A
chart of estimated annual growth rates in world population, 1800–2005.
Rates before 1950 are annualized historical estimates from the US Census Bureau. Red = USCB projections to 2025
A Malthusian catastrophe (also known as Malthusian check or Malthusian spectre) is a prediction that population growth will outpace agriculturalproduction – that there will be too many people and not enough food.
Famine seems to be the last, the
most dreadful resource of nature. The power of population is so superior
to the power of the earth to produce subsistence for man, that
premature death must in some shape or other visit the human race. The
vices of mankind are active and able ministers of depopulation. They are
the precursors in the great army of destruction, and often finish the
dreadful work themselves. But should they fail in this war of
extermination, sickly seasons, epidemics, pestilence, and plague advance
in terrific array, and sweep off their thousands and tens of thousands.
Should success be still incomplete, gigantic inevitable famine stalks
in the rear, and with one mighty blow levels the population with the
food of the world.
Notwithstanding the apocalyptic image conveyed by this particular
paragraph, Malthus himself did not subscribe to the notion that mankind
was fated for a "catastrophe" due to population overshooting resources.
Rather, he believed that population growth was generally restricted by
available resources:
The passion between the sexes has
appeared in every age to be so nearly the same that it may always be
considered, in algebraic language, as a given quantity. The great law of
necessity which prevents population from increasing in any country
beyond the food which it can either produce or acquire, is a law so open
to our view...that we cannot for a moment doubt it. The different modes
which nature takes to prevent or repress a redundant population do not
appear, indeed, to us so certain and regular, but though we cannot
always predict the mode we may with certainty predict the fact.
Malthus proposed two kinds of population checks: preventive and positive.
A preventive check is a conscious decision to delay marriage or abstain from procreation based on a lack of resources.
This type of check is unique to humanity, because it requires
foresight. Malthus argued that man is incapable of ignoring the
consequences of uncontrolled population growth, and would intentionally
avoid contributing to it.
According to Malthus, a positive check is any event or circumstance
that shortens the human life span. The primary examples of this are war, plague and famine. However, poor health and economic conditions are also considered instances of positive checks.
Neo-Malthusian theory
Wheat yields in developing countries since 1961, in kg/ha.
The steep rise in crop yields in the U.S. began in the 1940s. The
percentage of growth was fastest in the early rapid growth stage. In
developing countries maize yields are still rapidly rising.
After World War II, mechanized agriculture produced a dramatic increase in productivity of agriculture and the Green Revolution
greatly increased crop yields, expanding the world's food supply while
lowering food prices. In response, the growth rate of the world's
population accelerated rapidly, resulting in predictions by Paul R. Ehrlich, Simon Hopkins,
and many others of an imminent Malthusian catastrophe. However,
populations of most developed countries grew slowly enough to be
outpaced by gains in productivity.
Growth in food production has been greater than population growth. Food per person increased since 1961.
Historians have estimated the total human population back to 10,000 BC.
The figure on the right shows the trend of total population from 1800
to 2005, and from there in three projections out to 2100 (low, medium,
and high).
The United Nations population projections out to 2100 (the red, orange,
and green lines) show a possible peak in the world's population
occurring by 2040 in the first scenario, and by 2100 in the second
scenario, and never ending growth in the third.
The graph of annual growth rates (at the top of the page) does
not appear exactly as one would expect for long-term exponential growth.
For exponential growth it should be a straight line at constant
height, whereas in fact the graph from 1800 to 2005 is dominated by an
enormous hump that began about 1920, peaked in the mid-1960s, and has
been steadily eroding away for the last 40 years. The sharp fluctuation
between 1959 and 1960 was due to the combined effects of the Great Leap Forward and a natural disaster in China. Also visible on this graph are the effects of the Great Depression, the two world wars, and possibly also the 1918 flu pandemic.
Though short-term trends, even on the scale of decades or
centuries, cannot prove or disprove the existence of mechanisms
promoting a Malthusian catastrophe over longer periods, the prosperity
of a major fraction of the human population at the beginning of the 21st
century, and the debatability of the predictions for ecological collapse made by Paul R. Ehrlich in the 1960s and 1970s, has led some people, such as economist Julian L. Simon, to question its inevitability.
