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annarita ruberto
Worked at Ministry of National Education
Attended University of Salento
Lives in Ravenna (Italy)
25,218 followers|22,490,117 views


Simulation of gas cloud after close approach to the black hole at the centre of the Milky Way

This view shows a simulation of how a gas cloud that has been observed approaching the supermassive black hole at the centre of the galaxy may break apart over the next few years. This is the first time ever that the approach of such a doomed cloud to a supermassive black hole has been observed.

The remains of the gas cloud are shown in red and yellow, with the cloud's orbit marked in red. The stars orbiting the black hole are also shown along with blue lines marking their orbits. This view simulates the expected positions of the stars and gas cloud in the year 2021.

Credit: ESO/MPE/Marc Schartmann_


#space #astronomy #black_hole #Milky_Way #science
Hans Youngmann's profile photoThomas Brandtstaetter's profile photoStefano Muccinelli's profile photoPhil Stracchino's profile photo
Here you can see the REAL gravitational force. It's not the attraction, it's the tides.
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Total Eclipse of the Moon: April 15, 2014

A total eclipse of the Moon occurs during the early morning hours of April 15, 2014 and is visible from most of North and South America. For observers in westernmost North America and Hawaii, the eclipse actually begins on the evening of April 14. Northwestern Africa and Greenland will see the beginning stages of the eclipse before moonset while northeastern Asia and Australia witness the later stages after moonrise.
During a total lunar eclipse, the Moon's disk can take on a dramatically colorful appearance from bright orange to blood red and more rarely dark brown to very dark gray. One of the great things about lunar eclipses is that they are completely safe to view with the naked eye. No special filters are required to protect your eyes like those used for solar eclipses. You don't even need a telescope to watch the eclipse, although a good pair of binoculars will help.

An eclipse of the Moon can only take place at Full Moon, and only if the Moon passes through some portion of Earth's shadow. The shadow is actually composed of two cone-shaped parts, one nested inside the other. The outer shadow or penumbra is a zone where Earth blocks some (but not all) of the Sun's rays. In contrast, the inner shadow or umbra is a region where Earth blocks all direct sunlight from reaching the Moon.

When only part of the Moon passes through the umbra, a partial lunar eclipse is seen. If the entire Moon passes through the umbral shadow, then a total eclipse of the Moon occurs. It is also possible to have an eclipse where the Moon passes through only the penumbra. Each of these three eclipses has a unique appearance (see Visual Appearance of Lunar Eclipses:

For more information on the how, what, why, when and where of lunar eclipses, see the special web page Lunar Eclipses for Beginners:

Text  and image source:

#space #lunar_eclipse #science 
Nasir Miyan's profile photoCathy Ranson's profile photoWilliam Jones's profile photoCcafs Cafaro's profile photo
Yeah nipped out to view it! Thanks for the heads up buddy! +Cathy Ranson :) 
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The long and winding road

" The long and winding road " is the title of the suggestive animated gif  below, found by me at this link:

That one reminded me of the homonymous The Beatles song.

You can watch the video here: The Beatles - The Long And Winding Road [w/ lyrics]

It's time of relaxing a bit. I wish all of you a great weekend.

#relax #week_end #animated_gif
Alexzandra angel's profile photoSai SK's profile photoSina Hazratpour's profile photoRd Turnbow's profile photo
+Mohan Pathak ;)
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Quasars: among the most luminous, powerful, and energetic objects known in the universe 

Quasars are among the most mysterious and fascinating celestial known objects. They are very distant galaxies, the most distant known by us, emitting a huge amount of energy from the nuclear region. Quasars are known by a few decades, and their discovery, as it often happens in astronomy, was random. They appear to telescope as bright dots with stellar appearance. Their spectrum instead shows different characteristics from the stars: the spectral lines are significantly redshifted.
This is due to the fact that they are extragalactic objects billions of light years away, and then subjected to a very high redshift.
Because of their distance, the optical  luminosity of quasars is very low: in fact it decreases in proportion to the square of the source's distance. The majority of the radiation emitted by quasars is part of the radio and infrared bands, to the contrary of normal galaxies, which emit predominantly in the optical window.

These objects were initially identified based on their radio emission. In the 50s, the first radio astronomers had cataloged many radio sources, whose nature was unknown; however, the resolving power of radio telescopes of that time was very poor, and did not allow to precisely determine the position of the radio sources and then to establish what kind of source it was. In the early 60s, the new radio telescopes allowed to obtain the exact location of some of these radio sources; once the location was known, it could be studied the optical counterpart of these sources. Some of them were then identified with nebulae, supernova remnants and radio galaxies.

