Crucial Superconducting Theory Confirmed

photo credit: Magnetic levitation is only one of the many properties of superconducting materials. ktsdesign/shutterstock

Superconductivity promises to revolutionize our world with efficient transport, cheaper electricity, and even hoverboards. Although it’s still a long road to that technology, a crucial theory has just been confirmed that could help.

The superconducting state happens suddenly when electrons in the material join in pairs. This formation is due to internal electrical currents that form the state when the right conditions arise. The theory was first proposed in 1989 by Professor Chandra Varma, and now he and colleagues from China and Korea have successfully proved it.

When some materials are cooled below a certain critical temperature, they become superconducting. They suddenly transmit electricity with zero resistance, thanks to the fact that electrons form pairs and move through the material effortlessly without repelling each other.

“I suggested that this behavior was happening because there was an unusual phase transition due to loops of currents flowing within the material. It was a very bold hypothesis because no such behavior had ever been observed,” said Professor Varma, now a distinguished professor of physics and astronomy at theUniversity of California Riverside

The experiment conducted at the National Laboratory for Superconductivity in Beijing used a laser to precisely measure the energies of the coupling electrons. The values were so accurate that it allowed them to prove that Varma had the right idea all along. The findings are published in the latest issue of Science Advances.

The critical temperature for all the superconducting materials is still significantly below zero, with thehottest superconductor still needing to be cooled to a temperature of -70ºC (-94ºF). But the scientists think their research could help develop room-temperature superconductors, which would allow for more efficient technology that doesn’t overheat, faster transportation, and more advanced scientific and medical instruments.

“I can in my theory predict precisely the parameters that a material must have in order to get higher temperature superconductors,” said Varma. “How can chemists and experimentalists (who make those materials) achieve those parameters? I can’t directly say, but the theory points to a certain direction.”

10 Amazing Photos Taken By Scott Kelly On His Year In Space

Commander Scott Kelly has just returned from his 340-day mission aboard the ISS. The record breaking mission has seen Kelly and Russian cosmonaut Mikhail Kornienko spend almost a year in space, and scientists hope to gain an insight into what long stays in microgravity do to the body, with views on missions to Mars in the future.

Over the last year, Commander Kelly has not only been in charge of the ISS and conducted important scientific experiments, but he has also been an avid scientific communicator, posting incredible photos on his Twitter page. Here’s a selection of his best shots.

This stunning colourful photo was posted by Kelly in February and shows Algeria’s Tassili N’Ajjer National Park. NASA/Scott Kelly

In this tweet, Kelly said: “#Bahamas, the strokes of your watercolors are always a refreshing sight.” The image of the Caribbean archipelagus was taken last July. NASA/Scott Kelly

This Zinnia plant was the first flower grown in space. The commander snapped this picture in January. NASA/Scott Kelly

“#GoodMorning #Egypt! Your colors never cease to amaze! #YearInSpace ” tweeted Kelly after taking this breathtaking picture of the Governorate of Wadi Al-Jadid, Egypt. NASA/Scott Kelly

“Day 207, dusk over the Indian Ocean with a yellow band on the horizon,” this tweet read. The yellow band is the light of the Sun reflecting on the atmosphere. NASA/Scott Kelly

Hurricane Patricia was the second most intense tropical cyclone on record and it was responsible for six casualties. Seeing it over Mexico before making landfall, Scott Kellyremarked on how menacing it looked. NASA/Scott Kelly

This incredible picture shows the aurora from last August. NASA/Scott Kelly

Our homes in the cosmos, Earth and the Milky Way are visibile in this beautiful picture. NASA/Scott Kelly

The Alps and the whole italian boot are visibile here through the clouds. He tweeted this inJanuary. NASA/Scott Kelly

A picture of the saltwater lake La’nga Co in Tibet. It’s Sanskrit name translates to “lake of the demon”, as the lake is devoid of fish and plants. Kelly tweeted this picture in January. NASA/Scott Kelly

The History of Gravity

Our understanding of gravity has gone through a few permutations, from Newton’s equations through to Einstein’s general relativity. With today’s discovery of gravitational waves, we look back on how our grasp of gravity has evolved over the centuries.

