New research brings superfast quantum computers closer

 

COMPUTERS

Melbourne, Oct 13 (PTI) Australian researchers have developed two new types of 'quantum bits' that process data with more than 99 per cent accuracy, overcoming a critical challenge that has held back the realisation of super powerful quantum computers.

Two research teams working in the same laboratories at The University of New South Wales Australia have created the quantum bits, or "qubits" - the building blocks for quantum computers - that each process quantum data with an accuracy above 99 per cent.

"For quantum computing to become a reality we need to operate the bits with very low error rates," said Professor Andrew Dzurak, who is Director of the Australian National Fabrication Facility at UNSW, where the devices were made.

"We've now come up with two parallel pathways for building a quantum computer in silicon, each of which shows this super accuracy," added Associate Professor Andrea Morello from UNSW's School of Electrical Engineering and Telecommunications.

The UNSW teams were first in the world to demonstrate single-atom spin qubits in silicon, reported in Nature in 2012 and 2013.

Now the team led by Dzurak has discovered a way to create an "artificial atom" qubit with a device remarkably similar to the silicon transistors used in consumer electronics.

Meanwhile, Morello's team has been pushing the "natural" phosphorus atom qubit to the extremes of performance.

Dr Juha Muhonen, a post-doctoral researcher and lead author on the natural atom qubit paper, noted: "The phosphorus atom contains in fact two qubits: the electron, and the nucleus. With the nucleus in particular, we have achieved accuracy close to 99.99 per cent. That means only one error for every 10,000 quantum operations."

The high-accuracy operations for both natural and artificial atom qubits is achieved by placing each inside a thin layer of specially purified silicon, containing only the silicon-28 isotope.

This isotope is perfectly non-magnetic and, unlike those in naturally occurring silicon, does not disturb the quantum bit. The purified silicon was provided through collaboration with Professor Kohei Itoh from Keio University in Japan.

The next step for the researchers is to build pairs of highly accurate quantum bits.

Large quantum computers are expected to consist of many thousands or millions of qubits and may integrate both natural and artificial atoms.

Morello's research team also established a world-record "coherence time" for a single quantum bit held in solid state.

"Coherence time is a measure of how long you can preserve quantum information before it's lost," Morello said.

The longer the coherence time, the easier it becomes to perform long sequences of operations, and therefore more complex calculations. The team was able to store quantum information in a phosphorus nucleus for more than 30 seconds.

The two findings have been published in the journal Nature Nanotechnology. PTI

Fish fossils give clues to origin of sex

 

FISH

London, Oct 19 (PTI) Sexual intercourse was invented 385 million years ago in Scotland by fish from an extinct group called placoderms, which are among the earliest vertebrate ancestors of humans, according to a new study.

Scientists have long been puzzled by the purpose of bony protrusions in placoderms that resembled a surplus pair of fins or limbs just in front of the tail.

A new study, to be published in the journal Nature, has found that the protrusions were in fact used by the fish to cling together as they mated, 'The Sunday Times' reported.

The 6 inch fish appear to have been the first in the fossil record to develop such appendages, suggesting it was the originator of the mating practices used by humans and most other vertebrates today.

Placoderm fossils have been found in Orkney and northern Scotland around John o' Groats.

The research was led by John Long, of Flinders University in Australia, with colleagues including Zerina Johanson, the curator of fossil fish at London's Natural History Museum.

Placoderms were a large group of mostly armoured fish that emerged about 450 million years ago, evolving into a range of species that included large marine predators 33ft long.

They were wiped out 360 million years ago in a mass extinction event but their 90 million years of dominance saw them evolve some of the key features of modern vertebrates.

Long and his colleagues travelled the world studying fossils in museum collections and collecting new ones for clues.

In 2009, Johanson and Long announced the discovery of a 365 million-year-old fossil fish from Australia that appeared to have been pregnant when it died, implying that fertilisation of eggs inside the body was already happening.

The fish involved in the new discovery is 20 million years older and comes from a far more primitive group of placoderms, called the antiarchs, researchers said. PTI

Scientists inch closer to creating artificial living systems

 

LIFE

London, Oct 21 (PTI) Scientists are one step closer to developing an artificial protocell - a basic ingredient for creating more advanced artificial life.

Protocells are the simplest, most primitive living systems, but creating an artificial protocell is far from simple, and so far no one has managed to do that.

One of the challenges is to create the information strings that can be inherited by cell offspring, including protocells.

Such information strings are like modern DNA or RNA strings, and they are needed to control cell metabolism and provide the cell with instructions about how to divide.

Now researchers from the Center for Fundamental Living Technology (FLINT), Department of Physics, Chemistry and Pharmacy, University of Southern Denmark have discovered

information strings with peculiar properties in a virtual computer experiment.

"Finding mechanisms to create information strings are essential for researchers working with artificial life," said head of FLINT, Professor Steen Rasmussen.

"In our computer simulation - our virtual molecular laboratory - information strings began to replicate quickly and efficiently as expected," said Rasmussen.

"However, we were struck to see that the system quickly developed an equal number of short and long information strings and further that a strong pattern selection on the strings had occurred.

"We could see that only very specific information patterns on the strings were to be seen in the surviving strings," said Rasmussen.

