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annarita ruberto
Worked at Ministry of National Education
Attended University of Salento
Lives in Ravenna (Italy)
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Giant Galaxy NGC 6872

Over 400,000 light years across NGC 6872 is an enormous barred spiral galaxy of type SB(s)b pec, at least 4 times the size of our own very large Milky Way. Also known as the Condor Galaxy, it is approximately five billion years old. It measures 522,000 light-years (160,000 pc), making it one of the largest-known spiral galaxies. A study, dating back to 2013, claims it is the largest one.
It was discovered on 27 June 1835 by English astronomer John Herschel.

NGC 6872 is 212 million light-years (65 Mpc) from Earth and toward the southern constellation Pavo, the Peacock. Its remarkable stretched out shape is due to its ongoing gravitational interaction, likely leading to an eventual merger, with the nearby smaller galaxy IC 4970, which is less than one twelfth as large.

IC 4970 is seen just below and right of the giant galaxy's core in this cosmic color portrait from the 8 meter Gemini South telescope in Chile. The idea to image this titanic galaxy collision comes from a winning contest essay submitted in 2010 to the Gemini Observatory by the Sydney Girls High School Astronomy Club.

In addition to inspirational aspects and aesthetics, club members argued that a color image would be more than just a pretty picture. In their winning essay they noted that "If enough colour data is obtained in the image it may reveal easily accessible information about the different populations of stars, star formation, relative rate of star formation due to the interaction, and the extent of dust and gas present in these galaxies".

►Image Credit: Sydney Girls High School Astronomy Club, Travis Rector (Univ. Alaska), Ángel López-Sánchez (Australian Astronomical Obs./ Macquarie Univ.), Australian Gemini Office

Further reading and references

#Universe, #NGC6872 , #CondorGalaxy , #astronomy , #space , #IC4970 , #constellation Pavo
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+annarita ruberto What a wonderful always! Thank you very much for your efforts in popularizing Science.
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Cubes Movin Up

An incredible creation by Dave Whyte (Bees & Bomb).

► Source>>

#gif, #processing, #design, #blackandwhite, #creativity, #animation, #cubes, #mathematics, #geometry, #cubes
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A Look Beyond The Horizon Of Events

A Proposed Solution To Calculating Black Hole Thermodynamics

Black holes are still very mysterious celestial bodies which, according to the majority of physicists, do not, however, escape the laws of thermodynamics.

As a result, these physical systems possess an entropy though no real agreement has been reached about the microscopic origin of this propriety and how it should be calculated.

A SISSA/Max Planck Institute (Potsdam) group has achieved important results in this calculation by applying a new formalism (Group Field Theory) of Loop Quantum Gravity (LQG), a very popular approach in the area of quantum gravity.

The result is consistent with the famous Bekenstein/Hawking law, whereby the entropy of a black hole is proportional to a quarter of its surface area, while it avoids many of the assumptions and simplifications of previous LQG theory attempts. Additionally, it lends support to the holography hypothesis, whereby the black hole that appears three-dimensional can be mathematically reduced to a two-dimensional projection.

► Read the Press release>>

► Link to the original paper "Horizon Entropy from Quantum Gravity Condensates" in Physical Review Letters:
► Link to arXiv paper>>
(thanks +Ron le Don)

► Images: Predicted appearance of non-rotating black hole
Credits: Brandon Defrise Carter
► Source Wikimedia commons:

#Physics, #Astrophysics , #HorizonEntropy , #QuantumGravityCondensates , #Blackholes , #GroupFieldTheory , #holography_hypothesis , #LoopQuantumGravity , #Research , # BlackHoleThermodynamics
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+Jelle Bos you're welcome!
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Escape Velocity from Every Planet in the Solar System: Resource for Kids

What is escape velocity?

In physics, escape velocity is the minimum speed needed for an object to "break free" from the gravitational attraction of a massive body (that is, to escape a massive body without ever falling back).
In other words, an object has to overcome the gravitational pull of a massive body for being free to escape into space.
For example, a rocket going into space needs to reach the escape velocity in order to make it off Earth and get into space.
A larger planet has more mass and requires a much greater escape velocity than a smaller planet with less mass.

More particularly, escape velocity is the speed at which the sum of an object's kinetic energy and its gravitational potential energy is equal to zero.

So, if the kinetic energy of an object, launched from the Earth, were equal in magnitude to the potential energy, then in the absence of friction resistance it could escape from the Earth.

