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Richter Magnitudes
Description Earthquake EffectsFrequency of Occurrence
Less than 2.0 Micro Microearthquakes, not felt.About 8,000 per day
2.0-2.9 Minor Generally not felt, but recorded.About 1,000 per day
3.0-3.9 Minor Often felt, but rarely causes damage.49,000 per year (est.)
4.0-4.9 LightNoticeable shaking of indoor items, rattling noises. Significant damage unlikely.
6,200 per year (est.)
5.0-5.9 ModerateCan cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings.
800 per year
6.0-6.9 StrongCan be destructive in areas up to about 100 miles across in populated areas.
120 per year
7.0-7.9 Major Can cause serious damage over larger areas. 18 per year
8.0-8.9 Great Can cause serious damage in areas several hundred miles across. 1 per year
9.0-9.9 Great Devastating in areas several thousand miles across. 1 per 20 years
10.0+ Great Never recorded; see below for equivalent seismic energy yield.Extremely rare (Unknown)
← London
← an earthquake of 3.7 - 4.6 every year
← an earthquake of 4.7 - 5.5 every 10 years
← an earthquake of 5.6 or larger every 100 years
Ninety percent of the world's earthquakes and 81% of the world's largest earthquakes occur
along the Ring of Fire. The next most seismic region (5–6% of earthquakes and 17% of the
world's largest earthquakes) is the Alpide belt which extends from Java to Sumatra through the
Himalayas, the Mediterranean, and out into the Atlantic. The Mid-Atlantic Ridge is the third
most prominent earthquake belt.[1][2]
Mount Tambora (or Tomboro) is an active stratovolcano on Sumbawa island, Indonesia.
Sumbawa is flanked both to the north and south by oceanic crust, and Tambora was formed by
the active subduction zones beneath it. This raised Mount Tambora as high as 4,300 m
(14,000 ft),[2] making it one of the tallest peaks in the Indonesian archipelago, and drained off a
large magma chamber inside the mountain. It took centuries to refill the magma chamber, its
volcanic activity reaching its peak in April 1815.[3]
Tambora erupted in 1815 with a rating of seven on the Volcanic Explosivity Index; the largest
eruption since the Lake Taupo eruption in AD 181.[4] The explosion was heard on Sumatra
island (more than 2,000 km or 1,200 mi away). Heavy volcanic ash falls were observed as far
away as Borneo, Sulawesi, Java and Maluku islands. The death toll was at least 71,000
people, of which 11,000–12,000 were killed directly by the eruption;[4] most authors estimated
92,000 people were killed but this figure is based on an overestimated calculation.[5] The
eruption created global climate anomalies; 1816 became known as the Year Without a
Summer because of the effect on North American and European weather. Agricultural crops
failed and livestock died in much of the Northern Hemisphere, resulting in the worst famine of
the 19th century.[4]
During an excavation in 2004, a team of archaeologists discovered cultural remains buried by
the 1815 eruption.[6] They were kept intact beneath the 3 m (10 ft) deep pyroclastic deposits.
Dubbed the Pompeii of the East, the artifacts were preserved in the positions they had
occupied in 1815.
Mount Tambora is located on Sumbawa Island, part of the Lesser Sunda Islands. It is a
segment of the Sunda Arc, a string of volcanic islands that form the southern chain of the
Indonesian archipelago.[7] Tambora forms its own peninsula on Sumbawa, known as the
Sanggar peninsula. At the north of the peninsula is the Flores Sea, and at the south is the
86 km (53.5 mi) long and 36 km (22 mi) wide Saleh Bay. At the mouth of Saleh Bay there is an
islet called Mojo.
Besides the seismologists and vulcanologists who monitor the mountain's activity, Mount
Tambora is an area of scientific studies for archaeologists and biologists. The mountain also
attracts tourists for hiking and wildlife activities.[8][9] The two nearest cities are Dompu and Bima.
There are three concentrations of villages around the mountain slope. At the east is Sanggar
village, to the northwest are Doro Peti and Pesanggrahan villages, and to the west is Calabai
village.
