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Dark matter ‘ghosts’ through galactic smash-ups

Dark matter ‘ghosts’ through galactic smash-ups
By Jonathan Webb
Science reporter, BBC News

Space

By observing multiple collisions between huge clusters of galaxies, scientists have witnessed dark matter coasting straight through the turmoil.

Dark matter is the mysterious, invisible stuff that makes up 85% of the matter in the cosmos – and these results rule out several theoretical models put forward to explain it.

This is because it barely interacts with anything at all, including the dark matter in the oncoming galaxies.
The work appears in Science magazine.

To conduct their study, astrophysicists looked at 72 smash-ups between galactic clusters, using two space telescopes: visible light was recorded by the Hubble Space Telescope, and X-rays by the Chandra Observatory.

Scouring multiple views of the collisions, the researchers tracked the movement of the three main components of galaxies: stars, clouds of gas, and dark matter.

The violently swirling clouds of gas are hot enough to glow with X-rays, which Chandra detects. And stars can be seen in regular, visible-light images from Hubble.

Dark matter is more difficult to “see” – but not impossible. Although it does not emit or absorb light, it does have gravity, and so it bends the path of light passing nearby. This warps our view of anything on the other side of it, in an effect called “gravitational lensing”.

“Looking through dark matter is like looking through a bathroom window,” said Dr Richard Massey from Durham University, one of the study’s authors. “All the objects that you can see in the distance appear slightly distorted and warped.”

Images were used from the Hubble Space Telescope (illustrated here) and the Chandra X-Ray Observatory

Using this distortion allowed Dr Massey, with colleagues from the University of Edinburgh, University College London and Switzerland’s Ecole Polytechnique Federale de Lausanne (EPFL), to “map” the dark matter in the clusters as they collided.

‘Smash it and see’

Galaxy clusters are vast and contain huge amounts of dark matter, so when they collide – over billions of years – it offers a unique glimpse of how the stuff behaves.

“We like these collisions because it’s exactly what we’d do in the lab,” Dr Massey told BBC News.
“If you want to figure out what something is made out of, you knock it, or you throw it across the room and see where the bits go.”

In this case, the bits went straight through each other.

Unlike the gas clouds, which grind to a turbulent halt, and the stars, which mostly glide past each other, the ubiquitous dark matter passes through everything and emerges unscathed, like a ghost.
“It seems not to interact with anything at all,” Dr Massey said.

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Here be ‘space dragons’

Dr Tom Kitching, UCL Mullard Space Science Laboratory

Our new measurements of the self-interaction of dark matter are some of the best yet. But statistically speaking, the strongest result from this study is in fact the confirmation that dark matter really does exist in these galaxy clusters.

We measured three things: the position of stars, the position of mass, and the position of gas. If there was no dark matter, then all of the mass that isn’t accounted for by the stars would be associated with the gas.
But we found an offset, which confirms that there is something in the clusters that is not gas, has mass, but that we cannot see: a dark matter. This detection is statistically very significant – corresponding to a probability of better than 99.99999999999% that dark matter exists in these clusters.

Sometimes I think dark matter is a terrible name. It was originally coined because the phenomenon does not emit or absorb light. But light is everywhere in the dark matter we have observed, passing within it and around it. Indeed, the lensing effect that we employed in our study uses the light from distant galaxies that has passed through dark matter.

So perhaps “transparent matter” or “clear matter” are better names. My favourite alternative is “materia incognita” (the unknown material). Maps used to be labelled “terra incognita” in areas that were unknown, and in a similar way we could be explicit about the unknown nature of this phenomenon.
However, thanks to studies like this one – and much more work planned for the coming years – our ignorance will one day end. Then we can finally give this “something” a proper name.

____________________________________________________________________________

Earlier observations of the “Bullet Cluster” – a bust-up between two particularly big groups of galaxies, now in its final stages – had already demonstrated dark matter’s weird lack of interactions, including with itself.
But this new, major survey was able to deliver much more precision, concluding that there was even less interaction than the previous work allowed for.

“If you bang your head against the wall, the electrostatic force between the molecules in your head and the ones in the wall cause a collision. This is what dark matter doesn’t seem to feel,” Dr Massey explained.
Dark matter does “feel” gravity; those interactions are the reason we know it is there, and the reason it is bound up in the galactic collisions to begin with. But the lack of almost any other interaction makes it even more mysterious than before.