1687: NEWTONIAN GRAVITY

Isaac Newton publishes Philosophiae Naturalis Principia Mathematica, giving a comprehensive account of gravity. This gave astronomers an accurate toolbox for predicting the motions of planets. But it was not without its problems, such as calculating the precise orbit of the planet Mercury.

All planets’ orbits precess – with the closest point of their orbit moving slightly with each revolution – due to the gravitational tugs from other planets.

Wes Mountain/The Conversation, CC BY-ND

The issue with Mercury’s orbit was that the amount of precession did not match what Newton’s theory predicted. It was only a small discrepancy, but big enough for astronomers to know it was there!

Wes Mountain/The Conversation, CC BY-ND

1859: PLANET VULCAN

To explain Mercury’s odd behaviour, Urbain Le Verrier proposed the existence of an unseen planet calledVulcan, which orbited closer to the sun. He suggested that the gravity from Vulcan was influencing Mercury’s orbit. But repeated observations revealed no signs of Vulcan.

Wes Mountain/The Conversation, CC BY-ND

1905: SPECIAL RELATIVITY

Albert Einstein shakes up physics with his special theory of relativity. He then started incorporating gravity into his equations, which led to his next breakthrough.

1907: EINSTEIN PREDICTS GRAVITATIONAL REDSHIFT

What we now call gravitational redshift was first proposed by Einstein from his thoughts in the development of general relativity.

Wes Mountain/The Conversation, CC BY-ND

Einstein predicted that the wavelength of light coming from atoms in a strong gravitational field will lengthen as it escapes the gravitational force. The longer wavelength shifts the photon to the red end of the electromagnetic spectrum.

1915: GENERAL RELATIVITY

Albert Einstein publishes general theory of relativity. The first great success was its accurate prediction of Mercury’s orbit, including its previously inscrutable precession.

The theory also predicts the existence of black holes and gravitational waves, although Einstein himself often struggled to understand them.

Wes Mountain/The Conversation, CC BY-ND

1917: EINSTEIN THEORISES STIMULATED EMISSION

In 1917, Einstein publishes a paper on the quantum theory of radiation indicatingstimulated emissionwas possible.

Einstein proposed that an excited atom could return to a lower energy state by releasing energy in the form of photons in a process called spontaneous emission.

In stimulated emission, an incoming photon interacts with the excited atom, causing it to move to a lower energy state, releasing photons that are in phase and have the same frequency and direction of travel as the incoming photon. This process allowed for the development of the laser (light amplification by stimulated emission of radiation).

1918: Prediction Of Frame Dragging

Josef Lense and Hans Thirring theorise that the rotation of a massive object in space would “drag” spacetime around with it.

1919: FIRST OBSERVATION OF GRAVITATIONAL LENSING

Gravitational lensing is the bending of light around massive objects, such as a black hole, allowing us to view objects that lie behind it. During a total solar eclipse in May 1919, stars near the sun were observed slightly out of position. This indicated that light was bending due to the sun’s mass.

Wes Mountain/The Conversation, CC BY-ND

1925: FIRST MEASUREMENT OF GRAVITATIONAL REDSHIFT

Walter Sydney Adams examined light emitted from the surface of massive stars and detected a redshift, as Einstein predicted.

1937: Prediction Of A Galactic Gravitational Lensing

Swiss astronomer Fritz Zwicky proposed that an entire galaxy could act as a gravitational lens.

1959: GRAVITATIONAL REDSHIFT VERIFIED

The theory was conclusively tested by Robert Pound and Glen Rebka by measuring the relative redshift of two sources at the top and bottom of Harvard University’s Jefferson Laboratory tower. The experimentaccurately measured the tiny change in energies as photons travelled between the top and the bottom.

Wes Mountain/The Conversation, CC BY-ND

1960: LASER INVENTED USING STIMULATED EMISSION

Theodore H. Maiman, a physicist at Hughes Research Laboratories in California, builds the first laser.

1960S: FIRST EVIDENCE FOR BLACK HOLES

The 1960s was the beginning of the renaissance of general relativity, and saw the discovery of galaxies that were powered by the immense pull of black holes in their centres.

There is now evidence of massive black holes in the hearts of all large galaxies, as well as there being smaller black holes roaming between the stars.