There are two ascent routes to reach the caldera. The first route starts from Doro Mboha
village at the southeast of the mountain. This route follows a paved road through a cashew
plantation until it reaches 1,150 m (3,800 ft) above sea level. The end of this route is the
southern part of the caldera at 1,950 m (6,400 ft), reachable by means of a hiking track.[10] This
location is usually used as a base camp to monitor the volcanic activity, because it only takes
one hour to reach the caldera. The second route starts from Pancasila village at the northwest
of the mountain. Using the second route, the caldera is only accessible by foot.[10]
The Sombrero Galaxy, an example of an unbarred spiral galaxy. Credit:Hubble Space Telescope/NASA/ESA
NGC 1300, an example of a barred spiral galaxy. Credit:Hubble Space Telescope/NASA/ESA
Hoag's Object, an example of a ring galaxy. Credit:Hubble Space Telescope/NASA/ESA
Milky Way Galaxy
Infrared image of the core of the Milky Way galaxy
Observation data
Type SBbc (barred spiral galaxy)
Diameter 100,000 light years
Thickness 1,000 light years
Number of stars 200 to 400 billion
Oldest star 13.2 billion years
Mass 5.8 × 1011 M☉
Sun's distance to galactic center 26,000 ± 1400 light-years
Sun's galactic rotation period 220 million years (negative rotation)
Spiral pattern rotation period 50 million years[1]
Bar pattern rotation period 15 to 18 million years[1]
Speed relative to the universe 590 km/s[2]
Supernovae : Candara X-Ray Telescope
" ketika langit pecah belah lalu menjadilah ia mawar merah, berkilat seperti minyak"(Ar-Rahman: 37)
Chandra X-ray Observatory
Organization NASA, SAO, CXC
Wavelength regime
X-ray
Orbit height10 000 km (perigee), 140 161 km (apogee)
Orbit period 3858 min, 64.3 h
Launch date 23 July 1999
Launch vehicle
Columbia STS-93
Deorbit date N/A
Mass 4 800 kg, 10 600 lb
Other namesAdvanced X-ray Astrophysics Facility, AXAF
COSPAR ID 1999-040B
Webpage http://chandra.harvard.edu/
Physical characteristics
Telescope style
4 nested pairs of grazing incidence paraboloid and hyperboloid mirrors
Diameter 1.2 m, 3.9 ft
Collecting area
0.04 m² at 1 keV, 0.4 ft² at 1 keV
Focal length 10 m, 33 ft
Instruments
ACIS imaging spectrometer
HRC camera
HETGShigh resolution spectrometer
LETGShigh resolution spectrometer
Hubble Space Telescope
The Hubble Space Telescope, from the Space Shuttle Discovery during the second servicing mission, STS-82
General information
NSSDC ID: 1990-037B
Organization: NASA/ESA/STScI
Launched: April 24, 1990
Deorbited: Likely between 2013 and 2021[1]
Mass: 11,110 kg (24,250 lb)
Orbit height: 589 km, 366 mi.
Orbit period: 96–97 min
Orbit velocity: 7,500 m/s, 16,800 mph (27,000 km/h)
Acceleration due to gravity:
8.169 m/s²
Location: Low Earth orbit
Type of orbit: Elliptical
Telescope style: Ritchey-Chretien reflector
Wavelength: Optical, ultraviolet, near-infrared
Diameter: 2.4 m (94 in)
Collecting area: approx. 4.5 m² (46 ft²) [2]
Focal length: 57.6 m (189 ft)
Instruments
NICMOS: infrared camera/spectrometer
ACS: optical survey camera (failed)
WFPC2: wide field optical camera
STIS: optical spectrometer/camera (failed)
FGS: three fine guidance sensors
Website: http://www.nasa.gov/hubble http://hubble.nasa.gov http://hubblesite.org http://www.spacetelescope.org
A galaxy (from the Greek root galaxias [γαλαξίας], meaning "milky," a reference to the Milky
Way) is a massive, gravitationally bound system consisting of stars, an interstellar medium of
gas and dust, and dark matter.[1][2] Typical galaxies range from dwarfs with as few as ten
million[3] (107) stars up to giants with one trillion[4] (1012) stars, all orbiting a common center of
mass. Galaxies can also contain many multiple star systems, star clusters, and various
interstellar clouds. The Sun is one of the stars in the Milky Way galaxy; the Solar System
includes the Earth and all the other objects that orbit the Sun.
Historically, galaxies have been categorized according to their apparent shape (usually
referred to as their visual morphology). A common form is the elliptical galaxy,[5] which has an
ellipse-shaped light profile. Spiral galaxies are disk-shaped assemblages with curving, dusty
arms. Galaxies with irregular or unusual shapes are known as peculiar galaxies, and typically
result from disruption by the gravitational pull of neighboring galaxies. Such interactions
between nearby galaxies, which may ultimately result in galaxies merging, may induce
episodes of significantly increased star formation, producing what is called a starburst galaxy.
