(Source)

Superfluidity consists of an anomalous liquid state of quantum nature which is under a very low temperature behaving as if it had no viscosity and exhibiting an abnormally high heat transfer. This phenomenon was observed for the first time in liquid helium and has applications not only in theories about liquid helium but also in astrophysics and theories of quantum gravitation.

Helium only ends boiling at 2.2 K and is when it becomes helium-II (superfluid helium), getting a thermal conductivity increased by a million times, in addition to becoming a superconductor. Its viscosity tends to zero, hence, if the liquid were placed in a cubic container it would spread all over the surface. Thus, the liquid can flow upwards, up the walls of the container. If the viscosity is zero, the flexibility of the material is non-existent and the propagation of waves on the material occurs under infinite velocity.

Because it is a noble gas, helium exhibits little intermolecular interaction. The interactions that it presents are the interactions of Van der Waals. As the relative intensity of these forces is small, and the mass of the two isotopes of helium is small, the quantum effects, usually disguised under the thermal agitation, begin to appear, leaving the liquid in a state in which the particles behave jointly, under effect of a single wave function. In the two liquids in which cases of superfluidity are known, that is, in isotopes 3 and 4 of helium, the first is composed of fermions whereas the second is composed of bosons. In both cases, the explanation requires the existence of bosons. In the case of helium-3, the fermions group in pairs, similar to what happens in the superconductivity with the Cooper pairs, to form bosons.

Helium’s liquidity at low temperatures allows it to carry out a transformation called Bose–Einstein condensation, in which individual particles overlap until they behave like one big particle.

Superfluid in astrophysics

The idea of superfluids existed within neutron stars was proposed by Russian physicist Arkady Migdal  in 1959. Making an analogy with Cooper pairs that form within superconductors, it is expected that protons and neutrons in the nucleus of a star of neutrons with sufficient high pressure and low temperature behave in a similar way forming pairs of Cooper and generate the phenomena of superfluidity and superconductivity.

The existence of this phenomenon was proven by NASA  in 2011 when analyzing the neutron star left by supernova Cassiopeia A.

sources: 1, 2, 3 & 4 animation: 1 & 2

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At Last, Scientists Have Found The Galaxy’s Missing Exoplanets: Cold Gas Giants

“By using the same instrument and leaving virtually no long-term gaps in the data, long-term, precise Doppler measurements finally became possible. A total of five brand new planets, one confirmation of a suggested planet, and three updated planets were announced in this latest study, bringing the total number of Jupiter-or-larger planets beyond the Jupiter-Sun distance up to 26. It shows us what we’d always hoped for: that our Solar System isn’t so unusual in the Universe; it’s just difficult to observe and detect planets like the ones we have.”

We’ve long suspected that there was nothing special about our Solar System; that Sun-like stars should have a wide variety of planets around them, including many of the types of worlds found orbiting our Sun. However, owing to the difficulty in making the kinds of measurements that would reveal them to us, our work has revealed a sample of planets biased towards two types of planets: the short-period worlds and the well-separated, high-mass worlds. Planets like Jupiter or Saturn were elusive for so long. But now, owing to research programs dedicated to monitoring nearby stars on decadal timescales, we’ve revealed a remarkable number of these worlds, many of which are now candidates for future direct imaging surveys.

The missing gas giants of the Universe, including worlds like the ones actually found orbiting our Sun, are finally within reach. Here’s how we’ve revealed them at last!

Created using still images taken by the Cassini spacecraft during it’s flyby of Jupiter and while at Saturn. Shown is Io and Europa over Jupiter’s Great Red Spot.

NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill

The Planets and their respective sizes compared to our Sun.

5 Ways the Moon Landing Changed Life on Earth

When Neil Armstrong took his first steps on the Moon 50 years ago, he famously said “that’s one small step for a man, one giant leap for mankind.” He was referring to the historic milestone of exploring beyond our own planet — but there’s also another way to think about that giant leap: the massive effort to develop technologies to safely reach, walk on the Moon and return home led to countless innovations that have improved life on Earth.

