What is the Universe?

In our Universe, elements were born

Stars were born from the elements

The EarthA celestial body
Light emitted from that celestial body

Rule 1 Looking into the distant Universe means looking into the pastTime

Our current location

4.6 billion years ago

10 billion years ago
12 billion
years agoLight
spreads out
in all directions

Light isemitted bycelestial bodies

13.8 billion
years ago

The birth of
the Universe
Celestial
bodies are created“The Universe as
we see it today”(the surface ofthe teardrop shape)

The light blue line illustrates the space that ismoving away from the Earth at exactly the speed oflight, as a result of the Universe’s expansion. Space
that is further away is moving away from the Eartheven faster than the speed of light. Because theexpansion of the Universe is the expansion of space
itself, even if the rate of change in the distance
between a given point in space and another point
exceeds the speed of light, it does not contradict the“principle of the constancy of the speed of light”.

Galaxy cluster
Shapley 8

1 billion years ago

The “Big Bang”(Hydrogenatomic nucleus)

NeutronPhotonElectron
Up quark
Down quark
Positron
Anti up quark
Anti down quark

Immediately after its formation, the Universe was a superheated, super-condensed fireball, heated by an incalculable energy*1.
This is what is now referred to as the Big Bang. During this event, huge volumes of elementary particles, including photons, werecreated. These photons flew about at the speed of light, but about 1 trillionth of a second after the beginning of the Big Bang,a “Higgs field” was formed. Interactions with this field impeded the movement of specific elementary particles, slowing themdown below the speed of light. With this hindered movement, the elementary particles gained inertial mass*2. There are two
types of elementary particles: particles, and antiparticles. When these two substances collide, they cease to exist, becoming
weightless particles similar to light. Because there were about 1 billion times more particles than antiparticles, the former wereleft behind*3. These left-over particles are believed to have become the substance of the Universe as we know it today.
Particle

Where did the
Big Bang occur?

*1 The temperature at this time was a billion billion billion degrees (1x1027K).
*2 There are two types of mass: inertial mass, which manifests as hindered movement, and gravitational mass, which causes
universal gravitation. These two types of mass are exactly the same, but the reason for this is still unknown.
*3 Antiparticles are still being created and disappearing today.

Antiparticle

The entire Universe as we
see it today wa s createdthrough the Big Bang. In otherwords, the Big Bang occurredin every location in the Univer se. If you go back far
enough in time, every place inthe Universe was where thespot the Big Bang took place.

Space on the widest part of
the teardrop was travelingaway at exactly the speed oflight at the moment when it
emitted that light. The surfaceof the teardrop lower than thewidest point (further in thepast) represents space moving
away faster than the speed oflight. We are also observing
light emitted by celestial bodies that are moving away fasterthan the speed of light, when
the light which reaches us justnow was emitted.

The beginningof the Big Bang
Inflation

Matter particles

Up quark,
down quark,
etc.

LeptonPhotonParticles thattransmit power

Formation of
the Higgs field

Quark

Electron,neutrino,etc.
A medium forelectromagnetic power

Weak boson

A mediumfor the weak force thatacts between elemental particles

4.6 billion
years ago

Formation of our Solar System, and the EarthThe Earth was born 4.6 billion years ago, andseveral hundred million years later, a collision
between the Earth and a celestial body the sizeof Mars gave birth to the Moon.

Some stars
are leftbehind as
neutronstars or?
black holes. A very smallpart of abinary system+

6h15h49.8m

18h

9 billion years ago

0h

11 billion years ago

Galaxy cluster
JKCS 041

The path of a celestial
body and light
12 billion years ago

13 billion years ago
Birth ofthe first star

The white dot te d line s rep resent the paths t aken bygala x y cluster JKCS 041 as it
moved away from us due to the
expansion of the Universe. The
yellow dotted lines represent
02hlight emit ted at this time by
18.9m
gala xy cluster JKCS 041; thelight reached us by following apath along the teardrop’s surface.

