By: Carl Sagan
Summary
by Mounir Aswad,
Introduction
Cosmos has 13 chapters,
corresponding to the 13 episodes of the Cosmos television series.
The book covers a broad range of topics, comprising Sagan's reflections on anthropological, cosmological, biological, historical, and astronomical matters from antiquity to contemporary times. Sagan explores 15 billion years of cosmic evolution and the development of science and civilization.
He also discusses the underlying premises of science by providing biographical anecdotes about many prominent scientists, placing their contributions in the broader context of the development of modern science.
Shortly after release, Cosmos became the best-selling science book ever published in the English language and was the first science book to sell more than half a million copies. It was only surpassed in the late 1980s by Stephen Hawking's A Brief History of Time.
The book covers a broad range of topics, comprising Sagan's reflections on anthropological, cosmological, biological, historical, and astronomical matters from antiquity to contemporary times. Sagan explores 15 billion years of cosmic evolution and the development of science and civilization.
He also discusses the underlying premises of science by providing biographical anecdotes about many prominent scientists, placing their contributions in the broader context of the development of modern science.
Shortly after release, Cosmos became the best-selling science book ever published in the English language and was the first science book to sell more than half a million copies. It was only surpassed in the late 1980s by Stephen Hawking's A Brief History of Time.
Regarding my Summary:
To summarize a scientific book is a tricky business.
Instead, what I have opted to do is to go over points I find interesting or
were repeated several times. An example of repeated mentions in this book is
the referral to Ptolemy (AD 100 – 170) and Johannes Kepler (1571 – 1630).
Further, I categorized the book for
easier referral, these Categories are: Popular Figures (Sorted by dates),
Autonomy, Planets, Physics and Einstein’s related.
File Format
This summary is written using Microsoft Word 365 and utilizes Heading
Categorization, however, on the internet
it losses this functionality. If you are reading this on the web and would like
to get the original file, email me: maswad at gmail.com. In MS Word, to navigate, click view and
check Navigation Pane. Categories can be collapsed or expanded from both the
navigation and from the main window.
Popular Figures
Pythagoras 570 – c. 495 BC
Ancient Ionian Greek philosopher
and the eponymous founder of Pythagoreanism. (The Ionians were one of the four
major tribes that the Greeks considered themselves to be divided from during
the ancient period; the other three being the Dorians, Aeolians, and Achaeans. Unlike
the austere and militaristic Dorians, the Ionians are renowned for their love
of philosophy, art, democracy, and pleasure – Ionian traits that were most
famously expressed by the Athenians).
Pythagoras influenced Plato, whose dialogues,
especially his Timaeus, exhibit Pythagorean teachings.
Pythagorean ideas on mathematical perfection also impacted ancient Greek art.
Pythagorean ideas on mathematical perfection also impacted ancient Greek art.
His teachings underwent a major
revival in the first century BC among Middle Platonists, coinciding with the
rise of Neopythagoreanism.
Pythagoras continued to be
regarded as a great philosopher throughout the Middle Ages and his philosophy
had a major impact on scientists such as Nicolaus Copernicus, Johannes Kepler,
and Isaac Newton.
Pythagorean symbolism was used throughout early modern European esotericism and his teachings as portrayed in Ovid's Metamorphoses influenced the modern vegetarian movement.
Pythagorean symbolism was used throughout early modern European esotericism and his teachings as portrayed in Ovid's Metamorphoses influenced the modern vegetarian movement.
Aristagoras (497/496 BC)
Key player during the early years
of the Ionian
Revolt against the Persian Achaemenid
Empire. He was the son-in-law of Histiaeus,
and inherited the tyranny of Miletus from him.
Democritus (460–c.370 BC)
Greek philosopher of Abdera; pupil
of Leucippus.
His theory of the nature of the physical world was the most radical and scientific attempted up to his time.
His theory of the nature of the physical world was the most radical and scientific attempted up to his time.
He held that all things were
composed of atoms.
Plato's own writings were
frequently copied, and unlike nearly all of his philosophical contemporaries,
Plato's entire work is believed to have survived intact for over 2,400 years.
Conversely, none of Democritus' writings have survived, and only fragments are
known from his vast body of work. Still, these fragments are enough to let many
consider Democritus to be "The Father of Modern Science".
Plato (424/423 – 348/347 BC)
Athenian
philosopher during the Classical
period in Ancient
Greece, founder of the Platonist
school of thought, and the Academy,
the first institution of higher learning in the Western
world.
He is widely considered the
pivotal figure in the history
of Ancient Greek
and Western
philosophy,
along with his teacher, Socrates, and his most famous student,
Aristotle
Plato has also often been cited as
one of the founders of Western religion and spirituality.
The so-called Neoplatonism
of philosophers
The philosopher Plato
is said to have greatly disliked fellow-philosopher Democritus
and wanted all of Democritus' books burned.
Plato's own writings were
frequently copied, and unlike nearly all of his philosophical contemporaries,
Plato's entire work is believed to have survived intact for over 2,400 years.
Conversely, none of Democritus' writings have survived, and only fragments are
known from his vast body of work. Still, these fragments are enough to let many
consider Democritus to be "The Father of Modern Science".
Aristotle (384–322 BC)
Greek philosopher, the founder of
the Lyceum and the Peripatetic school of philosophy and Aristotelian tradition.
Along with his teacher Plato, he has been called the "Father of Western Philosophy".
Aristotle was revered among medieval Muslim scholars as "The First Teacher" and among medieval Christians like Thomas Aquinas as simply "The Philosopher".
Along with his teacher Plato, he has been called the "Father of Western Philosophy".
Aristotle was revered among medieval Muslim scholars as "The First Teacher" and among medieval Christians like Thomas Aquinas as simply "The Philosopher".
Ptolemy (AD 100 – 170)
A mathematician, astronomer, geographer and astrologer. He lived in the city of Alexandria in the
Roman province of Egypt, under the rule of the Roman Empire.
Ptolemy wrote several scientific treatises, three of which were of
importance to later Byzantine, Islamic and Western European science.
1)
The first is the Astronomical Treatise.