Small galaxies that lack a coherent structure could also be referred to as irregular galaxies.[6]
There are probably more than 100 billion (1011) galaxies in the observable universe.[7] Most
galaxies are 1,000 to 100,000[4] parsecs in diameter and are usually separated by distances on
the order of millions of parsecs (or megaparsecs).[8] Intergalactic space (the space between
galaxies) is filled with a tenuous gas of an average density less than one atom per cubic meter.
The majority of galaxies are organized into a hierarchy of associations called clusters, which, in
turn, can form larger groups called superclusters. These larger structures are generally
arranged into sheets and filaments, which surround immense voids in the universe.[9]
Although it is not yet well understood, dark matter appears to account for around 90% of the
mass of most galaxies. Observational data suggests that supermassive black holes may exist
at the center of many, if not all, galaxies. They are proposed to be the primary cause of active
galactic nuclei found at the core of some galaxies. The Milky Way galaxy appears to harbor at
least one such object within its nucleus.[10]
The parsec (symbol pc) is a unit of length used in astronomy. The length of the parsec is
based on the method of trigonometric parallax, one of the oldest methods for measuring the
distances to stars.
The name parsec stands for "parallax of one second of arc", and one parsec is defined to be
the distance from the Earth to a star that has a parallax of 1 arcsecond. The actual length of a
parsec is approximately 3.086×1016 m, or about 3.262 light-years
Mean distancefrom Earth
1.496×1011 m8.31 min at light speed
Visual brightness (V) −26.74m [1]
Absolute magnitude 4.83m [1]
Spectral classification G2V
Metallicity Z = 0.0177[2]
Angular size 31.6' - 32.7' [3]
Adjectives solar
nova (pl. novae) is a cataclysmic nuclear explosion caused by the accretion of hydrogen onto
the surface of a white dwarf star. Novae are not to be confused with Type Ia supernovae, or
another form of stellar explosion first announced by Caltech in May 2007, Luminous Red
Novae.
Contents
[hide]
1 Development
2 Occurrence rate, and astrophysical
significance
3 Historical significance
4 Novae as distance indicators
5 References
← 5.1 Bright novae since 1890
← 5.2 Recurrent novae
6 Notes
7 See also
8 External links
[edit] Development
If a white dwarf has a close companion star that overflows its Roche lobe, the white dwarf will
steadily accrete gas from the star's outer atmosphere. The companion may be a main
sequence star, or one that is ageing and expanding into a red giant. The captured gases
consist primarily of hydrogen and helium, the two principal constituents of ordinary matter in
the universe. The gases are compacted on the white dwarf's surface by its intense gravity,
compressed and heated to very high temperatures as additional material is drawn in. The white
dwarf consists of degenerate matter, and so does not inflate at increased heat, while the
accreted hydrogen is compressed upon the surface. The dependence of the hydrogen fusion
rate on temperature and pressure means that it is only when it is compressed and heated at
the surface of the white dwarf to a temperature of some 20 million K that a nuclear fusion
reaction occurs; at these temperatures, hydrogen burns via the CNO cycle. For most binary
system parameters, the hydrogen burning is thermally unstable and rapidly converts a large
amount of the hydrogen into other heavier elements in a runaway reaction.[1] (Hydrogen fusion
can occur in a stable manner on the surface, but only for a narrow range of accretion rates.)
The enormous amount of energy liberated by this process blows the remaining gases away
from the white dwarf's surface and produces an extremely bright outburst of light. The rise to
peak brightness can be very rapid or gradual which is related to the speed class of the nova;
after the peak, the brightness declines steadily.[2] The time taken for a nova to decay by 2 or 3
magnitudes from maximum optical brightness is used to classify a nova via its speed class. A
fast nova will typically take less than 25 days to decay by 2 magnitudes and a slow nova will
take over 80 days.[3]
In spite of their violence, the amount of material ejected in novae is usually only about
1/10,000th of a solar mass, quite small relative to the mass of the white dwarf. Furthermore,
only five percent of the accreted mass is fused to power the outburst. [1] Nonetheless, this is
enough energy to accelerate nova ejecta to velocities as high as several thousand kilometers
per second—higher for fast novae than slow ones—with a concurrent rise in luminosity from a
few times solar to 50,000–100,000 times solar.[1][4]
A white dwarf can potentially generate multiple novae over time as additional hydrogen
continues to accrete onto its surface from its companion star. An example is RS Ophiuchi,
which is known to have flared six times (in 1898, 1933, 1958, 1967, 1985, and again in 2006).
Eventually, however, either the white dwarf will run out of material, or collapse into a neutron
star, or explode as a type Ia supernova.
Occasionally a nova is bright enough and close enough to be conspicuous to the unaided eye.
