WEBVTT

1
00:00:03.439 --> 00:00:08.880
Welcome to Bedtime Astronomy. Explore the
wonders of the cosmos with our soothing Bedtime

2
00:00:08.880 --> 00:00:14.759
Astronomy podcast. Each episode offers a
gentle journey through the stars, planets,

3
00:00:14.800 --> 00:00:19.800
and beyond, perfect for unwinding after
a long day. Let's travel through the

4
00:00:19.800 --> 00:00:23.519
mysteries of the universe as you drift
off into a peaceful slumber under the night

5
00:00:23.519 --> 00:00:34.359
sky. The colors of the universe. Colors in the universe are more than

6
00:00:34.560 --> 00:00:41.920
just esthetic features, bear the language
through which the cosmos communicates its underlying processes

7
00:00:42.119 --> 00:00:49.560
and properties. Every hue, from
the fiery reds of nebulae to the icy

8
00:00:49.679 --> 00:00:57.079
blues of distant galaxies, tells a
story about the physical conditions and chemical compositions

9
00:00:57.200 --> 00:01:06.719
of astronomical objects. Understanding these colors
requires an exploration of the science behind them,

10
00:01:07.280 --> 00:01:15.159
revealing the intricate workings of the universe. The colors of celestial objects are

11
00:01:15.239 --> 00:01:22.519
primarily a result of the light they
emit or reflect. This light, when

12
00:01:22.560 --> 00:01:30.480
analyzed through spectroscopy, provides a wealth
of information about the object's temperature, composition,

13
00:01:30.239 --> 00:01:38.120
and motion. The fundamental principle behind
this is that different elements and molecules

14
00:01:38.159 --> 00:01:46.239
emit an absorbed light at specific wavelengths, creating distinct spectral lines that can be

15
00:01:46.319 --> 00:01:53.000
observed and studied. Stars are among
the most prominent colored objects in the night

16
00:01:53.079 --> 00:02:01.200
sky, and their colors are directly
related to their temperatures. Potter stars emit

17
00:02:01.280 --> 00:02:07.519
more blue and ultraviolet light, giving
them a blue or blue white appearance.

18
00:02:08.719 --> 00:02:15.400
B stars, often classified as O
and B type stars, can reach temperatures

19
00:02:15.400 --> 00:02:23.479
of up to thirty thousand kelvin or
more. In contrast, cooler stars emit

20
00:02:23.560 --> 00:02:30.879
more red and infrared light, resulting
in a red or orange hue. B

21
00:02:31.080 --> 00:02:38.759
stars classified as K and M type
stars have surface temperatures ranging from about two

22
00:02:38.800 --> 00:02:47.240
thousand to four thousand kelvin the sun, but G type star as a surface

23
00:02:47.360 --> 00:02:58.240
temperature of approximately five thousand, eight
hundred kelvin and appears yellow. The color

24
00:02:58.280 --> 00:03:01.680
of a star also in the hates
its stage in the stellar life cycle.

25
00:03:04.879 --> 00:03:12.039
Yng massive stars burn hot and blue, while older, less massive stars cool

26
00:03:12.199 --> 00:03:17.800
and turn red as they approach the
end of their lifespans. For example,

27
00:03:19.520 --> 00:03:25.039
red giants and supergiants are stars in
the later stages of their evolution, having

28
00:03:25.159 --> 00:03:34.719
exhausted the hydrogen fuel in their cores
and expanded in size. Beetlejuice, a

29
00:03:34.759 --> 00:03:40.039
red supergiant in the constellation Orion,
is a classic example of such a star,

30
00:03:40.879 --> 00:03:49.639
its deep red color signaling its advanced
age and cooler surface temperature. In

31
00:03:49.680 --> 00:03:55.439
addition to stars, nebulae exhibit a
stunning array of colors that reveal their composition

32
00:03:55.719 --> 00:04:04.039
and the processes occurring within them.
Emission nebulae, such as the Orion nebula,

33
00:04:04.639 --> 00:04:10.800
glow with vivid colors due to the
ionization of their gas by nearby hot

34
00:04:10.800 --> 00:04:17.199
stars. The red and pink hues
in these nebulae are primarily due to hydrogen

35
00:04:17.240 --> 00:04:26.079
atoms, which emit red light when
they recombine with electrons. Green and blue

36
00:04:26.120 --> 00:04:34.680
colors in nebulae can be attributed to
ionized oxygen and helium, respectively. Reflection

37
00:04:34.879 --> 00:04:40.680
nebulae, on the other hand,
do not emit their own light, but

38
00:04:40.800 --> 00:04:47.639
reflect the light of nearby stars.
These nebulae often appear blue because blue light

39
00:04:47.839 --> 00:04:54.839
is scattered more efficiently by the dust
particles within the nebula, similar to the