A 2004 study by a group of prominent economists and ecologists, including Kenneth Arrow and Paul Ehrlich
suggests that the central concerns regarding sustainability have
shifted from population growth to the consumption/savings ratio, due to
shifts in population growth rates since the 1970s. Empirical estimates
show that public policy (taxes or the establishment of more complete
property rights) can promote more efficient consumption and investment
that are sustainable in an ecological sense; that is, given the current
(relatively low) population growth rate, the Malthusian catastrophe can
be avoided by either a shift in consumer preferences or public policy
that induces a similar shift.
A 2002 study by the UN Food and Agriculture Organization
predicts that world food production will be in excess of the needs of
the human population by the year 2030; however, that source also states
that hundreds of millions will remain hungry (presumably due to economic
realities and political issues).
Criticism
Karl Marx and Friedrich Engels
argued that Malthus failed to recognize a crucial difference between
humans and other species. In capitalist societies, as Engels put it,
scientific and technological "progress is as unlimited and at least as
rapid as that of population". Marx argued, even more broadly, that the growth of both a human population in toto and the "relative surplus population" within it, occurred in direct proportion to accumulation.
Henry George
criticized Malthus's view that population growth was a cause of
poverty, arguing that poverty was caused by the concentration of
ownership of land and natural resources. George noted that humans are
distinct from other species, because unlike most species humans can use
their minds to leverage the reproductive forces of nature to their
advantage. He wrote, "Both the jayhawk and the man eat chickens; but the
more jayhawks, the fewer chickens, while the more men, the more
chickens."
Ester Boserup suggested that population levels determined agricultural methods, rather than agricultural methods determining population.
Julian Simon
was another economist who argued that there could be no global
Malthusian catastrophe, because of two factors: (1) the existence of new
knowledge, and educated people to take advantage of it, and (2)
"economic freedom", that is, the ability of the world to increase
production when there is a profitable opportunity to do so.
D.E.C. Eversley observed that Malthus appeared unaware of the
extent of industrialization, and either ignored or discredited the
possibility that it could improve living conditions of the poorer
classes.
In contrast to these criticisms, some individuals, such as Joseph Tainter, argue that science has diminishing marginal returns and that scientific progress is becoming more difficult, harder to achieve, and more costly. (DJS: also see Ray Kurzxweil.)
Simon wrote many books and articles, mostly on economic subjects. He is best known for his work on population, natural resources, and immigration. His work covers cornucopian views on lasting economic benefits from natural resources and continuous population growth, even despite limited or finite physical resources, empowered by human ingenuity, substitutes, and technological progress. His works are also cited by libertarians against government regulation.
He is also known for the famous Simon–Ehrlich wager, a bet he made with ecologist Paul R. Ehrlich.
Ehrlich bet that the prices for five metals would increase over a
decade, while Simon took the opposite stance. Simon won the bet, as the
prices for the metals sharply declined during that decade.
Simon examined different raw materials, especially metals and
their prices in historical times. He assumed that besides temporary
shortfalls, in the long run prices for raw materials remain at similar
levels or even decrease. E.g. aluminium was never as expensive as before 1886 and steel
used for medieval armor carried a much higher price tag in current
dollars than any modern parallel. A recent discussion of commodity index
long-term trends supported his positions.
His 1984 book The Resourceful Earth (co-edited by Herman Kahn), is a similar criticism of the conventional wisdom on population growth and resource consumption and a direct response to the Global 2000
report. For example, it predicted that "There is no compelling reason
to believe that world oil prices will rise in the coming decades. In
fact, prices may well fall below current levels". Indeed, oil prices
trended downward for nearly the next 2 decades, before rising above 1984
levels in about 2003 or 2004. Oil prices have subsequently risen and
fallen, and risen again. In 2008, the price of crude oil reached $100
per barrel, a level last attained in the 1860s (inflation adjusted).
Later in 2008, the price again sharply fell, to a low of about $40,
before rising again to a high around $125. Since mid-2011, prices were
slowly trending downward until the middle of 2014, but falling
dramatically until the end of 2015 to ca. $30. Since then prices were
relatively stable (below $50).
Simon was skeptical, in 1994, of claims that human activity caused global environmental damage, notably in relation to CFCs, ozone depletion and climate change, the latter primarily because of the perceived rapid switch from fears of global cooling and a new ice age (in the mid-1970s) to the later fears of global warming.
Simon also listed numerous claims about alleged environmental
damage and health dangers from pollution as "definitely disproved".
These included claims about lead pollution & IQ, DDT, PCBs, malathion, Agent Orange, asbestos, and the chemical contamination at Love Canal. He dismissed such concerns as a mere "value judgement."