2)
The second is the Geography, which is a thorough
discussion of the geographic knowledge of the Greco-Roman world.
3)
The third is the Astrological Treatise in which he
attempted to adapt Horoscopic Astrology to the Aristotelian natural philosophy
of his day. This is sometimes known as the Apotelesmatika but more commonly
known as the Tetrabiblos from the Greek meaning "Four Books".
Pythagoreanism (6th Century)
Originated in the 6th century BC,
based on the teachings and beliefs held by Pythagoras and his followers, the
Pythagoreans.
Pythagorean ideas exercised a
marked influence on Plato and
through him, on all of Western philosophy. Many of the surviving
sources on Pythagoras originate with Aristotle
and the philosophers of the Peripatetic school.
As a philosophic tradition,
Pythagoreanism was revived in the 1st century BC, giving rise to Neopythagoreanism. The worship of Pythagoras
continued in Italy and as a religious community Pythagoreans appear
to have survived as part of, or deeply influenced, the Bacchic cults and Orphism.
Nicolaus Copernicus (1473 – 1543)
A Renaissance-era mathematician and astronomer, who
formulated a model of the universe that placed the Sun rather than the Earth at
the center of the universe.
Tycho Brahe (1546 – 1601)
A Danish nobleman, astronomer, and writer known for his accurate and
comprehensive astronomical and planetary observations.
Well known in his lifetime as an Astronomer,
Astrologer and Alchemist, he has been described as "the first competent
mind in modern astronomy to feel passional for exact empirical facts." His
observations were some five times more accurate than the best available
observations at the time.
Tycho worked to combine what he
saw as the geometrical benefits of the Copernican system with the philosophical
benefits of the Ptolemaic system into his own model of the universe, the
Tychonic system.
His system correctly saw the Moon as orbiting Earth, and
the planets as orbiting the Sun, but erroneously considered the Sun to be orbiting the Earth.
Furthermore, he was the last of
the major naked-eye astronomers, working without telescopes for his
observations.
In his De nova stella (On the New
Star) of 1573, he refuted the Aristotelian belief in an unchanging celestial
realm.
After disagreements with the new
Danish king, Christian IV, in 1597, he went into exile, and was invited by the
Bohemian king and Holy Roman Emperor Rudolph II to Prague, where he became the
official imperial astronomer. He built an observatory at Benátky nad Jizerou.
There, from 1600 until his death in 1601, he was assisted by Johannes Kepler, who
later used Tycho's astronomical data to develop his three laws of planetary motion (see below).
Galileo Galilei (1564– 1642)
Italian astronomer, physicist and
engineer, sometimes described as a polymath.
Galileo has been called the
"father of observational astronomy", the "father of modern
physics", the "father of the scientific method" and the
"father of modern science".
The principle of relativity,
inertia, projectile motion and also worked in applied science and technology,
describing the properties of pendulums and "hydrostatic balances",
inventing the thermoscope and various military compasses, and using the
telescope for scientific observations of celestial objects.
Galileo studied speed and
velocity, gravity and free fall.
His contributions to observational
astronomy include the telescopic confirmation of the phases of Venus (See below),
the observation of the four largest satellites of Jupiter, the observation of Saturn and the analysis
of sunspots.
It was Galileo's observations of Venus that proved the
theory. Using his telescope, Galileo found that Venus went through phases, just
like our Moon. But, the nature of these phases could only be explained by Venus
going around the Sun,
not the Earth.
Galilean moons
The Galilean moons are the four
largest moons of Jupiter—Io, Europa, Ganymede, and Callisto. They were first
seen by Galileo Galilei in December 1609 or January 1610, and recognized by him
as satellites of Jupiter in March 1610. They were the first objects found to
orbit another planet.
Johannes Kepler (1571 – 1630)
A German astronomer,
mathematician, and astrologer. He is a key figure in the 17th-century
scientific revolution, best known for his laws of planetary motion, and his books Astronomia nova,
Harmonices Mundi, and Epitome Astronomiae Copernicanae. These works also provided one of the
foundations for Newton's theory of universal gravitation.
Kepler lived in an era when there
was no clear distinction
between astronomy and astrology, but there was a strong division between
astronomy (a branch of mathematics within the liberal arts) and physics (a
branch of natural philosophy).
Kepler also incorporated religious
arguments and reasoning into his work, motivated by the religious conviction
and belief that God had created the world according to an intelligible plan
that is accessible through the natural light of reason.
Kepler described his new astronomy
as "celestial physics" as "an excursion into Aristotle's
Metaphysics", and as "a supplement to Aristotle's On the
Heavens", transforming the ancient tradition of physical cosmology by
treating astronomy as part of a universal mathematical physics..
Kepler's laws improved the model
of Copernicus If the orbital eccentricities (non-negative
real number that uniquely characterizes its shape, ie; a measure of how much a
conic section deviates from being circular) of the planetary orbits are taken
as zero, then Kepler basically agreed with Copernicus:
1.
The planetary orbit is a
circle
2.
The Sun is at the center of
the orbit
3.
The speed of the planet in
the orbit is constant
Isaac Newton 25 December (1642 – 20 March 1726)
Widely recognized as one of the
most influential scientists of all time.
His book “Philosophiæ Naturalis
Principia Mathematica” (Principles of Natural Philosophy) first published in
1687, laid the foundations of classical mechanics.
Newton also made seminal
contributions to optics, and shares credit with Gottfried Wilhelm Leibniz for
developing the infinitesimal calculus.
Newton formulated the laws of
motion and universal gravitation that formed the dominant scientific viewpoint
until it was superseded by the theory of relativity.
Newton used his mathematical
description of gravity to prove Kepler's laws of planetary motion (see below), the trajectories
of comets, the precession of the equinoxes, account for tides, eradicating
doubt about the Solar System's heliocentricity.
He demonstrated that the motion of
objects on Earth and celestial bodies could be accounted for by the same
principles.
Newton's inference that the Earth
is an oblate spheroid (flattened at the poles) was later confirmed by the
geodetic measurements of Maupertuis, La Condamine, and others.
Newton built the first practical
reflecting telescope and developed a sophisticated theory of color based on the
observation that a prism separates white light into the colors of the visible
spectrum.