13.8 billion years ago

Expanding at
Cosmic Microwave Background,
about 60x
observed by the Planck spacecraft. This
the speed of lightis what the Universe
looked like whenthe “fog lifted”.

Starting from “Fluctuations in the 'Nothingness'”?

It is possible that in the newborn Universe, the number of dimensions was different from what we know today. According
to one theory, the Universe originally had 11 dimensions, but eventually, superfluous dimensions fell away, leaving only
the three dimensions of space and one dimension of time. Another theory regarding the beginning of the Universe states
Gluon A medium for the strongthat the Universe was born from “Fluctuations in the 'Nothingness'”. This Fluctuations in the 'Nothingness' is a state inforce that connects quarks
which minuscule universes are born and then disappear in an absence of substance, space, and even time. The theory
Higgs particle Particles that
“Fluctuations in thegoes that one of these universes grew without disappearing, for some unknown reason, becoming the Universe in which'Nothingness'”?
accompany activity in the Higgs field
we now live. But where did this Fluctuations in the 'Nothingness' come from? And whatever it was that caused thisFluctuations in the 'Nothingness', where did it come from? Will we ever find our way to the beginning of the beginning?
32
A pushpin hole is about a hundred thousand billion billion billion (1x10 ) times the size of the Universe when it first came into being.

The entire Universe expanded
as a result of this inflation
Where in the Universe are we?

In this diagram, the center is drawn as “the Universe as we
see it today”, which we can interact with through our observations. We do
not know, however, where “the Universe as we see it today” is positioned in
the Universe as a whole, outside of the scope of our observations.

Supernova
explosion

Red
giant
Red
Wolf- supergiant
Rayet star

02h
26.7m

The oldest
known galaxy:
SXDF-NB1006-2

Gradually
grows darker

Planetary
nebula12h36.7m

Supernova
1997ff

White
dwarf

10 million –10 billion years

12h

10
thousandyears

8 billion years ago

1 billion –100 billion years

01h
52.7m

Stars are created in clouds of gas and dust orbiting withingalaxies. The lifetime of a star, and its final form, differ
depending on the star’s mass. Many of the materials thatmake up the stars ultimately return to the UniSupernova
verse, becoming the maexplosion
terials for the next generation of stars.

Several hundred
million years

7 billion years ago

Mainsequence star
Brown
dwarf
ProtostarGas and dust
Highmass

Lowmass

The heavier the star,
the less time each process takes.

The radius of “the Universe as we see it today” was approximately
41 million light years when the Universe became transparent to radiation.

Approx.
370,000
years* For example, imagine a single virus instantly growing larger than a galaxy cluster.

Giving birth to the Universe

Creation of the Earth and formationof the Moon

08h24.2m

6 billion years ago

The birth and evolution of life on the Earth

Currently, many life forms, including human beings, thrive on dry land on the Earth. Long ago,
however, life only existed in the oceans. The first life on the Earth came into being in the primevalseas*. Various elements in the ocean are believed to have combined and undergone chemical
reactions, gradually forming complex organisms, and eventually giving birth to the first life on Earth.
But if the Earth gave birth to life, then how did the Universe bring the Earth into being?
Shells formed in the water, which contains organic substances,and self-replicating organisms appeared.

*It is still not clearly understood when the first life on Earth was formed, but the oldest known fossil of a livingorganism is about 3.5 billion years old.

The stage is set for the formation of life

The Earth and the other planets of our Solar System were formed about 4.6 billion years ago. Gas anddust floating in interstellar space gradually condensed into a disk and formed the Sun at the center.
Around the same time, material further out in this disk collapsed to form the Earth and other planets*.
But where did this material come from? It was the remnants of stars that have long since disappeared.
*In galaxies throughout the Universe, there are innumerable places where gas and dust particles finer than grains of sandcoalesce together in huge volumes.

