Intro to Earth Sciences

What are the four spheres of the Earth?

-Atmosphere (air)

-Hydrosphere (water)

-Geosphere/lithosphere (land)

-Biosphere (life)

What is the Steady State Theory of the universe?

That the universe has, is, and always will be in the same state as we observe it to be now

Who is Edwin Hubble?

Popularized the Big Bang Theoryand provided evidence for the expansion of the universe through his observations of spectra of distant galaxies

What is the Big Bang Theory?

That all the matter started from a single point (called a singularity)

What does “planetes” mean?

Wandering stars in ancient Greek

What star did ancient peoples use for navigation and civil management?

Sirius A (brightest star in the night sky)

What is a galaxy?

A group of stars, dust, and gases held together by gravity

How big is the Milky Way?

Is a large spiral galaxy whose disk is about 100,000 light-years wide and about 10,000 light-years thick at the nucleus

Why is the Milky Way named the way it is?

Because it looks like spilled milk

How fast is the speed of light?

186,000 mi/sec (300,000 km/sec)

On average, how long does it take for sunlight to reach Earth?

8 minutes and 17 seconds

How long does it take for sunlight to reach the nearest star (Proxima Centauri)?

4.3 years

How long does it take for sunlight to reach the nearest galaxy (Andromeda)?

2.5 million years

In astronomy, what is the unit we use for distance?

-Light year (Distance that light travels in one year)
-Light speed (300,000 km/sec)

-1 light year = 9.5 trillion km

What shape is the Earth’s orbit around the Sun?

Elliptical (a closed oval path)

What is the plane of Earth’s orbit about the Sun called?

Plane of the ecliptic

What is the average distance from the Earth to the Sun?

150,000,000 km

When is the Earth’s farthest distance from the Sun (aphelion)?

July 4

When is the Earth’s closest distance from the Sun (perihelion)?

January 3

What distance is referred to by the perihelion?

147,255,000 km

What distance is referred to by the aphelion?

152,083,000 km

How long does it take for Voyager 1 to send a signal to Earth?

1.5 days or 36 hours

What is the Sun made of?

-Made of gas
-No sharp boundaries exist between its various layers

What are the four divisions to the Sun?

-Solar interior
-Visible surface (or photosphere)
-Two atmospheric layers (chromosphere and corona)

What is the photosphere?

Region of the sun that radiates energy to space (or the visible surface of the sun)

What does the photosphere consist of?

A layer of incandescent gas less than 500 km thick

True or False: Most of the elements found on Earth also occur on the sun.

True

Through what process does the Sun generate energy?

Nuclear fusion

What is the average temperature of the photosphere?

6000K(10,000F)

What is the corona?

The outer, weak layer of the solar atmosphere

What is the temperature of the corona?

The temperature at the top of the corona exceeds 1 million K

What is a solar wind?

A stream of protons and electrons ejected at high speed from solar corona

What is a sunspot?

A dark spot on the sun that is cool in contrast to the surrounding photosphere

Why do sunspots appear dark?

Because their temperature is about 500K less than its surroundings

What causes sunspots?

Caused by magnetic storms on the Sun

How long is the activity cycle of sunspots?

11 years

What are prominences?

Huge cloudlike structures consisting of chromospheric gases

How are prominences formed?

Are ionized gases trapped by magnetic fields that extend from regions of intense solar activity

What is energy?

Capacity of a physical system to do work; Unit is Joule (J)

What is solar energy?

Radiant energy from the Sun

Where does solar energy come from?

Is generated by the nuclear fusion reaction process in which pairs of hy

What are auroras?

Result of solar flairs:

Bright displays of ever-changing light caused by solar radiation interacting with the upper atmosphere in the region of the poles

What is solar radiation?

Occupies a portion of the electromagnetic spectrum of radiant energy

What is the range of visible light?

0.4 micrometers - 0.7 micrometers

What is a photon?

Small packet of light energy

What are the two natures of light?

Behaves like waves and some, like particles

What is spectroscopy?

The study of the properties of light that depend on wavelength

High energy (or shortwave radiation) is associated with …

High temperature

Low energy (or longwave radiation) is associated with …

Low temperature

What is insolation?

Solar radiation that reaches a horizontal plane at Earth

Insolation at the top of the atmosphere is expressed as the …

Solar constant (more accurately, solar average)

What is the solar constant?

1372W/m²

Earth only receives what fraction of the Sun’s total energy?

1 over 2 billion

What is the outer boundary of Earth’s energy system?

Thermopause (480 km)

Tropics receive more than how many times of what poles receive?

2.5 times

What is the subsolar point?

Location where insolation is perpendicular to the surface

Why does the Earth experience seasons?

1. Revolution

2. Rotation

3. Tilt of Earth’s axis

4. Axial parallelism

5. Sphericity

How does revolution contribute to Earth’s seasons?

-Earth revolves around the Sun
-Voyage takes one year

How does rotation contribute to Earth’s seasons?

-Earth rotates on its axis once every 24 hours

What are the dates of the equinoxes/solstices?

March 21-23: Spring Equinox
June 21-23: Summer Solstice
September 21-23: Fall Equinox
December 21-23: Winter Solstice

How does axial parallelism contribute to Earth’s seasons?

-Axis maintains alignment during orbit around the Sun
-North Pole points towards the North Star (Polaris)

How does axis tilt contribute to Earth’s seasons?

-Axis is tilted 23.5 degrees from plane of ecliptic

What Greek scientist developed proof of Earth’s curvature?

Eratosthenes