Armstrong took one small step on the lunar surface, but the Moon landing led to a giant leap forward in innovations for humanity.

Here are five examples of technology developed for the Apollo program that we’re still using today:

1. Food Safety Standards

As soon as we started planning to send astronauts into space, we faced the problem of what to feed them — and how to ensure the food was safe to eat. Can you imagine getting food poisoning on a spacecraft, hundreds of thousands of miles from home?

We teamed up with a familiar name in food production: the Pillsbury Company. The company soon realized that existing quality control methods were lacking. There was no way to be certain, without extensive testing that destroyed the sample, that the food was free of bacteria and toxins.

Pillsbury revamped its entire food-safety process, creating what became the Hazard Analysis and Critical Control Point system. Its aim was to prevent food safety problems from occurring, rather than catch them after the fact. They managed this by analyzing and controlling every link in the chain, from the raw materials to the processing equipment to the people handling the food.

Today, this is one of the space program’s most far-reaching spinoffs. Beyond keeping the astronaut food supply safe, the Hazard Analysis and Critical Point system has also been adopted around the world — and likely reduced the risk of bacteria and toxins in your local grocery store. 

2. Digital Controls for Air and Spacecraft

The Apollo spacecraft was revolutionary for many reasons. Did you know it was the first vehicle to be controlled by a digital computer? Instead of pushrods and cables that pilots manually adjusted to manipulate the spacecraft, Apollo’s computer sent signals to actuators at the flick of a switch.

Besides being physically lighter and less cumbersome, the switch to a digital control system enabled storing large quantities of data and programming maneuvers with complex software.

Before Apollo, there were no digital computers to control airplanes either. Working together with the Navy and Draper Laboratory, we adapted the Apollo digital flight computer to work on airplanes. Today, whatever airline you might be flying, the pilot is controlling it digitally, based on the technology first developed for the flight to the Moon.

3. Earthquake-ready Shock Absorbers

A shock absorber descended from Apollo-era dampers and computers saves lives by stabilizing buildings during earthquakes.

Apollo’s Saturn V rockets had to stay connected to the fueling tubes on the launchpad up to the very last second. That presented a challenge: how to safely move those tubes out of the way once liftoff began. Given how fast they were moving, how could we ensure they wouldn’t bounce back and smash into the vehicle?

We contracted with Taylor Devices, Inc. to develop dampers to cushion the shock, forcing the company to push conventional shock isolation technology to the limit.

Shortly after, we went back to the company for a hydraulics-based high-speed computer. For that challenge, the company came up with fluidic dampers—filled with compressible fluid—that worked even better. We later applied the same technology on the Space Shuttle’s launchpad.

The company has since adapted these fluidic dampers for buildings and bridges to help them survive earthquakes. Today, they are successfully protecting structures in some of the most quake-prone areas of the world, including Tokyo, San Francisco and Taiwan.

4. Insulation for Space

We’ve all seen runners draped in silvery “space blankets” at the end of marathons, but did you know the material, called radiant barrier insulation, was actually created for space?

Temperatures outside of Earth’s atmosphere can fluctuate widely, from hundreds of degrees below to hundreds above zero. To better protect our astronauts, during the Apollo program we invented a new kind of effective, lightweight insulation.

We developed a method of coating mylar with a thin layer of vaporized metal particles. The resulting material had the look and weight of thin cellophane packaging, but was extremely reflective—and pound-for-pound, better than anything else available.

Today the material is still used to protect astronauts, as well as sensitive electronics, in nearly all of our missions. But it has also found countless uses on the ground, from space blankets for athletes to energy-saving insulation for buildings. It also protects essential components of MRI machines used in medicine and much, much more.

Image courtesy of the U.S. Marines

5. Healthcare Monitors

Patients in hospitals are hooked up to sensors that send important health data to the nurse’s station and beyond — which means when an alarm goes off, the right people come running to help.

This technology saves lives every day. But before it reached the ICU, it was invented for something even more extraordinary: sending health data from space down to Earth.