But also, to a startling degree,
the decision about whether the overall effect of a child or migrant is
positive or negative depends on the values of whoever is making the
judgment – your preference to spend a dollar now rather than to wait for
a dollar-plus-something in twenty or thirty years, your preferences for
having more or fewer wild animals alive as opposed to more or fewer
human beings alive, and so on.
Simon was also the first to suggest that airlines should provide incentives for travelers to give up their seats on overbooked flights, rather than arbitrarily taking random passengers off the plane (a practice known as "bumping").
Although the airline industry initially rejected it, his plan was later
implemented with resounding success, as recounted by Milton Friedman in
the foreword to The Ultimate Resource II. Economist James Heins said in 2009 that the practice had added $100 billion to the United States economy in the last 30 years. Simon gave away his idea to federal de-regulators and never received any personal profit from his solution.
Although not all of Simon's arguments were universally accepted, they contributed to a shift in opinion in the literature on demographic economics from a strongly Malthusian negative view of population growth to a more neutral view. More recent theoretical developments, based on the ideas of the demographic dividend and demographic window, have contributed to another shift, this time away from the debate viewing population growth as either good or bad.
Simon wrote a memoir, A Life Against the Grain, which was published by his wife after his death.
Wagers with rivals
Paul R. Ehrlich – first wager
Simon challenged Paul R. Ehrlich to a wager in 1980 over the price of metals a decade later; Simon had been challenging environmental scientists to the bet for some time. Ehrlich, John Harte, and John Holdren
selected a basket of five metals that they thought would rise in price
with increasing scarcity and depletion. Simon won the bet, with all five
metals dropping in price.
Supporters of Ehrlich's position suggest that much of this price drop came because of an oil spike driving prices up in 1980 and a recession
driving prices down in 1990, pointing out that the price of the basket
of metals actually rose from 1950 to 1975. They also suggest that
Ehrlich did not consider the prices of these metals to be critical
indicators, and that Ehrlich took the bet with great reluctance. On the
other hand, Ehrlich selected the metals to be used himself, and at the
time of the bet called it an "astonishing offer" that he was accepting
"before other greedy people jump in."
The total supply in three of these metals (chromium, copper and
nickel) increased during this time. Prices also declined for reasons
specific to each of the five:
The price of tin went down because of an increased use of aluminium, a much more abundant, useful and inexpensive material.
Better mining technologies allowed for the discovery of vast nickellodes, which ended the near monopoly that was enjoyed on the market.
The price of chromium fell due to better smelting techniques.
The price of copper began to fall due to the invention of fiber optic cable (which is derived from sand), which serves a number of the functions once reserved only for copper wire.
In all of these cases, better technology allowed for either more
efficient use of existing resources, or substitution with a more
abundant and less expensive resource, as Simon predicted, until 2011.
Paul R. Ehrlich – proposed second wager
In 1995, Simon issued a challenge for a second bet. Ehrlich declined, and proposed instead that they bet on a metric for human welfare. Ehrlich offered Simon a set of 15 metrics over 10 years, victor to be determined by scientists chosen by the president of the National Academy of Sciences
in 2005. There was no meeting of minds, because Simon felt that too
many of the metric's measured attributes of the world were not directly
related to human welfare, e.g. the amount of nitrous oxide in the atmosphere.
For such indirect, supposedly bad indicators to be considered "bad",
they would ultimately have to have some measurable detrimental effect on
actual human welfare. Ehrlich refused to leave out measures considered
by Simon to be immaterial.
Simon summarized the bet with the following analogy:
Let me characterize their [Ehrlich
and Schneider's] offer as follows. I predict, and this is for real, that
the average performances in the next Olympics will be better than those
in the last Olympics. On average, the performances have gotten better,
Olympics to Olympics, for a variety of reasons. What Ehrlich and others
say is that they don't want to bet on athletic performances, they want
to bet on the conditions of the track, or the weather, or the officials,
or any other such indirect measure.
David South
The same year as his second challenge to Ehrlich, Simon also began a wager with David South, professor of the Auburn University School of Forestry. The Simon / South wager concerned timber prices. Consistent with his cornucopian analysis of this issue in The Ultimate Resource,
Simon wagered that at the end of a five-year term the consumer price of
pine timber would have decreased; South wagered that it would increase.
Before five years had elapsed, Simon saw that market and extra-market
forces were driving up the price of timber, and he paid Professor South
$1,000. Simon died before the agreed-upon date of the end of the bet, by which time timber prices had risen further.