His work on light was collected in
his highly influential book Opticks, published in 1704.
He also formulated an empirical
law of cooling, made the first theoretical calculation of the speed of sound,
and introduced the notion of a Newtonian fluid.
In addition to his work on
calculus, as a mathematician Newton contributed to the study of power series, generalized
the binomial theorem to non-integer exponents, developed a method for
approximating the roots of a function, and classified most of the cubic plane
curves.
He was a devout but unorthodox
Christian who privately rejected
the doctrine of the Trinity. Unusually for a member of the Cambridge
faculty of the day, he refused to take holy orders in the Church of England.
Thomas Henderson (1798 – 1844)
Scottish astronomer and
mathematician.
Noted for being the first person
to measure the distance to Alpha
Centauri (The closest star system and closest planetary system to the
Solar System at 4.37 light-years from the Sun) , the first to determine the parallax of a fixed
star. It is a triple star
system, consisting of three stars: α Centauri A (officially Rigil
Kentaurus), Centauri B (officially Toliman) and α Centauri C (officially
Proxima Centauri).
William Huggins (1824 – 1910)
English astronomer best known for
his pioneering work in astronomical spectroscopy (The study of the interaction
between matter and electromagnetic radiation. Historically, spectroscopy
originated through the study of visible light dispersed according to its
wavelength, by a prism) together with his wife Margaret Lindsay Huggins
Percival Lowell (1855 – 1916)
American businessman, author,
mathematician, and astronomer who fueled speculation that there were canals on
Mars.
He formed the beginning of the
effort that led to the discovery of Pluto 14 years after his death.
Wolf V. Vishniac (1922 – 1973)
American microbiologist and
professor of biology at the University of Rochester.
He died on a research trip to the
Antarctic attempting to retrieve equipment in a crevasse (Deep crack, or fracture,
found in an ice sheet or glacier) . The crater Vishniac on Mars is named in his
honor.
Wolf Vishniac contributed greatly
to the search for life on Mars by developing a special miniature laboratory
that could be transported to that planet, known as the "Wolf Trap".
Ionia
An ancient region on the central
part of the western coast of Anatolia in present-day Turkey.
It was named after the Ionian tribe who, in the Archaic Period (600–480 BC), settled mainly the shores and islands of the Aegean Sea.
Ionian states were identified by tradition and by their use of Eastern Greek.
It was named after the Ionian tribe who, in the Archaic Period (600–480 BC), settled mainly the shores and islands of the Aegean Sea.
Ionian states were identified by tradition and by their use of Eastern Greek.
According to Greek tradition, the
cities of Ionia were founded by colonists from the other side of the Aegean.
Their settlement was connected with the legendary history of the Ionic people
in Attica, which asserts that the colonists were led by Neleus and Androclus,
sons of Codrus, the last king of Athens.
Ionia was settled by the Greeks
probably during the 11th century BC.
Several centuries later Ionia was
the place where Western philosophy began and was the homeland of Thales,
Anaximander, Anaximenes and Heraclitus.
They were natural-philosophers of the Ionian School of philosophy and tried to explain the phenomena according to non-supernatural laws. They also searched a simple material-form behind the appearances of things (origin) and this conception had a great influence on the early archaic art in Greece.
They were natural-philosophers of the Ionian School of philosophy and tried to explain the phenomena according to non-supernatural laws. They also searched a simple material-form behind the appearances of things (origin) and this conception had a great influence on the early archaic art in Greece.
The Ionian cities formed a
religious and cultural (as opposed to a political or military) confederacy, the
Ionian League
Astronomy
The Cambrian explosion (541 million years ago)
https://en.wikipedia.org/wiki/Cambrian_explosion
The Cambrian explosion or Cambrian radiation was an event approximately 541 million years ago in the Cambrian period when most major animal phyla/phylum (also referred to as “Division”) is a level of classification or taxonomic rank below kingdom and above class, i.e.: Kingdom\Phylum\Class) appeared in the fossil record. It lasted for about 13–25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification of other organisms.
The Cambrian explosion or Cambrian radiation was an event approximately 541 million years ago in the Cambrian period when most major animal phyla/phylum (also referred to as “Division”) is a level of classification or taxonomic rank below kingdom and above class, i.e.: Kingdom\Phylum\Class) appeared in the fossil record. It lasted for about 13–25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification of other organisms.
Before the Cambrian explosion most
organisms were simple, composed of individual cells occasionally organized into
colonies. As the rate of diversification subsequently accelerated, the variety
of life began to resemble that of today. Almost all present animal phyla
appeared during this period.
How Elements Form, Destiny of a Sun, Stages of a Star
Helium and hydrogen composed 99%
of the universe.
1)
Nuclear Fusion: Hydrogen
fuses into helium releasing a photon that takes 1 million year to reach the
surface of the sun into space.
2)
Neutrino: Fusion releases a neutrino which carries an angular momentum
unlike the photon. Matter is transparent to Neutrino When we look at the sun
Neutrinos pass through our eyeballs.
3)
Sun Fusion expected to continue for 5 to 6 billion years, the Helium
then will cause the sun to undergo another Fusion reaction ... For a while, the
sun exterior will expand and cool, Gravity growth at the surface, it becomes a
red giant devouring Mercury Venus and maybe the Earth
4)
The ash will continue until all of the sun interior becomes oxygen and
carbon, the sun will contract every few millenniums eventually spewing
atmosphere into space, the interior will flood the shell with ultraviolet light
introducing red and blue fluorescent extending beyond Pluto.
In Summary: Hydrogen fuses
into helium into carbon into oxygen Into neon into magnesium into silicon into
sulfur ...etc. until all these gather to form other planets.
Kepler's laws of planetary motion
Three scientific laws describing the motion of planets around the Sun.
1.
The orbit of a planet is an ellipse with
the Sun at one focus (or one of the two foci). (Focuses or foci are special
points with reference to which any of a variety of curves is constructed.
For example, one or two foci can be used in defining conic sections, the four
types of which are the circle, ellipse, parabola, and hyperbola.
2.
A line segment joining a planet and the Sun sweeps
out equal areas during equal intervals of time.
