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

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Gregorio Ricci- Curbastro, Father of Tensor Calculus

Perhaps many people have never heard the name "Gregorio Ricci- Curbastro", even if he was a high-level mathematician.

The following text (translated by me in English) is an excerpt from a long article (in Italian), which I dedicated to such an extraordinary person:

[...]Ricci- Curbastro bequeathed to science the tensor calculus, by developing the theory of curved spaces of any dimension. Einstein was the first to take advantage of tensor calculus power in his General Theory of Relativity, but the concept of curvature (introduced by Carl Friedrich Gauss and developed by Riemann and others) was subsequently an extraordinary instrument, which made possible the solution of one among the greatest mathematical problems: the classification of three-dimensional manifolds (G. Perelman, 2003).

In fact, the "Ricci flow" allowed to solve the Poincaré conjecture, proposed a century ago by the great French mathematician of whom name it bears.
This conjecture was considered, throughout the mid-twentieth century, the most important unsolved problem in topology.
Grigory Yakovlevich Perel'man used in a brilliant way a strategy consisting in changing Richard Hamilton's geometrization program by means of Ricci flow. Such a geometrization approach is particularly innovative compared to previous and more aimed programs of topological sort.

In conclusion, we specify that Ricci -Curbastro work has also repercussions in image processing and in robotics, and many real-life applications in physics and engineering.

We can read on the plaque, placed on Ricci's home:
"He gave science the absolute differential calculus, an essential tool for the theory of general relativity, new vision of the universe." [...]

In my article, I pointed out of course that Ricci-Curbastro former student Tullio Levi-Civita (another ingenious mathematician) had a relevant part  in developing tensor calculus.

Relevant links:

Ricci calculus >>
Tensor calculus>>
General Relativity and The Absolute Differential Calculus>> 
Applications of the Absolute Differential Calculus by A.J. McConnell >>
Levi-Civita: Absolute Differential Calculus>>
Gregorio Ricci-Curbastro on Wikipedia>>
Tullio Levi-Civita on Wikipedia>>

#mathematics   #history_of_mathematics   #great_mathematicians   #scienceeveryday   #sciencesunday   #science  
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NASA Unveils Celestial Fireworks as Official Image for Hubble 25th Anniversary

The brilliant tapestry of young stars flaring to life resemble a glittering fireworks display in the 25th anniversary NASA Hubble Space Telescope image, released to commemorate a quarter century of exploring the solar system and beyond since its launch on April 24, 1990.

“Hubble has completely transformed our view of the universe, revealing the true beauty and richness of the cosmos” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate. “This vista of starry fireworks and glowing gas is a fitting image for our celebration of 25 years of amazing Hubble science.”

The sparkling centerpiece of Hubble’s anniversary fireworks is a giant cluster of about 3,000 stars called Westerlund 2, named for Swedish astronomer Bengt Westerlund who discovered the grouping in the 1960s. The cluster resides in a raucous stellar breeding ground known as Gum 29, located 20,000 light-years away from Earth in the constellation Carina.

Read the full article, where we can watch a wondeful video>>

For more information on the Hubble Space Telescope, visit>>

For image files and more information about Westerlund 2, visit>>

#GoddardSpaceFlightCenter   #HubbleSpaceTelescope   #Stars #Universe #Hubble25thanniversary #NASA #constellation #space #Astronomy
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+Andy Durand You're very  welcome! Glad you appreciate. ☺
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Milky Way Over Joshua Tree National Park

A stunning photo by astrophotographer Shreenivasan Manievannan.


#milky_way_galaxy #astrophotography
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+giorgio armani What a pity you could not see the Milky Way! Anyway the place deserved very much.☺
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annarita ruberto

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What do you see?

► Source>>

 #gif #loop #color #black #waves #trails 
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A work of art !
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Ocean Worlds

Earth isn't the only ocean world in our solar system. Oceans could exist in diverse forms on moons and dwarf planets, offering clues in the quest to discover life beyond our home planet. 

This illustration depicts the best-known candidates in our search for life in the solar system.