When the Apollo astronauts flew to the Moon, they were hooked up to a system of sensors that sent real-time information on their blood pressure, body temperature, heart rate and more to a team on the ground.

The system was developed for us by Spacelabs Healthcare, which quickly adapted it for hospital monitoring. The company now has telemetric monitoring equipment in nearly every hospital around the world, and it is expanding further, so at-risk patients and their doctors can keep track of their health even outside the hospital.

Only a few people have ever walked on the Moon, but the benefits of the Apollo program for the rest of us continue to ripple widely.

In the years since, we have continued to create innovations that have saved lives, helped the environment, and advanced all kinds of technology.

Now we’re going forward to the Moon with the Artemis program and on to Mars — and building ever more cutting-edge technologies to get us there. As with the many spinoffs from the Apollo era, these innovations will transform our lives for generations to come.

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All cats are beautiful 🐱❤️

Earth as viewed from 10,000 miles. In 1969, the Apollo 4 unmanned test flight made a great ellipse around Earth as a test of the translunar motors and of the high speed entry required of a manned flight returning from the moon. A 70mm camera was programmed to look out a window toward Earth, and take a series of photographs from “high apogee”. Coastal Brazil, Atlantic Ocean, West Africa, Antarctica, looking west. This photograph was made when the Apollo 4 spacecraft, still attached to the S-IVB (third) stage, was orbiting Earth at an altitude of 9,544 miles. source

Why 2020 Might Be The Best Geminid Meteor Shower Of All-Time

“As the large parent body of the Geminids, asteroid 3200 Phaethon, continues on its tight orbit around the Sun, it will continue to expel matter and be torn apart, bit by tiny bit. The asteroid is about the size of the one that struck Earth 65 million years ago, causing our last great mass extinction. But instead of colliding with us all at once, this ~6 km wide asteroid is slowly dissipating in the presence of the Sun, creating tails of matter and ions but also an ever-thickening debris stream.

With each mid-December that rolls past, Earth slams through that debris stream, creating a show that gets progressively more spectacular with each set of orbits that regularly tick by. Over the past 15 years, the Geminids have regularly been one of the two best displays of meteor showers on Earth, and it’s eminently possible that 2020 will set a new record. The Moon, the Earth, and all of the other predictable conditions are just right for a spectacular show. If the clouds cooperate on December 13 and 14, treat yourself to the greatest natural show of the year. With all that 2020 has brought us, we can all use a cosmic treat like this one.”

Can everyone just have a good thing to enjoy? Can we all just have something nice that we don’t have to fight over? Well, nature might deliver what humanity has been unable to bring us for 2020: a natural show that can’t be stopped by anything, except for clouds. 

Get your Geminid fix today, and then look up on December 13/14 to fully enjoy the show!

Greatest Hits — Craters We Love

Our solar system was built on impacts — some big, some small — some fast, some slow. This week, in honor of a possible newly-discovered large crater here on Earth, here’s a quick run through of some of the more intriguing impacts across our solar system.

1. Mercury: A Basin Bigger Than Texas

Mercury does not have a thick atmosphere to protect it from space debris. The small planet is riddled with craters, but none as spectacular as the Caloris Basin. “Basin” is what geologists call craters larger than about 186 miles (300 kilometers) in diameter. Caloris is about 950 miles (1,525 kilometers) across and is ringed by mile-high mountains.

For scale, the state of Texas is 773 miles (1,244 kilometers) wide from east to west.

2. Venus: Tough on Space Rocks

Venus’ ultra-thick atmosphere finishes off most meteors before they reach the surface. The planet’s volcanic history has erased many of its craters, but like almost any place with solid ground in our solar system, there are still impact scars to be found. Most of what we know of Venus’ craters comes from radar images provided by orbiting spacecraft, such as NASA’s Magellan.

Mead Crater is the largest known impact site on Venus. It is about 170 miles (275 kilometers) in diameter. The relatively-flat, brighter inner floor of the crater indicates it was filled with impact melt and/or lava.

