Tag Archives: magnetism

Earth might develop ‘junk’ rings — but engineers are working to prevent that

Earth may one day have its own ring system — one made from space junk.

Rendering of man-made objects in Earth’s orbit. Image via ESA.

Whenever there are humans, pollution seems to follow. Our planet’s orbit doesn’t seem to be an exception. However, not all is lost yet! Research at the University of Utah is exploring novel ideas for how to clear the build-up before it can cause more trouble for space-faring vessels and their crews.

Their idea involves using a magnetic tractor beam to capture and remove debris orbiting the Earth.

Don’t put a ring on it

“Earth is on course to have its own rings,” says University of Utah professor of mechanical engineering Jake Abbott, corresponding author of the study, for the Salt Lake Tribune. “They’ll just be made of space junk.”

The Earth is on its way to becoming the fifth planet in the Solar System to gain planetary rings. However, unlike the rock-and-ice rings of Jupiter, Saturn, Neptune, and Uranus, Earth’s rings will be made of scrap and junk. It would also be wholly human-made.

According to NASA’s Orbital Debris Program Office, there are an estimated 23,000 pieces of orbital debris larger than a softball; these are joined by a few hundreds of millions of pieces smaller than a softball. These travel at speeds of 17,500 mph (28,160 km/h), and pose an immense threat to satellites, space travel, and hamper research efforts.

Because of their high speeds, removing these pieces of space debris is very risky — and hard to pull off.

“Most of that junk is spinning,” Abbott added. “Reach out to stop it with a robotic arm, you’ll break the arm and create more debris.”

A small part of this debris — around 200 to 400 — burns out in the Earth’s atmosphere every year. However, fresh pieces make their way into orbit as the planet’s orbit is increasingly used and traversed. Plans by private entities to launch thousands of new satellites in the coming years will only make the problem worse.

Abbott’s team proposes using a magnetic device to capture or pull debris down into low orbit, where they will eventually burn up in the Earth’s atmosphere.

“We’ve basically created the world’s first tractor beam,” he told Salt Lake Tribune. “It’s just a question of engineering now. Building and launching it.”

The paper “Dexterous magnetic manipulation of conductive non-magnetic objects” has been published in the journal Nature.

Saturn rings.

Saturn’s rings are raining down — in about 100 million years, they’ll be gone

New research from NASA found that Saturn, the ring planet, is losing its rings.

Saturn and rings.

Image NASA / Cassini Imaging Team via Wikimedia.

Observations made decades ago by Voyager 1 and Voyager 2 show that Saturn is devouring its own rings, NASA reports. The particles making up these striking structures are falling onto the planet as a rain of dust and ice, propelled by Saturn’s gravity and magnetic field.

One ring to bind them

“We estimate that this ‘ring rain’ drains an amount of water products that could fill an Olympic-sized swimming pool from Saturn’s rings in half an hour,” said James O’Donoghue of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the study’s lead author.

“[…] The rings have less than 100 million years to live. This is relatively short, compared to Saturn’s age of over 4 billion years.”

The research actually began with scientists trying to figure out if Saturn formed with its rings or acquired them later. The second scenario seems to be the more likely, the team reports. In fact, they estimate that the rings are no older than 100 million years. The team based this age on how much it would take for the C-ring to form from a (hypothetical) original B-ring-like structure. Here’s a chart for your convenience:

Saturn rings.

Saturn rings and with their major subdivisions.
Image credits NASA / JPL / Space Science Institute via Wikimedia.

There are quite a number of theories in regards to how Saturn got its rings (the most prevalent of which we’ve talked about here). If they’re younger than the planet itself, the rings could be the product of collisions between Saturn and small, icy moons. Such a mechanism would be supported by the rings’ present makeup — chunks of water ice ranging from several yards across to microscopic sizes.

Still, the finding that Saturn acquired its rings later in life is, perhaps, overshadowed by the realization that it’s eventually going to lose them. O’Donoghue says, we’re “lucky to be around” while Saturn still has rings. They’re probably around the middle of their lifetime, he adds. The other side of the coin is that we’ve perhaps missed out on seeing similarly lush ring systems around Jupiter, Uranus, and Neptune. While these gas giants do have ring systems today, they’re thin, wispy things.

Black belt giant

The first hints that Saturn’s rings were raining down on the planet came from Voyager readings on (seemingly) unrelated phenomena: variations in Saturn’s ionosphere (electrically-charged upper atmosphere), density variations in its rings, and the planet’s three dark bands These bands encircle the planet at high altitudes (stratosphere) at northern mid-latitudes, and were first spotted by the Voyager 2 mission in 1981.