Simon's reasoning for his early exit out of the bet was due to
"the far-reaching quantity and price effects of logging restrictions in
the Pacific-northwest."
He believed this counted as interference from the U.S. government,
which rendered the bet worthless according to his economic principles.
Simon's bet only considered the possibility of prices being driven up by
Alabama's government; he did not believe anything worthwhile was shown
when U.S. logging restrictions drove the prices up.
We now have in our hands—really, in
our libraries—the technology to feed, clothe, and supply energy to an
ever-growing population for the next seven billion years. (Simon along The State of Humanity: Steadily Improving 1995)
Diamond claims that a continued stable growth rate of earth's
population would result in extreme over-population long before the
suggested time limit. Regarding the attributed population predictions
Simon did not specify that he was assuming a fixed growth rate as
Diamond, Bartlett and Hardin have done. Simon argued that people do not
become poorer as the population expands; increasing numbers produce what
they needed to support themselves, and have and will prosper while food
prices sink.
There is no reason to believe that
at any given moment in the future the available quantity of any natural
resource or service at present prices will be much smaller than it is
now, or non-existent. (Simon in The Ultimate Resource, 1981)
Diamond believes, and finds absurd, Simon implies it would be possible to produce metals, e.g. copper, from other elements.
For Simon, human resource needs are comparably small compared to the
wealth of nature. He therefore argued physical limitations play a minor
role and shortages of raw materials tend to be local and temporary. The
main scarcity pointed out by Simon is the amount of human brain power
(i.e. "The Ultimate Resource") which allows for the perpetuation of
human activities for practically unlimited time. For example, before
copper ore became scarce and prices soared due to global increasing
demand for copper wires and cablings, the global data and
telecommunication networks have switched to glass fiber backbone
networks.
This is my long-run forecast in
brief, ...The material conditions of life will continue to get better
for most people, in most countries, most of the time, indefinitely.
Within a century or two, all nations and most of humanity will be at or
above today's Western living standards. I also speculate, however, that
many people will continue to think and say that the conditions of life
are getting worse.
This and other quotations in Wired are supposed to be the reason for Bjørn Lomborg's The Skeptical Environmentalist. Lomborg has stated that he began his research as an attempt to counter what he saw as Simons' anti-ecological arguments but changed his mind after starting to analyze the data.
Legacy
The Institute for the Study of Labor established the annual Julian L. Simon Lecture to honor Simon's work in population economics. The University of Illinois at Urbana-Champaign held a symposium discussing Simon's work on April 24, 2002.
The university also established the Julian Simon Memorial Faculty
Scholar Endowment to fund an associate faculty member in the business
school. India's Liberty Institute also holds a Julian Simon Memorial Lecture. The Competitive Enterprise Institute gives the Julian Simon Memorial Award annually to an economist in the vein of Simon; the first recipient was Stephen Moore, who had served as a research fellow under Simon in the 1980s.
Personal life
Simon
was married to Rita James Simon, who was also a longtime member of the
faculty at the University of Illinois at Urbana-Champaign and later
became a public affairs professor at American University. Simon suffered from a long time depression, which allowed him to work only a few productive hours in a day. He also studied psychology of depression and wrote a book on overcoming it. Simon was Jewish. He died of a heart attack at his home in Chevy Chase in 1998 at age 65.
It's Getting Better All the Time : 100 Greatest Trends of the Last 100 Years by Stephen Moore, Julian Lincoln Simon ISBN1-882577-97-3manuscript finished posthumously by Stephen Moore
Coronal mass ejections are often associated with other forms of
solar activity, but a broadly accepted theoretical understanding of
these relationships has not been established. CMEs most often originate
from active regions on the Sun's surface, such as groupings of sunspots associated with frequent flares. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days.
Follow a CME as it passes Venus then Earth, and explore how the Sun drives Earth's winds and oceans.
Arcs rise above an active region on the surface of the Sun.
Coronal mass ejections release large quantities of matter and
electromagnetic radiation into space above the Sun's surface, either
near the corona (sometimes called a solar prominence), or farther into the planetary system, or beyond (interplanetary CME). The ejected material is a magnetized plasma consisting primarily of electrons and protons. While solar flares are very fast (being electromagnetic radiation), CMEs are relatively slow.
Coronal mass ejections are associated with enormous changes and disturbances in the coronal magnetic field. They are usually observed with a white-light coronagraph.