Exoplanet κ Andromedae b

Dust ring around Fomalhaut(α Piscis Austrini)

Exploding stars scatter elements throughout the Universe

Formation of the oceans

10 billion years ago“Inflation”: The rapid expansion of the Universe

Types of elemental particles

Traces of primordial life

The life of a star

The beginning of space and time

In the incredible heat of the Big Bang, the energy that had pervaded the Universe up to that time was transformed
into heat. In the very short time of less than one second from just after the birth of the Universe to just before the
Big Bang - the period called "inflation" - the Universe expanded at a fantastic rate, increasing in size billions uponbillions of times*. The newborn Universe is believed to have been inflated at a fantastic pace by “vacuum energy”,
which is similar to the dark energy that accelerates the current expansion of the Universe but is much larger, on ascale of 10100 times. And with this inflation, time and space became integral parts of the Universe.

3.8 billion
years ago

5 billion years ago

Celestial bodies
moving away fasterthan the speed of light

The Universe as a superheated fireball

Proton14h
11.3m

Fossilized prokaryotic organisms (bacteria)

100 million –100 billion years

About three minutes after the birth of the Universe: that’s the time it took to create all of the matter that exist in
the Universe around us. During these three minutes, the superheated Universe cooled off as it expanded at anincredible rate. Quarks, another type of elementary particle and a building block of matter, gathered to form
protons and neutrons. Then, these protons and neutrons came together to form the "atomic nuclei" of hydrogenand helium, the lightest of all the elements. About 92% of all the atomic nuclei created at this time were hydrogen,and the remaining 8% were helium. Now, let’s take a closer look at the instant in which the Universe was born.

4 billion
years ago

3.5 billion
years ago

1 billion

Radio galaxy
3C 324The Earth’s magnetic field became stronger,
blocking radiation from the Sun and fromouter space, and creating an environment on
Earth that was capable of supporting life.

100 thousand –100 million years 1 million –100 million years

According to numerous theories, including the “Inflating
Universe” theory, the Universe is far more expansive
than the scope illustrated
in this diagram. We canestimate what lies outside of these lines, but itwould be impossible toconfirm these speculations objectively.

Development of geomagnetism

The formation of geomagnetism

3 billion years ago
22h
47.2m

A fossil of a living organism
from about 3.5 billion years ago

The formation of our Solar System, and the Earth

10 thousand –1 million years

Galaxy cluster RX
J0152.7-1357

The starting point in the creation of matter

Heliumatomicnucleus

There are believed to have been two periods
at least in history during which the entire
surface of the Earth was frozen over.

The first supercontinent

About
1 million years

Supernova 1997as

Is there anythingoutside of theinverted cone?

The three minutes in which everything was created
The fog of the
Universe lifts“Snowball Earth”

1 million

After the initial period of
inflation, the speed of
expansion gradually decreased (decelerating
expansion), but an increase in the speed of
expansion has been
observed, from about
6 billion years ago up
to the present (accelerating expansion).

Using space as the x-axis andtime as the y-axis, all celestialbodies currently visible to us
can be arranged on thesurface of this teardrop. The
light emitted by these stars
reaches the Earth after
traveling along the surface of
this teardrop. The further
Galaxydown we go on this diagram,clusterthe further into the past we
3C 295are looking, so we can seethat light from the stars has
traveled to the Earth out ofthe past.

2.7 billion years ago

Life was formed from a variety of elements

The type of violent collision that caused theextinction of the dinosaurs has occurred on
numerous occasions throughout the Earth’s
history.

Appearance of multi-celled organisms

clus
ter J
KCS
041

The
accelerating
expansion of the
Universe

This inverted cone shape
represents the path of
expansion taken by “theUniverse as we see ittoday”, from the birthof the Universe to thepresent. The objects
on the outermost edge
are furthest away fromus, and are currently
traveling at more than
three times the
speed of light.

Galaxy cluster
CL 2244-02

45 billion light years

Collisions of celestial bodies

by g
alax
y

The path of
expansion*1: When substances are broken down into their most basic ingredients, the smallest component, which cannot be broken down any
further, is referred to as an “elementary particle”. Electrons and photons are examples of these elementary particles.
*2: The light that was dispersed when this happened can still be observed by humans today, as “cosmic microwave background radiation”.

