- astronomical unit (AU):
- 1.495979 x 1011 meters
- parsec (pc):
- 3.086 x 1016 meters
- 2.06265 x 105 AU
- 3.262 LY
- light year (LY):
- 9.4605 x 1015 meters
- 6.324 x 104 AU
An astronomical unit is the average distance between the Earth and Sol, the sun. A parsec is
a distance based on an
object whose parallax is one second of arc (which is 1/60 of a minute, which in turn is 1/60 of a
degree, with 360 degrees
in the full circle). A light year is the distance that a photon travels in a vacuum in a year's time.
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144 square inches=1 square foot
9 square feet=1 square yard
4,640 square yards=1 acre
1550 square inches=1 square meter
10.76 square feet=1 square meter
100 square meters=1 are (10 meters on a side)
100 ares=1 hectare (100 meters on a side)
43,560 square feet=1 acre (approx. 208 feet on a side)
640 acres=1 square mile (5,280 feet on a side)
2.47 acres=1 hectare
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Note: In some contexts, you may see capacity differentiated from volume. For all practical
purposes using these measurements, there is no need to distinguish between them.
3 teaspoons=1 tablespoon
2 tablespoons=1 ounce (liquid)
8 ounces=1 cup
16 ounces=1 pint
32 ounces=1 quart
128 ounces=1 gallon
2 cups=1 pint
4 cups=1 quart
2 pints=1 quart
8 pints=1 gallon
4 quarts=1 gallon
7.8 gallons=1 cubic foot
1 cubic centimeter=1 milliliter (not exactly because of early error in calibration of the metric
system, but VERY close)
1000 liters=1 cubic meter
1 cubic deciliter=1 liter
61,024 cubic inches=1 cubic meter
61 cubic inches=1 liter
264.2 gallons (US)=1 cubic meter
220 gallons (Imperial)=1 cubic meter
1 cubic meter=1 stere
35.3156 cubic feet=1 stere
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Note: English to metric (and vice versa) conversions are at standard gravity. This is relevant
only
when considering mass vs. weight. Of course, anything will weigh slightly less at the top of Mt.
Everest than it will on the beach, but not enough so you can tell the difference (you'd have to go
out a few decimal places to even find the difference). The fundamental correspondence between
mass and volume is that 1 liter of water at STP weighs one kilogram (and, of course, one pint of
water weighs one pound).
If you have trouble understanding the distance between mass and weight, envision it like
this:
mass
represents the actual substance or matter that's there, while weight is the effect of gravity on that
mass. So a pound of butter only weighs about 2 2/3 ounces on the moon, but a kilogram of
butter
(mass) is still a kilogram of butter on the moon. When we use kilograms/grams for weight on
Earth, it is with the understanding that we have set these quantities at fundamental Earth gravity.
2.205 pounds=1 kilogram
35.274 ounces=1 kilogram
28.4 grams=1 ounce
2000 pounds=1 ton
1000 kilograms=1 tonne (or metric ton)
1.102 tons=1 tonne (or metric ton)
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03-26-2000: Note--The conversion between F/C was before now accidentally reversed, and
Celsius was misspelled. These have now been corrected.
1.8 degrees Fahrenheit=1 degree Celsius (or Kelvin)
Conversion:
(F-32)/1.8=C
1.8C+32=F
K=C+273.15
Zero degrees Celsius is the freezing point of water, and equals 32 degrees Fahrenheit
100 degrees Celsius is the boiling point of water, and equals 212 degrees Fahrenheit
-40 degrees C is exactly equal to -40 degrees F
Zero degrees Kelvin is absolute zero
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Time is measured in the metric system in seconds for all scientific purposes. As in the old
systems,
for everyday usage, there are:
60 seconds = 1 minute
3600 seconds = 1 hour
60 minutes = 1 hour
86,400 seconds = 1 day
1,440 minutes = 1 day
24 hours = 1 day
604,800 seconds = 1 week
10,080 minute = 1 week
7 days = 1 week
equatorial year = 365.2422 ephemeris days
sidereal year = 365.2564 ephemeris days
sidereal year = 3.155815 x 107 seconds
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Go to Heretical Physics
Elemental, or particle, physics is still very much an area of exploration. Whereas
astronomical
scales in the universe seem to be ruled by the laws of relativity, and the human macroscopic
scale
seem to be ruled by Newtonian physics, the subatomic level seems to be ruled by quantum
mechanics.