A rocket moving out of a gravity well does not actually need to attain escape velocity to escape, but could achieve the same result (escape) at any speed with a suitable mode of propulsion and sufficient propellant to provide the accelerating force on the object to escape. Escape velocity is only required to send a ballistic object on a trajectory that will allow the object to escape the gravity well of the mass M.

In closing, for example the escape velocity from Earth is about 11.2 km/s or 40,270 km/h (25,020 mph).

This topic isn't so simple, therefore an animation like this below can help its understanding, in particular by the kids.

► Here's how fast you'd have to go to leave every planet in the solar system in one tidy, animated GIF from Tech Insider>>

Further reading for deepening

#SolarSystem, #physics , #escape_velocity , #animation , #educational_resource
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+Rodney Miller sorry, but you said a lot of nonsense. +Richard Nelson 
gave you always correct answers. For this reason, I said nothing before. Now, I think to close comments because the discussion became boring and meaningless.

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Saturn's Serpent Storm

In early December 2010, a new, remarkably bright storm- nicknamed "the Serpent Storm"- erupted in Saturn's northern hemisphere.

Amateur astronomers first spotted it in early December, with the ringed gas giant rising in planet Earth's predawn sky. Orbiting Saturn, the Cassini spacecraft was able to record this close-up of the complex disturbance from a distance of 1.8 million kilometers on December 24th, 2010.

Over time, the storm has evolved, spreading substantially in longitude, stretching far around the planet.
Saturn's thin rings are also seen slicing across this space-based view, casting broad shadows on the planet's southern hemisphere.

Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA; Color Composite: Jean-Luc Dauvergne

► Source>>

More information and images about the Serpent Storm

#SolarSystem, #SaturnSerpentStorm, #Cassinispacecraft, #space, #planets, #Astronomy
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Relationship Between the Unit Circle and the Sine and Cosine Functions

I share another great animation about sine and cosine functions that can facilitate the understanding of them.

We have the unit circle (with radius = 1) in green, placed at the origin at the bottom right. In the middle of this circle, in yellow, is represented the angle theta (θ). This angle is the amount of counter-clockwise rotation around the circle starting from the right, on the x-axis, as illustrated.
An exact copy of this little angle is shown at the top right, as a visual illustration of the definition of θ. At this angle, and starting at the origin, a (faint) green line is traced outwards, radially. This line intersects the unit circle at a single point, which is the green point spinning around at a constant rate as the angle θ changes, also at a constant rate.
The vertical position of this point is projected straight (along the faint red line) onto the graph on the left of the circle. This results in the red point. The y-coordinate of this red point (the same as the y-coordinate of the green point) is the value of the sine function evaluated at the angle θ, that is: y coordinate of green point = sin θ

As the angle θ changes, the red point moves up and down, tracing the red graph. This is the graph for the sine function. The faint vertical lines seen passing to the left are marking every quadrant along the circle, that is, at every angle of 90° or π/2 radians.
Notice how the sine curve goes from 1, to zero, to -1, then back to zero, at exactly these lines. This is reflecting the fact sin(0) = 0, sin(π/2) =1, sin(π) = 0 and sin(3π/ 2)= -1.
A similar process is done with the x-coordinate of the green point.

However, since the x-coordinate is tilted from the usual convention to plot graphs (where y = f(x), with y vertical and x horizontal), an “untilt” operation was performed in order to repeat the process again in the same orientation, instead of vertically. This was represented by a “bend”, seen on the top right. Again, the green point is projected upwards (along the faint blue line) and this “bent” projection ends up in the top graph’s rightmost edge, at the blue point. The y-coordinate of this blue point (which, due to the “bend” in the projection, is the same as the x-coordinate of the green point) is the value of the cosine function evaluated at the angle θ, that is: x coordinate of green point = cos θ.

The blue curve traced by this point, as it moves up and down with changing θ, is the the graph of the cosine function. Notice again how it behaves at it crosses every quadrant, reflecting the fact cos(0) = 1, cos(π/2) = 0, cos(π) = -1 and cos(3π/2) = 0.

► Image and explanation source>>

#trigonometric_functions, #sine, #cosine, #mathematics, #animation
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+Alejandro Perales another troll! Go elsewhere, please. I detest trolls.
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Manipulation Of Specific Neurons Helps To Erase Bad Memories

Imagine if memory could be tuned in such a way where good memories are enhanced for those suffering from dementia or bad memories are wiped away for individuals with post-traumatic stress disorder. A Stony Brook University research team has taken a step toward the possibility of tuning the strength of memory by manipulating one of the brain’s natural mechanisms for signaling involved in memory, a neurotransmitter called acetylcholine. Their findings are published in the journal Neuron.

