Solar System: Things To Know This Week

The simple physics behind a Fidget Spinner

When you want something to spin for a really long time you need to make sure that the friction does not slow it down.

And we can do this by adopting ball bearings. This is so because friction offered due to rolling is much smaller than due to sliding.

And many Fidget spinners indeed use ceramic ball bearings to keep them spinning for a long time. **

Mass Distribution

The next most crucial component is the Angular Momentum. Angular momentum is equal to the product of rotational velocity and the moment of inertia. 

And by distributing more mass towards the edge, the fidget spinner gains high moment of inertia keeping it spinning longer. 

That’s why the spinners have that weird peculiar shape.

But, Why do they feel alive ?

The angular momentum of a fidget spinner happens to point outwards from the spinner’s center.

And so to change the direction of the momentum — rotating the spinner with your fingers — you must apply a force. You push on the spinner, and the spinner pushes back on you.

That’s why a fidget spinner feels like it fights you, like it’s alive.

- Nerdist

A very fascinating toy nevertheless!

** Spin Test : Ceramic Vs Steel ball bearings

*** Fidget spinner trick shots

Solar System: Things to Know This Week

Reaching out into space yields benefits on Earth. Many of these have practical applications — but there’s something more than that. Call it inspiration, perhaps, what photographer Ansel Adams referred to as nature’s “endless prospect of magic and wonder.“ 

Our ongoing exploration of the solar system has yielded more than a few magical images. Why not keep some of them close by to inspire your own explorations? This week, we offer 10 planetary photos suitable for wallpapers on your desktop or phone. Find many more in our galleries. These images were the result of audacious expeditions into deep space; as author Edward Abbey said, "May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view.”

1. Martian Selfie

This self-portrait of NASA’s Curiosity Mars rover shows the robotic geologist in the “Murray Buttes” area on lower Mount Sharp. Key features on the skyline of this panorama are the dark mesa called “M12” to the left of the rover’s mast and pale, upper Mount Sharp to the right of the mast. The top of M12 stands about 23 feet (7 meters) above the base of the sloping piles of rocks just behind Curiosity. The scene combines approximately 60 images taken by the Mars Hand Lens Imager, or MAHLI, camera at the end of the rover’s robotic arm. Most of the component images were taken on September 17, 2016.

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2. The Colors of Pluto

NASA’s New Horizons spacecraft captured this high-resolution, enhanced color view of Pluto on July 14, 2015. The image combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC). Pluto’s surface sports a remarkable range of subtle colors, enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode.

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3. The Day the Earth Smiled

On July 19, 2013, in an event celebrated the world over, our Cassini spacecraft slipped into Saturn’s shadow and turned to image the planet, seven of its moons, its inner rings — and, in the background, our home planet, Earth. This mosaic is special as it marks the third time our home planet was imaged from the outer solar system; the second time it was imaged by Cassini from Saturn’s orbit, the first time ever that inhabitants of Earth were made aware in advance that their photo would be taken from such a great distance.

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4. Looking Back

Before leaving the Pluto system forever, New Horizons turned back to see Pluto backlit by the sun. The small world’s haze layer shows its blue color in this picture. The high-altitude haze is thought to be similar in nature to that seen at Saturn’s moon Titan. The source of both hazes likely involves sunlight-initiated chemical reactions of nitrogen and methane, leading to relatively small, soot-like particles called tholins. This image was generated by combining information from blue, red and near-infrared images to closely replicate the color a human eye would perceive.

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5. Catching Its Own Tail

A huge storm churning through the atmosphere in Saturn’s northern hemisphere overtakes itself as it encircles the planet in this true-color view from Cassini. This picture, captured on February 25, 2011, was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the planet. The storm is a prodigious source of radio noise, which comes from lightning deep within the planet’s atmosphere.

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6. The Great Red Spot

Another massive storm, this time on Jupiter, as seen in this dramatic close-up by Voyager 1 in 1979. The Great Red Spot is much larger than the entire Earth.

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7. More Stormy Weather

Jupiter is still just as stormy today, as seen in this recent view from NASA’s Juno spacecraft, when it soared directly over Jupiter’s south pole on February 2, 2017, from an altitude of about 62,800 miles (101,000 kilometers) above the cloud tops. From this unique vantage point we see the terminator (where day meets night) cutting across the Jovian south polar region’s restless, marbled atmosphere with the south pole itself approximately in the center of that border. This image was processed by citizen scientist John Landino. This enhanced color version highlights the bright high clouds and numerous meandering oval storms.

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8. X-Ray Vision

X-rays stream off the sun in this image showing observations from by our Nuclear Spectroscopic Telescope Array, or NuSTAR, overlaid on a picture taken by our Solar Dynamics Observatory (SDO). The NuSTAR data, seen in green and blue, reveal solar high-energy emission. The high-energy X-rays come from gas heated to above 3 million degrees. The red channel represents ultraviolet light captured by SDO, and shows the presence of lower-temperature material in the solar atmosphere at 1 million degrees.

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9. One Space Robot Photographs Another

This image from NASA’s Mars Reconnaissance Orbiter shows Victoria crater, near the equator of Mars. The crater is approximately half a mile (800 meters) in diameter. It has a distinctive scalloped shape to its rim, caused by erosion and downhill movement of crater wall material. Since January 2004, the Mars Exploration Rover Opportunity has been operating in the region where Victoria crater is found. Five days before this image was taken in October 2006, Opportunity arrived at the rim of the crater after a drive of more than over 5 miles (9 kilometers). The rover can be seen in this image, as a dot at roughly the “ten o'clock” position along the rim of the crater. (You can zoom in on the full-resolution version here.)