Some of the underlying concepts of quantum mechanics are that 1) energy and some other
quanta
can be measured in discrete units, like having a bag of candy, which is composed of individual
pieces, and it can only be made lighter or heavier by adding or subtracting whole pieces; 2)
many
of the descriptors on the subatomic level are probabilistic, that is, e.g., the position of an electron
at
any one time can be only said to be at any particular spot with a calculated probability; 3) that
(my
own interpretation) scalars based on spatial dimensions cannot be measured concurrently with
scalars based on time dimensions. This is from the Heidelberg uncertainty principle, which
actually states that we can know a particle's momentum, OR its position, but never both at once.
Having just used the term scalar, let me explain:
Tensors are combinations of linked measurements of particles. Tensors of the first order
only
measure one characteristic, and are called scalars. Thus, if you're driving to Grandma's, your
speed (technically, not velocity) in miles per hour would be a scalar, since only one thing is
being
measured. Tensors of the second order measure two characteristics, and are called vectors.
Thus,
the fact that you're going due north in the car, coupled with its speed, is a vector (and is,
properly,
the car's velocity). When the term tensor is used by itself, it generally means tensors of the third
order and above. It's certainly possible in physics to have things like tensors of the seventh
order.
Here are the fundamental groups of subatomic particles:
- Quarks: These are the basic building blocks of matter as we know it. There are twelve of
them now believed to exist--that is, six varieties, with each having an antimatter partner.
Looking
at it from another viewpoint, it could be stated that there are actually 36 varieties (more on that
in
gluons, below) The basic types are: charm, strange, up, down, top, and bottom. These are in
partnered pairs; charm and strange go together, as do up and down, and top and bottom. The
charm, up, and top quarks correspond as a group with the same spin of 2/3, while the strange,
down, and bottom quarks correspond as a group with the same spin of -1/3. By far the most
commonly known are the up and down quarks, while the most elusive is the bottom quark.
- Gluons: These are believed to come in eight flavors, corresponding to the color
combinations
of quarks. As mentioned above, the twelve quarks and anti-quarks can be multiplied by three to
a
total of 36, because another characteristic of quarks has been assigned, called color. With three
colors, there must be six gluons to mediate binding between any combination of pairs: aa, ab,
ac, bb, bc. There are believed to be another two. They are called gluons because they "glue"
together the quarks.
- Leptons: This is a very particular family of particles, with the same tabular structure as
quarks. That is, there are three pairs, with each pair being divided between two classes. The
varieties, in pairs, are: electron, electron neutrino, tauon, tau neutrino, muon, and mu neutrino.
Electrons are, of course, quite common, while neutrinos can be detected only with excruciating
difficulty.
- Gage bosons: These are particles that correspond to the four elemental physical forces:
electromagnetism, gravity, weak nuclear force, and strong nuclear force.
- The photon, a massless particle, is well-known to be the mediator of electromagnetism,
which is radiation through space, wholly distinct from electricity, which is a function
through matter of electrons. The electromagnetic spectrum travels through the absolute
vacuum of space, whereas sound waves do not. The electromagnetic spectrum as we
know it ranges from radiation with a very high frequency, high energy levels, and short
wavelength at one end, going to low frequency, low energy, and long wavelength at the
other. From the short end, they are: 1) cosmic rays, 2) gamma rays, 3) x-rays, 4)
ultraviolet, 5) optical spectrum, from violet to red, 6) near infrared, 7) mid-infrared, 8)
far infrared, 9) heat radiation, 10) microwaves, 11) radio and television waves. At the
beginning end, there may be many millions of waves within any one pixel on this page,
while at the broadcast wave end, the waves may a city block long or longer (this is VLF,
very low frequency!). Photons have long been known to act both like waves and like
particles. The spectrum seen by the human eye has everything to do with the size of the
eye and of the light-sensitive cells in the retina.
- Higgs-boson particles are thought to mediate the weak nuclear force. These are X+, X-,
and Z0. They are massive particles, and are actually mesons.
- Gluons, already discussed, are believed to mediate the strong nuclear force.
- No gage particles have ever been detected for gravity. There are theoretical particles,
such as the graviton, or even gravitino, but these have never been shown to actually
exist. Obviously, something must produce the force of gravity, but it's a tough nut to
crack!
- Baryons: These include protons and neutrons. There are many, many other baryons, but the
proton and neutron are the only ones known to commonly occur in normal space-time.
Baryons are made up of a combination of quarks, three quarks to a boson, held together with
gluons. The quarks in baryons are all normal (positive) matter. However, recent evidence has
indicated that quarks are zipping through a boson constantly, but there is always the triad in
addition to the other quarks, which both appear and annihilate as pairs.
- Mesons: There are many of these, as well, but are generally only transient in reactions.
Mesons are also made up of a combination of quarks, but in this case are composed of one
normal
quark and one anti-quark.