"The explanation had to be found in the way the strings interacted with each other," Rasmussen added.

According to Rasmussen, a so-called self-organising autocatalytic network was created in the virtual pot, into which he and his colleagues poured the ingredients for information strings.

An autocatalytic network is a network of molecules, which catalyse each other's production. Each molecule can be formed by at least one chemical reaction in the network, and each reaction can be catalysed by at least one other molecule in the network.

This process will create a network that exhibits a primitive form of metabolism and an information system that replicates itself from generation to generation.

This autocatalytic set quckly evolved into a state where strings of all lengths existed in equal concentrations, which is not what is usually found. Further, the selected strings had strikingly similar patterns, which is also unusual.

"We might have discovered a process similar to the processes that initially sparked the first life. We of course don't know if life actually was created this way - but it could have been one of the steps. Perhaps a similar process created sufficiently high concentrations of longer information strings when the first protocell was created," said Rasmussen.

The research is described in the journal Europhysics Letters. PTI

Oldest DNA ever found sheds light on humans' global trek

 

DNA

Paris, Oct 22 (AFP) Scientists said today they had unravelled the oldest DNA ever retrieved from a Homo sapiens bone, a feat that sheds light on modern humans' colonisation of the planet.

A femur found by chance on the banks of a west Siberian river in 2008 is that of a man who died around 45,000 years ago, they said.

Teased out of collagen in the ancient bone, the genome contains traces from Neanderthals -- a cousin species who lived in Eurasia alongside H. sapiens before mysteriously disappearing.

Previous research has found that Neanderthals and H.sapiens interbred, leaving a tiny Neanderthal imprint of just about two percent in humans today, except for Africans.

The discovery has a bearing on the so-called "Out of Africa" scenario: the theory that H. sapiens evolved in East Africa around 200,000 years ago and then ventured out of the continent.

Dating when Neanderthals and H. sapiens interbred would also indicate when H. sapiens embarked on a key phase of this trek -- the push out of Eurasia and into South and later Southeast Asia.

The new study, published in the journal Nature, was headed by Svante Paabo, a renowned geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who has pioneered research into Neanderthals.

The bone found at the Irtyush River, near the settlement of Ust'-Ishim, carries slightly more Neanderthal DNA than non-Africans today, the team found.

But it takes the form of relatively long strips, whereas Neanderthal DNA in our genome today has been cut up and dispersed in tiny sections as a result of generations of reproduction.

These differences provide a clue for a "molecular calendar", or dating DNA according to mutations over thousands of years.

Using this method, Paabo's team estimate interbreeding between Neanderthals and H. sapiens occurred 7,000 to 13,000 years before the Siberian individual lived -- thus no more than 60,000 years ago.

This provides a rough date for estimating when H. sapiens headed into South Asia, Chris Stringer, a professor at Britain's Natural History Museum, said in a comment on the study.

If today's Australasians have Neanderthal DNA, it is because their forebears crossed through Neanderthal territory and mingled with the locals.

"The ancestors of Australasians, with their similar input of Neanderthal DNA to Eurasians, must have been part of a late, rather than early, dispersal through Neanderthal territory," Stringer said in a press release. (AFP)

Giant black holes can block new stars

 

BLACKHOLES

Washington, Oct 22 (PTI) Massive black holes spewing out radio-frequency-emitting particles at near-light speed can block formation of new stars in ageing galaxies, a new study has found.

The research provides crucial new evidence that it is these jets of "radio-frequency feedback" streaming from mature galaxies' central black holes that prevent hot free gas from cooling and collapsing into baby stars.

"When you look into the past history of the universe, you see these galaxies building stars," said Tobias Marriage, assistant professor of physics and astronomy at Johns Hopkins University and co-lead author of the study.

"At some point, they stop forming stars and the question is: Why? Basically, these active black holes give a reason for why stars stop forming in the universe," Marriage said.

Johns Hopkins postdoctoral fellow Megan Gralla found that the Sunyaev-Zel'dovich effect signature - typically used to study large galaxy clusters - can also be used to learn a great deal about smaller formations.

The SZ effect occurs when high-energy electrons in hot gas interact with faint light in the cosmic microwave background, light left over from earliest times when the universe was a thousand times hotter and a billion times denser than today.

"The SZ is usually used to study clusters of hundreds of galaxies but the galaxies we're looking for are much smaller and have just a companion or two," Gralla said.

"What we're doing is asking a different question than what has been previously asked," Gralla said.

"We're using a technique that's been around for some time and that researchers have been very successful with, and we're using it to answer a totally different question in a totally different subfield of astronomy," Gralla added.

In space, hot gas drawn into a galaxy can cool and condense, forming stars. Some gas also funnels down into the galaxy's black hole, which grows together with the stellar population.

This cycle can repeat continuously; more gas is pulled in to cool and condense, more stars begin to shine and the central black hole grows more massive.

But in nearly all mature galaxies - the big galaxies called "elliptical" because of their shape - that gas doesn't cool any more.

"If gas is kept hot, it can't collapse," Marriage said.

When that happens there are no new stars.

Researchers found that the elliptical galaxies with radio-frequency feedback – relativistic radio-frequency-emitting particles shooting from the massive central black holes at their centre at close to the speed of light - all contain hot gas and a dearth of infant stars.

