Term
|
Definition
| includes the surface, below the surface, in oceans and lakes, and in the atmosphere |
|
|
Term
| Arguments for Existence of Extraterrestrial Life |
|
Definition
There is nothing unusual about the earth
The milky way and sun are ordinary
Plants are known to orbit most stars
Some planets are similar to earth |
|
|
Term
| Arguments against Existence of Extraterrestrial Life |
|
Definition
Maybe the earth is unusual in ways that we dont fully appreciate
We have not discovered any evidence for life |
|
|
Term
|
Definition
| Will disprove a Hypothesis, but never prove it. |
|
|
Term
|
Definition
| A broad overaraching conceptual framework that incorporates many related hypotheses and is well-supported by experimental Data. We are quite confident that it is "correct" |
|
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Term
|
Definition
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|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| 1,000,000,000,000 = 10^12 |
|
|
Term
|
Definition
| measured Distance or Lenth |
|
|
Term
1 km = ? meters
1 km = how many miles |
|
Definition
1000 meters
about .62 miles |
|
|
Term
|
Definition
| about 39 inches, a little over 3 feet |
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Term
|
Definition
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Term
|
Definition
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Term
|
Definition
|
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is the formula for Speed? |
|
Definition
|
|
Term
| What is the speed of light? |
|
Definition
|
|
Term
|
Definition
Speed that light travels in a year
905 X 10^12 |
|
|
Term
|
Definition
A change in speed and/or direction
Speeding up
Slowing Down
Changing Direction |
|
|
Term
| What would give an object no Acceleration? |
|
Definition
| Moving at a constant speed and in a straight line or at rest |
|
|
Term
|
Definition
|
|
Term
| How forces affect mottion |
|
Definition
-With motion comes force.
-Force does not exist without motion.
-With more motion, more force takes place.
-Force is mass times acceleration.
-So if you increase the mass or speed/acceleration, you increase the force. |
|
|
Term
| Several forces action an object they will? |
|
Definition
combine to produce a net force or total force
Example - two equal forces pulling opposite directs will equal a net force of zero |
|
|
Term
| Net forces cause ____________ if the net force is not __________ |
|
Definition
|
|
Term
| If net force on an object is zero the acceleration will be? |
|
Definition
|
|
Term
| How much force is necessary to keep an object moving? |
|
Definition
none
an object in motion stays in motion until an force stops it |
|
|
Term
| What is the equation for Force |
|
Definition
F=ma
Force = mass x acceleration |
|
|
Term
| What is Gravitational Force |
|
Definition
Occurs between Masses
The larger the mass the stronger the force
THE LARGER THE DISTANCE BETWEEN THE
MASSES, THE WEAKER THE FORCE
The force always pulls masses together |
|
|
Term
| Electrical Force occurs between ________ _____________ |
|
Definition
|
|
Term
Electrical Force
The larger the charge the _________ the force |
|
Definition
|
|
Term
Electrical Force
The Larger the distance between the charges the ________ the force |
|
Definition
|
|
Term
Electrical Force
(Like a magnet) If both are the same charge then they will _______ |
|
Definition
|
|
Term
| The electrical force of the _________ of an atom is __________ charge, while the Electors are ________ charged keeping them in orbit around the ________ |
|
Definition
Nucleus
Positively
Negatively
Nucleus |
|
|
Term
|
Definition
| Elements are the fundamental type o substance and can be found of the Periodic Table |
|
|
Term
|
Definition
| Compose of a nucleus and the orbiting Electorns |
|
|
Term
|
Definition
| Part of Atom that contains the Protons and Neutrons |
|
|
Term
|
Definition
| Positively charged particle in the nucleus of an atom |