Later, a NASA Goddard researcher named Jack Connerney linked (paper here) these bands to the planet’s massive magnetic field. Connerney’s hypothesis was that the bands form as electrically-charged ice particles from Saturn’s rings flowed down magnetic field lines. Tiny particles can get electrically charged by ultraviolet light from the Sun or by plasma clouds emanating from micrometeoroids impacting the rings.

Essentially, water pouring into the planet’s upper atmosphere was what formed these bands. The water would literally wash away haze in Saturn’s stratosphere, making them less reflective of light — so the bands appear darker.

So what actually causes the rings to rain down? Well, they’re generally kept in orbit by an interplay between the planet’s gravitational field (which pulls them down) and the centrifugal force generated by the rings’ rotation (which pushes them outwards, or ‘up’).

Things become more complicated when Saturn’s magnetic field gets involved, however. Those electrically-charged particles we talked about earlier also start feeling the pull of the planet’s magnetic field, which curves towards Saturn at its rings. In some parts of the rings, this magnetic pull is enough to dramatically shift the balance of forces on particles — it neutralizes, to an extent, the centrifugal force. Gravity takes hold, pulling the particles down on the planet.

These infalling bits of water chemically react in Saturn’s ionosphere, generating H3+ ions. O’Donoghue picked up on these ions using the Keck telescope in Mauna Kea, Hawaii, as H3+ ions glow in infrared light. The team saw glowing infrared bands in Saturn’s northern and southern hemispheres where magnetic field lines enter the planet. By analyzing the infrared light output, the team calculated the quantity of infalling ring matter (i.e. of how fast they are degrading).

The highest influx of infalling ice, the paper adds, is found in an area in southern Saturn. Some of the matter spewed by Enceladus’ ice geysers also finds its way down to the gas giant, which Connerney says isn’t “a complete surprise.”

So far, the results are pretty solid. However, the team says observing Saturn as it goes around the sun (on a 29.4-year orbit) would conclusively prove or disprove the findings. On its trek, Saturn’s rings will be exposed to various degrees of ultraviolet light — which charges ice particles in the rings. If researchers find that different levels of exposure to sunlight change the quantity of ‘rain’ on Saturn, the study’s conclusions would be confirmed.

The paper “Observations of the chemical and thermal response of ‘ring rain’ on Saturn’s ionosphere” has been published in the journal Icarus.

Swirl patterns.

Unique swirl patterns point to the Moon’s magnetic past

The unique swirl patterns may be produced by ancient magma tubes.

Swirl patterns.

An image of the Reiner Gamma lunar swirl from NASA’s Lunar Reconnaissance Orbiter.
Image credits NASA / LRO / WAC science team.

If you prop up a telescope and look at the Moon, you’re likely to see some curious-looking shapes dotting its surface. Many people take them to be craters left over from meteorite impacts, since this is, after all, the Moon.

That would be jumping to conclusions, however, according to a team from the Rutgers University. These bright, undulating shapes are known as ‘lunar swirls’ and up until now, they were somewhat of a mystery.

Cheesy swirls

One of the most striking features of these swirls is that they come hand-in-hand with powerful — but localized — magnetic fields. These swirls, as well as their strange magnetism, have been known for decades. Efforts to map magnetic activity on the Moon (it doesn’t have a magnetic field of its own) during the Apollo 15 and 16 missions were the first to identify these swirls as sources of magnetism back in 1979.

Since then, try as we might, we just couldn’t make heads or tails of the swirls. Each new tidbit of information only seemed to compound the problem further. For example, the swirls are less pronounced and less intricate at higher altitudes. Every swirl has its own magnetic signature, but there are also magnetic fields on the Moon that are completely distinct from swirls. To top it all off, the swirls show geological signs suggesting they’re new formations (they’re much less weathered than the surrounding rocks) — however, they’re definitely not new formations; we’ve seen them up there for decades now.

Reiner.

Reiner Gamma (60 km width, same swirl as above), seen by the Clementine spacecraft.
Image credits NASA.

“The cause of those magnetic fields, and thus of the swirls themselves, had long been a mystery,” said planetary scientist Sonia Tikoo of Rutgers University-New Brunswick.

“To solve it, we had to find out what kind of geological feature could produce these magnetic fields – and why their magnetism is so powerful.”

Computer modeling allowed the team to discover that, in order to fit the observed magnetic signature, each swirl has to form close to or directly above narrow structures that are close to the surface and can create a magnetic field. One structure that would fit this description are lava tubes, or lava dikes — the products of ancient volcanic activity, the team explains.