Cause
Scientific research has shown that the phenomenon of magnetic reconnection is closely associated with CMEs and solar flares. In magnetohydrodynamic
theory, the sudden rearrangement of magnetic field lines when two
oppositely directed magnetic fields are brought together is called
"magnetic reconnection". Reconnection releases energy stored in the
original stressed magnetic fields. These magnetic field lines can become
twisted in a helical structure, with a 'right-hand twist' or a 'left
hand twist'. As the Sun's magnetic field lines become more and more
twisted, CMEs appear to be a 'valve' to release the magnetic energy
being built up, as evidenced by the helical structure of CMEs, that
would otherwise renew itself continuously each solar cycle and
eventually rip the Sun apart.
On the Sun, magnetic reconnection may happen on solar arcades—a
series of closely occurring loops of magnetic lines of force. These
lines of force quickly reconnect into a low arcade of loops, leaving a
helix of magnetic field unconnected to the rest of the arcade. The
sudden release of energy during this process causes the solar flare and
ejects the CME. The helical magnetic field and the material that it
contains may violently expand outwards forming a CME.
This also explains why CMEs and solar flares typically erupt from what
are known as the active regions on the Sun where magnetic fields are
much stronger on average.
Aurora borealis stretch across Quebec and Ontario early on the morning of 8 October 2012.
Impact on Earth
When the ejection is directed towards Earth and reaches it as an interplanetary CME (ICME), the shock wave of traveling mass causes a geomagnetic storm that may disrupt Earth's magnetosphere, compressing it on the day side and extending the night-side magnetic tail. When the magnetosphere reconnects on the nightside, it releases power on the order of terawatt scale, which is directed back toward Earth's upper atmosphere.
Solar energetic particles can cause particularly strong aurorae in large regions around Earth's magnetic poles. These are also known as the Northern Lights (aurora borealis) in the northern hemisphere, and the Southern Lights (aurora australis) in the southern hemisphere. Coronal mass ejections, along with solar flares of other origin, can disrupt radio transmissions and cause damage to satellites and electrical transmission line facilities, resulting in potentially massive and long-lasting power outages.
Energetic protons released by a CME can cause an increase in the number of free electrons in the ionosphere,
especially in the high-latitude polar regions. The increase in free
electrons can enhance radio wave absorption, especially within the
D-region of the ionosphere, leading to Polar Cap Absorption (PCA)
events.
Humans at high altitudes, as in airplanes or space stations, risk exposure to relatively intense solar particle events.
The energy absorbed by astronauts is not reduced by a typical
spacecraft shield design and, if any protection is provided, it would
result from changes in the microscopic inhomogeneity of the energy
absorption events.
This
video features two model runs. One looks at a moderate coronal mass
ejection (CME) from 2006. The second run examines the consequences of a
large coronal mass ejection, such as the Carrington-class CME of 1859.
A typical coronal mass ejection may have any or all of three
distinctive features: a cavity of low electron density, a dense core
(the prominence, which appears on coronagraph images as a bright region embedded in this cavity), and a bright leading edge.
Most ejections originate from active regions on the Sun's surface, such as groupings of sunspots
associated with frequent flares. These regions have closed magnetic
field lines, in which the magnetic field strength is large enough to
contain the plasma. These field lines must be broken or weakened for the
ejection to escape from the Sun. However, CMEs may also be initiated in
quiet surface regions, although in many cases the quiet region was
recently active. During solar minimum, CMEs form primarily in the coronal streamer belt near the solar magnetic equator. During solar maximum, they originate from active regions whose latitudinal distribution is more homogeneous.
Coronal mass ejections reach velocities from 20 to 3,200 km/s (12
to 1,988 mi/s) with an average speed of 489 km/s (304 mi/s), based on SOHO/LASCO
measurements between 1996 and 2003. These speeds correspond to transit
times from the Sun out to the mean radius of Earth's orbit of about 13
hours to 86 days (extremes), with about 3.5 days as the average. The
average mass ejected is 1.6×1012 kg (3.5×1012 lb).
However, the estimated mass values for CMEs are only lower limits,
because coronagraph measurements provide only two-dimensional data. The
frequency of ejections depends on the phase of the solar cycle: from about one every fifth day near the solar minimum to 3.5 per day near the solar maximum.
These values are also lower limits because ejections propagating away
from Earth (backside CMEs) usually cannot be detected by coronagraphs.
