The 'Greenhouse Effect

One of the most interesting concepts bought up in class was the Greenhouse Effect. I found some nice slides explaining the Greenhouse effect, that I will use with my students.


The 'Greenhouse Effect

The greenhouse effect is a natural occurrence that maintains Earth's average temperature at approximately 60 degrees Fahrenheit.
The greenhouse effect is a necessary phenomenon that keeps all Earth's heat from escaping to the outer atmosphere. Without the natural greenhouse effect it is certain that we would all be lost. Temperatures on Earth would be much lower than they are now, and the existence of life on this planet would not be possible. The global average temperature would drop precipitously 33 degrees from its current 15° to -18°C. The Earth would become an ice planet.
However, too many greenhouse gases in Earth's atmosphere could increase the greenhouse effect. This could result in an increase in mean global temperatures as well as changes in precipitation patterns.
The Earth's atmosphere, a thin blanket of gases, protects the planet from the harshest of the sun's ultraviolet radiation. The atmosphere, by trapping the Earth's warmth, keeps rivers and oceans from freezing. Carbon dioxide and water vapor are the most important gases in creating the insulating or "greenhouse effect" of the atmosphere.

Extremophiles Are Alive & Well - Everywhere!!

Definition - Lover of extremes
History - Suspected about 30 years ago
Known and studied for about 20 years
Temperature extremes - Boiling or freezing, 1000C to -10C (212F to 30F)
Chemical extremes - Vinegar or ammonia (<5 pH or >9 pH)
Highly salty, up to ten times seawater
How we sterilize & preserve foods today
What are they? - Microbes living where nothing else can.
How do they survive? - Extremozymes
Why are they are interesting? - Extremes fascinate us & the idea of
life on other planets is even more fascinating.

Thermophiles
There are microbes called thermophiles, or heat-lovers, that live in temperatures so hot, the microbes could actually melt if they hadn’t developed tricks and tools to handle such extreme heat. Thermophiles have certain proteins, or enzymes, that are specially geared to working in high temperatures even as hot at 284° F (140° C). Keep in mind that water boils at 212° F (100° C). The normal-temperature proteins and enzymes in your body would start unfolding and breaking apart long before it got as hot as 284° F. Understanding the biology of thermophiles may help scientist understand the boundaries of which life can exist on other planets.




Psychrophiles
On the opposite end of the spectrum from the thermophiles, psychrophiles
burgeon in extreme cold. Life cannot grow where liquid water can’t exist,
but it does grow at or slightly below freezing temperature.
The most studied psychrophilic environment is Antarctic sea ice. This area is mainly populated with algae, diatoms, and bacteria. Certain species in this ecosystem are incapable of reproduction at temperatures above 2 degrees centigrade. Psychrophiles also inhabit the ocean’s freezing cold floor.
Among the most well known psychrophiles are the worms that dwell in methane
ice at the bottom of the Sea of Cortez. Psychrophiles are probably the
least studied of extremophiles, so obviously little is known about them.




Additional information:
Low temperature
Arctic and Antarctic
1/2 of Earth’s surface is oceans between 10C & 40C
Deep sea –10C to 40C
Most rely on photosynthesis

Black/white photo: Methane worm up-close





Halophiles
The word halophile means, “salt loving”. A halophile is an organism that can grow in higher salt concentrations than the norm.
Based on optimal saline environments halophilic organisms can be grouped into three categories: extreme halophiles, moderate halophiles, and slightly halophilic or halotolerant organisms.
Some extreme halophiles can live in solutions of 35 % salt. This is extreme compared to seawater which is only 3% salt.
Diversity of Halophilic Organisms
Halophiles are a broad group that can be found in all three domains of life. They are found in salt marshes, subterranean salt deposits, dry soils, salted meats, hypersaline seas, and salt evaporation pools.

The Big Bang!!

Did you know that the matter in your body is billions of years old? 

According to most astrophysicists, all the matter found in the universe today -- including the matter in people, plants, animals, the earth, stars, and galaxies -- was created at the very first moment of time, thought to be about 13 billion years ago. The universe began, scientists believe, with every speck of its energy jammed into a very tiny point. This extremely dense point exploded with unimaginable force, creating matter and propelling it outward to make the billions of galaxies of our vast universe. Astrophysicists dubbed this titanic explosion the Big Bang. 

The Big Bang was like no explosion you might witness on earth today. For instance, a hydrogen bomb explosion, whose center registers approximately 100 million degrees Celsius, moves through the air at about 300 meters per second. In contrast, cosmologists believe the Big Bang flung energy in all directions at the speed of light (300,000,000 meters per second, a hundred thousand times faster than the H-bomb) and estimate that the temperature of the entire universe was 1000 trillion degrees Celsius at just a tiny fraction of a second after the explosion. Even the cores of the hottest stars in today's universe are much cooler than that. 

There's another important quality of the Big Bang that makes it unique. While an explosion of a man-made bomb expands through air, the Big Bang did not expand through anything. That's because there was no space to expand through at the beginning of time. Rather, physicists believe the Big Bang created and stretched space itself, expanding the universe. 