The late-stage collision of the Bullet Cluster yielded previous observations of dark matter

“In all of these collisions that we’ve seen, it just seems to go straight through. And now we’ve seen loads more of them, we would have been able to detect any deceleration of this dark matter, if it had interacted in the ways that most theories predict,” Dr Massey said.

So although some theories remain, many can now be ruled out. This includes the idea that dark matter is some sort of “dark” version of ordinary matter, made of “dark atoms”. It must be more outlandish than that, Dr Massey said.
“Basically, we’re saying: Back to the drawing board! Let’s come up with some more ideas.”

Space has some really interesting stuff going on. Here’s a clip featuring some of the sounds of outer space.


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The Secret of Fibonacci Numbers

 

 

The Secret of Fibonacci Numbers

Have you ever heard of the Fibonacci number sequence? They are really spooky, or rather one of those natural mysteries.

OK, the Fibonacci sequences looks like this:  0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, …

Can you figure out how they come about?

It’s quite simple really. You take the number 1 and add it to itself which gives you 2. You then add the 2 to the 1 which =3. then 3+2 = 5. 5+3= 8 and so on like this. 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, …

A bit freaky.

But it gets freakier.

The Fibonacci numbers are Nature’s numbering system. They appear everywhere in Nature, from the leaf

Fibonacci in nature

arrangement in plants, to the pattern of the florets of a flower, the bracts of a pinecone, or the scales of a pineapple. The Fibonacci numbers are therefore applicable to the growth of every living thing, including a single cell, a grain of wheat, a hive of bees, and even all of mankind.

Plants do not know about this sequence – they just grow in the most efficient ways. Many plants show the Fibonacci numbers in the arrangement of the leaves around the stem. Some pine cones and fir cones also show the numbers, as do daisies and sunflowers. Sunflowers can contain the number 89, or even 144. Many other plants, such as succulents, also show the numbers. Some coniferous trees show these numbers in the bumps on their trunks. And palm trees show the numbers in the rings on their trunks.

Fibonacci in plants

Why do these arrangements occur? In the case of leaf arrangement, or phyllotaxis, some of the cases may be related to maximizing the space for each leaf, or the average amount of light falling on each one. Even a tiny advantage would come to dominate, over many generations. In the case of close-packed leaves in cabbages and succulents the correct arrangement may be crucial for availability of space.

In the seeming randomness of the natural world, we can find many instances of mathematical order involving the Fibonacci numbers themselves and the closely related “Golden” elements.

Fibonacci in Plants

Phyllotaxis is the study of the ordered position of leaves on a stem. The leaves on this plant are staggered in a spiral pattern to permit optimum exposure to sunlight. If we apply the Golden Ratio to a circle we can see how it is that this plant exhibits Fibonacci qualities. Click on the picture to see a more detailed illustration of leaf arrangements.

By dividing a circle into Golden proportions, where the ratio of the arc length are equal to the Golden Ratio, we find the angle of the arcs to be 137.5 degrees. In fact, this is the angle at which adjacent leaves are positioned around the stem. This phenomenon is observed in many types of plants.

Fibonacci in trees

The number of petals in a flower consistently follows the Fibonacci sequence. Famous examples include the lily, which has three petals, buttercups, which have five (pictured at left), the chicory’s 21, the daisy’s 34, and so on. Phi appears in petals on account of the ideal packing arrangement as selected by Darwinian processes; each petal is placed at 0.618034 per turn (out of a 360° circle) allowing for the best possible exposure to sunlight and other factors.

The head of a flower is also subject to Fibonaccian processes. Typically, seeds are produced at the center, and then migrate towards the outside to fill all the space. Sunflowers provide a great example of the

Sun flower seeds

Here are just a few plants that have their leaves and settles arranged according to Fibonacci numbers

Fibonacci Petals

3 petals lily, iris
5 petals buttercup, wild rose, larkspur, columbine
8 petals delphiniums
13 petals ragwort, corn marigold, cineraria
21 petals aster, black-eyed susan, chicory
34 petals plantain, pytethrum
55, 89 petals michelmas daisies, the asteraceae family

Fibonacci in the planets and outer space?