Gluon

2 billion
years ago

40 billion light years

Celestial bodies outside of our Solar System are so far away that even if we found a planet that could becalled another Earth, we would not be able to send a probe to explore it directly. Therefore we must use
other methods to determine whether those planets could sustain life; for example, by observing the planet’s
surface environment or atmosphere using space telescopes or extremely large telescopes on Earth to confirm
whether water exists there in liquid form, or by looking for traces of substances such as oxygen, ozone, andThirty Meter Telescope (TMT) will be built at the top
methane (referred to as “biomarkers”), which living organisms could potentially form. Future research willof Mauna Kea in Hawaii by international cooperation
help to clarify whether analogs to terrestrial planets and terrestrial life exist elsewhere in the Universe.

The human body, which could be compared to a small “Universe”, comprises
materials called elements. Modern science has determined that these elements
originated in the stars and were scattered through space eons ago. Let’s goback in time to unravel the mysteries of human beings and the Universe.

We can observe galaxy cluster JKCS 041 through the light emitted at the top of the teardrop. We
can estimate this to be its current position, but we have no way of knowing whether this galaxy
cluster still exists, because on a universal scale, we are unable to observe the “present”.

light
emi
tted

“The Universe as
we see it today”

About 370,000 years after the birth of the Universe, “the fog of the Universe lifted”. Up until that time, the Universe wassuperheated, with huge volumes of “electrons*1” flying back and forth. These electrons crashed into photons, preventing
light from moving in a straight line, and making the entire Universe opaque, as though in the middle of a fog. When thetemperature of the Universe dropped to around 3,000K, however, electrons bonded with atomic nuclei to form
“atoms”, which no longer impeded the movement of light. In this way, the Universe became much clearer*2. Atoms withsimilar properties, referred to as elements, would eventually become the materials from which the first stars formed.

Helium atom

1.9 billion
years ago

30 billion light years

Development of photosynthetic organisms (cyanobacteria)

We know from observations that galaxies already existed in the Universe about
13.1 billion years ago, but we don’t know exactly when the first stars were born.
We believe that the first star had about 40 times more mass than our Sun. A varietyof elements were created inside this giant star. These elements were scatteredby a supernova explosion and they became seeds of new generations of stars.

He

13h
27.9m

The birth of science
7 million years ago: The birth of human beings
65 million years ago: The extinction of the dinosaurs
Mass extinction at the end of the Paleozoic Era
The Cambrian Explosion (diversification of life forms)“Snowball Earth”

22h
01.8m

Galaxy cluster
Abell 1689

Electrons combine with atomic nuclei

Electron

250 million years ago
540 million years ago
600 million years ago
700 million years ago

Galaxy cluster
Abell 3827

Atoms appear, and the fog of the Universe lifts

Hydrogen atom

The Sun20 billion light years

The “Transit Method” used to findplanets outside of our Solar System
as they pass in front of stars

WHAT IS THE MATERIALS’ ORIGIN OF HUMANS?

(from the periodic table)
Segments in white are the elements thatform the materials of the human body

The human body is made up of cells. Withinthese cells, human genomes, which are theblueprints for the human body, are drawn
with DNA. These cells and DNA are in turnmade up of elements.

13h11.6m

The birth of stars and galaxies

H

EuropaAbout 45 billion light years: the current radius of “The Universe as we see it today”
10 billion light years

Today

Based on observations by astronomers up to now, we have learned that there are many diverse planetary systems
outside of our own. Recently, in addition to large, heavy “Jovian” planets, astronomers have discovered planets thatare similar to Earth in both size and mass. Furthermore, a number of the planets discovered could potentially sustain
large bodies of liquid water on the surface, given that they maintain an appropriate distance from their host stars, as
is in the case of Earth. It may not be long before we finally discover a planet that could be called “Another Earth”.