That provides crucial evidence for their hypothesis that this radio-frequency feedback is the "off switch" for star-making in mature galaxies.

The study was published in the journal Monthly Notices of the Royal Astronomical Society. PTI

Human skin cells reprogrammed directly into brain cells

 

SKINCELLS

Washington, Oct 24 (PTI) Scientists have developed a new method to convert human skin cells directly into a specific type of brain cell affected by Huntington's disease, an ultimately fatal neurodegenerative disorder.

Unlike other techniques that turn one cell type into another, the new process does not pass through a stem cell phase, avoiding the production of multiple cell types, said researchers.

The researchers, at Washington University School of Medicine in St Louis, demonstrated that these converted cells survived at least six months after injection into the brains of mice and behaved similarly to native cells in the brain.

"Not only did these transplanted cells survive in the mouse brain, they showed functional properties similar to those of native cells," said senior author Andrew S Yoo, assistant professor of developmental biology.

"These cells are known to extend projections into certain brain regions. And we found the human transplanted cells also connected to these distant targets in the mouse brain.

That's a landmark point about this paper," Yoo said.

The researchers produced a specific type of brain cell called medium spiny neurons, which are important for controlling movement. They are the primary cells affected in Huntington's disease.

The research involved adult human skin cells, rather than more commonly studied mouse cells or even human cells at an earlier stage of development.

To reprogramme these cells, Yoo and his colleagues put the skin cells in an environment that closely mimics the environment of brain cells.

They knew from past work that exposure to two small molecules of RNA, a close chemical cousin of DNA, could turn skin cells into a mix of different types of neurons.

In past research, Yoo and his colleagues showed that exposure to two microRNAs called miR-9 and miR-124 altered the machinery that governs packaging of DNA.

These microRNAs appear to be opening up the tightly packaged sections of DNA important for brain cells, allowing expression of genes governing development and function of neurons.

Knowing exposure to these microRNAs alone could change skin cells into a mix of neurons, the researchers then started to fine tune the chemical signals, exposing the cells to additional molecules called transcription factors that they knew were present in the part of the brain where medium spiny neurons are common.

"We think that the microRNAs are really doing the heavy lifting," said co-first author Matheus B Victor, a graduate student in neuroscience.

"They are priming the skin cells to become neurons. The transcription factors we add then guide the skin cells to become a specific subtype, in this case medium spiny neurons," Victor said.

The study appears in the journal Neuron. PTI

'Dead' hearts transplanted into living patients in world first

 

HEART

Sydney, Oct 24 (PTI) In a breakthrough, a team of doctors, including an Indian-origin surgeon, today said they have successfully performed the world's first heart transplant in Australia using a "dead heart", a major development that could save many lives.

The procedure, using hearts that had stopped beating, has been described as a "paradigm shift" that will herald a major increase in the pool of hearts available for transplantation.

It is predicted the breakthrough will save the lives of 30 per cent more heart transplant patients.

Until now, transplant units have relied solely on still-beating donor hearts from brain-dead patients.

But the team at the lung transplant unit of St Vincent's Hospital here announced they had transplanted three heart failure patients using donor hearts that had stopped beating for 20 minutes.

The first patient who received a heart Michelle Gribilas said she felt a decade younger and was now a "different person".

Cardiothoracic surgeon Kumud Dhital, who performed the transplants with hearts donated after circulatory death (DCD), said he "kicked the air" when the first surgery was successful.

It was possible thanks to new technology, he said. "The incredible development of the preservation solution with this technology of being able to preserve the heart, resuscitate it and to assess the function of the heart has made this possible, he said.

Hearts are the only organ that is not used after the heart has stopped beating - known as donation after circulatory death.

Beating hearts are normally taken from brain-dead people, kept on ice for around four hours and then transplanted to patients.

The novel technique used in Sydney involved taking a heart that had stopped beating and reviving it in a machine known as a "heart-in-a-box".

The heart is kept warm, the heartbeat is restored and a nourishing fluid helps reduce damage to the heart muscle.

Gribilas, 57, who was suffering from congenital heart failure. She had the surgery more than two months ago.

"Now I'm a different person altogether," she said. "I feel like I'm 40 years old - I'm very lucky."

There have since been a further two successful operations.

Prof Peter MacDonald, head of St Vincent's heart transplant unit, said: "This breakthrough represents a major inroad to reducing the shortage of donor organs."

It is thought the heart-in-a-box, which is being tested at sites around the world, could save up to 30 per cent more lives by increasing the number of  available organs.

The breakthrough has been welcomed around the world.

The British Heart Foundation described it as a "significant development". PTI

The SUN has CHANGED in a way we've NEVER SEEN: Mars trips may be OFF

 

Only nuke power can save us from radiation

By Lewis Page, 22 Oct 2014

A drop in the solar wind of a kind never yet seen in the space age has made travel beyond Earth orbit a lot more dangerous, according to boffins, so much so that a manned mission to Mars may not be feasible for many decades.

"The behavior of the sun has recently changed and is now in a state not observed for almost 100 years," says professor Nathan Schwadron. "Starting in about 2006, we observed the longest solar minimum and weakest solar activity observed in the space age."