Fibonacci in space

Not surprisingly, spiral galaxies also follow the familiar Fibonacci pattern. The Milky Way has several spiral arms, each of them a logarithmic spiral of about 12 degrees. As an interesting aside, spiral galaxies appear to defy Newtonian physics. As early as 1925, astronomers realized that, since the angular speed of rotation of the galactic disk varies with distance from the center, the radial arms should become curved as galaxies rotate. Subsequently, after a few rotations, spiral arms should start to wind around a galaxy. But they don’t — hence the so-called winding problem. The stars on the outside, it would seem, move at a velocity higher than expected — a unique trait of the cosmos that helps preserve its shape.

 

US …..

Faces, both human and nonhuman, abound with examples of the Golden Ratio. The mouth and nose are each positioned at golden sections of the distance between the eyes and the bottom of the chin. Similar proportions can been seen from the side, and even the eye and ear itself (which follows along a spiral).

It’s worth noting that every person’s body is different, but that averages across populations tend towards phi. It has also been said that the more closely our proportions adhere to phi, the more “attractive” those traits are perceived. As an example, the most “beautiful” smiles are those in which central incisors are 1.618 wider than the lateral incisors, which are 1.618 wider than canines, and so on. It’s quite possible that, from an evo-psych perspective, that we are primed to like physical forms that adhere to the golden ratio — a potential indicator of reproductive fitness and health.

Looking at the length of our fingers, each section — from the tip of the base to the wrist — is larger than the preceding one by roughly the ratio of phi.

Even our bodies exhibit proportions that are consistent with Fibonacci numbers. For example, the measurement from the navel to the floor and the top of the head to the navel is the golden ratio. Animals

Animals

Animal bodies exhibit similar tendencies, including dolphins (the eye, fins and tail all fall at Golden Sections), starfish, sand dollars, sea urchins, ants, and honey bees.

Honey Bee

Honey bees follow Fibonacci in other interesting ways. The most profound example is by dividing the number of females in a colony by the number of males (females always outnumber males). The answer is typically something very close to 1.618. In addition, the family tree of honey bees also follows the familiar pattern. Males have one parent (a female), whereas females have two (a female and male). Thus, when it comes to the family tree, males have 2, 3, 5, and 8 grandparents, great-grandparents, gr-gr-grandparents, and gr-gr-gr-grandparents respectively. Following the same pattern, females have 2, 3, 5, 8, 13, and so on. And as noted, bee physiology also follows along the Golden Curve rather nicely.

 

The Golden Rectangle

The Golden rectangle has been known since antiquity as one having a pleasing shape, and is frequently found in art and architecture as a rectangular shape that seems ‘right’ to the eye. It is mentioned in Euclid’s Elements and was known to artists and philosophers such as Leonardo da Vinci.

One of the interesting properties of the golden rectangle is that if you cut off a square section whose side is equal to the shortest side, the piece that remains is also a golden rectangle.

In the figure below, the yellow rectangle is in the same proportion as the original larger rectangle after the gray square is cut off.Both the rectangles ABCD and PBCQ are golden rectangles.

Golden Rectangle

 

 

 



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Bright spotlight on Dawn mission to Ceres

Bright spotlight on Dawn mission to Ceres
By Jonathan Amos
BBC Science Correspondent

The bright spots inside a 92km-wide crater have been the big surprise of the encounter so far

Scientists say they are hugely excited to learn the origin of two bright spots on the surface of Ceres.

The US space agency’s Dawn probe is bearing down on the dwarf planet and on Friday will be captured by its gravity.

That will allow the satellite to spiral down in altitude in the coming months, to take ever sharper images of the spots, which sit inside a wide crater.

The striking features could be where an impact has dug out surface deposits and exposed the dwarf’s interior layers.

But deputy project scientist Dr Carol Raymond cautioned that the resolution of Dawn’s imagery was not good enough at the moment to make any definitive statements.

“These spots were extremely surprising and they have been puzzling to everyone who has seen them,” the Nasa Jet Propulsion Laboratory researcher told reporters.

“They show up in a 92km-wide crater that’s about 19 degrees North latitude. The spot in the centre is about twice as bright as the spot on the side of the crater, and as yet it has not been resolved, meaning it is smaller than the 4km pixel size [of the images].

“But its apparent brightness is already off-scale; it’s consistent with high reflective materials.”

Intriguingly, the European Space Agency’s Herschel telescope reported last year seeing water vapour coming from two sectors on Ceres. One of these sectors includes the location of the spots. That could be very significant, Dr Raymond said.

“The association with the impact crater may indicate that impact heating resulted in exposure of underlying ice [and] its vaporisation; and perhaps we’re seeing a deposit left behind which is rich in material like salts.”