|
|
Term
|
Definition
| Negatively charged particle orbiting around the nucleus |
|
|
Term
|
Definition
Particle in Nucleus
Has no electric charge
Adds mass to nucleus
Determines the isotope |
|
|
Term
|
Definition
| Variety of an element with a specific number of neutrons |
|
|
Term
|
Definition
| an atom in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. |
|
|
Term
|
Definition
| Several Atoms bound together by chemical bonds. Example H2O or O2 |
|
|
Term
|
Definition
| A substance whose molecules consist of Atoms of two or more different elements. A group of molecules |
|
|
Term
| Chemical Bonds can happen when.. |
|
Definition
Atoms share some of their electrons
Atoms transfer some electons making one atom negatively charged and the other positively which makes the "attack" each other and hold together |
|
|
Term
Size of an atom
The Nucleus is much ________ then the Entire atom, but contains the most _________ |
|
Definition
|
|
Term
Temperature
Molecules are always in ________ |
|
Definition
|
|
Term
Temperature
Temperature of an object increase when.. |
|
Definition
|
|
Term
Temperature
At the __________ Temperature, not all Molecules move the same speed. The _______ molecules will move faster. |
|
Definition
|
|
Term
| Every substance can be in what three phases? |
|
Definition
|
|
Term
Fahrenheit
Absolute Zero
Water Freezes
Water Boils |
|
Definition
|
|
Term
|
Definition
MASS / VOLUME
– MASS IS HOW HEAVY SOMETHING IS
– VOLUME IS THE AMOUNT OF ROOM (IN 3 DIMENSIONS)
THAT SOMETHING TAKES UP
– DENSITY DESCRIBES HOW TIGHTLY THE MASS IS
SQUEEZED TOGETHER |
|
|
Term
|
Definition
The area is where the force is spread
– EXAMPLE: IF I PUSH ON A TABLE WITH A PALM OF MY HAND, THE AREA IS THE AREA OF THE PALM OF MY
HAND. IF I PUSH JUST AS HARD (SAME FORCE), BUT
JUST WITH ONE FINGER INSTEAD OF MY ENTIRE PALM, THE AREA IS LESS, SO THE PRESSURE IS LARGER |
|
|
Term
|
Definition
Kinetic
Potential
Light
Sound
Thermal
Mass |
|
|
Term
|
Definition
|
|
Term
|
Definition
Stored Energy
– ELASTIC (EXAMPLE: STRETCHED OR
COMPRESSED SPRING)
– GRAVITATIONAL
– ELECTRICAL
– CHEMICAL
– NUCLEAR |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Distance between two adjacent peaks |
|
|
Term
|
Definition
| Number of waves or peaks passing by a given locations per second |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Height of the wave (half of the total height) |
|
|
Term
|
Definition
| A partial of light and carries energy |
|
|
Term
THE LARGER THE ENERGY PER PHOTON
Then... |
|
Definition
The shorter the wavelength
The higher the frequency
The bluer the coler |
|
|
Term
THE SMALLER THE ENERGY PER PHOTON
Then... |
|
Definition
The Longer the wavelength
The lower the frequency
The redder the color |
|
|
Term
| THE BRIGHTNESS OF THE LIGHT IS RELATED TO... |
|
Definition
|
|
Term
|
Definition
| A Very large, hot ball of gas that emits large amounts of light. The light and hear are produced by nuclear fusion (small nuclei combining to produce larger nuclei)occurring in the center of the star |
|
|
Term
|
Definition
| A fairly large object (but not much smaller than a star) that orbits around a star (sun). It can be rocky or gaseous. There is no nuclear fusion occurring inside |
|
|
Term
|
Definition
| smaller object that orbits around a planet |
|
|
Term
|
Definition
| The sun, the 8 planets and smaller bodies (dwarf planets, comets, asteroids...) that orbit the sun and the moons that orbit the planets |
|
|
Term
|
Definition
| A large cluster of stars (1 million to 1 trillion stars). Many of these stars have their own solar systems. |
|
|
Term
|
Definition
| The galaxy in which our solar system is located. |
|
|
Term
|
Definition
| An explosion that started the universe approximately 13.7 billion years ago. All of the matter in the universe was expelled outward from the explosion. Galaxies are still moving apart from each other as a result |
|
|
Term
|
Definition
|
|
Term