The extragalactic nature of quasars was only discovered in 1963 by astronomer Maarten Schmidt. He found that the spectral lines, emitted by the radio source 3C ​​273, had spaced wavelengths in the same way as the hydrogen lines; however, rather than in the optical band, they were much more redshifted. Assuming this redshift was due to the Doppler effect, this meant that the 3C 273 was moving away from us at 48,000 km/s, too high speed for a star:  it must be a source outside of our galaxy, and also far away.

In 1960, it was discovered that 3C 48, an object of the radio sources frequence, corresponded in the optical frequence to a blue, faint, stellar-looking object. Although its spectrum was unusual, rich in emission lines, subsequently other radio sources were discovered like this, but you thought that they simply were peculiar stars with radio emission. Their spectral lines bear no resemblance to any known line. Subsequently, other compact radio sources were identified with objects of stellar appearance and they were called " quasars* " (_quasi-stellar radio sources).

After this discovery, other radio sources and quasars were examined, and for all of them the conclusion was the same: they were extragalactic objects, billions of light years away! Calculating, based on the distance and apparent brightness, their intrinsic brightness, it was discovered that these objects radiate with an enormous power, amounting to hundreds of times that of the most brilliant galaxies.

By studying the brightness of quasars, it was discovered that it increases and decreases, sometimes almost periodically, with timescales equal to a few days or weeks. These variations indicate that the source of this huge brightness must be very small: a few days-light. This is because the speed of light is the maximum speed at which the information can spread; if the size of the source were greater than the distance traveled by light in a given time interval, its parts could not "exchange information", ie to interact on that time scale, but they would be uncorrelated from one another. In this way, there may not occur the brightness variations, which are due to reciprocal changes of the various parts of the source.

By studying quasars with powerful tools, it was discovered a faint emission surrounding the compact sources. These are the optical counterparts of quasars, which have been identified as galaxies. The nature of quasar was then partly revealed: they are far galaxies with very small and powerful active nuclei. They are barely visible because of their enormous distance.

But what is the central engine of quasars? Certainly not the nuclear reactions that occur inside stars: even adding up the contributions of all the stars in a galaxy, you would not get a power comparable to that of a quasar, and especially not concentrated in such a small region. It is thought that this type of objects is fed, as Seyfert galaxies and radio galaxies, by a giant black hole located in the nucleus of the galaxy. Around it there would be an accretion disk of gas and stars in rapid rotation around its axis; from the disk, the matter would fall continuously on the black hole, producing radiation with enormous power. It would suffice that the black hole would increase each year of a mass slightly greater than that one of the Sun to explain the observed brightness.

One of the most important reasons for which astrophysicists study the quasars is their enormous distance: the most distant quasars are at 13 billion light years away and beyond! Since the speed of light is finite, this also means that the radiation of quasars, that we observe today, was emitted billions of years ago: these objects appear to us as they were in the first billion years of the universe's life ... In this sense it is sometimes said that quasars may represent the infancy of galaxies. It is unclear, however, if all galaxies have crossed a phase of this type, in the course of their life, or if the quasars are peculiar objects.

Image explanation
This artist’s impression shows how ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun, may have looked. This quasar is the most distant yet found and is seen as it was just 770 million years after the Big Bang. This object is by far the brightest object yet discovered in the early Universe.
Credit: ESO/M. Kornmesser


Watch " What Is A Quasar? " from +Fraser Cain:
What Is A Quasar?

#space #astrophysics #quasar #science #sciencesunday #scienceeveryday
Alexzandra angel's profile photoSai SK's profile photoStefano Muccinelli's profile photoSPACE & EARTH's profile photo
yes .
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Fjord in East Greenland Seen by NASA's Operation IceBridge

This view of the frozen fjord downstream of Violingletscher (Violin Glacier) in Østgrønland (East Greenland) was seen during an Operation IceBridge survey flight on April 5, 2014.

NASA’s Operation IceBridge images Earth's polar ice in unprecedented detail to better understand processes that connect the polar regions with the global climate system. IceBridge utilizes a highly specialized fleet of research aircraft and the most sophisticated suite of innovative science instruments ever assembled to characterize annual changes in thickness of sea ice, glaciers, and ice sheets. In addition, IceBridge collects critical data used to predict the response of earth’s polar ice to climate change and resulting sea-level rise. IceBridge also helps bridge the gap in polar observations between NASA's ICESat satellite missions.

News source:

Read more about IceBridge's 2014 Arctic campaign:

Image Credit: NASA/Michael Studinger

#NASA #IceBridge_Operation #Greenland #science #climate_change #polar_ice
Adriano Maini's profile photoLuca O's profile photoStefano Muccinelli's profile photoSPACE & EARTH's profile photo
+Sreekumar A B You're welcome!:)
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Have her in circles
25,218 people
How to solve a physics problem

Do you want to solve a physics problem? Are you desperate and do not know what to do? Keep calm and follow SMBC suggestions!;)

Watch the comics strip in large format:

#comics #physics #science
Dean Addison's profile photoJyoti Dahiya's profile photoDavid Blackford's profile photoBrewster Malevich's profile photo
+Sai SK I think that sometimes it can happen. :)
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Approximated Heptagon Inscribed in a Circle

During this time at school, I'm doing with my first- year students (11 years old)  the construction of regular polygons. Among those, the regular heptagon's construction presents particular problems because its perfect construction, only with straightedge and compass, is impossible.