There may not be much of this going on this century

It's a story we've already reported on here at the Reg: some solar physicists, noting that the current "solar maximum" is an especially damp squib, suspect that the Sun may be entering a so-called "Maunder Minimum", a lengthy spell of low to no activity. Such a minimum occurred from 1645-1715.

The down side of this from a deep-space astronaut's point of view is that the solar wind normally has the effect of reducing the amount of dangerous cosmic radiation that can reach the inner solar system. While particles and radiation from the Sun are dangerous to astronauts, cosmic rays are even worse, so the effect of a solar calm is to make space even more radioactive than it already is.

Deep-space astronauts, of course, are even rarer than normal astronauts. A normal astronaut travels only to low Earth orbit - as on a mission to the International Space Station, for instance - where he or she remains well protected by the Earth magnetic fields. The only astronauts who have ever been further from Earth than this were the Apollo moon explorers of the 1960s and 70s, and they went only on brief missions, carefully timed to reduce radiation risks.

Schwadron and his colleagues have been assessing data from an instrument called the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard NASA's Lunar Reconnaissance Orbiter currently circling the moon. The LRO was originally intended to scout ahead of a new US manned moon programme, and as such one of its purposes was to assess the effects of radiation on astronauts.

Lacking a President Kennedy to get them funded, the planned manned moon missions were cancelled - and judging by what Schwadron and his crew have found in the CRaTER data that might be just as well. They write:

Galactic cosmic radiation presents a more significant challenge: the time to 3 per cent Risk of Exposure Induced Death (REID) in interplanetary space was less than 400 days for a 30 year old male and less than 300 days for a 30 year old female in the last cycle 23–24 minimum. The time to 3 per cent REID is estimated to be ~20 per cent lower in the coming cycle 24–25 minimum. If the heliospheric magnetic field continues to weaken over time, as is likely, then allowable mission durations will decrease correspondingly.

For the sake of planning, a 3 per cent risk of an astronaut dying due to radiation exposure during a mission is seen as the acceptable limit: it's a dangerous job, after all (one should note that the death would probably be after the mission from cancer, perhaps many years later, rather than from severe radiation sickness while still in space). From Schwadron and his crew's analysis, if a lengthy solar quiet spell is indeed on the cards, the maximum time an astronaut can reasonably spend in space will be well under a year.

That's potentially bad news for a Mars trip, as under current planning assumptions both outward and return flights would take six months - and further exposure would be suffered during time spent on Mars, though less than the same period spent in space.

"While these conditions are not necessarily a showstopper for long-duration missions to the moon, an asteroid, or even Mars, galactic cosmic ray radiation in particular remains a significant and worsening factor that limits mission durations," says Schwadron, gloomily.

The scholarly paper setting out the team's research can be found here, published by the journal Space Weather.

http://www.theregister.co.uk/2014/10/22/the_sun_has_changed_in_a_way_weve_never_seen_mars_trips_may_be_off/

Mars' Moons: Facts About Phobos & Deimos

by Nola Taylor Redd, SPACE.com Contributor   |   March 27, 2013 07:00pm ET

Editor's Note: NASA's Curiosity rover has recently taken some great photos and videos of Phobos and Deimos, including footage of Phobos eclipsing the sun on Aug. 17. To see these images, check out the following stories:

• Curiosity Rover Snaps Best Mars Solar Eclipse Photos Ever
• Wow! Curiosity Rover Captures 2 Mars Moons Together In Stunning NASA Video
• Curiosity Sees Martian Moons: Phobos and Deimos (Time-Lapse Video)

Of the four rocky, terrestrial planets, only Mars has more than one moon. The two small bodies that orbit the red planet are both smaller than Earth's moon, and raise a number of questions about the formation of the early solar system.

Identity crisis

Phobos and Deimos bear more resemblance to asteroids than to Earth's moon. Both are tiny — the larger, Phobos, is only 14 miles across (22 kilometers), while the smaller, Deimos, is only 8 miles (13 km), making them some of the smallest moons in the solar system.

Both are also made up of material that resembles Type I or II carbonaceous chondrites, the substance that makes up asteroids. With their elongated shapes, they even look more like asteroids than moons.

Even from Mars, the moons don't look like moons. The more distant moon, Deimos, appears more like a star in the night sky. When it is full and shining at its brightest, it resembles Venus as seen on Earth. Phobos has the closest orbit to its primary of any moon in the solar system, but still only appears a third as wide as Earth's full moon.

Phobos orbits only 3,700 miles (6,000 km) from the Martian ground. Its surface is marred by debris that may have come from impacts on Mars. It travels around the planet three times a day, zipping across the Martian sky approximately once every four hours. At times, an observer on the surface would be unable to see the moon because of the curvature of the planet. The fast-flying moon appears to travel from west to east.

Deimos orbits much farther away, tending to stay 12,470 miles (20,069 km) from the red planet's surface. The moon takes about 30 hours, a little over a Martian day, to travel around its host.

Lunar origins

Because of their odd shapes and strange composition, scientists thought for a long time that both moons were born asteroids. Jupiter's gravity could have nudged them into orbit around Mars, allowing the red planet to capture them.