40
00:04:54.839 --> 00:05:00.600
way Earth's atmosphere scatters blue light from
the Sun, making the sky I appear

41
00:05:00.680 --> 00:05:11.519
blue. Planetary nebulae formed from the
outer layers of a dying star also showcase

42
00:05:11.600 --> 00:05:19.439
a variety of colors. The ring
nebula, for instance, displays fibrant greens,

43
00:05:20.199 --> 00:05:29.079
reds, and blues. These colors
correspond to different elements present in a

44
00:05:29.120 --> 00:05:35.279
nebula, green from ionized oxygen,
red from ionized nitrogen, and blue from

45
00:05:35.319 --> 00:05:45.920
helium. The specific colors and patterns
observed in planetary nebulae can provide valuable information

46
00:05:46.120 --> 00:05:53.360
about the star's mass, composition and
the processes that occurred during its final stages

47
00:05:53.439 --> 00:06:01.879
of evolution. Galaxies, the vast
systems of stars, gas and dust bound

48
00:06:01.920 --> 00:06:08.879
together by gravity, also display a
range of colors that reflect their age and

49
00:06:09.040 --> 00:06:17.519
star forming activity. Spiral galaxies like
the Milky Way often have blue arms and

50
00:06:17.600 --> 00:06:26.600
a yellowish core. The blue regions
indicate active star formation, where young,

51
00:06:27.279 --> 00:06:34.439
ot blue stars dominate the light output. The yellowish core is composed of older,

52
00:06:35.079 --> 00:06:45.000
cooler stars, primarily yellow and red
giants. Elliptical galaxies, on the

53
00:06:45.040 --> 00:06:51.240
other hand, tend to appear more
uniformly reddish or yellowish, indicating a population

54
00:06:51.399 --> 00:07:00.120
of older stars and a lack of
recent star formation. These color differences help

55
00:07:00.120 --> 00:07:06.920
astronomers determine the history and evolution of
galaxies, providing insights into the processes that

56
00:07:08.040 --> 00:07:16.480
shape the universe. Even seemingly empty
regions of space are filled with the faint

57
00:07:16.519 --> 00:07:23.959
glow of the cosmic microwave background radiation, a relic from the early universe.

58
00:07:26.160 --> 00:07:32.040
This radiation, which permeates the universe
as a temperature of just two point seven

59
00:07:32.199 --> 00:07:39.920
kelvin and appears as a uniform faint
glow in the microwave part of the spectrum.

60
00:07:41.399 --> 00:07:47.199
Detailed measurements of its slight temperature variations, however, reveal a pattern that

61
00:07:47.279 --> 00:07:55.040
corresponds to the density fluctuations in the
early universe, which eventually led to the

62
00:07:55.079 --> 00:08:03.240
formation of galaxies and large scale structures. The study of these temperature variations,

63
00:08:03.240 --> 00:08:11.040
often represented in false color images,
provides crucial information about the origins and evolution

64
00:08:11.319 --> 00:08:18.680
of the universe. The colors of
planets within our own Solar System also tell

65
00:08:18.800 --> 00:08:28.480
us about their atmospheres and surfaces.
Mars miln as the red planet bowse its

66
00:08:28.600 --> 00:08:37.360
distinctive color to iron oxide rust on
its surface. Jupiter's Great Red Spot and

67
00:08:37.440 --> 00:08:43.480
its overall banded appearance are due to
complex atmospheric processes and the presence of different

68
00:08:43.559 --> 00:08:54.679
chemicals such as ammonia and methane at
various altitudes. Uranus and Neptune appure blue

69
00:08:54.799 --> 00:09:00.480
due to the presence of methane in
their atmospheres, which absorbs red LFE and

70
00:09:00.519 --> 00:09:09.240
reflects blue light. The study of
exoplanets, or planets orbiting stars outside our

71
00:09:09.320 --> 00:09:18.519
Solar System as revealed a surprising variety
of colors and atmospheric compositions. For instance,

72
00:09:20.240 --> 00:09:26.039
the exoplanet HD one eight nine seven
three three B appears deep blue,

73
00:09:26.720 --> 00:09:33.080
not because of water, but likely
due to silicate particles in its atmosphere which

74
00:09:33.200 --> 00:09:41.159
scatter blue light. Analyzing the colors
and spectra of exoplanets allows scientists to infer

75
00:09:41.279 --> 00:09:54.519
their atmospheric compositions, temperatures, and
potential for habitability. Comets, the icy

76
00:09:54.639 --> 00:10:01.000
wanters of the Solar System, also
display colors that reveal their common positions and

77
00:10:01.120 --> 00:10:09.039
activities. As comets approach the Sun, their ices vaporize, releasing gas and

78
00:10:09.159 --> 00:10:16.879
dust that form a glowing coma entail. The specific colors observed in a comet's

79
00:10:16.919 --> 00:10:26.399
coma and tail can indicate the presence
of different molecules. For example, the

80
00:10:26.440 --> 00:10:31.960
green color often seen in the coma
is due to diatomic carbon C two,

81
00:10:31.720 --> 00:10:37.840
while the blue color in the ion
tail is due to ionized carbon monoxide.