1966: First Observation Of Gravitational Time Delays

American astrophysicist Irwin Shapiro proposed that if general relativity is valid, then radio waves will be slowed down by the sun’s gravity as they bounce around the solar system.

Wes Mountain/The Conversation, CC BY-ND

The effect was observed between 1966-7 by bouncing radar beams off the surface of Venus and measuring the time taken for the signals to return to Earth. The delay measured agreed with Einstein’s theory.

We now use time-delays on cosmological scales, looking at the time differences in flashes and flares between gravitationally lensed images to measure the expansion of the universe.

1969: FALSE DETECTION OF GRAVITATIONAL WAVES

American physicist Joseph Weber (a bit of a rebel) claimed the first experimental detection of gravitational waves. His experimental results were never reproduced.

Wes Mountain/The Conversation, CC BY-ND

1974: INDIRECT EVIDENCE FOR GRAVITATIONAL WAVES

Joseph Taylor and Russell Hulse discover a new type of pulsar: a binary pulsar. Measurements of the orbital decay of the pulsars showed they lost energy matching the amounts predicted by general relativity. They receive the 1993 Nobel Prize for Physics for this discovery.

Wes Mountain/The Conversation, CC BY-ND

1979: FIRST OBSERVATION OF A GALACTIC GRAVITATIONAL LENS

The first extragalactic gravitational lens was discovered, when observers Dennis Walsh,Bob Carswell andRay Weymann saw two identical quasi-stellar objects, or “quasars”. It turned out to be one quasar that appears as two separate images.

Since the 1980s, gravitational lensing has become a powerful probe of the distribution of mass in the universe.

1979: LIGO RECEIVES FUNDING

US National Science Foundation funds construction of the Laser Interferometer Gravitational-Wave Observatory (LIGO).

1987: ANOTHER FALSE ALARM FOR GRAVITATIONAL WAVES

A false alarm on direct detection from Joseph Weber (again) with claimed signal from the supernova SN 1987A using his torsion bar experiments, which consisted of large aluminium bars designed to vibrate when a large gravitational wave passed through it.

1994: LIGO CONSTRUCTION BEGINS

It took a long time, but the construction of LIGO finally began in Hanford, Washington, and Livingston, Louisiana.

2002: LIGO Starts First Search

In August 2002, LIGO starts searching for evidence of gravitational waves.

2004: FRAME DRAGGING PROBE

NASA launches Gravity Probe B to measure the spacetime curvature near the Earth. The probe contained gyroscopes that rotated slightly over time due to the underlying spacetime. The effect is stronger around a rotating object which “drags” spacetime around with it.

Wes Mountain/The Conversation, CC BY-ND

The gyroscopes in Gravity Probe B rotated by an amount consistent with Einstein’s theory of general relativity.

Wes Mountain/The Conversation, CC BY-ND

2005: LIGO HUNT ENDS

After five searches, the first phase of LIGO ends with no detection of gravitational waves. The sensors then undergo an interim refit to improve sensitivity, called Enhanced LIGO.

2009: Enhanced LIGO

An upgraded version called Enhanced LIGO starts new hunt for gravitational waves.

2010: ENHANCED LIGO HUNT ENDS

Enhanced LIGO fails to detect and gravitational waves. A major upgrade, called Advanced LIGO begins.

2014: ADVANCED LIGO UPGRADE COMPLETED

The new Advanced LIGO has finished installation and testing and is nearly ready to begin a new search.

2015: FALSE ALARM #3 FOR GRAVITATIONAL WAVES

The indirect signature of gravitational waves in the early universe was claimed by theBICEP2 experiment, looking at the cosmic microwave background. But it looks like this wasdust in our own galaxy spoofing the signal.

2015: LIGO UPGRADED AGAIN

Advanced LIGO starts a new hunt for gravitational waves with four times the sensitivity of the original LIGO. In September, it detects a signal that looks likely to be from the collision between two black holes.

2016: GRAVITATIONAL WAVE DETECTION CONFIRMED

After rigorous checks, the Advanced LIGO team announce the detection of gravitational waves.