Brain mechanisms underlying memory are not well understood, but most scientists believe that the region of the brain most involved in emotional memory is the amygdala. Acetylcholine is delivered to the amygdala by cholinergic neurons that reside in the base of the brain. These same neurons appear to be affected early in cognitive decline. Previous research has suggested that cholinergic input to the amygdala appears to strengthen emotional memories.

[...] In the paper, titled “Cholinergic Signaling Controls Conditioned Fear Behaviors and Enhances Plasticity of Cortical-Amygdala Circuits,” Dr. Role and colleagues used a fear-based memory model in mice to test the underlying mechanism of memory because fear is a strong and emotionally charged experience.[...]

Read the full story>>

► The scientific paper published in the journal Neuron>>

Animation explanation: Nineteenth century psychologist, Herman Ebbinghaus, demonstrated that we normally forget 40% of new material with the first twenty minutes, a phenomenon known as the forgetting curve. But this loss can be prevented through memory consolidation, the process by which information is moved from our fleeting short-term memory to our more durable long-term memory, thanks to the hippocampus…and a good night’s sleep!
► From the TED-Ed Lesson The benefits of a good night’s sleep - Shai Marcu. Animation by Javier Saldeña>>

#neuroscience, #memorymodel, #brain, #neurons, #stressdisorder, #Acetylcholine, #amygdala, #science, #animation, #cholinergicneurons, #research
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The Brachistochrone Problem

The Brachistochrone Problem is an optimization problem and also one of the most famous problems in the history of mathematics. It was posed by Swiss mathematician Johann Bernoulli to the readers of Acta Eruditorum in June, 1696 as a challenge:

“I, Johann Bernoulli, address the most brilliant mathematicians in the world. Nothing is more attractive to intelligent people than an honest, challenging problem, whose possible solution will bestow fame and remain as a lasting monument. Following the example set by Pascal, Fermat, etc., I hope to gain the gratitude of the whole scientific community by placing before the finest mathematicians of our time a problem which will test their methods and the strength of their intellect. If someone communicates to me the solution of the proposed problem, I shall publicly declare him worthy of praise.”

The problem he posed was the following:

Given two points A and B in a vertical plane, what is the curve traced out by a point acted on only by gravity, which starts at A and reaches B in the shortest time.

Five mathematicians responded with solutions: Isaac Newton, Jakob Bernoulli (Johann's brother), Gottfried Leibniz, Ehrenfried Walther von Tschirnhaus and Guillaume de l'Hôpital.
History records Newton as solving it the fastest. Newton found the problem in his mail, in a letter from Johann Bernoulli, when he arrived home from the mint at 4 p.m., and stayed up all night to solve it and mailed the solution by the next post. This story gives some idea of Newton's power, since Johann Bernoulli took two weeks to solve it.

Johann Bernoulli was not the first to consider the brachistochrone problem. Galileo in 1638 had studied the problem (without the benefit of Calculus) in his famous work Discourse on two new sciences. His version of the problem was first to find the straight line from a point A to the point on a vertical line which it would reach the quickest. He correctly calculated that such a line from A to the vertical line would be at an angle of 45 reaching the required vertical line at B say.
He calculated the time taken for the point to move from A to B in a straight line, then he showed that the point would reach B more quickly if it travelled along the two line segments AC followed by CB where C is a point on an arc of a circle.
Although Galileo was perfectly correct in this, he then made an error when he next argued that the path of quickest descent from A to B would be an arc of a circle - an incorrect deduction.

The animation below visualizes the problem of brachistochrone. The path that describes this curve of fastest descent is given the name Brachistochrone curve (after the Greek for shortest 'brachistos' and time 'chronos') and it is a cycloid.

The problem can be solved with the tools from the calculus of variations and optimal control.
To calculate the optimal path requires minimizing a function that minimizes some other variables. This is the calculus of variations. There are many excellent papers available that walk through the process.

Animation source>>

Further reading and references

#mathematics, #BrachistochroneProblem, #historyofmathematics, #cycloid, #animation, #science , #sciencesunday , #scienceeveriday  
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+Pasqualino de BENEDICTIS in fact, Leibniz solved this problem.
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What Is J002E3?