3. Earth: Still Craters After All These Years

Evidence of really big impacts — such as Arizona’s Meteor Crater — are harder to find on Earth. The impact history of our home world has largely been erased by weather and water or buried under lava, rock or ice. Nonetheless, we still find new giant craters occasionally.

A NASA glaciologist has discovered a possible impact crater buried under more than a mile of ice in northwest Greenland.

This follows the finding, announced in November 2018, of a 19-mile (31-kilometer) wide crater beneath Hiawatha Glacier – the first meteorite impact crater ever discovered under Earth’s ice sheets. 

If the second crater, which has a width of over 22 miles (35 kilometers), is ultimately confirmed as the result of a meteorite impact, it will be the 22nd largest impact crater found on Earth.

4. Moon: Our Cratered Companion

Want to imagine what Earth might look like without its protective atmosphere, weather, water and other crater-erasing features? Look up at the Moon. The Moon’s pockmarked face offers what may be humanity’s most familiar view of impact craters.

One of the easiest to spot is Tycho, the tight circle and bright, radiating splat are easy slightly off center on the lower-left side of the full moon. Closer views of the 53-mile (85 kilometer)-wide crater from orbiting spacecraft reveal a beautiful central peak, topped with an intriguing boulder that would fill about half of a typical city block.

5. Mars: Still Taking Hits

Mars has just enough atmosphere to ensure nail-biting spacecraft landings, but not enough to prevent regular hits from falling space rocks. This dark splat on the Martian south pole is less than a year old, having formed between July and September 2018. The two-toned blast pattern tells a geologic story. The larger, lighter-colored blast pattern could be the result of scouring by winds from the impact shockwave on ice. The darker-colored inner blast pattern is because the impactor penetrated the thin ice layer, blasting the dark sand underneath in all directions.

6. Ceres: What Lies Beneath

The bright spots in Ceres’ Occator crater intrigued the world from the moment the approaching Dawn spacecraft first photographed it in 2015. Closer inspection from orbit revealed the spots to be the most visible example of hundreds of bright, salty deposits that decorate the dwarf planet like a smattering of diamonds. The science behind these bright spots is even more compelling: they are mainly sodium carbonate and ammonium chloride that somehow made their way to the surface in a slushy brine from within or below the crust. Thanks to Dawn, scientists have a better sense of how these reflective areas formed and changed over time — processes indicative of an active, evolving world.

7. Comet Tempel 1: We Did It!

Scientists have long known we can learn a lot from impact craters — so, in 2005, they made one themselves and watched it happen.

On July 4, 2005, NASA’s Deep Impact spacecraft trained its instruments on an 816-pound (370-kilogram) copper impactor as it smashed into comet Tempel 1.

One of the more surprising findings: The comet has a loose, “fluffy” structure, held together by gravity and contains a surprising amount of organic compounds that are part of the basic building blocks of life.

8. Mimas: May the 4th Be With You

Few Star Wars fans — us included — can resist Obi Wan Kenobi’s memorable line “That’s no moon…” when images of Saturn’s moon Mimas pop up on a screen. Despite its Death Star-like appearance, Mimas is most definitely a moon. Our Cassini spacecraft checked, a lot — and the superlaser-looking depression is simply an 81-mile (130-kilometer) wide crater named for the moon’s discoverer, William Herschel.

9. Europa: Say What?

The Welsh name of this crater on Jupiter’s ocean moon Europa looks like a tongue-twister, but it is easiest pronounced as “pool.” Pwyll is thought to be one of the youngest features we know of on Europa. The bright splat from the impact extends more than 600 miles (about 1,000 kilometers) around the crater, a fresh blanket over rugged, older terrain. “Fresh,” or young, is a relative term in geology; the crater and its rays are likely millions of years old.

10. Show Us Your Greatest Hits

Got a passion for Stickney, the dominant bowl-shaped crater on one end of Mars’ moon Phobos? Or a fondness for the sponge-like abundance of impacts on Saturn’s battered moon Hyperion (pictured)? There are countless craters to choose from. Share your favorites with us on Twitter, Instagram and Facebook.

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