But the orbits of the moons make such a birth appear unlikely. Both moons take stable, nearly circular paths around the red planet. Captured bodies tend to move more erratically. An atmosphere could have slowed the pair down and settled them into their present-day orbits, but the air on the Martian planet is thin and insufficient for such a task.

It is possible that the moons formed like the planet, from debris left over from the creation of Mars. Gravity could have drawn the remaining rocks into the two oddly shaped bodies.

But it is more likely that the moons spawned from a violent birth, much like Earth's moon. A collision, common in the early solar system, could have blown chunks of the red planet into space, and gravity may have pulled them together into the moons. Similarly, an early moon of Mars could have been impacted by a large object, leaving Phobos and Deimos as the only remaining bits.

Discovery and death

For years, scientists thought that Mars had no moon. Johannes Kepler suggested the possibility of two moons around the red planet, but only from a numerical standpoint; Earth had one moon and Jupiter, at the time, was known to have four, so the middle planet would likely have two.

It wasn't until American astronomer Asaph Hall made a thorough study of the planet in 1877 that the tiny, closely orbiting bodies were found. Hall discovered Deimos on Aug. 12 and Phobos on Aug. 18. The two tiny bodies had been hidden in the glare from the planet.

Hall named the two satellites for the sons of the Greek god of war, Ares (Mars to the Romans). The twin boys, Phobos (Fear) and Deimos (Dread or Panic), attended their father in battle.

But the sons won't be in attendance around Mars forever. Phobos is slowly spiraling inward at a rate of 6 feet (1.8 meters) every century. Within 50 million years, the moon will either collide with Mars or become a ring of rubble around it. Deimos, on the other hand, is slowly drifting away from the planet.

— Nola Taylor Redd, SPACE.com contributor

http://www.space.com/20413-phobos-deimos-mars-moons.html

Oppositions of Mars

 

     Since the Earth has a shorter orbital period than Mars, we pass in between Mars and the Sun on a fairly regular basis (on the average, every 780 days, or 2 years and 50 days). When we do so, we see Mars in the opposite direction from the Sun, at opposition (see Planetary Aspects for more about general positions of the planets relative to each other). We are also, at that time, about as close as we can be during that particular two-year interval, or synodic period of revolution.
     If Mars' orbit were nearly circular, as ours is, each time we lap Mars we and it would be about the same distance from the Sun as usual, and our distance from Mars would be about the same -- a little less than 49 million miles, or the difference between our orbital sizes. But Mars' orbit is not as circular as ours, having an eccentricity of 0.093, which means that its distance from the Sun varies by a little over 9%, or a little over 13 million miles. As a result, depending upon where Mars is in its orbit when we lap it, we can pass as little as 35 million miles from it (if it is near perihelion), or as much as 63 million miles from it (if it is near aphelion).
     As shown in the diagram below, the approximately 2 years and 2 months synodic period of Mars means that wherever we lap Mars in one synodic period, we will lap it a little further along in its (and our) orbit, the next time. So if it is near perihelion at one opposition, and relatively close to us, as it was in 2003, at subsequent oppositions it will be further and further from perihelion, and further and further from us, until it is near aphelion at opposition, and as far from us as possible for an opposition, as it will be in 2010 and 2012; then it will be closer and closer to perihelion, and to us, at each succeeding opposition, until the next perihelion opposition, which occurs every seven or eight synodic periods, or 15 to 17 years after the previous perihelion opposition.

     Diagram showing the relative position of the Earth and Mars at various oppositions from 1995 to 2020 (with lines between the planets in black for oppositions from 1995 to 2007 and in red for later ones). The distance (in Mmi, or millions of miles) between the Earth and Mars at closest approach is also shown. In general, the closer Mars is to perihelion at opposition, the closer it is to the Earth, and the closer it is to aphelion at opposition, the further it is from the Earth. But although opposition and closest approach are close together at perihelion (as in 2003) and aphelion (as in 2012), if Mars is moving away from the Sun (between perihelion and aphelion), closest approach is several days earlier than opposition. Similarly, if Mars is moving toward the Sun (between aphelion and perihelion), closest approach is several days later than opposition. As a result, the distance at closest approach can be somewhat different than might be expected, based only on Mars' position at opposition.
     Note that (1) the date of opposition corresponds to the Earth's position in its orbit (we are at the point marked by the direction to the Vernal Equinox on the first day of autumn, in late September), so the dates are steadily later in the year as you move eastward (counterclockwise) around the orbits; (2) each opposition is further along the orbits of the Earth and Mars, because it takes just over two years for the Earth to lap Mars; and (3) when Mars is near perihelion and moving faster, it takes longer for the Earth to "catch up" with it, and successive oppositions are further apart than usual, whereas when Mars is near aphelion and moving slower, it takes less time for the Earth to catch up with Mars, and successive oppositions aren't as far apart as usual.