3.
The square of the orbital period of a planet (Time
to complete one Orbit) is directly proportional to the cube of the semi-major
axis of its orbit. (The more distant the planet, the slower it moves but
according to the mathematic law)
Radio astronomy
is a subfield of astronomy that
studies celestial objects at radio frequencies. The first detection of radio
waves from an astronomical object was in 1932.
The first detection of radio waves
from an astronomical object was in 1932.
Radio astronomy is conducted using
large radio antennas referred to as radio telescopes, that are either used
singularly, or with multiple linked telescopes
Nebula (Latin for "cloud"), Beginning Of a Star
A Nebula is a giant cloud of dust and gas in space (mostly Hydrogen and Helium). Some Nebulae (more than one Nebula) formed from the
gas and dust thrown out by the explosion of a dying star, such as a supernova. Other
nebulae are regions where new stars are beginning to form.
The dust and gases in a Nebula are
very spread out, but gravity can slowly begin to pull together clumps of dust
and gas. As these clumps get bigger and bigger, their gravity gets stronger and
stronger. Eventually, the clump of dust and
gas gets so big that it collapses from its own gravity. The collapse causes the
material at the center of the cloud to heat up-and this hot core is the
beginning of a star.
The closest known Nebula to Earth is called the Helix Nebula. It is
the remnant of a dying star—possibly one like the Sun. It is approximately 700 light-years away from Earth.
The
Orion Nebula is a diffused Nebula situated in the Milky Way, being south of
Orion's Belt in the constellation of Orion. It is one of the brightest Nebulae
and is visible to the naked eye in the night sky.
What does the edge of the Universe look like?
when we look at a galaxy that’s
billions of light years away, that light
has needed to travel for billions of years to reach our eyes. A galaxy whose
light takes 13 billion years to reach us must be less than one billion years
old, and so the farther away we look, we’re basically looking back in time.
Each galaxy has a spectrum
associated with it, where clouds of gas absorb light at very particular
wavelengths, based on the simple physics of the atom. As the Universe expands,
that wavelength stretches, so the more distant galaxies appear redder than they otherwise would.
From where we are today, we can
look out in any direction we like and see the same cosmic story unfolding.
Today, 13.8 billion years after the Big Bang, we have the stars and galaxies we
know today. Earlier, galaxies were smaller, bluer, younger and less evolved.
Before that, there were the first stars, and prior to that, just neutral atoms.
Before neutral atoms, there was an ionized plasma, then even earlier there were
free protons and neutrons, spontaneous creation of matter-and-antimatter, free
quarks and gluons, all the unstable particles in the Standard Model, and
finally the moment of the Big Bang itself. Looking to greater and greater
distances is equivalent to looking all the way back in time.
with the theoretical boundary of
the Big Bang located 46.1 billion light years from our current position — this
is not a real boundary in space. Instead, it’s simply a boundary in time;
there’s a limit to what we can see because the speed of light allows
information to only travel so far over the 13.8 billion years since the hot Big
Bang. That distance is farther than 13.8 billion light years because the fabric
of the Universe has expanded (and continues to expand), but it’s still limited.
But what about prior to the Big
Bang? If we could somehow take a “snapshot” of the entire Universe, going way
beyond the observable part, as it exists 13.8 billion years after the Big Bang
everywhere, it would all look like our nearby Universe does today. There would
be a great cosmic web of galaxies, clusters, filaments, and cosmic voids,
extending far beyond the comparatively small region we can see. Any observer,
at any location, would see a Universe that was very much like the one we see
from our own perspective.
The individual details would be
different, just as the details of our own solar system, galaxy, local group,
and so on, are different from any other observer’s viewpoint. But the Universe
itself isn’t finite in volume; it’s only the observable part that’s finite. The
reason for that is that there’s a boundary in time — the Big Bang — that
separates us from the rest. We can approach that boundary only through
telescopes (which look to earlier times in the Universe) and through theory.
Until we figure out how to circumvent the forward flow of time, that will be
our only approach to better understand the “edge” of the Universe. But in
space? There’s no edge at all. To the best that we can tell, someone at the
edge of what we see would simply see us as the edge instead!
Spiral galaxy
Most spiral galaxies consist of a
flat, rotating disk containing stars, gas and dust, and a central concentration
of stars known as the bulge.
The Milky Way is a barred spiral,
although the bar itself is difficult to observe from Earth's current position
within the galactic disc. The most convincing evidence for the stars forming a
bar in the galactic center comes from several recent surveys, including the
Spitzer Space Telescope.
Galaxy M31 (Type of Spiral Galaxy)
The Andromeda Galaxy, also known
as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a spiral galaxy
approximately 780
kiloparsecs (2.5 million light-years) from Earth, and the nearest major galaxy to the
Milky Way. The galaxy's name stems from the area of the Earth's sky
in which it appears, the constellation of Andromeda.
The virial mass of the Andromeda
Galaxy is of the same order of magnitude as that of the Milky Way, at a
trillion solar masses (1012M☉).
The Milky Way and Andromeda
galaxies are expected to collide in ~4.5 billion years, merging to form a giant
elliptical galaxy or a large lenticular galaxy.
With an apparent magnitude of 3.4,
the Andromeda Galaxy is among the brightest of the Messier objects making it visible to the
naked eye from Earth on moonless nights, even when viewed from areas with
moderate light pollution.
Nova
A nova or classical nova is a
transient astronomical event that causes the sudden appearance of a bright,
apparently "new" star, that slowly fades over several weeks or many
months gradually returning to its original brightness. All observed
novae involve a white dwarf in a close binary system.
Classical nova eruptions are the
most common type of nova. They are likely created in a close binary star system
consisting of a white dwarf and either a main sequence, subgiant,
or red giant star. When the orbital period falls in the range of several days
to one day, the white
dwarf is close enough to its companion star to start drawing accreted matter
onto the surface of the white dwarf, which creates a dense but
shallow atmosphere
From the dramatic and sudden
energies created, the now hydrogen-burnt
atmosphere is then dramatically expelled into interstellar space, and its brightened envelope is
seen as the visible light created from the nova event, and previously was mistaken as a
"new" star. A few novae produce short-lived nova remnants,
lasting for perhaps several centuries.