| When did the galaxies from |
|
Definition
| the first couple billion years |
|
|
Term
| How old is our sun and solar system |
|
Definition
| about 4.6 billion years old |
|
|
Term
|
Definition
Distance between the Earth and Sun
About 150,000,000km
A unit of distance used within the solar system |
|
|
Term
|
Definition
The distance light travels in on Year
About 9.5 x 10^12 km or 63,300 AU
A unit of Distance used for stars |
|
|
Term
|
Definition
About 3.26 Light Years
Another Unit of Distance used for stars |
|
|
Term
| How long does it take light to travel from the moon to earth |
|
Definition
Moon's distance = 239,228 miles
divided by the speed of light
1.3 seconds |
|
|
Term
| Light travel from Sun to Earth |
|
Definition
|
|
Term
| Light travel across the solar system |
|
Definition
|
|
Term
| light travel from nearby stars to earth |
|
Definition
|
|
Term
| light travel across milky way |
|
Definition
|
|
Term
| light travel from nearby galaxies to earth |
|
Definition
|
|
Term
| light travel from farthest galaxies from earth |
|
Definition
|
|
Term
| The moon orbits around the |
|
Definition
|
|
Term
| The earth orbits around the |
|
Definition
|
|
Term
| Planets in our Solar System |
|
Definition
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune |
|
|
Term
| The Solar system is shaped like a _______ |
|
Definition
Flattened Disk
because all planets orbit the sun in the same direction and their orbits are nearly in the same plane |
|
|
Term
|
Definition
Spiral
Elliptical
Irregular |
|
|
Term
| What shape is the Milky way |
|
Definition
Spiral
Shaped like a flattened disk with spiral arms
Where must bright stars are in the spiral arms |
|
|
Term
|
Definition
a classification of stars based on their spectral characteristics
Hotter to colder
bluer to redder
Sun is a G2 Star |
|
|
Term
HERTZSPRUNG-RUSSELL
(HR) DIAGRAM |
|
Definition
Plot of brightness of the vertical axis and spectral type (or temperature or color on the horizontal axis.
- THE HIGHER UP THE DOT, THE BRIGHTER THE
STAR. THE LOWER THE DOT, THE FAINTER THE
STAR.
- THE FARTHER THE DOT IS TO THE LEFT, THE
HOTTER AND BLUER THE STAR. THE FARTHER
THE DOT IS TO THE RIGHT, THE COOLER AND
REDDER THE STAR. |
|
|
Term
| On the Hertzprung-Russel diagram, most star are in the "main sequence", meaning? |
|
Definition
A HOTTER STAR IS
ALSO BRIGHTER (UPPER LEFT). A COOLER STAR IS
ALSO FAINTER (LOWER RIGHT). |
|
|
Term
|
Definition
A MAIN SEQUENCE
STAR EVENTUALLY EVOLVES INTO A GIANT OR
SUPERGIANT. THEY ARE LARGE AND COOL RED OR ORANGE).
Are cooler (Redder), but very bright; which means they are larger in size
They are located in the top right of H-R diagram |
|
|
Term
|
Definition
“DEAD” STARS, END STAGES OF
STELLAR EVOLUTION.
THEY ARE YELLOW TO WHITE IN COLOR AND
FAINT. They are smaller in size They are located in the bottom left of teh H-R diagram. |
|
|
Term
|
Definition
MOST STARS ARE THIS TYPE,
INCLUDING THE SUN. THE SIZE, TEMPERATURE,
AND BRIGHTNESS OF A MAIN SEQUENCE STAR
REMAINS RELATIVELY CONSTANT FOR A LONG
PERIOD OF TIME (MILLIONS TO BILLIONS OF
YEARS) |
|
|
Term
| What causes absorption lines? |
|
Definition
| as light passes through the cooler, less dense gas near the "Surface" certain wavelength are absorbed. |
|
|
Term
| What can be learned from absorption lines? |
|
Definition
| you can determine the composition of the star |
|
|
Term
| Many aspects of a stars life depend on? |
|
Definition
|
|
Term
|
Definition
| a space cloud full of mostly hydrogen and then helem |
|
|
Term
|
Definition
AS THE NEBULA CONTRACTS, GRAVITATIONAL
POTENTIAL ENERGY IS LOST. SOME OF THE
ENERGY CHANGES TO KINETIC ENERGY OF
ROTATION AS THE CLOUD'S ROTATION SPEEDS UP.
SOME OF IT CHANGES TO THERMAL ENERGY
(HEAT).
- AS A RESULT, THE CENTRAL PART OF THE CLOUD GETS HOT ENOUGH:
•FOR MOLECULES TO BREAK APART INTO ATOMS
•THEN FOR ATOMS TO IONIZE (ELECTRONS REMOVED)
•THEN FOR HYDROGEN NUCLEI TO START TO FUSE TO FORM HELIUM NUCLEI.