Current knowledge of coronal mass ejection kinematics indicates
that the ejection starts with an initial pre-acceleration phase
characterized by a slow rising motion, followed by a period of rapid
acceleration away from the Sun until a near-constant velocity is
reached. Some balloon CMEs, usually the slowest ones, lack this
three-stage evolution, instead accelerating slowly and continuously
throughout their flight. Even for CMEs with a well-defined acceleration
stage, the pre-acceleration stage is often absent, or perhaps
unobservable.
Coronal waves (bright fronts propagating from the location of the eruption)
Post-eruptive arcades
The association of a CME with some of those phenomena is common but
not fully understood. For example, CMEs and flares are normally closely
related, but there was confusion about this point caused by the events
originating beyond the limb. For such events no flare could be detected.
Most weak flares do not have associated CMEs; most powerful ones do.
Some CMEs occur without any flare-like manifestation, but these are the
weaker and slower ones.
It is now thought that CMEs and associated flares are caused by a
common event (the CME peak acceleration and the flare impulsive phase
generally coincide). In general, all of these events (including the CME)
are thought to be the result of a large-scale restructuring of the
magnetic field; the presence or absence of a CME during one of these
restructures would reflect the coronal environment of the process (i.e.,
can the eruption be confined by overlying magnetic structure, or will
it simply break through and enter the solar wind).
Theoretical models
It
was first postulated that CMEs might be driven by the heat of an
explosive flare. However, it soon became apparent that many CMEs were
not associated with flares, and that even those that were often started
before the flare. Because CMEs are initiated in the solar corona (which
is dominated by magnetic energy), their energy source must be magnetic.
Because the energy of CMEs is so high, it is unlikely that their
energy could be directly driven by emerging magnetic fields in the
photosphere (although this is still a possibility). Therefore, most
models of CMEs assume that the energy is stored up in the coronal
magnetic field over a long period of time and then suddenly released by
some instability or a loss of equilibrium in the field. There is still
no consensus on which of these release mechanisms is correct, and
observations are not currently able to constrain these models very well.
These same considerations apply equally well to solar flares, but the observable signatures of these phenomena differ.
Interplanetary coronal mass ejections
Illustration of a coronal mass ejection moving beyond the planets toward the heliopause
CMEs typically reach Earth one to five days after leaving the Sun. During their propagation, CMEs interact with the solar wind and the interplanetary magnetic field
(IMF). As a consequence, slow CMEs are accelerated toward the speed of
the solar wind and fast CMEs are decelerated toward the speed of the
solar wind. The strongest deceleration or acceleration occurs close to the Sun, but it can continue even beyond Earth orbit (1 AU), which was observed using measurements at Mars and by the Ulysses spacecraft. CMEs faster than about 500 km/s (310 mi/s) eventually drive a shock wave. This happens when the speed of the CME in the frame of reference moving with the solar wind is faster than the local fast magnetosonic speed. Such shocks have been observed directly by coronagraphs in the corona, and are related to type II radio bursts. They are thought to form sometimes as low as 2 Rs (solar radii). They are also closely linked with the acceleration of solar energetic particles.
Related solar observation missions
NASA mission Wind
On 1 November 1994, NASA launched the Wind spacecraft as a solar wind monitor to orbit Earth's L1
Lagrange point as the interplanetary component of the Global Geospace
Science (GGS) Program within the International Solar Terrestrial Physics
(ISTP) program. The spacecraft is a spin axis-stabilized satellite that
carries eight instruments measuring solar wind particles from thermal
to >MeV energies, electromagnetic radiation from DC to 13 MHz radio
waves, and gamma-rays. Though the Wind spacecraft is over two
decades old, it still provides the highest time, angular, and energy
resolution of any of the solar wind monitors. It continues to produce
relevant research as its data has contributed to over 150 publications
since 2008 alone.
NASA mission STEREO
On 25 October 2006, NASA launched STEREO, two near-identical spacecraft which, from widely separated points in their orbits, are able to produce the first stereoscopic
images of CMEs and other solar activity measurements. The spacecraft
orbit the Sun at distances similar to that of Earth, with one slightly
ahead of Earth and the other trailing. Their separation gradually
increased so that after four years they were almost diametrically
opposite each other in orbit.
NASA mission Parker Solar Probe
The Parker Solar Probe
was launched on 12 August 2018 to measure the mechanisms which
accelerate and transport energetic particles i.e. the origins of the
solar wind.
