Astronomy Unit 1 Test

What is red shifting

light is stretching/ going away

What does red shifting tell us about our universe?

tell how far away an object is from Earth

What energies make up our universe?

Normal matter(5), dark matter(60%), dark energies(27)

Blue shifting means

the object is coming towards us

What is dark energy

we don’t know yet

Universe is larger than a galaxy- true or false

true

First gases that existed after the big bang

nitrogen and helium 

The Milky way galaxy was made by other smaller galaxies merging together- true or false

true

Order from largest to smallest:

Universe, galaxy, solar system, star, planet, moon and asteroid.

What is the Big Bang?

The Big Bang was the sudden expansion of the universe from its once, single-compressed atom.

Is a galaxy close to the Milky Way moving away from us slowly or quickly?

Galaxies are moving away from us slowly.

What is the theory that explains the solar systems formation?

The Solar Nebula Theory.

Main events during solar systems formation

-started as a cloud of dust(AKA a nebula-mostly made of hydrogen and helium)

-supernova causes nebula to collapses on itself

-forms a flat spinning disk, heats up, and pulls more dust/gas into center

-materials clump together= form the protosun(held in place by gravity->pulls in more dust/gas and is flattened  by gravity)

-Planetesimals form out of chunks

-Planetesimals collide w/larger ones, inner & outer planets form

what is condensation?

The process of forming solid particles from the solar nebula(which is dust and interstellar gas).

Why did the spinning cloud of dust and gas speed up?

The nebula contracts because of its own gravity. As it contracts, it spins faster and faster. 

KNOWN as the conservation of angular momentum. 

What are planetesimals?

Baby/mini planets. Small, oddly shaped beginnings of our planets- formed out of chunks of rock inside swirling disk.

Why are the inner planets rocky and the outer planets gaseous?

Inner planets- Gravity on these planets is not strong enough to hold lighter elements, such as gas. Once the protosun gives off light, it produces solar winds that either boil away or blow away gasses towards the outer planets. 

Gravity of the protosun pulled in heavier elements.

What is the frost line?

Lies between Mars and Jupiter.

Is the area that was cold enough for hydrogen compounds to condense into ices. 

Draw a diagram showing what was condensing at different distances from the sun.

Sun -> Mercury -> Venus -> Earth -> Mars      -> Jupiter -> Saturn -> Uranus -> Neptune 

What event do scientists believe may have started our solar system? And what evidence do we have for it?

The impact/shockwaves of a supernova. Asteroids(meteorites) from the origin of our solar system can still be found on Earth. Some meteorites contain a special atom called nickel-60, and is known as the sister of iron-60, which can only be found in one place- a supernova.

What is the current accepted age of the Earth?

4.6 billion years old

How old did the church believe the Earth was?

6,000 years old or 4004 B.C.

who is considered the father of toxicology

James Hutton

What did Lord Kelvin suggest about Earth’s early history?

He thought that the earth had hardened from a once molten state. Thought that the Earth’s initial condition was uniformly high, and that it eventually cooled and reached a constant temperature on its surface.

Why were Kelvin’s age approximations for the Earth off?

He thought the Earth was between 20-400 millions years old. His estimation was off because he had not yet known about radioactive decay. Radioactive decay releases energy, and continuously adds heat and slows the cooling process of the Earth.

Where did most of the Earth’s water come from?

Asteroids.

 What provided most of Earth’s early oxygen?  Where can this be found today?

Cyanobacteria, which leaves behind a layered rock- called stromatolites. They can be found in a northern part of the Mexican desert, Cuatro ciénegas.

How long did it take for the Earth’s core to form?

1-1.5 billion years 

What are siderophile elements?  Lithophile elements?

Metal(iron= Fe) loving, partition(separate) into metallic liquids. Strongly enriched in the core but depleted in the silicate Earth. 

Rock-loving, partition into silicate phases, concentrated in the silicate phases of the Earth (crust and mantle). -concentrated in the minerals of the Earth's crust.