Read full story>>

Infographic source (watch larger image)>>

#solar_system #NASA #infographics #space #science
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+gnarlytreesnex Da trap mastar You're welcome!
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Asteroid 2014 YB35 will safely pass Earth at 4.5 million km on the morning of Friday, March 27. 

There are ways to report on occasional close approaches by near-Earth objects (NEOs) that convey the respectful awareness of their presences and the fact that our planet shares its neighborhood with many other objects, large and small… and that sometimes their paths around the Sun bring them unnervingly close to our own.

Then there’s just straight-up over-sensationalism intended to drum up page views by scaring the heck out of people, regardless of facts.

Apparently this is what’s happened regarding the upcoming close approach by NEO 2014 YB35. An asteroid of considerable (but definitely not unprecedented) size – estimated 440-990 meters in diameter, or around a third of a mile across – YB35 will pass by Earth on Friday, March 27, coming as close as 11.7 times the distance between Earth and the Moon at 06:20 UTC.

11.7 lunar distances. That’s 4.5 million kilometers, or almost 2.8 million miles. Cosmically close, sure, but far from “skimming”…and certainly with no danger of an impact or any of the nasty effects that would be a result thereof. None. Zero. Zilch. NASA isn’t concerned, and you shouldn’t be either.

Read the full article>>

Further reading>>

#asteroid #NEO_2014_YB35
There are ways to report on occasional close approaches by near-Earth objects (NEOs) that convey the respectful awareness of their presences and the fact that our planet shares its neighborhood wit...
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+Sumurusluva Will
I rather think if such a genuine catastrophe was to befall the Earth, we(the general public) would be the LAST to hear about it...!

Let's hope not! ☺ 
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annarita ruberto

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What Your Body Looks Like Top To Bottom

Amazing! There is no doubt, in my opinion of course...

Gif source>>

I thank +Chad Haney for his clarifying comment:

It's a cadaver that was physically sliced and scanned (like a desktop scanner).
Visible human project
Sister post to the Visible Human project

I thank too +Rajini Rao 

#body    #anatomy #biology   #science #animated_gif
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Cool, but gruesome.
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Happy Earth Day 2015

Today, April 22, 2015 is Earth Day's 45th anniversary.

Earth Day is an annual event, celebrated on April 22, on which day events worldwide are held to demonstrate support for environmental protection.
It was first celebrated in 1970, and is now coordinated globally by the Earth Day Network, and celebrated in more than 192 countries each year.

Go to Earth Day's website>>

I chose a sky view of Earth from Suomi NPP that we can see below>>

This composite image of southern Africa and the surrounding oceans was captured by six orbits of the NASA/NOAA Suomi National Polar-orbiting Partnership spacecraft on April 9, 2015, by the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument.
Tropical Cyclone Joalane can be seen over the Indian Ocean.

Winds, tides and density differences constantly stir the oceans while phytoplankton continually grow and die. Orbiting radiometers such as VIIRS allows scientists to track this variability over time and contribute to better understanding of ocean processes that are beneficial to human survival on Earth. The image was created by the Ocean Biology Processing Group at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

For more information, please visit>> and

Image Credit: Ocean Biology Processing Group at NASA's Goddard Space Flight Center

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+Mohan Pathak I perfectly understand what you mean because I was intrigued by this photo.
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What Happens When a Missile or Meteor Hits

Study explains why soil and sand get stronger when they are struck harder

When a missile or meteor strikes the earth, the havoc above ground is obvious, but the details of what happens below ground are harder to see.

Duke University physicists have developed techniques that enable them to simulate high-speed impacts in artificial soil and sand in the lab, and then watch what happens underground close-up, in super slow motion.

In a study in the journal Physical Review Letters, they report that materials like soil and sand actually get stronger when they are struck harder.

The findings help explain why attempts to make ground-penetrating missiles go deeper by simply shooting them harder and faster have had limited success, the researchers say. Projectiles actually experience more resistance and stop sooner as their strike speed increases.

