ASTRONOMY AND
COSMOLOGY
Galaxy
huge
of dustbounded
gases
A
:
collection
star
and
of
,
stats
-
Spiral
•
Barred
•
•
•
•
•
.
.
space
so
where
strong
light
It
is
star
place
gravity
that
using
reaction
.
rock
in
stones
moving
When
they
earth 's
enter
they
.
small
A
:
or
space
atmosphere
meteor
become
A
:
.
collection
of
rock
gas dust,
and ice Due to heat
frozen
,
dust
and
gas
trail
is
behind forming
left
tail
a
.
Asteroid
in
when
.
:
A
size
large
in
stone that
are
space Meteoroids
small stones broken
floats
is
escape
produced
dies
.
produce
heat
that
Meteoroid
.
even
cannot
light
and
Ha
Astronomy
Elliptical galaxy
lenticular
galaxy
Irregular galaxy
Peculiar
galaxy
A
He
cloud
Comet
spiral
:
and
fusion
galaxy
Black hole
a
the
-
force
gravitational
Types
by
huge
gas mostly
A
:
.
.
out
of
can
around
asteroid
have
a
an
star
.
body
1
:
celestial
A
that
Orbits
.
a
stat
Spherical shaped
2.
They
orbit
.
Planet
due
gravity
sufficient
No
around it
to
3
.
dehri
clear orbit
;
.
dwarf
Pluto
is
a
Kuiper
's
nett
.
planet
as
it
orbits
along
with
other
masses
in
Stellar
to
stars
between
slats
related
:
Interstellar
:
91s
→
Luminosity
→
The
word
or
emitting
luminous
energy
flux
Radiant
means
per
-
to that
glowing
luminosity incident
the
unit
intensity
surface
surface
Luminosity
→
-
the
star
surface
•
power
by
d
of
Area
Surface
A--41T¢
'
The
includes
electromagnetic
"
is
area
and
only
.
the
temperature
Son's
nil
all
but
luminosity
•
emitted
radiation
radiations
body
total
→
.
light
→
the
radiation
The
→
is
.
.
•
-
normal
area
by
effected
radiant
of
.
luminosity
Proxima Centauri
I
surface
:
=
4×10
"
4×10
"
¥
=
=
W
L
:
d
:
>
u¥d
luminosity
distance
surface
.
a
↳
W
Radiations
e
.
Surface
Area
1W )
from
center
of
star to
Standard
Candles
1
luminosity
body of known
standard candle
A
a
called
is
6
.
←
→
luminosity
for
I
=
I
any
is
radiation
1400 Wm
=L
not
for light
just heat
e.
g.
,
but
✗
ultra
L
=
4
Earth
4%11.5×-10
3.96×10
I
start
.
distance
±
r
→
←
"
"
T
"
to
"
)
of
star
=
Radius
Earth
of
sphere
-
W
•
•
Type 1- A Supernova
Cepheid Variables
}
Typical
Standard
Candles
→
and
body
Black
radiation
When
and
✗
reflect
+
p
incident
9
=L
p
I
→
A
body
able
are
→
A
appears
body
is
radiations
•
to
colored
color
•
object
absorb , transmit
can
.
absorbed
fraction
reflected fraction
:
:
fraction
transmitted
:
7--1
because
transparent
pass through
0=0
,
,
p
=
All radiations
0
.
.
get reflected
red
appears
radiation
is
appears
as
,
✗
+
p
-
1
Some
.
absorbed
gets
&
some
.
to
all
black
all
absorb
objects
opaque
which
7=0
because
opaque
appears
it
body
a
on
radiation
that
I
+
is
Radiations
body
Black
colors
as
reflected
the
be
all
back
get
'
radiations
color
radiations
.
of object
absorbed
get
reflect
and
and
.
e.
only
g. Red
need is
absorbed
that
box
reflected
and
no
.
body
Black
Black
body
It
1.
its
A
.
all
is
A
is
Blake
at
a
a
body
radiation
is
radiations
black
that
black
A
.
,
a
black
is
body
radiation
of
.
.
properties
radiation
incident
irrespective
it
because
of
does not
.
perfect
Than
a
emits
in
emitter
black
.
other
No
surface
body provided being
perfectly diffused
either
time
.
as
Does not
all
possible
directions
emitter
-
specific
several
has
any
absorber
perfect
a
as
can
at
emit
same
.
body
acts
considered
reflecting
not
The
absorbs
body
temperature
.
surface
a
any
black
thence )
is
radiations
wavelength
more
3
body
Black
complexly
reflect
2
:
.