Trans-Neptunian objects

Celestial bodies composed of ice,found outside of Neptune’s orbit

Table of human materials“Snowball Earth”

Why are galaxies distributed in the form of a mesh? The answer is “dark matter”, a
substance that remains unexplained, and which cannot be directly observed. It isbelieved that in volumes containing dark matter, gravity caused even more dark
matter to gather and create "large-scale structures" in the form of a three-dimensional
mesh. Normal matter then collapsed onto the sites where large amounts of dark
matter resided, eventually forming galaxies embedded in these large-scale structures.

The oldest galaxy yet discovered:
SXDF-NB1006-2(13.09 billion years ago)

Pluto
MakemakeHaumeaEris

NeptuneNerve cell

Speed oflight

Does life exist in the vast expanses of the Universe outside of our Solar System? In 1995, for the
first time in history, astronomers discovered a planet around a distant star. Since then, astronomers
have discovered more than 800 planets outside of our Solar System, using a variety of clues; forexample, minute variations in the movement of stars resulting from the revolution of planets
around the stars, or slight changes in the brightness of stars when planets pass in front of them.

Plutoid

UranusElement

DNA

Space

WMAP spacecraftand other sources

The first star brings light to the Universe

The first star in the Universe(simulated image)Looking for “Another Earth”

Developments in space exploration technologies have enabled new scientific research aimed at seeking out
1999
2005
life on other planets. We can now send probes directly to other planets in our Solar System to look for
traces of life. Among the main targets for these probes are Mars, where liquid was thought to exist on theplanet’s surface, and Europa (one of Jupiter’s moons), where an ocean is believed to lie hidden under athick layer of ice. There is little likelihood of finding intelligent life or advanced life forms there, but one
Marks found on Mars, where waterday, we may discover microorganisms on these celestial bodies similar to those found on Earth.
is thought to have flowed

Space, moving away at the speed of light

The mesh of the Universe

These are simulated images of the evolution of large-scale structures in the Universe.
The blue gaseous substance represents dark matter. In reality, dark matter is invisible.

SaturnGiant planets composed mainly of hydrogen and helium

Path
of

SubaruTelescope* ‘Normal matter’ is the basic components that comprise all substances in the world around us. All things, fromanimals to stars in the night sky, including our own bodies, are made up of combinations of normal matter.

Large-scale structures
have formed

Ape-men Humanity

Jupiter-type or “Jovian” planets

Planets composed mainly of rock

The EarthDark matter and large-scale structures

Fluctuations have formedin the distributionof dark matter

Asteroid belt

Terrestrial planetsTime

Our Solar System

Visible light is not the only form of “light”; radio waves, X-rays and gamma rays are also asort of “light”. Collectively they are called “electromagnetic waves”. We can observe theUniverse by using telescopes to capture the electromagnetic waves emitted by celestialbodies. Through a variety of observation methods, we can gain hints that help us to learn
about our Universe.

This is the state of the Universe, as brought to light by recent observations. About
70% of the Universe is “dark energy”, a mysterious form of energy that accelerates the expansion of the Universe. About 30% is an unidentified substance Normal
Darkmattermattercalled “dark matter”, and about 5% is made up of normal matter*. The
5%27%
Universe has a diverse layered structure comprising galaxies with tens
Composior hundreds of billions of stars, galaxy clusters that contain hundreds
Dark energy
tion of the68%
or even thousands of galaxies, and a large, mesh-like structure of
Universe, asgalaxies that are spread out across hundreds of millions of light years.
determined by the

Dark matter is distributed
uniformly

JupiterThis diagram, shaped like an inverted cone, is a graphical representation of the expansion of the Universe. At the centeris the Earth, where we stand as we observe the Universe. We are thus at the center of the diagram. But where is thecenter of the Universe? In fact, astronomers believe that the Universe is homogeneous and isotropic; that is, in “theUniverse as we see it today”, there is no unique location that could be called the “center of the Universe”.