The object, named J002E3, was discovered Sept. 3, 2002 on a near earth orbit by Canadian amateur astronomer Bill Yeung, observing from El Centro, Calif.

Initially thought to be an asteroid, it has since been tentatively identified as the S-IVB third stage of the Apollo 12 Saturn V rocket (designated S-IVB-507). When the third stage of the Apollo 12 mission failed to crash on the Moon as planned (NASA used such impacts to generate ‘Moonquakes’ that could be studied by lunar seismographs to gain information on the Moon’s interior), its subsequent orbital evolution was alternatively dominated by the attraction of the Sun and Earth.

Later study discovered that the object’s spectral signature matched the white paint used on Apollo rockets. J002E3’s orbit was quite unusual, spending some time in the Sun-Earth first Lagrange point before swooping close enough to Earth to endanger operational satellites.

NASA had originally planned to direct the S-IVB into a solar orbit, but an extra long burn of the ullage motors meant that venting the remaining propellant in the tank of the S-IVB did not give the rocket stage enough energy to escape the Earth–Moon system, and instead the stage ended up in a semi-stable orbit around the Earth after passing by the Moon on November 18, 1969.
It is thought that J002E3 left Earth orbit in June 2003, and that it may return to orbit the Earth in the mid-2040s.

Animation explanation: Computer simulation of J002E3's motion, alternating between six Earth orbits and a heliocentric orbit.
The motion of J002E3, showing how the object was captured into its chaotic orbit around the Earth by passing near the L1 point, looping around the Earth for 6 orbits, and then leaving Earth's orbit. The Sun is to the left in these animations.
Animation link>>

Further Reading and References

#SolarSystem, #asteroid, #nearearthobject, #spacedebris, #J002E3object, #astronomy, #space, #animation, #science
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This post dates back to 2013 and I just got hold of that one. So I decided to include it in a collection.

#blackhole #cosmology #galaxy #astronomy #space #astrophysics #science #scienceeveryday #sciencesunday 

Gif source:

The gif  has been developed, in my opinion, using this simulated view of a 10-solar-mass black hole 600 miles (900 km) away from the observer -- and against the plane of the Milky Way Galaxy. (Courtesy Ute Kraus, Physics education group Kraus, Universität Hildesheim, Space Time Travel, (background image of the milky way: Axel Mellinger) via Wikimedia at; click to biggify.)

More information: Step by Step into a Black Hole

#blackhole #cosmology #galaxy #astronomy #space #astrophysics #science #scienceeveryday #sciencesunday  
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Fantastic fiction 
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The Red Square Nebula: One of the Most Beautiful Objects in the Universe

The Red Square Nebula is a celestial object located in the area of the sky occupied by star MWC 922 in the constellation Serpens.
The first images of this bipolar nebula, taken using the Mt. Palomar Hale telescope in California, were released in April 2007. It is notable for its square shape, which according to Sydney University astrophysicist Peter Tuthill, makes it one of the most symmetrical celestial objects ever discovered. So, if symmetry is a sign of splendor, then the Red Square nebula is one of the most beautiful objects in the universe.

In effect, the startling degree of symmetry and level of intricate linear form make the Red Square nebula around MWC 922 the most symmetrical object of comparable complexity ever imaged. The overall architecture displays a twin opposed conical cavities (known as a bipolar nebula), along the axis of which can be seen a remarkable sequence of sharply defined linear rungs or bars. This series of rungs and conical surfaces lie nested, one within the next, down to the heart of the system, where the hyperbolic bicone surfaces are crossed by a dark lane running across the principle axis.

What could cause a nebula to appear square? No one is quite sure.

The below image combines infrared exposures from the Hale Telescope on Mt. Palomar in California, and the Keck-2 Telescope on Mauna Kea in Hawaii. A leading progenitor hypothesis for the square nebula is that the central star or stars somehow expelled cones of gas during a late developmental stage. For MWC 922, these cones happen to incorporate nearly right angles and be visible from the sides.
Supporting evidence for the cone hypothesis includes radial spokes in the image that might run along the cone walls.
Researchers speculate that the cones viewed from another angle would appear similar to the gigantic rings of supernova 1987A, possibly indicating that a star in MWC 922 might one day itself explode in a similar supernova.

After MWC 922 ejects most of its material into space, it will contract into a dense stellar corpse known as a white dwarf, shrouded by clouds of its own remains.