Novae most often occur in the sky
along the path of the Milky Way, especially near the observed galactic center
in Sagittarius; however, they can appear anywhere in the sky. They occur far
more frequently than galactic supernovae, averaging about ten per year.
Supernova
A Supernova, is a powerful
and luminous stellar explosion. At its
peak brightness, the optical luminosity of a supernova can be comparable to
that of an entire galaxy, before fading over several weeks or months.
A supernova is a transient
astronomical event, occurring
during the last evolutionary stages of a massive star
OR
when a white dwarf is triggered into runaway nuclear fusion. The original star, called the progenitor, either collapses to a neutron star or black hole, or it is completely destroyed.
OR
when a white dwarf is triggered into runaway nuclear fusion. The original star, called the progenitor, either collapses to a neutron star or black hole, or it is completely destroyed.
Only three naked-eye supernova events have been observed in the Milky Way during the last thousand years.
The most recent directly observed supernova in the Milky Way was Kepler's Supernova in 1604.
The most recent naked-eye supernova was SN 1987, the explosion of a blue supergiant star in the Large Magellanic Cloud, a satellite of the Milky Way.
Most supernovae are triggered by
one of two basic mechanisms:
1)
The sudden re-ignition of nuclear fusion in a
degenerate star or
2)
The sudden gravitational collapse of
a massive star's core.
Pulsar (type of neutron star)
Highly magnetized rotating neutron
star or white dwarf that emits a beam of Electromagnetic radiation.
This radiation can be observed only when the beam of emission is pointing toward Earth and is responsible for the pulsed appearance of emission. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.
This radiation can be observed only when the beam of emission is pointing toward Earth and is responsible for the pulsed appearance of emission. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.
Quasar (quasi-stellar object; QSO)
Extremely luminous Active Galactic
Nucleus (AGN), in which a supermassive black hole with mass ranging from
millions to billions of times the mass of the Sun is surrounded by a gaseous
accretion disk.
AGN (Active Galactic Nucleus (AGN)
is a compact region at the center of a galaxy that has a much higher than
normal luminosity over at least some portion of the electromagnetic spectrum
with characteristics indicating that the luminosity is not produced by stars.
Library of Alexandria
Founded by the Ptolemaic dynasty different
than the modern library in Alexandria named (Bibliotheca Alexandrina).
It was one of the largest and most significant libraries of the ancient worldز
The idea of a universal library in Alexandria may have been proposed by Demetrius of Phalerum ( 350 – c. 280 BC) was an Athenian orator (Public speaker) originally from Phalerum, a student of Theophrastus, and perhaps of Aristotle, and one of the first Peripatetics (Aristotelian philosopher) on in northern Greece who became ruler of Egypt, part of Alexander's former empire).
It was one of the largest and most significant libraries of the ancient worldز
The idea of a universal library in Alexandria may have been proposed by Demetrius of Phalerum ( 350 – c. 280 BC) was an Athenian orator (Public speaker) originally from Phalerum, a student of Theophrastus, and perhaps of Aristotle, and one of the first Peripatetics (Aristotelian philosopher) on in northern Greece who became ruler of Egypt, part of Alexander's former empire).
The Library quickly acquired a
large number of papyrus scrolls, due largely to the Ptolemaic kings' aggressive
and well-funded policies for procuring texts. (40,000 to 400,000 scrolls).
Despite the widespread modern
belief that the Library was burned once and cataclysmically destroyed, the
Library actually declined gradually over the course of several centuries,
starting with the purging of intellectuals from Alexandria in 145 BC. he
Library dwindled during the Roman Period, due to lack of funding and support.
Its membership appears to have ceased by the 260s AD. Between 270 and 275 AD,
the city of Alexandria saw a rebellion and an imperial counterattack that
probably destroyed whatever remained of the Library, the Serapeum (The daughter
library) was vandalized and demolished in 391 AD under a decree issued by
Coptic Christian Pope Theophilus of Alexandria.
Meteor
A meteor is what you see when a
space rock falls to Earth. It is often known as a shooting star or falling star
and can be a bright light in the night sky, though most are faint. A few
survive long enough to hit the ground. That is called a meteorite, and a large
one sometimes leaves a hole in the ground called a crater.
Meteor showers, are dust particles
that came out of comets.
Meteoroid
A rock that has not yet hit the
atmosphere is called a "meteoroid". Meteoroids may range in size from
large pieces of rock to tiny dust particles floating in space that did not form
planets.
Meteoroids are significantly
smaller than asteroids, and range in size from small grains to one-meter-wide
objects
There are several types of
meteorites including: stony, carbonaceous chondrites, and iron-nickel.
Stony meteorites are named because they are largely made up of stone-like mineral material.
Carbonaceous chondrites have a high carbon content. Iron-nickel meteorites are mostly iron often with significant nickel as well.
Stony meteorites are named because they are largely made up of stone-like mineral material.
Carbonaceous chondrites have a high carbon content. Iron-nickel meteorites are mostly iron often with significant nickel as well.
Comets
Comets are cosmic snowballs of frozen gases, rock and
dust that orbit the Sun.
When frozen, t When a comet's orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets, they are the size of a small town.
When frozen, t When a comet's orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets, they are the size of a small town.
Comet nuclei range from a few
hundred meters to tens of kilometers.
Halley's Comet
Officially designated 1P/Halley,
is a short-period comet visible from Earth every 75–76 years.
Halley last appeared in the inner
parts of the Solar System in 1986
and will next appear in mid-2061.
Clear records of the comet's
appearances were made by Chinese, Babylonian, and medieval European chroniclers.
The comet's periodicity was first
determined in 1705
by English astronomer Edmond Halley.
Spectroscopy
It is the study of the interaction
between matter and electromagnetic radiation.
Historically, spectroscopy
originated through the study of visible light dispersed according to its wavelength, by a prism
Later the concept was expanded
greatly to include any interaction with radiative energy as a function of its
wavelength or frequency, predominantly in the electromagnetic spectrum, though
matter waves and acoustic waves can also be considered forms of radiative
energy.