Funded by the Defense Threat Reduction Agency, the research may ultimately lead to better control of earth-penetrating missiles designed to destroy deeply buried targets such as enemy bunkers or stockpiles of underground weapons.

To simulate a missile or meteor slamming into soil or sand, the researchers dropped a metal projectile with a rounded tip from a seven-foot-high ceiling into a pit of beads.

During collision, the kinetic energy of the projectile is transferred to the beads and dissipates as they butt into each other below the surface, absorbing the force of the collision.

► Read the full article on DukeTODAY, where you can watch an interesting video about Meteor Impact in Slow Motion {Duke University Research}>>

► Read Nonlinear Force Propagation During Granular Impact, the paper in the journal Physical Review Letters>>

► The animated gif below, created from Youtube video courtesy of Duke, shows the phenomenon at high impact speed.

#science #tech #physics #gif #slow_motion #projectile #meteor   #missiles #energy #force
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+David Shealy For answering your question, I think we should do a specific study with the models you mentioned.
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ALMA Sees Einstein Ring in Stunning Image of Lensed Galaxy

Astronomers have discovered that a distant galaxy -- seen from Earth with the aid of a gravitational lens -- appears like a cosmic ring, thanks to the highest resolution images ever taken with the Atacama Large Millimeter/submillimeter Array (ALMA).  

Forged by the chance alignment of two distant galaxies, this striking ring-like structure is a rare and peculiar manifestation of gravitational lensing as predicted by Albert Einstein in his theory of general relativity.

Gravitational lensing occurs when a massive galaxy or cluster of galaxies bends the light emitted from a more distant galaxy, forming a highly magnified, though much distorted image. In this particular case, the galaxy known as SDP.81 (its formal name is HATLAS J090311.6+003906) and an intervening galaxy line up so perfectly that the light from the more distant one forms a nearly complete circle as seen from Earth.

Discovered by the Herschel Space Observatory, SDP.81 is an active star-forming galaxy nearly 12 billion light-years away, seen at a time when the Universe was only 15 percent of its current age. It is being lensed by a massive foreground galaxy that is a comparatively nearby 4 billion light-years away.

"Gravitational lensing is used in astronomy to study the very distant, very early Universe because it gives even our best telescopes an impressive boost in power," said ALMA Deputy Program Scientist Catherine Vlahakis. "With the astounding level of detail in these new ALMA images, astronomers will now be able to reassemble the information contained in the distorted image we see as a ring and produce a reconstruction of the true image of the distant galaxy."

The new SDP.81 images were taken in October 2014 as part of ALMA’s Long Baseline Campaign, an essential program to test and verify the telescope’s highest resolving power, achieved when the antennas are at their greatest separation: up to 15 kilometers apart.

Read the full article, where you can find some images and an interesting Vimeo video>>

► The paper, "ALMA Long Baseline Observations of the Strongly Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z=3.042," is located here>>

Animated gif created from a Vimeo video; credit: NRAO/AUI/NSF, ALMA (NRAO/ESO/NAOJ), Dana Berry / SkyWorks.
The radio image portion of the video is of galaxy SDP.81, mentioned above.

#ring_of_fire #gravitational_lensing #ALMA #space #astronomy
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+David Shealy My students are fascinated by Astronomy even if  it's not an easy branch of knowledge...or pheraphs they like it also for such a peculiarity. 
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annarita ruberto

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Sun for Kids! ;)

I teach science and math to middle school students. In my experience, Astronomy is a fascinating subject, but also difficult, for young students because the objects of study are distributed in the vastness of the cosmos.

In particular, the students are very interested in the solar system. Therefore, I try to find solutions for their learning, such as:

► organize educational visits at the planetarium and astronomical observatory, in my region;
► build, together with students, scale models of the solar system;
► use software such as Google Sky, Stellarium, Celestia;
► use astronomy simulations and animations like these >>

Animated gifs, as the one shown below, are also useful. My middle school students liked it so much.

► Gif source >>

#astronomy #sun #solar_system #education
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Yas,it really very good in seen
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Just for fun!

Try if you're a genius. ;)

► Image seen on LinkedIn.

#fun #math
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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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