These tubes are left-overs from the same basalt lava flows which, 3 to 4 billion years ago, created the dark and wide basalt plains seen over the lunar surface. This would explain why those underground formations became magnetized. The magnetic fields generated by the tubes would also deflect incoming solar wind particles, helping to insulate the swirls from weathering effects.

When Moon rock (regolith) is heated to around 600° Celsius (875° Kelvin or 1,112° Fahrenheit) in an environment that lacks oxygen but has a magnetic field, it becomes ‘imprinted’ with this field itself — it becomes magnetized. Heat causes some minerals in the rock to break down, releasing iron, which becomes magnetized across the same direction as the surrounding field.

This process doesn’t usually take place on Earth, because there’s a lot of oxygen here. It can’t take place on the Moon today, because it lost both its lava flows and its magnetic field. However, according to some of the team’s prior research, the lunar magnetic field persisted up to 2 billion years longer. So their hypothesis fits the timeline.

“No one had thought about this reaction in terms of explaining these unusually strong magnetic features on the Moon,” Tikoo said. “This was the final piece in the puzzle of understanding the magnetism that underlies these lunar swirls.”

The team hopes that the next mission to the Moon will study these swirls directly, and confirm or disprove their hypothesis.

The paper “Lunar Swirl Morphology Constrains the Geometry, Magnetization, and Origins of Lunar Magnetic Anomalies” has been published in the Journal of Geophysical Research: Planets.

The Ever-changing and Skepticized Van Allen Belts

The Van Allen belts are two radiation belts. These are zones of electrically charged particles which are poised, encompassing the Earth far above the surface, and held there by the planet’s magnetic field. The first of the belts was discovered in early 1958 through data collected by Explorer I (the United States’ first space satellite) and the Explorer III and Pioneer satellites, under James Alfred Van Allen and his team at the University of Iowa.

Similar radiation belts have since been found surrounding other planets, but the term of Van Allen belts only refers to those two belts (and sometimes other belts that are transitorily formed) which surround the Earth. They have been dubbed the Van Allen belts after the American physicist credited with their discovery.

Each of the two belts surrounds the Earth in a sort of doughnut-shaped formation. The inner belt reaches from approximately 600 to 3,000 miles above the Earth, and the outer belt from about 9,300 to 15,500 miles above the Earth. Astronomers have determined that the belts consist of many electrically charged particles, like protons and electrons. Earth’s magnetic field traps these particles, directing them to the magnetic poles.

The particles move in spiral paths along a system of flux lines, curving from the north magnetic pole to the south magnetic pole. As the particles come nearer either pole, the converging flux lines reflect them toward the opposite pole. This effect keeps the particles of the Van Allen belts bouncing between the poles. The belts receive new particles from the solar wind, a continuous stream of charged particles emitted from our sun.

Chart Showing the Van Allen Belts in Proportion to Earth

 

Other particles can be gained by solar flares and cosmic rays. Intense solar activity can disrupt the belts, leading to magnetic storms. Such disruptions also affect radio reception, cause surges in power lines, and produce auroras.

Ever since their discovery, the Van Allen belts have concerned and inspired people’s minds. Hollywood feature film and TV producer, writer, and director Irwin Allen came out with his science fiction movie Voyage to the Bottom of the Sea in 1961, three years after the discovery of the first belt. The main plot conceived by Allen and Charles Bennett revolves around saving all life on Earth from the natural inferno that was created when a meteor shower pierced the Van Allen radiation belt, catching it ablaze.

Ice burgs begin to melt in the Arctic, entire forests are engulfed in flames, and the crews of sea-going vessels traveling on the ocean’s surface are baked alive. Eventually, scientist Admiral Harriman Nelson proposes to shoot a nuclear missile from his submarine Seaview into the burning belt at a certain projection and time, which would, in theory, overwhelm and extinguish the skyfire, essentially “amputating” the belt from the Earth.

Scene from Irwin Allen’s 1961 Film Voyage to the Bottom of the Sea. Source: 20th Century Fox.

 

Even today, decades later, people are concerned about the radiation belts. A prominent group of physicists wants the belts eliminated altogether. A plan was even suggested in which long conducting tethers that are charged with a high voltage are deployed from satellites into the belts. It would force charged particles that come into contact with the tethers to have their pitch angle altered.

Over time, theoretically, this would dissolve the inner belts. The belts pose certain difficulties and dangers (mainly caused by radiation) whenever a satellite, telescope, or human is to be launched into outer space. There is a decent scientific argument in that these belts provide anything useful, or that we could do away with them without a negative effect.