Spectroscopy, primarily in the
electromagnetic spectrum, is a fundamental exploratory tool in the fields of
physics, chemistry, and astronomy, allowing the composition, physical structure
and electronic structure of matter to be investigated at atomic scale,
molecular scale, macro scale, and over astronomical distances.
Alpha Centauri
Is the closest star system and
closest planetary system to the Solar System at 4.37 light-years (1.34 parsec)
from the Sun.
It is a triple star system,
consisting of three stars: α Centauri A (officially Rigil Kentaurus), Centauri
B (officially Toliman) and α Centauri C (officially Proxima Centauri).
Albedo
Albedo, (meaning 'whiteness') is
the measure of the diffuse reflection of solar radiation out of the total solar
radiation received by an astronomical body (e.g. a planet like Earth).
It is dimensionless and measured
on a scale from 0 (corresponding to a black body that absorbs all incident
radiation) to 1 (corresponding to a body that reflects all incident radiation).
The average albedo of the Earth
from the upper atmosphere, its planetary albedo, is 30–35% because of cloud
cover, but widely varies locally across the surface because of different
geological and environmental features.
Tunguska event
The Tunguska event was a large explosion that occurred
near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk
Krai), Russia, on the morning of 30 June 1908.
The explosion flattened 2,000
square kilometers of forest,
It is attributed to the air burst
of a meteor. It is classified as an impact event, even though no impact crater
has been found.
The object is thought to have
disintegrated at an altitude of 5 to 10 kilometers
Role of Clay Minerals in Chemical Evolution and the Origins of Life
It was Bernal (1951), however, who
first suggested that clay minerals played a key role in chemical evolution and
the origins of life because of their ability to take up, protect (against
ultraviolet radiation), concentrate, and catalyze the polymerization of,
organic molecules.
Cains-Smith (1982) has suggested
that clay minerals can store and replicate structural defects, dislocations,
and ionic substitutions, and act as ‘genetic candidates.
Clay minerals would have formed by
weathering of volcanic glass and rocks.
Water would have come into contact
with volcanic glass and rocks, opening the way to clay mineral formation.
The bio-organic compounds of
‘life’ comprise amino acids, nucleic acid bases, sugars, and lipids
Pioneer 1
On October 11, 1958,
Pioneer 1 became the first spacecraft under the auspices of NASA, the newly
formed space agency of the United States.
it did not reach the Moon as planned due to a programming error in the upper stage.
it did not reach the Moon as planned due to a programming error in the upper stage.
The spacecraft ended transmission when it reentered the Earth's atmosphere
after 43 hours of flight on October 13, 1958
Pioneer 10
An American space probe, launched
in 1972.
Completed the first mission to the planet Jupiter.
Became the first of five artificial objects to achieve the escape velocity that will allow them to leave the Solar System. Became the first spacecraft to traverse the asteroid belt.
Completed the first mission to the planet Jupiter.
Became the first of five artificial objects to achieve the escape velocity that will allow them to leave the Solar System. Became the first spacecraft to traverse the asteroid belt.
Radio communications were lost
with Pioneer 10 on January 23, 2003,
Voyager 1
A space probe launched by NASA on September 5, 1977 to study the outer
Solar System,
Part of the Voyager program to
study the outer Solar System.
Initially, Voyager 1 was planned
as "Mariner 11" of the Mariner program. Due to budget cuts, the
mission was scaled back to be a flyby of Jupiter and Saturn and renamed the Mariner Jupiter-Saturn
probes, then changed later to Voyager.
The probe's objectives included
flybys of Jupiter, Saturn, and Saturn's largest moon, Titan.
Voyager 1 was launched 16 days
after its twin, Voyager 2.
Having operated for 41 years, 10
months and 7 days as of July 12, 2019, the spacecraft still communicates with
the Deep Space Network to receive routine commands and to transmit data to
Earth.
At a distance of 146 AU (21.8 billion km;
13.6 billion mi) from Earth as of July 11, 2019 it is the most distant man-made object
from Earth
After completing its primary
mission with the flyby of Saturn on November 12, 1980, Voyager 1 became the third of five artificial
objects to achieve the escape velocity required to leave the Solar
System.
On August 25, 2012, Voyager 1 became
the first spacecraft to
cross the heliopause ( where the solar wind's strength is no longer
great enough to push back the stellar winds of the surrounding stars) and enter
the interstellar medium (The matter and radiation that exists in the space
between the star systems in a galaxy, This matter includes gas in ionic,
atomic, and molecular form, as well as dust and cosmic rays.)
Voyager 1's extended mission is
expected to continue until about 2025 when its radioisotope thermoelectric
generators will no longer supply enough electric power to operate its
scientific instruments.
Voyager 2
Voyager 2is a space probe launched
by NASA on August 20, 1977, to study the outer planets. Part of the Voyager
program,
It was launched on trajectory that
took longer to reach Jupiter
and Saturn but
enabled further encounters with Uranus and Neptune
It is the only spacecraft to have visited either of these two ice giant
planets.
Its primary mission ended with the
exploration of the Neptunian system on October 2, 1989, , after having visited
the Uranian system in 1986, the Saturnian system in 1981, and the Jovian system
in 1979.
Voyager 2 is now in its extended
mission to study the outer reaches of the Solar System and has been operating
for 41 years, 10 months and 21 days as of 11 July 2019. It remains in contact
through the NASA Deep Space Network.
At a distance of 120 AU (1.80×1010 km)
(about 16.4 light-hours) from the Sun as of February 25, 2019, moving at a
velocity of 15.341 km/s (55,230 km/h) relative to the Sun, Voyager 2 is the
fourth of five spacecraft to achieve the escape velocity that will allow them to leave the
Solar System.
The probe left the heliosphere for
interstellar space on November 5, 2018, becoming the second artificial object to do so, and has
begun to provide the first direct measurements of the density and temperature
of the interstellar plasma.
Metallic hydrogen
Metallic hydrogen is a
phase of hydrogen in which it behaves like an electrical conductor. This phase was predicted in
1935.