82
00:10:37.159 --> 00:10:46.879
Coplus. In addition to natural celestial
objects, human made spacecraft and telescopes have

83
00:10:48.000 --> 00:10:56.759
expanded our ability to observe and interpret
the colors of the universe. Space telescopes

84
00:10:56.879 --> 00:11:03.879
like Hubble, Chundra and James W
Web capture images and various wavelengths from ultraviolet

85
00:11:03.960 --> 00:11:09.320
to infrared, allowing us to see
the universe in ways not possible with the

86
00:11:09.440 --> 00:11:18.240
naked eye. These observations, often
rendered in false color images, provide a

87
00:11:18.279 --> 00:11:26.759
wealth of information about the physical processes
occurring in distant galaxies, nebulae, and

88
00:11:26.879 --> 00:11:35.480
other cosmic phenomena. Infrared observations,
for example, can reveal the heat emitted

89
00:11:35.519 --> 00:11:46.039
by dust and shrouded star forming regions
where visible light is blocked. Ultraviolet observations

90
00:11:46.159 --> 00:11:52.879
highlight the presence of hot young stars
and the energetic processes in active galaxies.

91
00:11:54.279 --> 00:12:01.080
X ray and gamma ray observations uncover
the high energy phenomena associated with black holes,

92
00:12:01.840 --> 00:12:11.360
neutron stars, and supernova remnants.
Each wavelength provides a different piece of

93
00:12:11.399 --> 00:12:20.399
the puzzle, contributing to a more
comprehensive understanding of the universe. Even the

94
00:12:20.519 --> 00:12:28.919
dark parts of the universe are not
truly devoid of color. The phenomenon known

95
00:12:28.000 --> 00:12:35.440
as gravitational lensing, where the gravity
of a massive object bends and amplifies the

96
00:12:35.559 --> 00:12:41.279
light from a more distant object,
can produce arcs and rings of distorted light.

97
00:12:43.440 --> 00:12:48.840
These effects allow astronomers to study the
distribution of dark matter, an invisible

98
00:12:48.919 --> 00:12:56.799
component of the universe that does not
emit light but exerts gravitational influence on visible

99
00:12:56.879 --> 00:13:05.440
matter. By analyze the colors and
shapes of lensed objects, scientists can infer

100
00:13:05.519 --> 00:13:11.000
the presence and distribution of dark matter, shedding light on one of the most

101
00:13:11.039 --> 00:13:20.159
mysterious aspects of the cosmos. Another
key concept in astronomy is called redshift.

102
00:13:20.639 --> 00:13:28.519
It helps us understand how the universe
is expanding. When we look at distant

103
00:13:28.559 --> 00:13:33.960
galaxies, we notice that their light
appears shifted towards the red end of the

104
00:13:33.039 --> 00:13:41.440
spectrum. This redshift happens because the
universe itself is stretching, which makes the

105
00:13:41.480 --> 00:13:50.000
wavelengths of light from these galaxies longer
and redder. To grasp this idea,

106
00:13:50.759 --> 00:13:56.120
imagine the sound of an ambulance siren
as it moves away from you. The

107
00:13:56.200 --> 00:14:03.159
pitch of the siren lowers because the
sound stretch out. This is called the

108
00:14:03.240 --> 00:14:11.039
Doppler effect. A similar effect happens
with light from distant objects in the universe.

109
00:14:13.240 --> 00:14:20.039
As these objects move away from us, their light stretches out, becoming

110
00:14:20.120 --> 00:14:28.759
redder. Edwin Hubble discovered in the
nineteen twenties that galaxies are moving away from

111
00:14:28.840 --> 00:14:35.879
us, and the farther away they
are, the faster they're moving. This

112
00:14:37.080 --> 00:14:43.759
relationship is known as Hubble's law.
It was one of the first pieces of

113
00:14:43.759 --> 00:14:48.919
evidence for the Big Bang theory,
which says that the universe started from a

114
00:14:48.919 --> 00:14:56.799
hot, dense point and has been
expanding ever since. Redshift isn't just about

115
00:14:56.840 --> 00:15:03.639
distant galaxies moving away from us.
It also tells us a lot about the

116
00:15:03.759 --> 00:15:11.279
universe's history and structure. For example, by measuring the redshift of galaxies,