According to some, if the belts were not there, the Earth would no longer possess a magnetic field. That means that cosmic ray particles would be at liberty to collide with our atmosphere in larger quantities, resulting in a higher background level of secondary “air shower neutrons”, leading to higher doses of background radiation on the surface. If the Van Allen belts were gone, it would definitely impact human life.

Other sources:

The World Book Encyclopedia Vol. 20. World Book, Inc., 1987.

Czech researchers turn graphene sheets into the first stable non-metallic magnets

Researchers have created the first stable non-metal magnet ever by treating graphene layers with non-metallic elements.

Image credits Wikimedia / AlexanderAlUS.

A team from the Regional Center of Advanced Technologies and Materials at the Palacky University, Olomouc, Czech Republic, announced that they have created the first non-metal magnet that can maintain its properties at room temperature. The process requires no metals — the team created their magnet by treating graphene layers with non-metallic elements such as fluorine, hydrogen, or oxygen.

“For several years, we have suspected that the path to magnetic carbon could involve graphene — a single two-dimensional layer of carbon atoms,” lead researcher Radek Zbořil, director of the RCATM, in a press release.

“[Through the process] we were able to create a new source of magnetic moments that communicate with each other even at room temperature. This discovery is seen as a huge advancement in the capabilities of organic magnets.”

They’ve also developed the theoretical framework to explain why their unique chemical treatment creates magnets without any metal.

“In metallic systems, magnetic phenomena result from the behavior of electrons in the atomic structure of metals,” explained co-author Michal Otyepka.

“In the organic magnets [i.e. the graphene ones] that we have developed, the magnetic features emerge from the behavior of non-metallic chemical radicals that carry free electrons.”

Graphene is already getting a lot of attention for its unique electrical and physical properties as well as electrical conductivity. Adding magnetism to the list of it can do opens up a whole new range of possibilities for a material that is in essence sheet carbon you can cook make from soy.

“Such magnetic graphene-based materials have potential applications in the fields of spintronics and electronics, but also in medicine for targeted drug delivery and for separating molecules using external magnetic fields,” the team adds.

The full paper “Room temperature organic magnets derived from sp3 functionalized graphene” has been published in the journal Nature.

Artist's impression of supernova 1993J. Credit: Wikimedia Commons

Superluminous supernovas explode twice, create some of the most powerful magnets in the universe

Artist's impression of supernova 1993J.  Credit: Wikimedia Commons

Artist’s impression of supernova 1993J. Credit: Wikimedia Commons

When a star is ready to drop the curtain, it goes out with a bang — a supernova explosion. Sometimes, however, some stars blow up twice. Now, astronomers studying these rare and mysterious cosmic events say they’ve uncovered a link between these double explosions and another class of novas called superluminous supernovas.

Supernovae are basically stellar eruptions, triggered either by the gravitational collapse of a massive star, or by the sudden re-ignition of nuclear fusion in a degenerate star. They are amazing manifestations of energy – for brief moments, a supernova can outshine an entire galaxy, radiating as much energy as the Sun or any ordinary star is expected to emit over its entire lifespan, before fading after a few weeks or months. A typical supernova will also eject enough material to seed 7,000 Earths. The shock breakout immediately precedes the ‘big event’ and is essentially a massive flash of brightness.

Maybe the rarest class of supernovas, however, are the superluminous kind. These are up to 100 times brighter than the regular variety. They’re also very rare. Only 0.1% of supernovas are superluminous and only 30 have been caught by astronomers so far.

These mysterious cosmic bodies are the focus of research nowadays as astronomers try to piece the puzzle of their origin. We still don’t know a lot about them, but previous work seems to suggest superluminous supernovas blow up twice, something that British researchers seem to confirm in this new study.

Using the Gran Telescopio Canarias, a telescope in Spain’s Canary Islands, astronomers spotted one of this rare gems in 2014. The superluminous supernova called DES14X3taz is located 6.4 billion light-years from Earth. The scientists were lucky enough to catch the explosion as it unfolded, and tracked its temperature for months. What they found was that after an initial spike of brightness, the supernova cooled off, only to turn the lights on much brighter some time later.

This graph shows the evolution of the apparent brightness of the new supernova. You can notice the initial peak, which rapidly drops for a couple of days. The brightness increases again for a double bang. Credit: Mathew Smith.

This graph shows the evolution of the apparent brightness of the new supernova. You can notice the initial peak, which rapidly drops for a couple of days. The brightness increases again for a double bang. Credit: Mathew Smith.

This initial spike of the dying star which had a mass 200 times greater than the sun was likely due to the ejection of a huge bubble of material. As this bubble grew to tremendous size, the material rapidly cooled. What was most remarkable, however, was that following the initial spike of brightness the star gave birth to a magnetar.