Short --------------------------------- Wavelength --------------------------------- Long
Gamma rays X-rays Ultraviolet rays Visible light Infrared light Radio waves

Countless stars shining in the darkness

Approx. 6.5 billion years later Approx. 13 billion years later

Apes

The Sun: One of the more than 100 billion light-emitting stars in the Milky Way galaxy

Mercury Venus Earth Mars

light on the
Earth.

Electromagnetic waves

The presumed current state of the Universe

Start of calculations

Early Prosimians Early Simians

Our Solar System includes: the Sun, eight planets, asteroids and comets(including trans-Neptunian objects and dwarf planets such as Pluto), and satellites.

The observable Universe (the teardrop-shaped image at the center of the
diagram) is only a drop in the bucket compared to the vast expanse of theactual Universe. Through the “Eyes of Science”, however, we havelearned a great deal using clues from the observable Universe. HowThe
was the observable Universe created (the bottom of the inverted
slope ofcone)? How has it expanded (the outer surface of the cone)? And
thisdoes a Universe exist beyond the outer limits of this cone? Thisyellow line
represents
diagram contains the results of many such scientific discoveries.
the speed of
The Universe is waiting for you to unravel its mysteries.

Our Galaxy

This vast Universe we can observe was once so small that it could not be seen. Modern
science is closing in on the secrets of the Universe, and is gradually gaining an understandingof the astounding origin behind the formation of the Universe itself. Let’s look back at thehistory of the Universe, starting from the moment of its formation some 13.8 billion years ago.

Spiral galaxy M 101

Early Mammals Early Primates

Earth is about 10 billion times the size of a pushpin hole.

Science is a method for understanding all of the objects and phenomena that comprise the Universe.
When we notice something strange, we naturally ask “Why?” This is the first step in science. Scientificmethodology means investigating the phenomena that interest us through experiments and observation,
so that we can gain a deeper understanding. Through this process, we find new ways of seeing and new
ways of thinking. This is scientific discovery. Science is one way of knowing the Universe around us.

Living organisms evolved into beings thatyearned to discover where they camefrom and where they are going, andabout the Universe that gave them life.
The result of this was the birth of science.

Center of the diagram

HOW DID OUR UNIVERSE COME INTO EXISTENCE?

Galaxy cluster Abell 426

Amphibians

Science was born

Does life exist somewhere in the Universe, aside from on the planet Earth? First, let’s look at the possibilities in ourown Solar System. Our Solar System comprises several celestial bodies of various sizes and environments.

Light Cone

Light emitted bycelestial bodies
spreads out
and expands

8 billion years ago

FishesWhat is science?

Looking for life on the planets of our Solar System

In space, distances are not always what they seem to be

When we talk about the distances to celestial bodies, we talk about “theToday’s Universe
path that light has traveled to reach us”. For example, light from the(the top surface of
the inverted cone) furthest point in the observable Universe has traveled for 13.8 billion years,
a distance that we refer to as “13.8 billion light years”. During that time,Space
however, the Universe has continued to expand, so the path that lighttakes has grown increasingly longer from the time the journey began, andthe starting point is much further away. By the time the light reaches us,that starting point is estimated to be as far as 47 billion light years away.
The Universe
expands to become
The Universe becomes visible through the“the Universe
Rule4
as we see it today”“Eyes of Science”

Today

center. The vertical represent s the and galaxies because the light they emit travels to where we are, but
passage of time, from the age of humans they are so far away that it takes time for light to even reach us. By thetime that light gets here, the stars that emitted that light have changed.
back to the birth of the Universe. The
The Earthhorizontal represents the breadth of
There is an “observable” Universe and much larger
Rule2
space that is the Universe. From its overall
volume that lies behind our ability to observe it
The Earthinverted cone shape, we can see that theis created
The “Current Universe” spreads out on all sides of the human being pictured at the
Universe has been expanding constantly
center of the diagram, but we are unable to see what this Universe really looks like.
ever since it first came into existence. This Remember Rule 1: What we see is the Universe as it was in the past. If we compare thisdiagram is a guide that will take you on a diagram to the celestial bodies that we can see with the naked eye or throughjourney through time and space. Keep these telescopes, we find a teardrop shape like the one shown in the center of the diagram.
four rules in mind as you uncover the secrets This is the only part of the Universe that we can see, and even these celestial bodies areo f t h e U n i v e r s e w i t h y o u r o w n e y e s . images from a different era, thousands, millions, or even billions of years ago.

