This document provides definitions and descriptions of key concepts in earth and life science. It defines science as using systematic methods like observation and experimentation to study the natural world. It then discusses the universe and branches of science like space, time, energy, matter, and dark matter. Space is described as the three-dimensional extent in which objects have position and direction. Time is the progress of existence from past to future. Energy must be transferred to objects to cause change, and is conserved. Matter occupies space and has mass. Dark matter is estimated to make up 85% of the universe's matter.

1. Earth and Life
Science

2. What is SCIENCE?
It is a set of tools and systematic methods for
studying the natural world through observation
and experimentation.

4. UNIVERSE
The physical universe is defined as all of space
a
a
n
n
d
dt
t
i
i
m
m
e
e((c
c
o
o
l
l
l
l
e
e
c
c
tt
i
i
v
v
e
e
l
l
y
yr
r
e
e
f
f
e
e
r
r
r
r
e
e
d
dt
t
o
oa
a
s
s
s
s
p
p
a
a
c
c
e
e
t
t
i
i
m
m
e
e
)
)
a
a
n
n
d
dtth
h
e
e
i
i
rrc
c
o
o
n
n
t
t
e
e
n
n
t
t
s
s
.
.S
S
u
u
c
c
h
hc
c
o
o
n
n
t
t
e
e
n
n
t
t
s
sc
c
o
o
m
m
p
p
r
r
i
i
s
e
eaallllof
energy in its various forms, including
electromagnetic radiation and matter, and
therefore planets, moons, stars, galaxies, and
the contents of intergalactic space.

5. BRANCHES OF SCIENCE

6. SPACE
Space is the boundless three-dimensional
extent in whichobjects and events have
relative position and direction.[
P1
]hPyhsyicsaicla
s
l
p
s
a
p
c
a
e
c
i
e
s
i
so
o
ftfe
t
e
n
n
c
c
o
o
n
n
c
e
c
e
i
vi
v
e
e
d
d
i
n
i
n
t
h
t
h
re
r
e
e
e
l
i
n
l
i
n
e
e
a
a
rr
d
d
i
m
i
m
e
e
n
n
s
s
i
o
i
o
n
n
s
,
s
,
a
a
l
l
t
t
h
h
o
o
u
u
g
g
h
hm
m
o
o
d
d
e
e
r
r
n
np
p
h
h
y
y
s
s
i
i
c
c
i
i
s
s
t
t
s
su
u
s
s
u
u
a
a
l
l
l
l
y
yc
c
o
o
n
n
s
s
i
i
d
d
e
e
r
riitt,,
withtime, to be part of a boundless four-
dimensional continuum knownas spacetime.
The concept of space is considered to be of
fundamental importance to an understanding of
the physical universe

7. TIME
Time is the indefinite
continued progress of existence and events that occur
in an apparently irreversible succession from the past,
through the present, into the future. It is a component
quantity of various measurements used
to sequence events, to compare the duration of events
or the intervals between them, and to quantify rates of
change of quantities in material reality or in
the conscious experience. Time is often referred to as a
fourth dimension, along with three spatial dimensions.

8. ENERGY
In physics, energy is the quantitative property
that must be transferred to an object in order to
perform work on, or to heat, the object. Energy
is a conserved quantity; the law of conservation
of energy states that energy can be converted in
form, but not created or destroyed.

9. MATTER
Matter has many definitions, but the most
common is that it is any substance which
has mass and occupies space. All physical
objects are composed of matter, in the form
of atoms, which are in turn composed of
protons, neutrons, and electrons.

10. DARK MATTER
Dark matter is a form of matter thought to
account for approximately 85% of the matter in
the universe and about a quarter of its total
mass–energy density or about
2.241×10−27 kg/m3.

11. Catastrophe theory deals with
the nonlinear phenomena in which
a continuous change in control
parameters results in a
discontinuous alteration of a
quantity characterizing the
examined system. ...
The theory describes only such
phenomena whose form is
resistant to perturbations–– that is,
structurally stable.
A scientific theory is a broad
explanation for events that is widely
accepted as true. To become a theory, a
hypothesis must be tested over and over
again, and it must be supported by a
great deal of evidence. People
commonly use the word theory to
describe a guess about how or why
something happens