- ONCE FUSION OF H TO He BEGINS, THE OBJECT BECOMES A MAIN SEQUENCE STAR. SO FAR, THE ELAPSED TIME IS A FEW MILLION YEARS. |
|
|
Term
| How does a star stay stable |
|
Definition
| becaue of the outward pressure and inward gravity (tem is maintained by energy release from nuclear reation) star is stable for millions to billions of years |
|
|
Term
|
Definition
| were partials that were not "pulled" into center (star) |
|
|
Term
| What happens at the end of the main sequence lifetime? |
|
Definition
Hydrogen in the core runs out
the more mass the shorter the life span b/c it hydrogen is used up more quickly |
|
|
Term
| When happens when a star begins to die (leaves main sequence) |
|
Definition
Outer part of star expands, brightens, and cools becoming a red Giant (or for bigger stars a super giant)
The core contracts, gets hotter and helium fuses to create carbon. In massive stars (super giant) it goes further and creates iron. |
|
|
Term
| Late stages of low mass stars |
|
Definition
*the outer part of star is ejected into space; which ools and leaves...
*the core (White Dwarf); very dense and small. It cools and dims until it becomes...
*Black Dwarf; emits no more light, its is made of carbon, nitrogen, and oxygen. |
|
|
Term
| Late stages of massive stars |
|
Definition
Super Nova
*the iron core of the Red supergiant collapses until the nuclei collides w/each other
*This causes them to bounce apart and explode
*this explosion causes the star to become really bright
*explosion cause fusion of heavy elements which go into the interstellar medium.. The star becomes a Neutron Star |
|
|
Term
|
Definition
*core of star left after supernova explosion
*ball of neutrons
*one teaspoon = billion tons
*Pulsars are radio waves from neutron stars
*Massive star go on to become Blackholes |
|
|
Term
|
Definition
| radio wave from neutron star |
|
|
Term
|
Definition
Neutron star that is massive and collapses even further
Has and escape velocity that exceeds the speed of light.. which means nothing can escape, not even light |
|
|
Term
|
Definition
speed needed to leave a star
the more massive but small an ovject the larger the E.V. |
|
|
Term
| Life Cycle of small mass stars (under 5 solar mass) |
|
Definition
– Formation from a nebula
– Main sequence (cooler, redder, fainter)
– Red giant
– Planetary nebula
– White dwarf
– Black dwarf |
|
|
Term
| Life Cycle of large mass stars (over 5 solar mass) |
|
Definition
– Formation from a nebula
– Main sequence (hotter, bluer, brighter)
– Red giant/supergiant
– Supernova explosion
– Neutron star or black hole |
|
|
Term
|
Definition
A MOLECULE COMPOSED OF CARBON AND
HYDROGEN ATOMS |
|
|
Term
|
Definition
| A SIMPLE ORGANIC MOLECULE SUCH AS AN AMINO ACID, SIMPLE SUGAR, FATTY ACID, OR GENETIC BASE |
|
|
Term
|
Definition
| A LARGE ORGANIC MOLECULE COMPOSED OF A CHAIN OF MONOMERS STRUNG TOGETHER |
|
|
Term
|
Definition
A PROTEIN IS A LONG POLYMER MADE OF
MONOMERS CALLED AMINO ACIDS.
EACH PROTEIN IS COMPOSED OF A CHAIN OF
HUNDREDS OF AMINO ACIDS.
PROTEINS USED IN LIFE ON EARTH ARE FORMED
FROM ONLY DIFFERENT 20 TYPES OF AMINO
ACIDS.
