Spaceship Earth: Our oasis in the emptiness of space.

*** 15 – 20 Co

Our star, the Sun, has a profound

influence on the climate on

Earth.

Here, a solar flare is shown, as

well as “granules” on

the Sun’s surface

The solar constant (the amount of radiation that reaches Earth) varies over the 11 year cycle of solar magnetic activity (X-ray view of 1991-1995 solar cycle).

1645 – 1715: The Maunder Minimum in Sun Spots

Did it affect Earth’s climate?

Rise in the amount of atmospheric CO2, measured on Mauna Loa.Summertime lows result from uptake of CO2 by vegetation.

Temperatures and amounts of atmospheric CO2 and CH4 during the past 4 glacial-interglacial cycles. The present-day levels of CO2 and CH4 (dashed lines) are higher than anytime during the past 150,000 years!

Layers of Earth’s atmosphere

Southern hemisphere ozone (O3) hole

Chlorofluorocarbon (CFC) refrigerant gases were introduced in the early 1930’s by General Motors engineers seeking a

replacement for hazardous materials used in refrigeration such as sulfur dioxide and ammonia. The use of CFCs has experienced dramatic growth, for air conditioning and

refrigeration equipment, but also in industrial applications, including:

•Propellant for aerosol cans •Blowing agent for insulating foam •Foam padding in furniture •Halon fire extinguishers •Automotive air conditioning •Highly evaporative cleaning solvents •Inhalers for asthma sufferers.

Probable cause of ozone depletion in the stratosphere

Tracking El Nino in the Pacific using satellites

Global distribution of aerosols throughout the year

More hurricanes?Hurricane Floyd and North Carolina Flooding

September 7 – 19, 1999

Replica of a Chinese

seismograph from 132 AD.

The original was 1.8 m in diameter.

Schematic of the functioning of the ancient Chinese seismograph

In an earthquake, P waves arrive first, S waves second, and L waves last

Typical seismogram of a major earthquake

Seismic waves from natural or man-made earthquakes

can be used to study and

decipher the structure of

the interior of Earth.

S waves do not travel through liquids,

indicating that the outer core of Earth

is liquid.

Relationship between the thermal gradient (i.e., the increase in T with

depth) and the melting point of silicates (mantel) and iron (core) as a function of increasing pressure in Earth with depth.

Since the melting point of iron at the pressures between a depth of ~2,900 and

~5,200 km in Earth is below the temperature at these depths, the iron in the outer core must be molten (liquid).

Summary