     The diagram above, although a good representation of our relative position and distance from Mars at various oppositions, only shows one full series of oppositions (all the way around the orbit), and part of another set. The table below lists all oppositions from 1995 to 2037, covering just over two series of oppositions, and shows that we were relatively close to Mars in 2001 and 2005, exceptionally close in 2003, and will be relatively close to Mars in 2020 and 2033, and within a million miles or so of the 2003 distance in 2018 and 2035.
     Note the following characteristics of the table (and the confirmation it gives of the statements made in the discussion of the diagram, above):
(1) Two dates are shown -- the date of opposition, when the Earth passes between Mars and the Sun, and the date of closest approach, which is a few days earlier than opposition when Mars is moving away from the Sun (and the Earth), and a few days later than opposition when Mars is moving toward the Sun (and the Earth).
(2) If the date of opposition is very close to perihelion, so that the date of closest approach is almost the same as the opposition date, as it was in 2003, we pass closer to Mars than if the date is further from perihelion, as it will be in 2018 and 2035.
(3) When we are lapping Mars near its perihelion, it takes longer to lap it than usual (almost 2 years and 2 months), because it is moving faster in that part of its orbit; and when we are lapping Mars near its aphelion, it takes less time to lap it than usual (just over 2 years and 1 month), because it is moving slower in that part of its orbit.

The Closest Opposition in 59,619 Years

You have probably heard, at some time in the last few years, that Mars was closer to the Earth than at any time in the last 60,000 years. As it happens, this was essentially true during the 2003 opposition, which was the closest approach of the two planets since 57,617 BC, when Mars was about twenty-five thousand miles closer (about 34,621,500 miles from Earth, versus 34,646,418 miles in 2003). You may not have heard, however, that we will be even closer to Mars at various times in the next millenium, and closer yet during each of the next twenty millenia. Why is this?
     If the orbits of the Earth and Mars were absolutely fixed, we would sometimes be a little closer to Mars at the nearest opposition in any 15 to 17 year period, and sometimes further away, but the very closest approaches would be more or less the same distance, as shown in the table above. However, our orbit, and that of every other planet, including Mars, is subject to small changes, or perturbations, caused by the gravitational effect of the planets on each other. If only the Sun influenced our motion, our orbit would be nearly fixed in space; but every time that Mercury or Venus laps us, or we lap one of the outer planets, the gravitational attraction of each planet for the other very slightly changes the orbit of each planet.
     The effects of these individual perturbations is very small, because the planets are much smaller than the Sun, and exert much less force on each other, than the Sun does on any of them. In addition, perturbations which occur in one part of an orbit change the orbit in one way, while perturbations which occur in another part of the orbit change the orbit in the opposite way. This will be discussed in more detail later, on a page about how Neptune controls the orbit of Pluto, and the "Plutinos"; but to summarize, if Mars is moving away from the Sun when we lap it, we slow it down a little, which tends to make its orbit smaller, and its orbital period shorter; while if Mars is moving toward the Sun when we lap it, we speed it up a little, which tends to make its orbit bigger, and its orbital period longer. And since, as shown in the diagram above, we lap it at different places at different times, the perturbations mostly cancel each other out over long periods of time.
     This does not mean, however, that they exactly cancel out, and every planet's orbit tends, as a result, to "wobble" slightly relative to its average orbit; or more accurately, the numbers which describe the orbits tend to slowly swing back and forth, relative to their average values.
     As shown in the diagram below, this effect applies (among other things) to the eccentricity of Mars' orbit. Over very long periods of time, the eccentricity averages about 5 or 6%, but there are times, such as now, when the eccentricity is larger; times, such as 200,000 years from now, when the eccentricity is almost twice the average value, or nearly 12%; and times, such as a million years ago and in the future, when the eccentricity is close to 0.

Changes in the eccentricity of Mars over a two-million-year period.

     Over long periods of time, the eccentricity of Mars' orbit varies, as a result of perturbations by other planets (primarily Jupiter), from as little as 0% to as much as 12%. (Jean Meeus, Griffith Observatory)

     At those times when its orbital eccentricity is small, Mars' distance from the Sun hardly changes, and as a result, its opposition distance from us is relatively constant, as well; but at those times when its eccentricity is large, Mars is substantially closer to the Sun at perihelion, and substantially further away at aphelion, and hence unusually close to us at perihelion oppositions, and unusually far from us at aphelion oppositions.
     As it happens, Mars had a substantially higher orbital eccentricity about 90,000 years ago, and for most of the next 60,000 years its eccentricity was gradually decreasing; while for the last 30,000 years, and the next 20,000 years, its eccentricity has been and will be gradually increasing. This means that over long periods of time, the distance between the Earth and Mars at perihelion oppositions is gradually getting smaller and smaller, and 20,000 years from now, that distance will be a few million miles smaller than it can ever be, now. It also means that for the last 30,000 years, while the eccentricity of Mars' orbit gradually increased, the perihelion opposition distance has been gradually getting smaller, as well. This doesn't mean that every perihelion opposition is going to be smaller; as shown in the table above, the next few perihelion oppositions will be a little further than the most recent one, simply because they aren't quite as close to the actual date of perihelion. Still, the closest oppositions are gradually getting very slightly closer. In recent years, there were close approaches on Aug. 18, 1845 and Aug. 23, 1924, which were only thirty thousand miles further than the 2003 opposition; and in coming years, there will be still closer oppositions, starting with the approach of August 28, 2287; but since that's a ways away, the 2003 opposition is at least slightly remarkable, no matter how you look at it.

http://cseligman.com/text/planets/marsoppositions.htm

The Opposition of Mars

 

March 28, 2014:  By the time you finish reading this story, you'll be about 1,000 km closer to the planet Mars.