The Red Square nebula discovery is detailed in the April 13 issue of the journal Science.

Image credit: Peter Tuthill (Sydney U.) & James Lloyd (Cornell)

You can see an image of Red Square Nebula, reworked by me thanks to GeoGebra software and so... made sparkling.>>

Further reading and references

#universe, #ReadSquareNebula, #bipolarnebula, #constellationSerpens, #starMWC922, #research, #space, #astronomy
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Mount St. Helens Eruption May 18, 1980

The 1980 eruption of Mt. St. Helens is the most studied volcanic eruption of the twentieth century. Although most people were unaware of the potential for such a violent display of volcanism in the contiguous U.S., volcanologists were keenly aware of the potential danger.

Months before it erupted, the U.S. Geological Survey (USGS) established a base of operations at Vancouver, Washington to monitor the volcano. On May 18, survey volcanologist David Johnston was camping on Coldwater Ridge, only a few miles north of Mt. St. Helens.

The eruption occurred that morning. At 8:32 a.m., Johnston radioed the USGS base and exclaimed: "Vancouver, Vancouver, this is it!"
The ensuing volcanic blast devastated the northern flank of the volcano, killing Johnston and 56 other victims.
At the same time, geologists Keith and Dorothy Stoffel were flying in a light plane only 400 meters above the summit of Mt. St. Helens.
From their vantage point, they witnessed one of the largest landslides ever recorded in historic times. Seconds later, a massive explosion shot out the north side of the volcano, toward Coldwater Ridge and Spirit Lake.
The explosion generated a billowing cloud with numerous lightning bolts thousands of meters high. The cloud began to expand rapidly toward their aircraft and appeared to be gaining on them, but by turning south they managed to outrun it and survive.

Mt. St. Helen's was known as one of the most picturesque stratovolcanoes in the Cascade Range before its violent eruption on May 18, 1980. It was declared a National Volcanic Monument by an act of congress in 1982.

St. Helens produced an additional five explosive eruptions between May and October 1980. Through early 1990 at least 21 periods of eruptive activity had occurred. The volcano remains active, with smaller, dome-building eruptions continuing into 2008.

Further reading and references

Animation explanation (source:
An animated series of images showing the May 18, 1980, eruption of Mt. St. Helens. Clearly visible in the first few images is the largest recorded landslide in history—the entire north face of the volcano sliding away following a shallow earthquake. The newly-exposed core of the volcano then erupted.

#MountStHelens, #history_of_science, #stratovolcano, #EruptionMay18_1980, #volcanism, #planetEarth, #Geology  
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Have her in circles
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I teach mathematics and science and work at educational research.
Science communication and e-learning. Scientific blogging
  • Ministry of National Education
    Tenured teacher at secondary school
  • "Scuola & Didattica" - Educational fortnightly magazine in Italian
    Freelance journalist of scientific and educational articles
  • Collaboration with various educational websites
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Ravenna (Italy)
Lecce - Firenze
We can achieve what strongly we want!
I teach mathematics and science and I write for "Scuola e Didattica"- Educational fortnightly magazine in Italian (Editrice La Scuola).

I'm also interested in web 2.0, social network and much more. I love reading, writing, painting, photography, good music, and more.

My posts are prevalently about Science and Mathematics for a general audience, but also about Art, beautiful images/photo and interesting  gifs. I share often scientific news that can be useful to many people.

I would like to look at the profiles of everyone who circles me, but there are too many. ;)
Anyway, I will definitely look at your profile if you engage with my posts.

Furthermore, I am interested in following people who post quality original content, regardless of the number of their followers. 

Instead I am not interested in following people if they never engage with my own content.

If you consider interesting my posts, you can circle me:). I'd like to read your posts and to interact with you here on Googleplus
Bragging rights
I experimented at school a research scholarship in Science, producing approximately over 200 pages of Materials for Science, published by IRRE- ER (Institute of Educational Research Emilia-Romagna, Italy). I was also part, along with 50 teachers selected nationwide, of The SENIS Project, a pilot project from Ministry of National Education for improving the scientific formation of teachers at secondary school. This Project has collected a lot of educational resources, published in a book by Ministry of National Education.
  • University of Salento
    Master's Degree in Physics
  • Classical Lyceum
  • University of Florence
    Advanced course in methods of communication and networked learning
  • University of Tuscia
    1. Advanced course on assessment/evaluation and managing portfolio. 2. Master in elearning and Learning Object
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