Dawn will spend 14 months studying the 950km-diameter dwarf planet, which is the largest object in the asteroid belt between Mars and Jupiter.

An artist’s impression of Dawn firing its ion engine on approach to Ceres

The satellite has turned up at Ceres having previously visited the asteroid Vesta. This 530km-wide rock had the look of a punctured football, the result of a colossal collision sometime in its past that ripped a big chunk out of its southern polar region.

Ceres, on the other hand, is big enough for gravity to have pulled it into a more spherical shape.

Scientists think both bodies are fledglings that never quite made it to the planetary big time.

In the case of Vesta, it underwent a lot of the same processes that transformed the early Earth, such as differentiating its insides to include an iron core.

In contrast, Ceres’s bid to reach the major planet league probably stalled quite quickly.

Researchers believe its interior is dominated by a rocky core topped by ice that is then insulated by rocky lag deposits at the surface.

The surface of Ceres is covered with craters of many shapes and sizes

A big question the mission hopes to answer is whether there is a liquid ocean of water at depth. Some models suggest there could well be.

The evidence may well be found in Ceres’ craters which have a very muted look about them. That is, the soft interior of the dwarf has undoubtedly had the effect of relaxing their original hard outline.

“One of the prime motivations of the Dawn mission is to examine these building blocks of the planets, Vesta and Ceres, which are two intact proto-planets from the very dawn of the Solar System. They’re literally fossils that we can investigate to really understand the processes that were going on at that time,” Dr Raymond said.

At capture, the satellite will be at a separation of about 40,000km. Controllers at Earth will work in the next few weeks to reshape the orbit to get it ready for science.

One issue is that Dawn approached the dwarf from its Sun-lit side. The probe has now gone over to the dark side, and it will not come back around again to take images until late April.

But then onwards, the pictures will just get better and better as the orbit is progressively lowered.

“We’ll get to our final orbit in December of this year at just [380km] from the surface, which for context is just a little bit lower than the International Space Station orbits around the Earth. From this vantage point, Dawn will acquire its highest detail and highest resolution images of the surface,” said Nasa project manager Robert Mase.

Discovered in 1801 by the Sicilian astronomer Father Giuseppe Piazzi, Ceres is named after the Roman goddess of agriculture and harvests.

Craters on Ceres will follow a similar theme and will be named after gods and goddesses of agriculture and vegetation from mythology. Other features on the dwarf will be named after agricultural festivals.

The soft outline of the big basin suggests that the surface has relaxed over time


Leonard Nimoy, Star Trek’s Mr Spock, dies at 83

 

 

Leonard Nimoy, Star Trek’s Mr Spock, dies at 83

Spock. Live Long and Prosper

US actor Leonard Nimoy, who played Mr Spock in the cult sci-fi series Star Trek, has died at the age of 83 in Los Angeles, his family has said.

His son, Adam, said he died of end-stage chronic obstructive pulmonary disease on Friday morning.

Nimoy had a long career as both an actor and director.

However he was best known for his portrayal of the half-human, half-Vulcan character in both the TV franchise and series of films.

Last year, the actor revealed he was suffering chronic lung disease COPD, despite stopping smoking 30 years ago.

It was reported earlier this week he had been taken to hospital on 19 February after suffering from chest pains.

He later tweeted: “A life is like a garden. Perfect moments can be had, but not preserved, except in memory.”

He signed off what was to be his final tweet with “LLAP” – a reference to his character’s famous catchphrase, “Live long and prosper”.

Spock’s Twitter

The same Twitter account was used by his granddaughter to confirm that he died at home on Friday in Bel-Air, California.

Dani Nimoy said her grandfather was an “extraordinary man, husband, grandfather, brother, actor, author – the list goes on – and friend.”

She added that special merchandise was being added to Nimoy’s website, with all proceeds going to the COPD foundation.

George Takei, who played Hikaru Sulu on Star Trek and was a friend of Nimoy’s, paid tribute to the actor.

“The word extraordinary is often overused but I think it’s really appropriate for Leonard”, Mr Takei told US broadcaster MSNBC.

“He was an extraordinarily talented man but he was also a very decent human being.”

Among the torrent of tributes on Twitter was a message from Nasa crediting Nimoy and Star Trek as an inspiration.

NASA Tweet

Thousands took to Twitter to pay tribute after Nimoy’s death was announced, including Star Trek actors past and present.