117
00:15:11.919 --> 00:15:18.840
we can determine their distance and how
fast they're moving. This helps us map

118
00:15:18.879 --> 00:15:26.080
out the universe and understand its large
scale structure. There are different types of

119
00:15:26.159 --> 00:15:33.519
red shift. The most common is
cosmological redshift, which is due to the

120
00:15:33.559 --> 00:15:43.480
expansion of the universe. There's also
gravitational redshift, which happens when light escapes

121
00:15:43.559 --> 00:15:50.120
from a strong gravitational field, like
near a black hole. The light loses

122
00:15:50.360 --> 00:16:00.159
energy and shifts to red Doppler redshift, as we discussed earlier, occurs when

123
00:16:00.200 --> 00:16:07.559
an object moves away from the observer, stretching the light waves. One of

124
00:16:07.600 --> 00:16:15.600
the most significant uses of redshift is
studying the cosmic microwave background radiation. It

125
00:16:15.679 --> 00:16:21.559
is the afterglow of the Big Bang
and is spread across the entire universe.

126
00:16:22.759 --> 00:16:30.559
It has a very uniform temperature,
but with slight variations. These variations give

127
00:16:30.679 --> 00:16:36.919
us a snapshot of the universe when
it was very young, just three hundred

128
00:16:36.919 --> 00:16:42.080
and eighty thousand years old, and
help us understand how galaxies and other structures

129
00:16:42.159 --> 00:16:52.919
formed. Redshift also plays a crucial
role in discovering how fast the universe is

130
00:16:52.000 --> 00:17:00.679
expanding. In the nineteen nineties,
astronomers studying distance and supernov found that the

131
00:17:00.840 --> 00:17:10.880
universe's expansion is accelerating. This surprising
discovery led to the concept of dark energy,

132
00:17:11.519 --> 00:17:21.039
a mysterious force driving this accelerated expansion. Additionally, redshift helps us find

133
00:17:21.200 --> 00:17:29.200
and study distant quasars, extremely bright
and distant objects powered by supermassive black holes.

134
00:17:30.400 --> 00:17:37.400
By analyzing the redshift of light from
quasars, astronomers can learn about the

135
00:17:37.480 --> 00:17:44.839
early universe and the formation of galaxies. Even when we look at planets,

136
00:17:45.599 --> 00:17:52.039
stars, and other objects in our
own galaxy, redshift helps us understand the

137
00:17:52.039 --> 00:18:00.160
emotion. For example, by measuring
the redshift of light from stars, we

138
00:18:00.240 --> 00:18:04.680
can determine how fast they are moving
towards or away from us, which helps

139
00:18:04.759 --> 00:18:12.200
us study the dynamics of our galaxy. In summary, redshift is like a

140
00:18:12.279 --> 00:18:19.400
cosmic speedometer. It tells us how
fast objects are moving away from us,

141
00:18:21.079 --> 00:18:26.960
reveals the universe's expansion, and helps
us understand the large scale structure and history

142
00:18:27.000 --> 00:18:37.039
of the cosmos. By studying redshift, astronomers unlock many of the universe's secrets

143
00:18:37.160 --> 00:18:45.960
and learn more about the forces shaping
everything around us. The interplay of colors

144
00:18:45.000 --> 00:18:51.680
in the universe is a testament to
the diversity and complexity of the processes that

145
00:18:51.720 --> 00:19:00.200
govern the cosmos. From the hot
blue stars blazing brightly in young stellar cluster

146
00:19:00.319 --> 00:19:07.319
to the cool red giants marking the
final stages of stellar evolution, each color

147
00:19:07.440 --> 00:19:14.440
reveals a piece of the story of
our universe. The vibrant hues of nebulae

148
00:19:14.480 --> 00:19:21.039
and galaxies, the subtle glow of
the cosmic microwave background, and the diverse

149
00:19:21.119 --> 00:19:26.559
colors of planets and comets all contribute
to our understanding of the universe's vast and

150
00:19:26.720 --> 00:19:37.200
intricate tapestry. Ultimately, the colors
of the universe are not just beautiful sites

151
00:19:37.240 --> 00:19:45.799
to behold, they are crucial tools
for scientific discovery. By studying these colors,

152
00:19:47.480 --> 00:19:55.279
astronomers and physicists can decipher the physical
conditions, compositions, and histories of

153
00:19:55.400 --> 00:20:03.759
celestial objects, unlocking the secrets of
the cosmos. The colors we observe in

154
00:20:03.799 --> 00:20:08.920
the night sky and through advanced telescopes
provide a window into the dynamic and ever

155
00:20:10.079 --> 00:20:15.039
changing universe, allowing us to explore
its wonders and deepen our knowledge of the

156
00:20:15.160 --> 00:22:00.519
natural world. Pa