Wes Mountain/The Conversation, CC BY-ND

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Crispy Grilled Cheese Is The Best Snack Ever

In springtime of last year, I was in Los Angeles with my mother-in-law, my sister, and my daughter Alex. We went all over the place, checking out restaurants and shops and trying bites of delicious food here and there. We also ate at Sur, the restaurant of Real Housewives of Beverly Hills Lisa Vanderpump, but that’s on the long list of Things I’ve Done But Have Forgotten to Write About. I need to start knocking things off on that list before it gets too long!

Anyway, one of the miscellaneous food places we went to was a cool little establishment called Stir Market, and they had this outlandishly preposterous grilled cheese sandwich, which featured buttered bread, cheese inside, outside, over, under, and all around.

Again: It was preposterous.

It’s been on my mind, so I made a replica yesterday…with one important exception! I did not have even asuggestion of good bread in the house…and good bread is absolutely required if you want to make this sandwich. The bread I used was fine, but it was soft and without form and void, and darkness was upon the face of the yeast.

(Sorry. Had a Genesis moment there.)

Anyway, please don’t make this sandwich unless you have a nice, substantial sourdough sandwich bread or some hearty Italian or French bread. One that isn’t soft and that doesn’t easily get soggy.

And make no mistake: my sandwich below turned out just fine! I ate every bite. But to quote the legendary 80’s pop artist Tiffany, “It coulda been so beautiful…”

First: Usually when you make a grilled cheese, it’s customary to grab…well, some cheese. I used a mix of cheddar…

And Monterey jack.

Always grate your own!

Now, you need some soft, soft butter. This was leftover from some lofty cookie idea I had on Saturday—one, by the way, I got distracted and forgot about. It’s how I roll.

And now I want a cookie.

Because I used soft, soft bread, I didn’t want it to get soggy, so I just spread on a super thin amount. If you use sourdough or other substantial bread, go ahead and spread on a little more. Just remember that the cheese will produce a little grease as it melts…which is why cheese is so dang good.

Sprinkle a small amount of cheese on both halves, making sure the cheese sticks to the buttah.

Turn over one of the slices (yes, butter and cheese side down, but it will be fine!) and put a nice layer of cheese on top. This will actually be the gooey center.

I’m not sure there’s going to be enough cheese in this sandwich.

Carefully lift the other piece and put it on top of the piece with the filling. Is this the craziest thing you’ve ever seen in your life?

It’s not?

Okay, fine. Maybe it’s the 17,449th craziest thing in your life.

But at least that’s something!

Place it in a skillet over medium-low (to medium, depending on how hot your stove gets) heat. I think a nonstick skillet might be the best bet…but I decided to take a walk on the wild side with iron.

Take a peek every now and then and make sure it isn’t burning…and when it looks nice and golden brown and—yes—crispy (look at that surface!) flip it to the other side. Then just keep on cooking it until the center is melted and gooey. You might need to flip it over another time or two to make sure it doesn’t burn before the cheese is melted. You can always turn the heat down if you feel you need a little more time.

Ahhh. It’s done! You can see that nice, thin, crispy outer coating. You can also see the softness of the bread. That won’t happen to you because you’re going to use good bread, right?

Good lands. I don’t say that very often, and when I do, it usually involves melted cheese.

Enjoy every bite! And use whatever melting cheese you want. (Swiss would be astounding.)

And at the risk of sounding like a broken record: Use good, crusty, substantial bread! You won’t be sorry.

Here’s the printable!

RECIPE

CRISPY GRILLED CHEESE

PREP TIME: 5 Minutes

DIFFICULTY: Easy

COOK TIME: 5 Minutes

SERVINGS:  1 Servings

INGREDIENTS

• 2 slices Good Sourdough Sandwich Bread Or Crusty French Bread
• Softened Butter
• Grated Cheese Of Your Choice: Cheddar, Jack, Swiss, Gruyere

INSTRUCTIONS

Heat a nonstick or iron skillet over medium-low heat.

Spread one side of both pieces of bread with a small amount of softened butter. Sprinkle a small amount of grated cheese on each slice—just enough to stick to the butter. Turn one piece over and place a larger amount of cheese on top (this will be the filling). Place the other piece on top. Carefully transfer it to the skillet and cook on both sides until the middle filling is melted and gooey (watch to make sure the surface doesn’t burn! It should be nice deep golden brown.)

Slice in half and dig in!