A
blackbody
.
a
perfect
act
as
absorber
both
at
or
a
the
emitter
perfecttime
same
.
→
Black
body
surfaces
or
→
→
→
an
basically
is
are
compared
emitter
Black
objects
Tie
is
star
is
a
are
black
a
to
reference surface
how
determine
that
object
Treated
as
body
is
which
an
good
real
absorber
.
blackbody
for infrared
ady for infrared
close to
with
radiations
(
radiations
(
perfect
perfect
-
absorber )
emitter )
Stephan
Boltzmann
-
luminosity
at
a
of
to
to
T
its
"
L
:
A
:
T
L
.
surface
Absolute
:
where
surface
:
equation
applied considering
is
at
Kelvins
0
.
If surrounding temp is higher
decreases
Luminosity
.
OAT
For
"
Boltzmann
constant
1 A
area
=
4117
5.67×10-8
)
must
versa
W/ will
"
L ✗
^
3A
blackbody
two
object
→
T
>
/
A
,
K
a
black
2L
T
→
3L
2T
body
=
radius
&
vice
OA
kelvins
.
"
(
L
→
24×1
→
3
→
surrounding
zero
.
.
La T
L
same
Holter star
1-
smaller
→
if
✗
the
tu
3T
not
having
,
have
A
[ ✗ 1-4
←
stars
luminosity
2A
LIW
this
surrounding
area
temperature
Luminosity 1W )
0
.
.
=
Stephan
:
T is
body
directly
.
Mathematically
0
black
Temperature
proportional
and
a
Law
T
is
"
"
✗
L
=
-
16L
81L
"
-
Ts )
at
temp
Ts
,
not
Diyala
Wien's
The
cement
wavelength
Law
peak intensity
at
inversely proportional
Thermodynamic temperature
is
to
.
✗ max
¥
✗
✗ mast
T
:
✗ max
so
=
0.0029
=
1kt
surface Temperature
✗ max
:
¥
wavelength having
intensity
<
Max
•
color
is
i. e.
higher
higher
no
.
temperatures
and
of
Higher Temp
is
so
photons
→
from
moves
.
all
At
of light
,
photon energy
the
intensity
•
coming
red
wavelengths
to
Brightness of light
increase
TIK
blue
not
object
and hence
white !
intensity
.
shorter
from
=
TIE +273
increases
.
due to
shift
when
Red
Hubble 's
stars
or
galaxies
move
away
from
frequency of light coming from it
the
decreases
observer
Hence
.
its
seen
in
The
shift
,
a
color
observed
the
shift
red
directly proportional
deaf
of receding
VIBGYOR
the
=
C
✗
•
Formula
v
•
is
Used
✓
of
Df_
v
is
much
to
the
v
:
H
:
d
:
I
=
H
C
when
calculate the
galaxy
c
speed
.
:
Hubble's
Earth
.
distance bfw source & observer
that
instant
of galaxies
Big Bang theory
is
of
radiations
.
'
the
.
the
constant
idea
theory
to
star
recession
This
Presence
a
Hd
v=
2.2×10-185
universe
of
from
star
speed of
at
smaller than
star /
of
the
lv )
proportional
so
>
f
applicable
where
speed
in c- X
.
DX
distance
✓ ✗ d
is
of
recession
directly
is
.
to
speed
is
frequency / wavelength
in
the
law
receding proves
that
expanding
cosmic
also
.
microwave
support
the
the
background
Big Bang
old is
How
v
universe ?
the
Hd
=
fastest galaxy
the
speed of light
c-
d
.
would
So
and
at
v=c
i. e.
hence
v=dz
as
Hd
v=
F
be
IT
it
4=1-1 ¢
=
H
time
1-
in
years
=
.
1
=
2.
T
of origin
2×10-18
4.55×10
4.55×10
"
s
"
365×24×3600
=
1.44×1010 years
a) L
=
OAT
"
6.0×1028--5.67×10 -8×17×13400 )
A--7.8×10
b)
A
"
'
m
41T v2
=
Itar
7.8×1021=411-82
r
=
2.5×1010
"
2.5×10
=
700×108
Tsun
m
"
=
35.7
✗
434hm
=
DX= -10.087hm
( recede )
=
a) ✗
I
☐✗
c
0.087
434
V=
=
=
V
393.3hm
=
×
398.6-393.3
=
=
503
-15.3hm
3×108
6.011104ms
393.3
"
V
b)
V=
Hd
4.04×106=2.2×10-18
D=
1.8×10
"
m
¥
=
V
3×108
-4.04×106 m/s
-
d