At high pressure and temperatures,
metallic hydrogen can exist as a liquid rather than a solid, and researchers think it might be
present in large quantities in the hot and gravitationally compressed interiors
of Jupiter, Saturn, and in some exoplanets.
Jet Propulsion Laboratory
(JPL) is a federally funded
research and development center and NASA field center in La Cañada Flintridge,
California,
Founded in the 1930s, the
laboratory's primary function is the construction and operation of planetary
robotic spacecraft, though it also conducts Earth-orbit and astronomy missions.
It is also responsible for operating NASA's Deep Space Network.
Among the laboratory's major
active projects are the Mars Science Laboratory mission
(which includes the Curiosity
rover), the Mars Reconnaissance Orbiter, the
Juno
spacecraft orbiting Jupiter,
the NuSTAR X-ray
telescope, the SMAP satellite for earth
surface soil moisture monitoring, and the Spitzer Space Telescope. It is also
responsible for managing the JPL Small-Body Database, and
provides physical data and lists of publications for all known small Solar System bodies.
Heliosphere
The heliosphere is the vast,
bubble-like region of space which surrounds and is created by the Sun.
In plasma physics terms, this is the cavity formed by the Sun in the surrounding interstellar medium.
The "bubble" of the heliosphere is continuously "inflated" by plasma originating from the Sun, known as the solar wind.
Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating our galaxy.
In plasma physics terms, this is the cavity formed by the Sun in the surrounding interstellar medium.
The "bubble" of the heliosphere is continuously "inflated" by plasma originating from the Sun, known as the solar wind.
Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating our galaxy.
Radiation levels inside and
outside the heliosphere differ; in particular, the galactic cosmic rays are
less abundant inside the heliosphere, so that the planets inside (including
Earth) are partly shielded from their impact.
Project Orion
Project Orion was a study
of a spacecraft intended to be directly propelled by a series of explosions of
atomic bombs behind the craft (nuclear pulse propulsion). Early versions of
this vehicle were proposed to take off from the ground with significant
associated nuclear fallout; later versions were presented for use only in
space. Six non-nuclear tests were conducted using models.
Planets
Jupiter
Jupiter is the fifth planet from
the Sun and the largest in the Solar System.
Jupiter and Saturn are gas giants;
the other two giant planets, Uranus and Neptune, are ice giants.
When viewed from Earth, Jupiter
can reach an apparent magnitude of −2.94, bright enough for its reflected light
to cast shadows, and making it on average the third-brightest natural object in
the night sky after the Moon and Venus.
Mass: one-thousandth
that of the Sun, but two-and-a-half times that of all the other planets in the
Solar System combined.
Name: after the
Roman god Jupite
Composition:
primarily composed of hydrogen with a quarter of its mass being helium,
Moons: 79 known
moons,[21] including the four large Galilean moons
Day on this Planet: Because
of its rapid rotation, the planet's shape is that of an oblate spheroid
Interesting Facts: Jupiter has been explored on several occasions
by robotic spacecraft, most notably during the early Pioneer and Voyager flyby
missions and later by the Galileo orbiter
Saturn
Saturn is the sixth planet from
the Sun and the second-largest in the Solar System,
It is a gas giant.
Mass: an average
radius about nine times that of Earth, It has only one-eighth the average density of Earth,
but with its larger volume Saturn is over 95 times more massive.
Name: named after
the Roman god of agriculture, its astronomical symbol represents the god's
sickle.
Composition: Core of iron–nickel and rock (silicon and
oxygen compounds). This core is surrounded by a deep layer of metallic hydrogen, an intermediate
layer of liquid hydrogen
and liquid helium,
and finally a gaseous
outer layer.
Moons: At least 62
moons. Titan, Saturn's largest moon, and the second-largest in the Solar
System, is larger than the planet Mercury, although less massive, and is the
only moon in the Solar System to have a substantial atmosphere.
Day on this Planet: 10h 33m 38s, based on studies of the
planet's C Ring
Interesting Facts:
A pale yellow hue due to ammonia
crystals in its upper atmosphere.
Electrical current within the
metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic
field, which is weaker than Earth's, but has a magnetic moment 580 times that of Earth due to Saturn's
larger size.
Saturn's magnetic field strength
is around one-twentieth of Jupiter's.
Wind speeds on Saturn can reach
1,800 km/h, higher than on Jupiter, but not as high as those on Neptune.
The planet's most famous feature
is its prominent ring system that is composed mostly of ice particles, with a
smaller amount of rocky debris and dust.
Physics, Atomic and Subatomic
Atomic Theory
The idea that all matter is made
up of tiny, indivisible particles, or atoms, is believed to have originated
with the Greek philosopher Leucippus of Miletus and his student Democritus of
Abdera in the 5th century B.C.
While the idea of the atom was
supported by some later Greek philosophers, it was fiercely attacked by others,
including Aristotle, who argued against the existence of such particles.
Quark
Type of elementary particle and a fundamental
constituent of matter.
Quarks combine to form composite particles called hadrons,
the most stable of which are protons and
neutrons,
Due to a phenomenon known as color confinement, quarks are never
directly observed or found in isolation; they can be found only within hadrons,
which include baryons
(such as protons and neutrons) and mesons.
For every quark flavor there is a
corresponding type of antiparticle,
known as an antiquark, that differs from the quark only in that some of
its properties (such as the electric charge) have equal
magnitude but opposite sign.
Four Dimensional Hypercube
Hypercube is an n-dimensional
analogue of a square (n = 2) and a cube (n = 3).
A four-dimensional space or 4D
space is a mathematical extension of the concept of three-dimensional or 3D
space.
Einstein's concept of spacetime
uses such a 4D space, though it has a Minkowski structure that is a bit more
complicated than Euclidean 4D space.
The Drake Equation
is a probabilistic argument used
to estimate the number of active, communicative extraterrestrial civilizations
in the Milky Way galaxy.
Richardson curve
L.F. Richardson was a British
meteorologist interested in war and wanted to understand its causes.
In the years between 1820 and
1945, he collected data on the hundreds of wars that had then been fought on
our planet. Richardson's results were published posthumously in a book called
'The Statistics of Deadly Quarrels'.