Earth and Mars are converging for a close encounter. As March gives way to April, the distance between the two planets is shrinking by about 300 km every minute.  When the convergence ends in mid-April, the gulf between Earth and Mars will have narrowed to only 92 million km--a small number on the vast scale of the solar system. 

Astronomers call this event an "opposition of Mars" because Mars and the Sun are on opposite sides of the sky.  Mars rises in the east at sunset, and soars almost overhead at midnight, shining burnt-orange almost 10 times brighter than a 1^st magnitude star.

A new ScienceCast video previews the April 2014 close approach of Mars.  Play it!

Oppositions of Mars happen every 26 months. Of a similar encounter in the 19^th century, astronomer Percival Lowell wrote that "[Mars] blazes forth against the dark background of space with a splendor that outshines Sirius and rivals the giant Jupiter himself."

In other words, it's really easy to see.

There are two dates of special significance:

April 8^th is the date of opposition, when Mars, Earth, and the sun are arranged in a nearly-straight line. 

If the orbits of Mars and Earth were perfectly circular, April 8^th would also be the date of closest approach.  However, planetary orbits are elliptical--that is, slightly egg-shaped--so the actual date of closest approach doesn't come until almost a week later.

Mars, photographed on March 6, 2014, by Australian amateur astronomer Anthony Wesley using a 16-inch telescope. More

On April 14^th, Earth and Mars are at their minimum distance: 92 million km, a 6+ month flight for NASA's speediest rockets. You won't have any trouble finding Mars on this night. The full Moon will be gliding by the Red Planet in the constellation Virgo, providing a can't-miss "landmark" in the midnight sky.  

Remarkably, on the same night that Mars is closest to Earth, there will be a total lunar eclipse.  The full Moon of April 14-15 will turn as red as the Red Planet itself.  A video from Science@NASA has the details.

Although these dates are special, any clear night in April is a good time to look at Mars.  It will be easy to see with the unaided eye even from brightly-lit cities.  With a modest backyard telescope, you can view the rusty disk of Mars as well as the planet's evaporating north polar cap, which has been tipped toward the sun since Martian summer began in February. Experienced astro-photographers using state-of-the-art digital cameras can tease out even more—for example, dust storms, orographic clouds over Martian volcanoes, and icy fogs in the great Hellas impact basin. The view has been described by some observers as "Hubblesque."

Update:  You're now 1000 km closer to Mars.

Credits:

Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA

More information:

The distances and velocities cited in this story were calculated by JPL's online HORIZONS ephemeris.  All velocities are correct for March 31, 2014.

Oppositions of Mars happen every 26 months. The racetrack model of planetary orbits explains why.  Earth and Mars are like runners on a track. Earth is on the inside, Mars is on the outside.  Every 26 months, speedy Earth catches up to slower Mars and laps it.  Opposition occurs just as Earth takes the lead.

Because planetary orbits are elliptical, not all oppositions are the same.  In 2003, Mars made its closest approach to Earth in 50,000 years, an apparition that mesmerized sky watchers all over the world.  The 2014 opposition of Mars is a much more "run-of-the-mill" opposition--not historic, but beautiful nonetheless.

http://science.nasa.gov/science-news/science-at-nasa/2014/28mar_opposition/

A new method to study the evolution of the universe

 

By IANS | 11 Oct, 2014, 04.06PM IST

While an effective tool for helping make stars, this cover presents a challenge for astrophysicists hoping to learn how the radiation that stars produce could be used in the ionisation process.

NEW YORK: In an effort to better understand how the universe evolved, a study co-authored by an Indian-origin scientist used a method to measure radiation leaks in large, star-forming galaxies in the universe.

The researchers used the radiation leak measurement method to help find the ideal star-forming galaxy that contained holes in its cold gas cover.

"The star forming regions in galaxies are covered with cold gases so the radiation cannot come out. If we can find out how the radiation gets out of the galaxy, we can learn what mechanisms ionised the universe," said Sanchayeeta Borthakur from the John Hopkins University in the US.

The researchers noted that an indicator used for studying star-forming galaxies that leak radiation, is also an effective measurement tool for other scientists to use.
Studying the radiation that seeps through the holes in its cold gas cover has been an ongoing conundrum for scientists for years.

Consisting of thick, dense cold gas, the cover stretches across a galaxy like a blanket.
While an effective tool for helping make stars, this cover presents a challenge for astrophysicists hoping to learn how the radiation that stars produce could be used in the ionisation process.

Scientists have been on a quest to find just the right galaxy with this character trait for decades.

Borthakur said scientists know that these leaky galaxies exist, but finding one has been a problem.

Using observations made with the Cosmic Origin Spectrograph on board the Hubble Space Telescope, the research team found the right galaxy to study.

In the study, the researchers credit a combination of unusually strong winds, intense radiation and a massive, highly star-forming galaxy for proving the validity of the indicator.

"This method first created by study co-author Timothy Heckman in 2001 can sort out what gas is present and also accurately measure the percentage of holes in the gas cover," Borthakur noted.