William Shatner, who as Captain Kirk acted alongside Nimoy for years in Star Trek, said he loved the actor “like a brother”.

“We will all miss his humor, his talent, and his capacity to love,” Mr Shatner said on Twitter.

Leonard Nimoy often gave Spock’s famous salute

Wil Wheaton, who played Wesley Crusher in Star Trek: The Next Generation, said: “We stood on your shoulders, and wouldn’t have had a galaxy to explore if you hadn’t been there, first. Thank you, Leonard, Rest in peace.”

More than a Vulcan
It was Nimoy’s casting as Spock in 1966 that made him in a star and, in many ways, defined his acting career.

He played the character in all three of the original series of the programme and later in several big-screen spin offs.

Nimoy had an ambivalent relationship with Spock, seeming to both cherish and resent his close association with the role.

His two volumes of autobiography – “I Am Not Spock” in 1975 and “I Am Spock” two decades later – seemed to epitomise his mixed feelings.

Leonard Nimoy 1931-2015 83 when he died
1965 appeared in rejected Star Trek pilot The Cage
1966-69 played Spock in original Star Trek series
4 Emmy award nominations, 3 for his character Spock
2013 appeared in Star Trek Into Darkness – his last film

Nimoy did have success outside of his Spock costume, in both acting and directing, and he pursued music, painting, and photography.

After the end of Star Trek’s initial run, he played master of disguise Paris in the hit adventure series Mission Impossible.

Later he directed two of the Star Trek films, The Search for Spock and The Voyage Home, and in 1987 helmed the hit comedy Three Men and a Baby, one of the highest-grossing films of that year.

Nimoy announced that he was suffering from COPD last year, writing: “I quit smoking 30 years ago. Not soon enough. Grandpa says, quit now!!”

COPD is an umbrella term for several lung diseases including chronic bronchitis, emphysema and some forms of bronchiectasis.

Sufferers experience increasing breathlessness during the advanced stages of the disease but it can be symptomless for a long time as it develops.

Shocking or intriguing NASA challenges physics to build faster than light spaceship warp drive

 

Shocking or intriguing NASA challenges physics to build faster than light spaceship warp drive

by Vandita from We Are Anonymous anahq.com

Starship

NASA scientist Harold White has stunned the world with his announcement that he and his team has begun work on the development of a faster-than-light Warp Drive spaceship that can move faster than the speed of light defying Albert Einstein’s Theory of Special Relativity. Warp Drive, which is all set to challenge the light speed barrier, could result in speeds that could take a spacecraft to Alpha Centauri in a only two weeks even though the system is 4.3 light-years away! The idea sounds fascinating but disobeys the laws of physics.

In his 1994 paper titled The Warp Drive: Hyper-Fast Travel Within General Relativity physicist Miguel Alcubierre had suggested a mechanism by which space-time could be “warped” both in front of and behind a spacecraft. The idea immediately caught White’s attention.

“Remember, nothing locally exceeds the speed of light, but space can expand and contract at any speed. However, space-time is really stiff, so to create the expansion and contraction effect in a useful manner in order for us to reach interstellar destinations in reasonable time periods would require a lot of energy,” White told io9.

Alcubierre Warp Drive

The Theory of Special Relativity does not allow objects to move faster than the speed of light within space-time. To increase the speed of moving objects to match the speed of light, it would need infinite amount of energy. White in a way suggested horrific amounts of energy —equal to the mass-energy of planet Jupiter (which is 1.9 × 1027 kilograms or 317 Earth masses). As a result, the idea was brushed aside as being far too impractical.

White later collaborated with Mark Rademaker, an artist, to create a new, more realistic design of what such a ship might actually look like. The updated model is more compact and chunkier and includes a sleek ship nestled at the center of two massive rings of negative energy which will create the warp bubble.

Mark Rademaker’s design of what such a ship might actually look like.

At the 100 Year Starship Conference in Atlanta, he said that the Warp Drive could be powered by a mass that’s even less than that of the Voyager 1 spacecraft. The reduction in mass from a Jupiter-sized planet to an object that weighs a mere 1,600 pounds completely reset White’s sense of plausibility — and NASA’s.

Warp Drive for FTL travel is at the level of speculation since NASA also considers that FTL travel is impossible. FTL results in time travel and time travel is considered far more impossible than light travel. Dr White too admits his research is still small-scale and is light years away from any type of engine that could be constructed into a spaceship like the USS Enterprise.