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Kingdom: Virusae
Viruses are usually not technically considered to be living things, because they cannot
perform
any function for themselves except cell entry and replication. However, they do contain DNA or
RNA or both.
Kingdom: Archeobacteria
The Archaeobacteria have only been recently discovered, living around volcanic vents on the
deep ocean floor.
Kingdom: Monera
The Monera include the bacteria (other than Archaeobacteria) and some "algae".
Kingdom: Protista
The Protista include all eukaryotic single-celled organisms. As such, it is cladistically
artificial.
Included are paramecia and euglenas.
Kingdom: Plantae
Go to Kingdom: Plantae
Kingdom: Fungi
The Fungi had long been lumped in with plants, but research has demonstrated them to be a
separate group, and actually probably more closely related to animals than plants. They include
mushrooms, shelf fungi, yeasts, molds, smuts, puffballs.
Kingdom: Animalia
This is NOT a comprehensive outline, but only includes some of the most important groups.
- Phylum: Coelenterata
- Phylum: Mollusca
- Class: Bivalvia: clams, oysters, mussels, scallops
- Class: Cephalopoda: octopus, squid, cuttlefish
- Class: Gastropoda: Conchs, whelks, snails and slugs
- Class: Nautilidae: nautilus and ammonites
- Phylum: Arthropoda (not all classes included)
- Class: Crustacea: shrimp, lobster, crab, crayfish, isopods
- Class: Arachnida: spiders, ticks, mites
- Class: Insecta: insects
- Phylum: Chordata
- Class: Pisces
- Class: Amphibia
- Order: Salamandrales
- Newts, mudpuppies, hellbenders, other salamanders
- Order: Ranales
- Frogs, tree frogs, and toads
- Class: Reptilia (the evolutionary division between these two orders probably justifies
their being placed in separate classes)
- Order: Testudines
- Order: Serpentia
- Class: Dinosauria
- Subclass: Dinosauria
- Subclass: Crocodilia
- Crocodiles, alligators, caymans, gavials
- Subclass: Aves
- Birds: raptors, songbirds, vultures, ducks, geese, storks, swans, ibis, gulls,
etc.
- Class: Mammalia
- Subclass: Monotremata
- Order: Monotremata
- Platypus and echidnas (Australia)
- Subclass: Marsupialia
- Order: Marsupialia
- Kangaroos, wallabies, koalas, wombats, opossums
- Subclass: Placentae
- Order: Insectivora
- Order: Chiroptera
- Order: Primatia
- Lemurs, tarsus, monkeys, apes, humans
- Order: Rodentia
- Mice, rats, beaver, muskrats, guinea pigs, hamsters, voles, naked mole rats,
etc.
- Order: Lagomorpha
- Rabbits, hares and pikas (allied with Rodentia, above)
- Order: Carnivora
- Family: Felidae
- Cats: lions, tigers, jaguars, leopards, cheetahs, pumas, ocelots, lynx,
bobcats, etc.
- Family: Procyonidae
- Family: Bassariscidae
- Ringtails (closely allied to the Procyonidae)
- Family: Mustelidae
- Stoats, weasels, ferrets, mink, martens, fishers, badgers, wolverines,
otter, sea otters
- Family: Mephitidae
- Skunks (previously included in the Mustelidae and allied to it, but
recent genetic research has shown that it should be listed separately)
- Family: Canidae
- Dogs, wolves, foxes, hyenas, jackals, coyotes
- Family: Ursidae
- Bears: black, brown, Kodiak, grizzly, sun, spectacled, polar, panda,
etc.
- Order: Pinnipedia
- Seals, sea lions, walruses (very closely allied to carnivora)
- Order: Perissodactyla
- Equidae
- Rhinocerotidae
- Tapiridae
- Hippopotamidae
- Order: Artiodactyla
- Giraffidae
- Camelidae
- Camels (dromedaries, Bactrian), llamas, alpacas, vicunas, guanacos
- Bovidae
- Cattle, oxen, buffalo, bison, antelope, sheep, goats
- Cervidae
- Deer, caribou, elk, moose
- Antilocapridae
- Suidae
- Tayassuidae
- Peccaries (closely allied to Suidae, above)
- Order: Proboscidea
- Order Hyracoidea
- Hyrax (allied to elephants, above)
- Order: Sirenia
- Sea cows, manatees, dugongs
- Order: Xenarthra
- Order: Tubulidentata
- One species, the Aardvark
- Order: Cetacea
- Whales, porpoises (this order is thought to be allied with the Hippopotamus
family; they should probably be placed in the same order)
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