History
First traces
The largest recorded geomagnetic perturbation, resulting presumably from a CME, coincided with the first-observed solar flare on 1 September 1859. The resulting solar storm of 1859
is now referred to as the Carrington Event, The flare and the
associated sunspots were visible to the naked eye (both as the flare
itself appearing on a projection of the Sun on a screen and as an
aggregate brightening of the solar disc), and the flare was
independently observed by English astronomers R. C. Carrington and R. Hodgson. The geomagnetic storm was observed with the recording magnetograph at Kew Gardens. The same instrument recorded a crochet, an instantaneous perturbation of Earth's ionosphere by ionizing soft X-rays. This could not easily be understood at the time because it predated the discovery of X-rays by Röntgen and the recognition of the ionosphere by Kennelly and Heaviside. The storm took down parts of the recently created US telegraph network, starting fires and shocking some telegraph operators.
Historical records were collected and new observations recorded
in annual summaries by the Astronomical Society of the Pacific between
1953 and 1960.
First clear detections
The first detection of a CME as such was made on 14 December 1971, by R. Tousey (1973) of the Naval Research Laboratory using the seventh Orbiting Solar Observatory (OSO-7).[24] The discovery image (256 × 256 pixels) was collected on a Secondary Electron Conduction (SEC) vidicon tube, transferred to the instrument computer after being digitized to 7 bits.
Then it was compressed using a simple run-length encoding scheme and
sent down to the ground at 200 bit/s. A full, uncompressed image would
take 44 minutes to send down to the ground. The telemetry was sent to ground support equipment (GSE) which built up the image onto Polaroid
print. David Roberts, an electronics technician working for NRL who had
been responsible for the testing of the SEC-vidicon camera, was in
charge of day-to-day operations. He thought that his camera had failed
because certain areas of the image were much brighter than normal. But
on the next image the bright area had moved away from the Sun and he
immediately recognized this as being unusual and took it to his
supervisor, Dr. Guenter Brueckner, and then to the solar physics branch head, Dr. Tousey. Earlier observations of coronal transients or even phenomena observed visually during solar eclipses are now understood as essentially the same thing.
1989-present
On 9 March 1989 a coronal mass ejection
occurred. On 13 March 1989 a severe geomagnetic storm struck the
Earth. It caused power failures in Quebec, Canada and short-wave radio
interference.
On 1 August 2010, during solar cycle 24, scientists at the Harvard–Smithsonian Center for Astrophysics
(CfA) observed a series of four large CMEs emanating from the
Earth-facing hemisphere of the Sun. The initial CME was generated by an
eruption on 1 August that was associated with NOAA Active Region 1092, which was large enough to be seen without the aid of a solar telescope. The event produced significant aurorae on Earth three days later.
According
to a report published in 2012 by physicist Pete Riley of Predictive
Science Inc., the chance of Earth being hit by a Carrington-class storm
between 2012 and 2022 is 12%.
Stellar coronal mass ejections
There have been a small number of CMEs observed on other stars, all of which as of 2016 have been found on M dwarfs. These have been detected by spectroscopy, most often by studying Balmer lines: the material ejected toward the observer causes asymmetry in the blue wing of the line profiles due to Doppler shift.
This enhancement can be seen in absorption when it occurs on the
stellar disc (the material is cooler than its surrounding), and in
emission when it is outside the disc. The observed projected velocities
of CMEs range from ≈84 to 5,800 km/s (52 to 3,600 mi/s). Compared to activity on the Sun, CME activity on other stars seems to be far less common.
Solar storm of 1859
From Wikipedia, the free encyclopedia
Sunspots of September 1, 1859, as sketched by Richard Carrington.
A and B mark the initial positions of an intensely bright event, which
moved over the course of five minutes to C and D before disappearing.
The solar storm of 1859 (also known as the Carrington Event) was a powerful geomagnetic solar storm during solar cycle 10 (1855–1867). A solar coronal mass ejection (CME) hit Earth's magnetosphere
and induced one of the largest geomagnetic storms on record, September
1–2, 1859. The associated "white light flare" in the solar photosphere was observed and recorded by British astronomers Richard C. Carrington (1826–1875) and Richard Hodgson (1804–1872).
The now-standard unique IAU identifier for this flare is SOL1859-09-01.
A solar storm of this magnitude occurring today would cause widespread disruptions and damage due to extended outages of the electrical grid. The solar storm of 2012 was of similar magnitude, but it passed Earth's orbit without striking the planet.
