Topic 1: Part 1 Flashcards
(20 cards)
What about the Earth’s temperature makes it habitable?
Not too hot, not too cold, within habitable zone, temperature that allows LIQUID water to exist
What helps heat the Earth’s surface and atmosphere from outer space?
Absorbed solar radiation; it causes atoms and molecules to vibrate. Note that NOT ALL solar radiation is absorbed.
Why is not all of the radiation from the sun absorbed by the Earth?
Some things on Earth like clouds and water reflect the solar radiation.
What determines how much a surface reflects?
Albedo; a term to describe the reflectivity of a surface. Higher albedo means higher reflectivity. Higher albedo is associated with lighter surfaces, like snow. Albedo is also affected by latitude, and a higher latitude generally correlates to a higher albedo.
Since Earth’s temperature is relatively constant over time, what does that mean?
ENERGY IN = ENERGY OUT. This is a concept called back radiation.
What form does energy travel in?
Wavelengths.
What is a greenhouse gas?
Any gas that absorbs or emits infrared radiation, because infrared radiation is what radiates back from Earth.
What wavelengths of energy correspond to solar energy and back radiation respectively?
Solar energy: Shortwave: visible spectrum and some UV
Back radiation: Longwave: infrared
What are some direct GHGs?
Water, carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs), and ozone.
What are some indirect GHGs and how do they contribute to the greenhouse effect?
Nitrogen oxides, carbon monoxide, and non-methane volatile organic compounds (NMVOC) break down in the atmosphere to produce greenhouse gases (carbon dioxide or ozone)
Sulphur dioxide contributes to aerosol formation which can warm or cool the atmosphere.
Are GHGs all bad?
No. Without greenhouse gases the temperature would plummet, but too much of a good thing can be (and in this case, is) bad.
What protects the Earth from harmful solar radiation?
Its magnetic field.
What processes are responsible for the creation of Earth’s magnetic field?
Convection in the liquid outer core is thought to be responsible.
How does the magnetic field protect the Earth?
Charged particles from the sun are forced to spiral around the lines of the field instead of slamming into Earth. This protects us from UV radiation and protects the ozone layer from being destroyed.
What creates an aurora?
Magnetic field lines directly pointing into the ground and intersecting with the atmosphere at the poles allow some space particles to escape the magnetosphere and react with air molecules. This creates an aurora.
What are the chemical ingredients for life?
They are six essential elemental ingredients: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur (CHNOPS)
These ingredients build all organisms.
Water is also a chemical ingredient and is critical for life.
What makes the chemical ingredients to life so essential?
Carbon bonds with other carbons easily to form long chains. Other atoms can easily bond to these chains, making carbon a building block for large complex organic molecules.
Nitrogen, hydrogen and oxygen are abundant and bond with carbon to form amino acids, fats, and RNA and DNA bases.
Sulfur in sulfides and sulfates acts as a catalyst.
Phosphate bonds store huge amounts of energy in metabolism, and breaking them allows bodily processes to occur.
Water is an excellent solvent.
What is the best solvent on Earth and why are solvents so critical?
The best solvent on Earth is water because it is abundant and able to dissolve many substances. Solvents are critical because they dissolve solids and allow ingredients for life to interact and carry out reactions necessary for life.
In summary, what are the three things that makes Earth habitable?
- Temperature; within the habitable zone (not too hot or cold, liquid water can exist).
- Protected from harmful solar radiation by magnetic field.
- Has the right chemical ingredients for life, carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur, and water.
Could life exist on other planets? What would it look like?
Maybe. Earth-like planets within habitable regions of other stars are the best candidates for finding life. In our own solar system, other planets or moons may have life consisting of microorganisms, extremophiles, subsurface ocean dwellers, and carbon-based but relying on a different solvent than water.