The story so far. Here are a number of clips from the BBC Explorations series that looks at what we have achieved so far in space travel.


Sources:

http://fossbytes.com/nasa-working-warp-drive-faster-than-light-spaceship/

http://io9.com/5963263/how-nasa-will-build-its-very-first-warp-drive

http://anonhq.com/shocking-or-intriguing-nasa-challenges-physics-to-build-faster-than-light-spaceship-warp-drive/

Alien star system buzzed the Sun

 

 

Alien star system buzzed the Sun
By Paul Rincon
Science editor, BBC News website

Scholz’s star – shown in this artist’s impression – is currently 20 light-years away. But it once came much closer

An alien star passed through our Solar System just 70,000 years ago, astronomers have discovered.

No other star is known to have approached this close to us.

An international team of researchers says it came five times closer than our current nearest neighbour – Proxima Centauri.

The object, a red dwarf known as Scholz’s star, cruised through the outer reaches of the Solar System – a region known as the Oort Cloud.

Scholz’s star was not alone; it was accompanied on its travels by an object known as a brown dwarf. These are essentially failed stars that lacked the necessary mass to get fusion going in their cores.

The findings are published in Astrophysical Journal Letters.

Observations of the dim star’s trajectory suggest that 70,000 years ago this cosmic infiltrator passed within 0.8 light years of the Sun. By comparison, Proxima Centauri is 4.2 light years away.

Close encounter
In the paper, astronomers led by Eric Mamajek at the University of Rochester, New York, say they are 98% certain that Scholz’s star travelled through what is known as the “outer Oort Cloud” – a region at the edge of the Solar System filled with trillions of comets a mile or more across.

This region is like a spherical shell around the Solar System and may extend out to as much as 100,000 Astronomical Units, or AU (one AU is the distance between the Earth and the Sun).

The Oort Cloud is thought to give rise to long-period comets that can swing past the Sun when their orbits are disturbed.

The Oort Cloud in perspective: 1 Astronomical Unit (AU) represents the distance from the Earth to the Sun

To determine the trajectory of the star, the researchers needed two pieces of information: the change in distance from the Sun to the star (its radial velocity) and the star’s motion across the sky (its tangential velocity).

Scholz’s star currently lies 20 light years away – making it a fairly nearby system. But it showed very slow tangential motion for a star this close. This indicated that it was either moving away from us or towards a future close encounter with the Solar System.

The radial velocity measurements confirmed that the binary star system was actually speeding away from us. By tracing its movements back in time, they found its close shave with the Sun occurred some 70,000 years ago.

Grand theft Oort-o?
A star passing through the Oort Cloud could potentially play gravitational havoc with the orbits of comets there, sending them on trajectories into the inner Solar System. But Dr Mamajek believes the effects of Scholz’s star on our cosmic neighbourhood were “negligible”.

“There are trillions of comets in the Oort cloud and likely some of them were perturbed by this object,” he told BBC News.

“But so far it seems unlikely that this star actually triggered a significant ‘comet shower’.”

The effect of a passing star on the Oort Cloud is a function of the star’s mass, speed and proximity. The worst case scenario for stirring up comets would be a slow-moving, massive star that came close to the Sun.

Scholz’s star came relatively close, but the binary system (the red dwarf and its brown dwarf companion) has a low mass and it was speeding by. These factors conspired to make its effect on the Oort Cloud very small.

While this is the closest flyby detected so far, Dr Mamajek thinks it’s not uncommon for alien stars to buzz the Sun. He says a star probably passes through the Oort Cloud every 100,000 years, or so.

But he suggests an approach as close – or closer – than that made by Scholz’s star is somewhat rarer. Dr Mamajek said mathematical simulations show such an event occurs on average about once every nine million years.

“So it is a bit of a strange coincidence that we happen to have caught one that passed so close within the past 100,000 years or so,” he said.


Project Blue Book: US Air Force UFO documents revealed

 

Project Blue Book: US Air Force UFO documents revealed
By Debbie Siegelbaum
BBC News, Chicago

Evidence of Martian attacks is not a part of the Air Force UFO documents

Amateur historian John Greenewald has spent nearly two decades requesting declassified information from the US government regarding UFOs.

Recently, he posted more than 100,000 pages of documents on the US Air Force’s internal UFO investigations to the internet. Here are the top five things to know from the open files of Project Blue Book.

1. Project Blue Book had a sizeable mission
The origins of the ambitious project can be traced to June 1947, UFO researcher Alejandro Rojas tells the BBC.