The Earths Energy Balance

Heat (heat energy) is the total kinetic energy of all the atoms in a substance.
The Earth's climate system constantly tries to maintain a balance between the energy that reaches the Earth from the Sun and the energy that is emitted to space. Scientists refer to this process as Earth's "radiation budget".
The Earth's energy balance diagram.
On the Moon where there is no atmosphere, a surface temperature far below freezing emits enough radiation to balance the absorbed solar energy.
Because of the tilt of the Earth's axis, incoming solar radiation is not evenly distributed on the Earth's surface and seasonal changes occur.
The Sun is not in the exact center of the Earth's orbit. During the Southern hemisphere summer the Earth is closer to the Sun than during the Northern hemisphere summer. The Earth is farthest from the Sun during the Southern hemisphere winter.
As the Sun's electromagnetic radiation penetrates the Earth's atmosphere it is selectively absorbed and scattered by molecules of gases, liquids, and solids.
The energy coming from the Sun to the Earth's surface is called solar insulation or shortwave energy.
The average temperature of the systemÂ’s radiating surfaces controls both the amount of energy and the wavelengths at which energy is emitted by any system. The temperature of the Sun's radiating surface, or photosphere, is more than 5500 degree C (9900 degree F).
Energy goes back to space from the Earth system in two ways: reflection and emission.
Reflection:
Part of the solar energy that comes to Earth is reflected back out to space in the same, short wavelengths in which it came to Earth.
The percentage of solar energy that is reflected back to space is called the Aledo.
Different surfaces have different albinos. Over the whole surface of the Earth, about 30 percent of incoming solar energy is reflected back to space.
Ocean surfaces (26% Aledo) and rain forests (15% Aledo) reflect only a small portion of the Sun's energy.
Deserts however, have high albedos (40%); they reflect a large portion of the Sun's energy.
A cloud usually has a higher Aledo than the surface beneath it; the cloud reflects more shortwave radiation back to space than the surface would in the absence of the cloud, thus leaving less solar energy available to heat the surface and atmosphere.
Emission:
Another part of the energy going back to space from the Earth is the long wave radiation emitted by the Earth. The solar radiation absorbed by the Earth increases the planet's temperature. Heat energy is emitted into space, creating a balance.


A cloud can absorb radiation emitted by the Earth's surface and radiates in all directions.
The long wave energy emitted from the surface of the Earth and absorbed by the atmosphere results in an increase in the ambient temperature (i.e., the greenhouse effect). This absorbed energy is then emitted both to space and back towards the Earth's surface.
The greenhouse effect is due mainly to water vapor in the atmosphere. Carbon dioxide, methane and other infrared-absorbing gases enhance this effect.

The Tilt Of The Earth's Axis & The Seasons

If the axis of Earth was perpendicular to the plane of its orbit (and the direction of incoming rays of sunlight), then the radioactive energy flux would drop as the cosine of latitude as we move from equator to pole. However, as seen in
Figure 6, the Earth axis tilts at an angle of 23.5° with respect to its plane of orbit, pointing towards a fix point in space as it travels around the sun. Once a year, on the Summer Solstice (on or about the 21st of June), the North Pole points directly towards the Sun and the South Pole is entirely hidden from the incoming radiation. Half a year from that day, on the Winter Solstice (on or about the 21st of December) the North Pole points away from the Sun and does not receive any sunlight while the South Pole receives 24 hours of continued sunlight. During Solstices, incoming radiation is perpendicular to the Earth surface on either the latitude of Cancer or the latitude of Capricorn, 23.5° north or south of the equator, depending on whether it is summer or winter in the Northern Hemisphere, respectively.

During the spring and fall (on the Equinox days, the 21st of March and 23rd of September) the Earth's axis tilts in parallel to the Sun and both Polar Regions get the same amount of light. At that time the radiation is largest at the true equator.

Effect of Earth's spherical shape

If the Earth were a disk with its surface perpendicular to the rays of sunlight, each point on it would receive the same amount of radiation, an energy flux equal to the solar constant. However, the Earth is a sphere and aside from the part closest to the sun, where the rays of sunlight are perpendicular to the ground, its surface tilts with respect to the incoming rays of energy with the regions furthest away aligned in parallel to the radiation and thus receiving no energy at all

Cause of the Seasons

Earth's Seasons Are Caused by the Axial Tilt! No Tilt, No Seasons.

Solstices: Locations in Earth's orbit when the axis is pointed the most toward or away from the Sun. The longest and shortest day of the year depending on which hemisphere you live, North or South.

Equinoxes: Locations in Earth's orbit when the axis is not pointed at all toward or away from the Sun, but tangent to it. Length of the day is the same for everyone on Earth. 12 hours of day and 12 hours of night.

Earth's rotation axis Precesses about in a 26,000 year cycle. This Changes the Date of Equinoxes and Solstices. 

Seasons happen because sunlight is distributed over the surface of Earth differently throughout the year, NOT because the Earth is closer or farther away.
When Sunlight is direct is delivers more energy per unit surface area than when it is indirect (or oblique).
Tilt also causes length of days to change. During summer, days are longer and sunlight is more direct. During winter, days are short and sunlight is more oblique.