystem
- the total amount of water on a planet; including water on the Earth’s surface, underground and in the air
• How is heat reabsorbed and redistributed on the surface of the Earth?

Hypsographic Curve

- a graphical representation of the proportion of land at various elevations(meters above or below sea level)

Biosphere

• Earth’s Subsystem
- areas or regions of the Earth that possess life; comprised of living organisms and nonliving factors from which organisms derive energy and nutrients
- the set of all life forms on Earth
- covers all ecosystems