The brightest recent example was Nova Cygni 1975. This nova appeared on August 29, 1975
in the constellation Cygnus about five degrees north of Deneb and reached magnitude 2.0
(nearly as bright as Deneb). The most recent was V1280 Scorpii which reached magnitude 3.7
on February 17, 2007.
[edit] Occurrence rate, and astrophysical significance
Astronomers estimate that the Milky Way experiences roughly 20 to 60 novae per year, with a
likely rate of about 40.[1] The number of novae discovered each year is much lower, probably
due to great distance and observational biases.[5] By comparison, the number of novae
discovered each year in the nearby Andromeda Galaxy is much lower; roughly ½ to ⅓ that of
the Milky Way.[6]
Spectroscopic observation of nova ejecta nebulae has shown that they are enriched in
elements such as helium, carbon, nitrogen, oxygen, neon, and magnesium.[1] The contribution
of novae to the interstellar medium is not great; novae supply only 1/50th the amount of
material to the Galaxy as supernovae, and only 1/200th that of red giant and supergiant stars.[1]
Recurrent novae like RS Ophiuchi (those with periods on the order of decades) are rare.
Astronomers theorize however that most, if not all, novae are recurrent, albeit on time scales
ranging from 1,000 to 100,000 years.[7] The recurrence interval for a nova is less dependent on
the white dwarf's accretion rate than on its mass; with their powerful gravity, massive white
dwarfs require less accretion to fuel an outburst than lower-mass ones.[1] Consequently, the
interval is shorter for high-mass white dwarfs.[1]
A supernova (plural: supernovae or supernovas) is a stellar explosion that creates an
extremely luminous object. A supernova causes a burst of radiation that may briefly outshine
its entire host galaxy before fading from view over several weeks or months. During this short
interval, a supernova can radiate as much energy as the Sun would emit over 10 billion years.[1] The explosion expels much or all of a star's material[2] at a velocity of up to a tenth the speed
of light, driving a shock wave into the surrounding interstellar medium. This shock wave
sweeps up an expanding shell of gas and dust called a supernova remnant.
Several types of supernovae exist that may be triggered in one of two ways, involving either
turning off or suddenly turning on the production of energy through nuclear fusion. After the
core of an aging massive star ceases to generate energy from nuclear fusion, it may undergo
sudden gravitational collapse into a neutron star or black hole, releasing gravitational potential
energy that heats and expels the star's outer layers. Alternatively, a white dwarf star may
accumulate sufficient material from a stellar companion (usually through accretion, rarely via a
merger) to raise its core temperature enough to ignite carbon fusion, at which point it
undergoes runaway nuclear fusion, completely disrupting it. Stellar cores whose furnaces have
permanently gone out collapse when their masses exceed the Chandrasekhar limit, while
accreting white dwarfs ignite as they approach this limit (roughly 1.38 [3] times the mass of the
Sun). White dwarfs are also subject to a different, much smaller type of thermonuclear
explosion fueled by hydrogen on their surfaces called a nova. Solitary stars with a mass below
approximately nine[4] solar masses, such as the Sun itself, evolve into white dwarfs without
ever becoming supernovae.
On average, supernovae occur about once every 50 years in a galaxy the size of the Milky
Way[5] and play a significant role in enriching the interstellar medium with heavy elements. In
our galaxy, about 200 supernova remnants have been found.[citation needed] Furthermore, the
expanding shock waves from supernova explosions can trigger the formation of new stars.[6]
Nova (plural novae) means "new" in Latin, referring to what appears to be a very bright new
star shining in the celestial sphere; the prefix "super-" distinguishes supernovae from ordinary
novae, which also involve a star increasing in brightness, though to a lesser extent and through
a different mechanism. According to Merriam-Webster's Collegiate Dictionary, the word
supernova was first used in print in 1926.