The heptagon is in fact the regular polygon with less number of sides which can't be built with elementary tools.

Before Gauss, the problem of the construction, with straightedge and compass, of regular polygons was open for 2000 years.  In Euclid's Elements (IV Book), Euclid had demonstrated that they could be built, with straightedge and compass, regular polygons with 3, 4, 5, 15 sides (and also those obtained by bisecting these sides). With regard to regular polygons with 7, 9, 11, 14, 17 sides it was not known  how to build them. 

The genius of Carl Friedrich Gauss discovered that a regular polygon of n sides is constructible with straightedge and compass only if n is an integer power of 2, or the product among a power of 2 and one or more Fermat primes.

Fermat primes are primes of form 2^(2^k) + 1, for some k >= 0.
The only known Fermat primes are F0= 3 , F1= 5, F2= 17, F3= 257, and F4= 65537 (sequence A019434 in OEIS:

Since 7 is not a Fermat prime, it's impossible to construct a regular heptagon with straightedge and compass, while it's possible to construct a regular 17-gon (heptadecagon).
Watch below an  approximated drawing of a regular heptagon inscribed in a circle showing animated straightedge  and compass.

Gif source:

#mathematics #regular_polygons #science #sciencesunday #scienceeveryday #scienceongoogleplus
Phillip James's profile photoDanny Köhler's profile photoStefano Muccinelli's profile photoJoel Murphy's profile photo
Bamos a cojer mamita
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Steel Wool Light Painting 

The gif below shows a particular technique, invented (?) by Benjamin Von Wong and called Steel Wool Light Painting

In this video (Steel Wool Light Painting Explaind), he describes how to use it. This technique involves the use of steel wool, burned to achieve spectacular effects of light, with  shots at slow shutter speed. 

The steel wool is placed inside of a normal whisk to beat the eggs attached to a chain. Then the steel wool is ignited with a standard 9 volt battery. By spinning this homebuilt tool  they are generated  light rays and sparks, which draw hieroglyphics on the camera sensor. 

Attention! The described technique can be potentially dangerous.

Gif source:

#light_painting #photography  
Cindy Murugi's profile photoSai SK's profile photoPABLO ARTURO CAAMAL PERES's profile photoAnanthy Kalaimani's profile photo
+annarita ruberto  I can confirm the 9v works :) 
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Symphony of colors 

I think that the colors and lines of this animated gif are really irresistible. The seemingly chaotic motion is anyway harmonious.

What do you think of it?

Gif source:

#animated_gif #stunning_colors
Iza GALLAGHER's profile photoPaul Sprenkle's profile photoStefano Muccinelli's profile photoSPACE & EARTH's profile photo
She isn't in facebook too intelligent
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Soft Microfluidic Assemblies of Sensors, Circuits, and Radios for the Skin

I share an interesting news.

Advances in microelectronics have yielded high-quality devices that allow for intensive signal collection or transmission. Sheng Xu (Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.) et al. show how to make a soft wearable system that is constructed like a stretchable circuit board, where the electronic components are bridged electrically by thin, meandering conducting traces that float in a highly visco-elastic polymer. A complete soft circuit capable of multisignal physiological sensing on skin was created, with potential for use in health monitoring or neonatal care.

The device has been reported on April 4 in the journal Science:

Researchers write in their abstract:
When mounted on the skin, modern sensors, circuits, radios, and power supply systems have the potential to provide clinical-quality health monitoring capabilities for continuous use, beyond the confines of traditional hospital or laboratory facilities. The most well-developed component technologies are, however, broadly available only in hard, planar formats. As a result, existing options in system design are unable to effectively accommodate integration with the soft, textured, curvilinear, and time-dynamic surfaces of the skin. Here, we describe experimental and theoretical approaches for using ideas in soft microfluidics, structured adhesive surfaces, and controlled mechanical buckling to achieve ultralow modulus, highly stretchable systems that incorporate assemblies of high-modulus, rigid, state-of-the-art functional elements. The outcome is a thin, conformable device technology that can softly laminate onto the surface of the skin to enable advanced, multifunctional operation for physiological monitoring in a wireless mode.

Gif source:

#Materials_Science #Engineering #health #science   #sciencesunday   #scienceeveryday   #scienceongoogleplus  
Isaiah Shomoye's profile photoTim Goral's profile photoAnthony Tobin's profile photoStefano Muccinelli's profile photo
+Anthony Tobin I wish you the same. :)
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Have her in circles
25,218 people
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
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
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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