ADDITIONAL TYPES OF AMINO ACIDS EXIST AND
COULD BE USED BY LIFE ELSEWHERE. |
|
|
Term
|
Definition
ARE THE MONOMERS THAT
MAKE UP PROTEINS. |
|
|
Term
| Amino acids are found in: |
|
Definition
*ALL TERRESTRIAL FORMS OF LIFE
*METEORITES (ROCKS THAT FALL TO EARTH FROM
SPACE)
*COMETS (CHUNKS OF ICE IN SPACE)
*INTERSTELLAR CLOUDS OR NEBULAE |
|
|
Term
EACH AMINO ACID CAN HAVE TWO
“ISOMERS” OR MOLECULAR
VERSIONS: |
|
Definition
L(Levo) left-handed (Life on earth)
D(Dexto) right-handed (meteorites)
they are molecular mirrors of eachother |
|
|
Term
|
Definition
PROVIDES A “BLUEPRINT” OR “RECIPE” FOR MAKING PROTEINS
– CARRIES INFORMATION ABOUT THE SEQUENCE OF AMINO ACIDS IN A PARTICULAR PROTEIN
FOUND IN EVERY CELL IN A LIVING ORGANISM
– IN “HIGHER” ORGANISMS, THE DNA IS
SEPARATED INTO LARGE PIECES CALLED
CHROMOSOMES (FOR EXAMPLE, 46 IN HUMANS)
CAN REPLICATE ITSELF
– WHEN A CELL DIVIDES INTO TWO, AN IDENTICAL COPY OF THE ORIGINAL DNA (A COPY OF EACH CHROMOSOME) GOES INTO EACH CELL |
|
|
Term
|
Definition
A STRING OF 3 GENETIC BASES GIVING THE
CODE (OR INSTRUCTION) FOR PLACING A PARTICULAR
AMINO ACID INTO A PROTEIN THAT IS UNDER
CONSTRUCTION. |
|
|
Term
|
Definition
A STRING OF ROUGHLY 1000 CODONS THAT IS
THE RECIPE FOR A PARTICULAR PROTEIN. |
|
|
Term
|
Definition
A LARGE PIECE OF DNA CONTAINING A
LARGE NUMBER OF GENES. |
|
|
Term
|
Definition
| ENTIRE SEQUENCE OF DNA IN AN ORGANISM. |
|
|
Term
|
Definition
DNA UNZIPS AND ONE STRAND IS
USED AS A TEMPLATE FOR CONSTRUCTING A NEW
STRAND. THIS IS SIMILAR TO DNA REPLICATION,
EXCEPT THAT THE NEWLY CONSTRUCTED STRAND IS
RNA INSTEAD OF DNA. (RNA USES U INSTEAD OF T, AND THE SUGAR IN BACKBONE IS SLIGHTLY DIFFERENT.) |
|
|
Term
|
Definition
RNA MOVES FROM THE NUCLEUS TO
A DIFFERENT PART OF THE CELL, WHERE THE GENETIC CODE IS READ AND CONVERTED TO AN AMINO ACID SEQUENCE BY A RIBOSOME. |
|
|
Term
|
Definition
MADE FROM MOLTEN ROCK (FROM A VOLCANO)
THAT COOLED AND SOLIDIFIED. |
|
|
Term
|
Definition
: MADE FROM SEDIMENTS (TINY CHIPS FROM
ROCKS THAT RESULT FROM EROSION) THAT ARE DEPOSITED
AND COMPRESSED GRADUALLY, USUALLY AT THE BOTTOM OF A BODY OF WATER. DEEPER LAYERS ARE OLDER, TOP LAYERS ARE YOUNGER. |
|
|
Term
|
Definition
MADE FROM ROCK THAT HAS BEEN HEATED
(BUT NOT ENOUGH TO MELT IT) AND/OR COMPRESSED ENOUGH TO CHANGE ITS STRUCTURE. |
|
|
Term
Cell Types
Prokaryotic Cell |
|
Definition
Small
No Nucleus
DNA is single |
|
|
Term
Cell Types
Eukaryotic Cells |
|
Definition
Large
mulit-cell
has nucleus
DNA is in chromosomes in nucleus
Large |
|
|
Term
|
Definition
STRUCTURES WITHIN A EUKARYOTIC CELL
THAT ARE SEPARATED FROM THE REST OF THE
CELL BY MEMBRANES.