Rule 3

Early Chordates

position of galaxy cluster JKC
S 041

Light reaches
The strange thing is that when we look at the Universe from the Earth,Experience the Universe
the
Earth
what we see is actually the Universe as it was in the distant past. For
using four rules(We
can seeexample, when we look at the Sun, we are actually seeing what it
This diagram illustrates the Universe looked like eight minutes ago. When we look at Pleiades (Star what the star
based on the latest research and cluster M45), what we are actually seeing is what this star cluster looked like10 billion years ago)
obser vations, with humans at the looked like about 400 years ago. Why does this happen? We see stars

and thenAbout 13.8 billion years: the age of the Universe -How to use this diagram

This diagram is based on the assumptionof the “Lemaitre Universe”, which is a uniform, isotropic Universe with no curvature.
Calculations are based on the latest obserPlanck spacecraft vational results from the Planck spacecraft.

Path of the

The Universe is the breadth of time and space that includes all physical entities. Humans, thelandscapes that we see, the plants and animals that live here - all of this is a part of the Universe. The
stars that shine in the night sky, the Milky Way, which spreads its pale light among the stars, andgalaxies so far away that they can only be seen with a huge telescope - all these things are part of the
Universe as well. The Universe encompasses all the things that we know, and everything beyond.

Humans were born from the stars

S 041
by galaxy cluster JKC
Path of light emitted

Earth’s orbit is about 100 trillion times the size of a pushpin hole.

The radius of “the Universe as we see it today” wassomewhere between a few centimeters and a few metersat the moment of the beginning of the Big Bang, but thiswas only a small part of the Universe as a whole.

The fog of the
Universe lifted

The Big Bang
The beginningof the Big Bang

Supernovae: The alchemy of the Universe

The fragments that became the material of our Solar System were formed in part by “supernovae” thatscattered various elements throughout the Universe. Explosions that glowed more than one billion
times brighter than the Sun instantly transformed the elements in the stars into other elements. There
are two types of supernovae. The first is explosions occurring in stars far more massive than the Sun, which
scatter oxygen and other elements created inside the star, and at the same time synthesize other elements
such as gold and silver. Iron, which is an essential element in the formation of the human body, is formed as aresult of a supernova explosion that occurs in a very small segment of a binary star that includes a white dwarf.

“Fluctuations in the 'Nothingness'”?

Inflation
The birth of
the Universe

Supernova remnant M 1(Crab Nebula)Part of a supernova remnant(Veil Nebula)Stars that melt into the Universe
Planetary nebulae with various shapes

Not all stars meet their end in supernovae. When comparatively low-mass stars like our Sun
approach the end of their lives, they slowly begin to diffuse the materials they have created into
space. They gradually lose their outer envelopes which spread into the far reaches of space, leaving
behind only a core. The remains of this phenomenon, referred to as a “planetary nebula”, can takeon many different shapes, some round and some long and narrow.

Old stars are element factories

The ring nebula M 57

Planetary nebula NGC 6302

Various shapes of planetary nebulae

Helium is surrounded by hydrogen
A cross-section of a red giant,Heliumwhich has more than 10 times the(α Orionis)
Carbon+oxygenmass of our Sun, on the day before
Oxygen+a supernova explosion begins
neon+
magnesium
Silicon
Iron
Betelgeuse is about 1,000 times
larger than our Sun. Its circumferenceis about the same as Jupiter’s orbit.
The image of the star’s coreBetelgeuseStars immediately before the end of their lives