How did Earth’s different layers begin to form?

As it formed and cooled, the lighter parts (like crust) floated to the surface, and the really dense parts (like iron and nickel in the core) sank to the center.

How does Earth’s mantle still have iron in it?

Iron is a heavy element that sank into the center of the core.

It remains solid due to the pressure put on it.

What is the accepted theory of moon formation?  Explain it.

Giant-impact theory- This proposes that the Moon formed during a collision between the Earth and another small planet(about the size of the planet Mars). The debris from this impact collected in an orbit around Earth to form the Moon

What evidence do we have that indicates the moon came from the Earth?

The moon and Earth are isotopically identical= suggesting both formed from the same batch of material. Isotopic compositions are like fingerprints for planets - each one has a different isotopic fingerprint EXCEPT THE EARTH AND THE MOON. 

Identical ratio of oxygen.

Why does the moon have less iron than the Earth?

Scientists believe that this is evidence of the moon forming after core formation trapped most of the iron in the center of Earth. The material that coalesced into the Moon comes from the outer mantles of the colliding bodies, rather than from their iron-rich(dense) cores.

List the main elements that make up the layers:

a. crust-

the outermost layer of the earth.

98% made up of Silicon, Oxygen, Aluminum, Magnesium, Calcium, Sodium, Potassium, rare elements.  

List the main elements that make up the layers:

b. mantle-

the layer underneath the crust, made up of Silicon, Oxygen, Iron, Aluminum, Calcium. Magnesium oxide, olivine, garnet, and pyroxene.

List the main elements that make up the layers:

c. outer core-

d. inner core-

c. a layer of liquid iron and nickel 

d.the innermost layer of the earth, is a solid layer made of iron and nickel. 

What 3 pieces of evidence do we have that supports the composition of the core?

 Density and gravity, seismic-wave data, earth's magnetic field.

List the chemical layers of the Earth.

Inner core, Outer core, mantle, crust.

List the mechanical layers of the Earth.

Lithosphere, Asthenosphere, and lower mantle.

Explain the difference between continental and oceanic crust.

Oceanic- The uppermost layer of the oceanic portion of tectonic plates(contains the upper and inner oceanic crust).

Makes up ⅔ of the Earth’s surface and makes up the ocean floor. Also continuously recycled by the mantle.

• thinner

• denser

• similar in composition to basalt (Si, O, Ca, Mg, and Fe)

Continental- Is thicker than oceanic. The crust is thick, rocky, and the outermost layer of the Earth.

• Thicker 

• lighter

  • similar to granite in composition (Si, O, Al, K, and Na)

Why is the core so important to all life on Earth?

-It creates Earth's magnetic field, which shields life forms from lethal cosmic rays.

-The movement of liquid iron in the outer core(caused by convection and Earth's rotation) generates a magnetic field around our planet. This magnetosphere deflects the charged particles streaming toward us from the Sun.

-Without our core, our planet would collapse and the surface would be destroyed.

Why can we not drill down to the core?

The core is around 6,000 km deep, and as hot as the sun. The deepest humanity has gone is 12km. 

6000km= 3730 miles

temp= 5,200° Celsius (9,392° Fahrenheit)

We have nothing that could withstand such pressure and temperatures.

What makes up the lithosphere?  How does it behave?

The rocky outer part of the Earth- it is made up of the crust and upper portion of the mantle. It is rigid, solid, and brittle.

What is the mohorovicic discontinuity?

The area between the crust and mantle where the velocity(speed) of seismic waves increases unexpectedly. Boundary between Earth’s crust and the mantle. 

What makes the asthenosphere different from the rest of the mantle?

Its temperature and pressure are so high that rocks soften(partially melt) and become semi-molten. The asthenosphere is more ductile(able to be stretched) than the lithosphere or lower mantle. 

What are you gonna do on the test?

sLAY