He found that the more people
killed in a war, the less likely it would occur, and the longer before you
would witness it, just as violent storms occur less frequently than
cloudbursts. His results can be graphed and simple extrapolation suggests that,
a war in which most of the world population is killed will not be reached for
about a thousand years (1820 + 1000=2820).
However, the proliferation of
nuclear weapons has very likely moved the curve down
Element 94 Plutonium
Einstein's
Arriving at E=mc2, Pursuing a beam of light-
Issue: I pursue a
beam of light with the velocity c (velocity of light in a vacuum), I should
observe such a beam of light as an electromagnetic field at rest though
spatially oscillating.
Problem: There seems
to be no such thing. neither on the basis of experience nor according to
Maxwell's equations. From the very beginning it appeared to me intuitively
clear that, judged from the standpoint of such an observer, everything would
have to happen according to the same laws as for an observer who, relative to
the earth, was at rest.
For how should the first observer
know or be able to determine, that he is in a state of fast uniform motion? One
sees in this paradox the germ of the special relativity theory is already
contained.
1895: Running Beside a Light Beam-
·
Light beam as: a set of
oscillating electric and magnetic fields rippling along at 186,000 miles a
second,
·
If he were to run alongside
it at just that speed, he will be able to look over and see a set of
oscillating electric and magnetic fields hanging right next to him, seemingly
stationary in space.
·
Impossible, as violate Maxwell’s equations;
o
“Any ripples in the fields
have to move at the speed of light and cannot stand still—no exceptions.”
· Worse, stationary fields wouldn’t jibe with
the principle of relativity
at the time
o
Basically, relativity said
that the laws of
physics couldn’t
depend on how fast you were moving;
o
All you could measure was the velocity of one object relative
to another.
·
Einstein's contradiction
o
Relativity dictated that
anything he could see while running beside a light beam, including the
stationary fields, should also be something Earthbound physicists could
create in the lab, which is not possible or impossible at the time.
·
This
problem would bug Einstein for another 10 years
1904: Measuring Light From a Moving Train-
·
Speed
of light was always constant: Maybe Maxwell’s equations worked for everybody, he
thought, but the speed of light was always constant.
· Ie; When you saw a light beam zip past
o
It wouldn’t matter whether its source was moving toward you,
away from you, or off to the side.
o
nor would it matter how fast the source was going
o
You would always measure that beam’s velocity to be 186,000
miles a second
o
That meant Einstein would never see the stationary, oscillating
fields, because he could never catch the light beam
· The Flaw:
· Imagine
o
Imagine firing a light beam along a railroad embankment
§ As a train roars by in the same direction
at, say, 2,000 miles a second.
o
Someone standing on the embankment would measure the light
beam’s speed as 186,000 miles a second.
o
someone on the train would
see it moving past at only 184,000 miles
a second
· Einstein concluded
o
If the speed of light was not constant, Maxwell’s equations would
somehow have to look different inside the railway carriage
o
and
the principle of relativity would be violated (laws of physics couldn’t depend on how fast you
were moving)
May 1905: Lightning Strikes a Moving Train
· Revelation
o
Observers in relative motion experience time differently
o
it’s perfectly possible for two events to happen simultaneously
from the perspective of one observer,
§ yet
§
happen
at different times from the perspective of the other. And both observers would
be right.
· Imagine
o
Observer standing on a railway embankment as a train goes
roaring by.
§ But this time, each end of the train is
struck by a bolt of lightning just as the train’s midpoint is passing.
§ Their light reaches his eye at the same
instant (Because the lightning strikes
are the same distance from the observer)
§ لإ Conclusion: They happened simultaneouslyز
o
Another observer on the train is sitting at its exact midpoint
§ From her perspective, the light from the
two strikes also has to travel equal distances
§ She will likewise measure the speed of
light to be the same in either direction
§ But
· Because the train is moving, the light
coming from the lightning in the rear has to travel farther to catch up.
· So it reaches her a few instants later than the light
coming from the front.
§ Conclusion: The strikes were not
simultaneous—that the one in front actually happened first.
o
Einstein Conclusion:
§ Simultaneity is what’s relative
September 1905: Mass and Energy
· Imagine:
o
Object sitting
at rest.
o
it spontaneously emits two identical pulses of light in opposite
directions.
o
The object will stay put,
§ But because each pulse carries off a
certain amount of energy,
§ the object’s energy content will decrease.
o
What would this process look like to a moving observer?
§ The object would just keep moving in a
straight line
§ But even though the two pulses’ speed would still be the same—the
speed of light—their
energies would be different:
· The pulse moving forward along the
direction of motion would now have a higher energy than the one moving
backward.
·
Conclusion:
o
The object does not only have to lose energy when the light pulses departed, it had
to lose a bit of mass,
as well.
o
mass and energy are interchangeable.
o
E = mc2
Time dilation
https://en.wikipedia.org/wiki/Time_dilation
Time dilation is a difference in
the elapsed time measured by two clocks, either due to their having a velocity difference
relative to each other, or by their being differently situated in a gravitational field.
After compensating for varying
signal delays due to the changing distance between an observer and a moving clock,
the observer will measure the moving clock as ticking slower than a clock that
is at rest in the observer's own reference
frame.
A clock that is close to a massive
body (and which therefore is at lower gravitational potential) will record
less elapsed time than a clock situated further from the said massive body (and
which is at a higher gravitational potential).
These predictions of the theory of relativity have been repeatedly
confirmed by experiment, and they are of practical concern, for instance in the
operation of satellite navigation systems such as GPS
and Galileo.
Wormhole (Einstein–Rosen bridge)
A speculative structure linking
disparate points in spacetime, and is based on a special solution of the
Einstein field equations solved using a Jacobian matrix and determinant.
A wormhole can be visualized as a
tunnel with two ends, each at separate points in spacetime.
Wormholes are consistent with the
general theory of relativity, but whether wormholes actually exist remains to
be seen. Many scientists postulate wormholes are merely a projection of the 5th
dimension, analogous to how a 2D being could only experience part of a 3D
object.
A wormhole could connect extremely
long distances such as a billion light years or more, short distances such as a
few meters, different universes, or different points in time
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