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10. Night Lights

Last, but far from least, is this remarkable new view of our home planet. Last week, we released new global maps of Earth at night, providing the clearest yet composite view of the patterns of human settlement across our planet. This composite image, one of three new full-hemisphere views, provides a view of the Americas at night from the NASA-NOAA Suomi-NPP satellite. The clouds and sun glint — added here for aesthetic effect — are derived from MODIS instrument land surface and cloud cover products.

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Americas at night

Discover more lists of 10 things to know about our solar system HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

5 things you didn’t know about... Concorde

Credit: British Airways

1. Operated by British Airways and Air France, Concorde went into operation in 1976, following 5,000 hours of flight testing. Seating 100 passengers, it catered to the privileged or business traveller. Concorde was withdrawn from service in 2003, after 27 years.

2. The most popular route for the British carrier was from London Heathrow to New York JFK in just three hours and 20 minutes. Cruising at Mach 2.02, passengers experienced heights of 60,000ft, a vantage point from which they could see the curvature of the Earth below and dark skies above at midday.

3. The four Olympus 593 engines that powered Concorde were twin spool turbojets.

4. The materials used for Concorde’s structure needed to withstand temperature extremes – subsonic speeds, the aircraft fuselage would experience lows of  -35°C, but at Mach 2 the temperature reached 127°C at the nose.

5. Concorde’s long, pointed nose cone played a key role in landing. Formed of resin-bonded glass fibre, as metals would interfere with the signals detecting storm clouds, the hydraulically powered nose cone could be moved independently to an angle of 12.5° on landing, allowing the pilot to see the approaching runway.

To find out more see page 60 of the June issue of Materials World or visit http://bit.ly/2qDPjJC. 

This is how scientists think birds see the Earth’s magnetic field.

See how the black patches align over certain areas? That dark patch at the base of their vision shows South, with the reverse indicating North. Researchers think this might be how birds like pigeons can use magnetic fields to navigate.

Here’s how it works: there’s a protein in their eyes called cryptochrome. When blue light hits it, it becomes active, and stays active for a little while. How long it stays active for, though, depends on the Earth’s magnetic field, and since cryptochrome is known to affect the sensitivity of the birds’ retinas to light, we think this is the effect it has on their vision.

We have this very same molecule in our eyes, but the molecule that lets it stay active for long enough to be affected by the magnetic field, superoxide, is toxic, so the antioxidants in our eyes lock it down too quickly.  Researchers think we’ve traded longevity for magnetovision.

Want to know more? We made a whole video answering the question, do blind birds can navigate!? Watch it here: https://youtu.be/7yBMUrlpe5s

Fibonacci trefoil

© Rafael Araujo

NTU and JTC develop enhanced fire protection for steel

Credit: shutterstock/Anusorn Abthaisong

Scientists from Nanyang Technological University (NTU), Singapore, and national industrial developer JTC have unveiled what they are calling a 3-in-1 coating for better fire and corrosion protection.

‘In a fire, our coating forms a compact charred layer that acts as a protective barrier against the heat,’ explained Aravind Dasari, a Principal Investigator at the NTU–JTC Industrial Infrastructure Innovation Centre.

Called FiroShield, the coating functions like regular paint and is easy to apply, according to the research team. It can be applied on bare steel without the need for sand blasting, and provides protection against fire for two hours. 

Dasari explained, ‘While typical fire coatings will also form a charred layer, those are thick and foam-like, which can fall off easily and leave the steel exposed to the fire. What we aimed at was an innovative coat that works differently from conventional intumescent coatings and can stick to the steel surface for as long as possible under high temperatures, and yet has durability and weather resistance under normal conditions without a need for a top coat of paint.’

To find out more see the January issue of Materials World or visit  bit.ly/2nft8Z3

These 17 Women Changed The Face Of Physics

Click through to read the rest.

Blackest is the new black: Scientists have developed a material so dark that you can't see it...

Puritans, Goths, avant-garde artists, hell-raising poets and fashion icon Coco Chanel all saw something special in it. Now black, that most enigmatic of colours, has become even darker and more mysterious.

A British company has produced a “strange, alien” material so black that it absorbs all but 0.035 per cent of visual light, setting a new world record. To stare at the “super black” coating made of carbon nanotubes – each 10,000 times thinner than a human hair – is an odd experience. It is so dark that the human eye cannot understand what it is seeing. Shapes and contours are lost, leaving nothing but an apparent abyss.

You might be an engineer if you know how long a zeptosecond is. (It's a trillionth of a billionth of a second!) http://ow.ly/uUUb30caXrH 

How did the Greeks know ?

Greeks had a strong geometric approach towards problems and as a result their methods are very intuitive.

In this post, we will look at the Method of exhaustion formulated by Archimedes that stands out as a milestone in the history of mathematics

Method of Exhaustion - Archimedes

                                                       Source

In order to find the bounds of pi, Archimedes came up with a remarkably elegant ‘algorithm’, which is as follows:

Lower bound

Inscribe a n-sided polygon in a circle —> Measure its perimeter(p) —> Measure its diameter(d) —> pi_min = p/d —-> Repeat with  n+1 sides.

Upper bound

Circumscribe a n-sided polygon in a circle —> Measure its perimeter(p) —> Measure its diameter(d) —> pi_max = p/d —-> Repeat with  n+1 sides.

And by following this procedure one could obtain the upper and lower bounds of pi !

Heres an animation made on geogebra for a circle of diameter 1. Watch how the lower and upper bounds vary.

Archimedes did this for a 96 sided polygon and found the value of pi  to be between 3.14103 and 3.1427. This is a good enough approximation for most of the calculations that we do even today!

Happy Holidays !