The editor of Open Minds magazine says a well-respected businessman and pilot, Kenneth Arnold, was flying over Washington state when he witnessed several unidentified flying objects.

Arnold later described the crafts as “skipping like saucers”, which the media adopted and took to calling flying saucers.

This high-profile incident – along with several others, including a rumoured UFO landing in Roswell, New Mexico, the same year – led the Air Force to launch an investigative body.

The Air Force says this wreckage, recovered near Roswell, New Mexico, came from a radar target

Named Project Blue Book and headquartered at Wright-Patterson Air Force Base in Ohio, the programme was reportedly comprising only a handful of staff.

Nonetheless the group investigated 12,618 UFO sightings in a two-decade period.

2. Project Blue Book was created in a time of public unease
Formed in the years immediately following World War Two, Project Blue Book was intended to stop the spread of public unease about a growing number of reported UFO sightings, including over such landmarks as the White House and US Capitol.

“There was a lot of hysteria with the public, and that to the military and government at the time was a big threat in itself,” Greenewald says. “It didn’t matter if UFOs were alien or not, they were causing a panic, so [the government] had to settle everybody’s nerves.”

Though frequently met with derision today, UFO sightings are said to have been discussed at the top levels of government in the 1940s and 1950s.

“It was taken very seriously back then,” Rojas says, with Central Intelligence Agency chiefs publicly claiming it was a real phenomenon and even then-Congressman Gerald Ford warning it needed to be investigated.

In 1966 a separate Air Force committee was set up to further delve into some of the cases within Project Blue Book. That group later released a report finding no evidence of UFO activity.

Project Blue Book was officially shuttered in 1969.

3. Many of the Project Blue Book cases appear open-and-shut
Though many credible sources, from Navy admirals to military and civilian pilots, reported seeing UFOs, most of the cases investigated by Project Blue Book were deemed caused by weather balloons, swamp gases, meteorological events or even temperature inversions.

In Seattle, Washington, in April 1956, a witness described seeing a “round, white object, one-half the size of the moon … [and] going round and round”, according to documents.

Investigators later concluded it was a meteor and closed the case.

Amateur UFO investigators believe the truth is still out there

In January 1961 in Newark, New Jersey, a witness reported viewing a dark grey object “about the size of a jet with no wings”.

That object was later deemed a jet aircraft flying in the area.

4. Some Project Blue Book cases aren’t so easily explained
According to Greenewald and Rojas, more than 700 Project Blue Book entries could not ultimately be explained by investigators. Many such cases cited insufficient data or evidence.

But even some of the closed cases raise more questions than answers for UFO researchers.

In one such example, a police officer in 1964 in Socorro, New Mexico, halted vehicular pursuit of a suspect after he saw a strange aircraft overhead.

The officer followed the craft – which he described as bearing a strange red insignia – and saw it land and two child-sized beings exit.

It later took off, leaving scorch marks and trace evidence on the ground.

“[Project] Blue Book labelled it unexplained; even after all these decades they still can’t explain it,” Greenewald says.

5. There is still information to be uncovered about UFO activity
Though Greenewald has amassed a stockpile of government documents, he says there are still many he – and the public – has not yet accessed.

One request to the National Security Agency yielded hundreds of pages, but they were so redacted only a few words were readable on each page, he says.

Other US government entities – including the Central Intelligence Agency and Defense Intelligence Agency – also conducted UFO investigations that have not been publicly released, Greenewald notes.

“I think Project Bluebook … is simply the tip of the iceberg,” he says, adding he will continue to request more information from the US government.

“There are secrets after conspiracies after scandals that continue to come out,” Greenewald concludes. “There’s always something to go after.”

Here’s a series of clips of interviews with people who claim to have been abducted by aliens.


New Horizons probe eyes Pluto for historic encounter

By Jonathan Amos

Science correspondent, BBC News

When it gets to Pluto, the New Horizons probe will have a packed schedule of observations

A Nasa probe is to start photographing the icy world of Pluto, to prepare itself for a historic encounter in July.

The New Horizons spacecraft has travelled 5bn km (3bn miles) over nine years to get near the dwarf planet.

And with 200m km still to go, its images of Pluto will show only a speck of light against the stars.

But the data will be critical in helping to align the probe properly for what will be just a fleeting fly-by.