Though it sounds like a magnetic centaur, a magnetar is, in fact, a type of neutron star — the collapsed core of the star following the nova event. Magnetars are among the most powerful magnets in the Universe. In this particular case, the creation of the magnetar triggered the second, much more powerful supernova event because it heated the bubble of matter initially expelled into outer space.

Mathew Smith, an astrophysicist at the University of Southampton in England, one of the lead authors of the study, peered through existing literature and databases and found this sort of double-peak events are very common among superluminous supernovas. The two may be intrinsically connected, the researchers conclude.

“What we have managed to observe, which is completely new” said Smith, “is that before the major explosion there is a shorter, less luminous outburst, which we can pick out because it is followed by a dip in the light curve, and which lasts just a few days.”

“The hunt is now on to find these events early and really tie down what causes them,” Smith said. “Fingers crossed we find some more.”

crystal_audio

Science turns psychedelic: an amazing TED talk

crystal_audio

A while ago, ZME Science featured the brilliant work of  Fabian Oefner, a Swiss artist and photographer, who mixes various artsy techniques (paints, photography, glasswork etc) with science.

crystal_audio1

Thus, he came up with some truly fantastic pieces of art from mixing paint with magnetic liquid, to using colored crystals that pattern under sound waves (pictured in the GIFs), to setting whiskey on fire. For your daily dose of awe, check out Oefner’s TED talk embedded in this article.

Wonder material graphene can be made magnetic – and turned on and off

Is there something that graphene can’t do? It’s the world’s strongest material, even when it has flaws, a graphene aerogel is also the lightest material known, it’s great for sensors, for headphones, it repairs itself, and boasts a swarm of other features and capabilities. Now, researchers from Manchester University have shown that they can create elementary magnetic moments in graphene and then switch them on and off.

graphene magnetism

This is the first time, with any material, that magnetization was swtiched on and off, instead of on and then reversed – which makes the prospects even more intriguing.

Modern society is so dependent on magnetic materials we can’t even imagine the world without them. Everything we do depends on them – be it hard disks, memory chips, or airplane navigation. When it comes to graphene, its magnetism is a little unconventional – whenever atoms are removed from its lattice, microscopic holes called vacancies appear – the physicists from Manchester have shown that electrons condense around these holes into small electronic clouds; each of these clouds behaves like a microscopic magnet carrying one unit of magnetism, spin. Dr Irina Grigorieva and her team have shown how to turn this magnetism on and off.

“This breakthrough allows us to work towards transistor-like devices in which information is written down by switching graphene between its magnetic and non-magnetic states. These states can be read out either in the conventional manner by pushing an electric current through or, even better, by using a spin flow. Such transistors have been a holy grail of spintronics.”

Dr Rahul Nair, who was in charge of the experimental effort, explained why this is such a big deal:

“Previously, one could only change a direction in which a magnet is magnetized from north to south. Now we can switch on and off the magnetism entirely. Graphene already attracts interest in terms of spintronics applications, and I hope that the latest discovery will make it a frontrunner.”

Nobel Laureate and co-author of the paper Professor Andre Geim, who discovered graphene as a material concluded there is much reason for optimism:

“I wonder how many more surprises graphene keeps in store. This one has come out of the blue. We have to wait and see for a few years but the switchable magnetism may lead to an impact exceeding most optimistic expectations.”

Crucial magnetic superconductor breakthrough opens new grounds in electronics

Researchers have reached what can only be described as a crucial milestone that opens the way for a new class of materials with amazing electronic properties.

Superconductivity is a relatively recently discovered feat, in which conducting materials oppose exactly zero resistance when electric current passes through them, below a certain temperature. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon.

In this research, physicists sandwiched two nonmagnetic insulators together and discovered a shocking result: the layer in which the two materials meet has both magnetic and superconucting portions – two properties that normally just don’t go together.

Scientists have long hoped to find in away to engineer magnetism in this class of materials, calle complex oxides, as a first step in developing a potential new form of computing memory for storage and processing. The team Stanford Institute for Materials and Energy Science (SIMES), a joint institute of the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University said that this opens “exciting possibilities for engineering new materials and studying the interplay of these normally incompatible states“.

The next step in this research is finding out if superconductivity and magnetism can in fact coexist, or if this is some sort of new exotic type of superconductivity that interacts actively with magnetism.

“Our future measurements will indicate whether they’re fighting one another or helping one another,” Moler said.

Either way, one thing’s for sure – we are on the brink of a major development in superconductivity.