The study appeared in the journal Science.

http://economictimes.indiatimes.com/magazines/panache/a-new-method-to-study-the-evolution-of-the-universe/articleshow/44783189.cms

LED There Be Light: 3 Share Nobel for Blue Diode

 

STOCKHOLM — Oct 7, 2014, 1:32 PM ET

By KARL RITTER and MALIN RISING Associated Press

In this combination of photos shows three winners of Nobel Prize in physics, from left, Meijo University Prof. Isamu Akasaki, 85, Nagoya University Prof. Hiroshi Amano, 54, and Shuji Nakamura, 60, of the University of California at Santa Barbara, U.S.A. The three Japanese scientists won Nobel Prize in physics Tuesday, Oct. 7, 2014 for the invention of blue light-emitting diodes — a new energy efficient and environment-friendly light source. (AP Photo/Kyodo News) JAPAN OUT, CREDIT MANDATORY  AP

Two Japanese scientists and a Japanese-born American won the Nobel Prize in physics on Tuesday for inventing blue light-emitting diodes, a breakthrough that has spurred the development of LED technology to light up homes, computer screens and smartphones worldwide.

Isamu Akasaki, Hiroshi Amano and naturalized U.S. citizen Shuji Nakamura revolutionized lighting technology two decades ago when they came up with a long-elusive component of the white LED lights that in countless applications today have replaced less efficient incandescent and fluorescent lights.

"They succeeded where everyone else had failed," the Nobel committee said. "Incandescent light bulbs lit the 20th century; the 21st century will be lit by LED lamps."

Red and green light-emitting diodes have been around since the mid-20th century and have been used in applications such as watches and calculators. But scientists had struggled for decades to produce the shorter-wavelength blue LED needed in combination with the others to produce white light when the three laureates made their breakthroughs in the early 1990s.

Their work enabled LED lights — more efficient and long-lasting than previous light sources — to be used in a range of applications, including street lights, televisions and computers.

"It is very satisfying to see that my dream of LED lighting has become a reality," Nakamura, 60, said in a statement released by the University of California, Santa Barbara, where he is a professor. "I hope that energy-efficient LED light bulbs will help reduce energy use and lower the cost of lighting worldwide."

Later, before his news conference, Nakamura was asked if he realized the importance of his research at the time.

"Nobody can make a cellphone without (blue) LED, my invention," he responded.

Akasaki, an 85-year-old professor at Meijo University and Nagoya University, said in a nationally-televised news conference in Japan that he had often been told that his research wouldn't bear fruit.

"But I never felt that way," he said. "I was just doing what I wanted to do."

Akasaki and Amano, 54, made their inventions while working at Nagoya University while Nakamura was working separately at Japanese company Nichia Chemicals. They built their own equipment and carried out thousands of experiments — many of which failed — before they made their breakthroughs.

Amano was on a plane and couldn't be reached by the Nobel judges Tuesday, said Jessica Balksjo Nannini, a spokeswoman for the Royal Academy of Sciences, which awards the physics prize.

The Nobel committee said LEDs contribute to saving the Earth's resources because about one-fourth of world electricity consumption is used for lighting purposes. They tend to last 10 times longer than fluorescent lamps and 100 times longer than incandescent light bulbs.

"The blue LED is a fundamental invention that is rapidly changing the way we bring light to every corner of the home, the street and the workplace — a practical invention that comes from a fundamental understanding of physics in the solid state," said H. Frederick Dylla, the executive director and CEO of the American Institute of Physics.

Phillip Schewe, a physicist at the Joint Quantum Institute at the University of Maryland, said the prize shows that physics research can provide a practical benefit, rather than just probing the mysteries of the universe.

LED technology holds particular promise in lighting up parts of the developing world with poor electricity grids, Nobel committee member Olga Botner said. Ultraviolet LEDs can also be used to sterilize water, she said.

"It is not just for lighting Christmas lights on the streets of Stockholm in December but really something that benefits mankind, particularly the Third World," she said.

Nadarajah Narendran, director of research at the Lighting Research Center at the Rensselaer Polytechnic Institute in Troy, New York, estimated that about 10 percent of illumination in U.S. homes, offices, streets and industries comes from LED lights. Within five years, he said, that fraction will probably exceed 30 percent as prices come down.

On Monday, U.S.-British scientist John O'Keefe split the Nobel Prize in medicine with Norwegian couple May-Britt Moser and Edvard Moser for breakthroughs in brain cell research that could pave the way for a better understanding of diseases like Alzheimer's.

The Nobel award in chemistry will be announced Wednesday, followed by the literature award on Thursday, the Nobel Peace Prize on Friday and the economics prize on Monday.

Worth 8 million kronor ($1.1 million) each, the Nobel Prizes are always handed out on Dec. 10, the anniversary of prize founder Alfred Nobel's death in 1896. Besides the prize money, each laureate receives a diploma and a gold medal.

Nobel, a wealthy Swedish industrialist who invented dynamite, provided few directions for how to select winners, except that the prize committees should reward those who "have conferred the greatest benefit to mankind."

Last year's physics award went to British scientist Peter Higgs and Belgian colleague Francois Englert for helping to explain how matter formed after the Big Bang.

———

Associated Press reporter Yuri Kageyama in Tokyo, and Malcolm Ritter in New York, contributed to this report.