Nucleus
Mitochondria
Chloroplasts |
|
|
Term
|
Definition
CARRY OUT CHEMICAL REACTIONS THAT RELEASE ENERGY
PROVIDE A SOURCE OF ENERGY FOR THE CELL
FOUND IN ALL EUKARYOTIC CELLS |
|
|
Term
|
Definition
FOUND IN CELLS OF PLANTS AND SOME BACTERIA (BUT NOT
ANIMALS)
CARRY OUT PHOTOSYNTHESIS
CO2
+ H20 --> O2
+ FOOD |
|
|
Term
|
Definition
Eukaryotic Cell
Single and Multi |
|
|
Term
| What are the Three Domains? |
|
Definition
|
|
Term
|
Definition
Prokaryotic
Single
Photosynthese |
|
|
Term
|
Definition
Prokaryotic
Single
Includes Extromphiles |
|
|
Term
| Five Domains for the Eukarya |
|
Definition
– PROTISTA (SINGLE-CELLED EUKARYOTES)
– MONERA (SINGLE-CELLED EUKARYOTES)
– FUNGI (MULTICELLULAR EUKARYOTES)
– PLANTS (MULTICELLULAR EUKARYOTES)
– ANIMALS (MULTICELLULAR EUKARYOTES) |
|
|
Term
|
Definition
| is an organism that thrives in physically or geochemically extreme conditions that are detrimental to most life on Earth |
|
|
Term
|
Definition
| is the hypothesis that life exists throughout the Universe, distributed by meteoroids, asteroids and planetoids. |
|
|
Term
| approximately how long ago did life start? |
|
Definition
|
|
Term
|
Definition
| used to estimate the number of "Technological" Civilization in the Milky Way Galaxy |
|
|
Term
| Technological civilizaitons are defined as |
|
Definition
one that is capable of (and interested in) engaging in interstellar communications with other civilizations.
Number is of civilizations that could be sending out radio (or other) signals that we might e able to receive. |
|
|
Term
| What does the N stand for in the Drake Equation? |
|
Definition
| Number of civilizations in the MW galaxy capable of communication (what we'd like to find) |
|
|
Term
| What does the N* stand for in the Drake Equation? |
|
Definition
| Number of stars in the MW glaxy |
|
|
Term
| What does the Fs stand for in the Drake Equation? |
|
Definition
| fraction of stars that are suitable stars (so the result of N*f(s)is number of suitable stars in MW galaxy) |
|
|
Term
| What does the N(p) stand for in the Drake Equation? |
|
Definition
| average number of planers that are suitable for life per each suitable star (N*f(s)n(p) is number of suitable planers in MW galaxy |
|
|
Term
| What does the f(l) stand for in the Drake Equation? |
|
Definition
fraction of suitable planets on which life actually originates
N*f(s)n(p)f(l) is number of planets with life on which life exist |
|
|
Term
| What does the f(i) stand for in the Drake Equation? |
|
Definition
| N*f(s)n(p)f(l)f(i) is number of planets with life on which intelligent life evolves |
|
|
Term
| What does the f(c) stand for in the Drake Equation? |
|
Definition
| fraction of plants with intelligent life on which technology sufficient for interstellar communication develops |
|
|
Term
| What does the f(now) stand for in the Drake Equation? |
|
Definition
| fraction of those civilizations that exist NOW (as opposed to ones that existed in the past,but dont exist any more) |
|
|
Term
|
Definition
L/t
L is the average lifetime of a technological civilization
t is the age of the Milky Way galaxy
This assumes that the probability of a civilization arising has remained constant over the lifetime of our galaxy - probably not true |
|
|
Term
|
Definition
Number of stars in the MW galaxy
400 billion stars (may be off by ~30%) |
|
|
Term
| Properties of a suitable star are |
|
Definition
main sequence
long enough main sequence lifetime
reasonable sized habitable zone
enough heavy elements (younger star)
not too close to center of galaxy
not in a binary/multiple star system |
|
|
Term
|
Definition
fraction of stars that are suitable
f(s) = 0.1 = 1/10 (optimistic case)
f(s) = 0.001 = 1/1000 (pessimistic case)
f(s) = 0.05 = 1/20 (my best estimate) |
|
|
Term
|
Definition
average number of suitable planets per suitable star
n(p) = 2 (optimistic case)
n(p) = 0.1 = 1/10 (pessimistic case)
n(p) = 0.5 = 1/2 (my best estimate) |
|
|
Term
| In order to develop a technological civilization, other thins such as: |
|
Definition
-Hands
-Living on dry land
-Certain kinds of climate
-Certain natural resources
-Animals that ca be domesticated |
|
|
Term
|
Definition
t = age of MW galaxy
l = average lifetime of a technological civilizatoin (in years) = the average lifetime of civilization with ability and desire to communicate |
|
|
Term
| What is the least well-known factor in the Drake Equation? |
|
Definition
|
|
Term
|
Definition
N ~ L
Very roughly
(to within a factor of a few 100 or few 1000) |
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