In many cases, when stars grow old, they become “red giants”, expanding so much that they swallow up any
planets around them. At around this time, the stars begin to run out of hydrogen at their center, which is the fuelfor the “nuclear fusion reactions” that allow the stars to shine, and new fusion reactions begin to take place,creating carbon and oxygen from helium. Stars far heavier than the Sun become red supergiants or Wolf-Rayetstars that have lost their outer layer, and even more fusion reactions occur in the star’s core, creating elements such as
silicon and iron. Many of the elements essential to the existence of human beings were created inside these aging stars.

is not a scale reproduction

Jupiter’s orbit

Stars mature and shine in space
Nuclear fusion reactions and the life of a star

Fixed stars spend most of their lives as “main sequence stars”, which is the name given to fixed stars that havecome of age. At the center of the stars, there is a series of nuclear fusion reactions that creates a helium atomfrom four hydrogen atoms. This reaction generates huge volumes of light. The period of time that a given starshines as a main sequence star depends on the star’s mass. Stars that are lighter than our Sun will live for morethan 10 billion years, but a star with 10 times the mass of our Sun will only live for a few tens of millions of years*.
*Our Sun’s life expectancy is just over 10 billion years. More than 5 billion years in the future, it will become a red giant, and in its final
stages, it will become a white dwarf.

Open cluster M 45 (Pleiades)

Double Star Albireo(β Cygni)

Globular cluster M 15

The birth and growth of stars
Protostars emit jets of gas

Gas and dust clouds are the materials that form stars. Huge volumes of this material cometogether to form baby stars or “protostars”. Some of this material is later ejected in fine but
powerful streams of gas called “jets” that are emitted from protostars. Fresh material continues
to collapse on the protostar, and as the core temperature and pressure increases, nuclear fusion
reactions begin, and the protostar finally begins to shine as a main sequence star.

Protostar M17-SO1

Protostellar Jet HH 47

Elements in the constantly changing Universe
Molecular clouds: the birthplace of stars

Places in galaxies with amounts of gas and dust at particularly high levels of concentration are
called “molecular clouds*”. These clouds are composed mainly of hydrogen molecules, but theyalso contain small amounts of water, carbon monoxide, alcohol, and other components. All ofthese substances are created from the diverse elements scattered through the Universe when the livesof stars from previous generations end. In other words, stars come from the elements, and return to theelements. The Earth and the Sun, the stars in the sky, and even our bodies are all part of this great cycleof elements. And if we trace them back far enough, we find that all of the substances that make up thisconstantly changing Universe were created in the first three minutes after the Universe was born .
*Molecular clouds appear as dark clouds, and sometimes appear to glow as they are illuminated by the light of nearby stars.

An infinitesimal fractionof a second

Supernova 1987A

Dark nebula LDN 57

The core of M42 (the Orion Nebula)Part of M16 (the Eagle Nebula)

One for Every Household:Diagram of Our Universe 2013 http://stw.mext.go.jp 1st Edition Issued: March 27, 2007, New Revised Edition Issued: March 25, 2013, New Revised 2nd Edition Issued: July 7, 2013, Supervision: Ministry of Education, Culture, Sports, Science and Technology(MEXT); The Astronomical Society of Japan, Teaching Materials Committee, Author and distributor: The Japan Foundation of Public Communication on Science and Technology (PCOST), Planning: Inter-University Research Institute Corporation, National Institutes of Natural Sciences, National Astronomical
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Hawaii Observatory, Subaru Telescope, Mitaka Campus 50cm Telescope, Ishigakijima Astronomical Observatory, 105cm Telescope, TMT Observatory Corporation, National Astronomical Observatory of Japan 4D Digital Universe Project (4D2U) / Eiichiro Kokubo, Masahiro Nagashima, Hideki Yahagi, Amane
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Trifonov,-E.N.,-Sussman,-J.L.,-Smooth bending of DNA in chromatin.In:"Molecular Mechanisms of Biological Recognition"(Ed. M. Balaban),-Elsevier-/-North Holland Biomed.Press,-1979,-pp.227-232-/-VLT-/-The Planck Collaboration
A pushpin hole is about 10 million times the size of a hydrogen atom.