The flare was associated with a major coronal mass ejection
(CME) that travelled directly toward Earth, taking 17.6 hours to make
the 150 million kilometre (93 million mile) journey. It is believed that
the relatively high speed of this CME (typical CMEs take several days
to arrive at Earth) was made possible by a prior CME, perhaps the cause
of the large aurora event on August 29 that "cleared the way" of ambient
solar windplasma for the Carrington event.
Because of a geomagnetic solar flare effect ("magnetic crochet") observed in the Kew Observatorymagnetometer record by Scottish physicist Balfour Stewart and a geomagnetic storm observed the following day, Carrington suspected a solar-terrestrial connection. Worldwide reports on the effects of the geomagnetic storm of 1859 were compiled and published by American mathematician Elias Loomis, which support the observations of Carrington and Stewart.
On September 1–2, 1859, one of the largest recorded geomagnetic
storms (as recorded by ground-based magnetometers) occurred. Auroras
were seen around the world, those in the northern hemisphere as far
south as the Caribbean; those over the Rocky Mountains in the U.S. were so bright that the glow woke gold miners, who began preparing breakfast because they thought it was morning. People in the northeastern United States could read a newspaper by the aurora's light. The aurora was visible as far from the poles as south-central Mexico, Queensland, Cuba, Hawaii, southern Japan and China, and even at lower latitudes very close to the equator, such as in Colombia. Estimates of the storm strength range from −800 nT to −1750 nT.
Telegraph systems all over Europe and North America failed, in some cases giving telegraph operators electric shocks. Telegraph pylons threw sparks. Some telegraph operators could continue to send and receive messages despite having disconnected their power supplies.
Those who happened to be out late
on Thursday night had an opportunity of witnessing another magnificent
display of the auroral lights. The phenomenon was very similar to the
display on Sunday night, though at times the light was, if possible,
more brilliant, and the prismatic hues more varied and gorgeous. The
light appeared to cover the whole firmament, apparently like a luminous
cloud, through which the stars of the larger magnitude indistinctly
shone. The light was greater than that of the moon at its full, but had
an indescribable softness and delicacy that seemed to envelop
everything upon which it rested. Between 12 and 1 o'clock, when the
display was at its full brilliancy, the quiet streets of the city
resting under this strange light, presented a beautiful as well as
singular appearance.
In 1909, an Australian gold miner C.F. Herbert retold his observations in a letter to The Daily News in Perth:
I was gold-digging at Rokewood, about four miles from Rokewood township (Victoria).
Myself and two mates looking out of the tent saw a great reflection in
the southern heavens at about 7 o'clock p.m., and in about half an hour,
a scene of almost unspeakable beauty presented itself, lights of every
imaginable color were issuing from the southern heavens, one color
fading away only to give place to another if possible more beautiful
than the last, the streams mounting to the zenith, but always becoming a
rich purple when reaching there, and always curling round, leaving a
clear strip of sky, which may be described as four fingers held at arm's
length. The northern side from the zenith was also illuminated with
beautiful colors, always curling round at the zenith, but were
considered to be merely a reproduction of the southern display, as all
colors south and north always corresponded. It was a sight never to be
forgotten, and was considered at the time to be the greatest aurora
recorded... The rationalist and pantheist saw nature in her most
exquisite robes, recognising, the divine immanence, immutable law,
cause, and effect. The superstitious and the fanatical had dire
forebodings, and thought it a foreshadowing of Armageddon and final
dissolution.
In June 2013, a joint venture from researchers at Lloyd's of London
and Atmospheric and Environmental Research (AER) in the United States
used data from the Carrington Event to estimate the current cost of a
similar event to the U.S. alone at $0.6–2.6 trillion.
Other evidence and similar events
Ice cores containing thin nitrate-rich
layers have been analysed to reconstruct a history of past solar storms
predating reliable observations. Researchers state that data from
Greenland ice cores show evidence of individual solar-proton events,
including the Carrington event.
More recent work by the ice core community shows that nitrate spikes
are not a result of solar energetic particle events, and, indeed, no
consistency is found in cores from Greenland and Antarctica, and nitrate
events can be due to terrestrial events, such as burnings, so use of
this technique is in doubt.
Less severe storms have occurred in 1921 and 1960, when widespread radio disruption was reported. The March 1989 geomagnetic storm knocked out power across large sections of Quebec. On July 23, 2012 a "Carrington-class" solar superstorm (solar flare, coronal mass ejection, solar EMP)
was observed; its trajectory missed Earth in orbit. Information about
these observations was first shared publicly by NASA on April 28, 2014.