Danah Zohar
The American philosopher Danah Zohar, the wife of British psychiatrist Ian Marshall, believes that consciousness is the bridge between the classical world and the quantum world. One of Quantum Mechanics' shortcomings is that it doesn't truly explain how reality emerges from the quantum world of elementary particles and probability waves. Zohar believes that the answer has always been in the theory, and that we simply refused to take it at face value. Zohar subscribes to the thesis of Bose-Einstein condensation advocated by Ian Marshall, which basically reduces mind/body duality to wave/particle duality. Zohar is fascinated by the behavior of bosons. Particles divide into fermions (such as electrons, protons, neutrons) and bosons (photons, gravitons, gluons). Bosons are particle of "relationship", as they are used to interact. When two systems interact (electricity, gravitation or whatever), they exchange bosons. Fermions are well-defined individual entities, just like large-scale matter is. But bosons can completely merge and become one entity, more like conscious states do. Zohar therefore claims that bosons are the basis for the conscious life, and fermions for the material life. The Bose-Einstein condensate is the extreme example of "bosonic" behavior (relationship, sharing of identities). Zohar imagines that such a condensate is the ideal candidate to provide the unity of consciousness. The properties of matter would arise from the properties of fermions. Matter is solid because fermions cannot merge. On the other hand, the properties of mind would arise from the properties of bosons: they can share the same state and they are about relationships. This would also explain how there can be a "self". The brain changes all the time and therefore the "self" is never the same. I am never myself again. How can there be a sense of "self"? Zohar thinks that the self does change all the time, but quantum interference makes each new self sprout from the old selves. Wave functions of past selves overlap with the wave function of the current self. Through this "quantum memory" each self reincarnates past selves. Zohar's quantum self is a "fluid" self, not a static self. One more time, it is the wave aspect of nature that makes a self possible, regardless of the fact that the matter of the brain changes all the time. By the same token, a self is woven into the waves of other selves and therefore becomes part of a bigger entity. Zohar draws a number of conclusions from this picture of the "quantum self" that may serve psychiatrist and possibly provide more solid foundations for psychoanalysis. Her theoretical premises, though, rely mostly on "similarities" between concepts of Quantum Theory and concepts of folk psychology.
Ian Marshall
The authors apply the indeterminacy of quantum mechanics to human society, in particular to justify a holistic vision of both social and individual life. They claim that the unity of consciousness is evidence that the mind is a quantum phenomenon, precisely the phenomenon of Bose-Einstein condensation. The book discusses Marshall's thesis (advanced years earlier) that the brain exhibits such a physical property and it is precisely this Bose-Einstein condensate that allows the brain to organize millions of neuronal processes into a coherent whole (thought).
Marshall thinks that the collapse of a wave function is not completely random, as predicted by Quantum Theory, but exhibits a preference for "phase difference". Such "phase differences" are the sharpest in Bose-Einstein condensates. This implies that the wave function tends to collapse towards Bose-Einstein
condensates, i.e. that there is a universal tendency towards creating the living and thinking structures that populate our planet. Marshall views this as an evolutionary principle built in our universe.
In other words, the universe has an innate tendency towards life and consciousness. They are ultimately due to the mathematical properties (to the behavior) of the quantum wave function, which favors the evolution of life and consciousness. Marshall thinks we "must" exist and think, in accordance with the strong anthropic principle (that things are the way they are because otherwise we would not exist).
Marshall can then solve the paradox of "adaptive evolution", discovered in 1988 by John Cairns: some bacteria can mutate very quickly, way too quickly for Darwin's theory to be true. If all genes mutated at that pace, they would mostly produce mutations that cannot survive. What drives evolution is natural selection, which prunes each generation of mutations. But natural selection does not have the time to operate on the very rapid mutations of these bacteria. There must be another force at work that "selects" only the mutations that are useful for survival. Marshall thinks that other force is the wave function's tendency towards choosing states of life and consciousness. Each mutation is inherently biased towards success.
By extending the same arguments at the interpersonal level, the authors arrive at a quantum model of community. The wave/particle dualism of Quantum Theory also relates to the role of humans in society: individual action can be better viewed as part of a bigger wave of actions of all individuals. Human behavior in general can be viewed as both particle and wave (both as a self with boundaries and an "unstructured potential"). The higher reality of society (for example, its nature as a shared repository of skills and knowledge) is due to the overlapping of the wave aspect of our personas.
The authors argue that the power, and even necessity, of pluralism in society is proven to be essential to evolution itself. This is a fascinating book that mixes Quantum Physics, speculations on the nature of mind and social and political philosophy. Quantum mechanisms and Darwin's theory of evolution get interpreted as a celebration of pluralism and diversity. They are both essential to our being what we are, and they are inherent in everything that happens and that we do. An uplifting, if not always plausible, message.
v • d • e
Milky Way Galaxy
Infrared image of the core of the Milky Way galaxy
Observation data
Type SBbc (barred spiral galaxy)
Diameter 100,000 light years
Thickness 1,000 light years
Number of stars 200 to 400 billion
Oldest star 13.2 billion years
Mass 5.8×1011 M☉
Sun's distance to galactic center 26,000 ± 1400 light-years
Sun's galactic rotation period 220 million years (negative rotation)
Spiral pattern rotation period 50 million years[1]
Bar pattern rotation period 15 to 18 million years[1]
Speed relative to the universe 590 km/s[2]