Pluto will be photographed repeatedly during the approach, to determine the probe’s position relative to the dwarf planet, explained Mark Holdridge, from the Johns Hopkins University’s Applied Physics Laboratory (JHUAPL) in Baltimore.

“We then perform a number of correction manoeuvres to realign our trajectory with the reference trajectory, thus ensuring we hit our aim point to travel through the Pluto system,” he said.

Any initial correction is likely to be made in March.

The Pluto system has five known moons. Others may be discovered in the coming months

When New Horizons arrives at Pluto it will be moving so fast – at almost 14km/s – that going into orbit around the distant world is impossible; it must barrel straight through instead.

One complication is that the seven different instruments aboard the spacecraft need to work at different distances to get their data, and so the team has constructed a very elaborate observation schedule for them all.

But what this means is that very precise timing will be required to make sure the flyby runs smoothly.

The closest approach to Pluto is set for around 11:50 GMT on 14 July – at a miss distance of roughly 13,695km from the surface.

Mission planners want the exact timings nailed to within 100 seconds. New Horizons will know then where and when to point the instruments.


Dwarf Planet Pluto – Demoted but undiminished

Synthetic view Hubble’s best is a synthetic composite of multiple views. What are those shapes?

  • Discovered by Clyde Tombaugh on 18 February 1930
  • It is named after the Roman god of the underworld
  • An average of 5.9bn km from Sun and orbits every 248 years
  • Measuring its diameter is difficult but roughly 2,300km
  • It has a thin nitrogen atmosphere that comes and goes

 


The Pluto mission is being billed as the last great encounter in planetary exploration.

For people who grew up with the idea that there were “nine planets”, this is the moment they get to complete the set.

Robotic probes have been to all the others, even the distant Uranus and Neptune. Pluto is the last of the “classical nine” to receive a visit.

Of course, this 2,300km-wide ice-covered rock was demoted in 2006 to the status of mere “dwarf planet”, but scientists say that should not dull our enthusiasm.

The dwarfs are the most numerous planetary class in the Solar System, and Nasa’s New Horizons probe is one of the first opportunities to study an example up close.

The first set of navigation pictures may not be anything special, but by May, the probe will be returning views of Pluto that are better than anything from Hubble. Come July, the view should be spectacular, said Andy Cheng, the principal investigator on the probe’s main camera, which is called LORRI.

As Rebecca Morelle reports, even the Hubble Space Telescope could only capture blurry images of Pluto
“The most recent surprise we had was with the Rosetta mission. Hubble had made a ‘shape model’ of Comet 67P but no-one expected it to look like a rubber duckie,” he told BBC News. “I am more than hopeful that we will get similar surprises with New Horizons – it’s what we should expect.”

Those surprises could include yet more moons (five are currently known) and possibly even rings like those seen around some of the bigger planets.

Pluto is currently 5bn km from Earth. It has taken New Horizons more than nine years to get to the dwarf’s doorstep.

Once the flyby is complete, the probe will be targeted at an even more distant object in the Kuiper Belt – the name given to the icy domain beyond the main planets. Scientists think this region of space, and beyond, may contain many thousands of Pluto-like objects. Some even speculate there are far-flung worlds that rival Mars and Earth in size.

The first optical navigation images should be back on Earth by Tuesday at the latest. They will show Pluto with its largest moon, Charon.

The clip below is an interesting look at humanities probing of the stars. From the BBC series Explorations

 

Mystery Mars haze baffles scientists

 

 

Mystery Mars haze baffles scientists

By Rebecca Morelle
Science Correspondent, BBC News

The plume appeared twice in 2012, and stretched for 1,000km

A mysterious haze high above Mars has left scientists scratching their heads.

The vast plume was initially spotted by amateur astronomers in 2012, and appeared twice before vanishing.

Scientists have now analysed the images and say that say the formation, stretching for more than 1,000km, is larger than any seen before.

Writing in the journal Nature, the researchers believe the plume could be a large cloud or an exceptionally bright aurora.

However, they are unsure how these could have formed in the thin upper reaches of the Martian atmosphere.

“It raises more questions than answers,” said Antonio Garcia Munoz, a planetary scientist from the European Space Agency.

Around the world, a network of amateur astronomers keep their telescopes trained on the Red Planet.

They first spotted the strange plume in March 2012 above Mars’ southern hemisphere.

Damian Peach was one of the first stargazers to capture images of the phenomenon.

He told BBC News: “I noticed this projection sticking out of the side of the planet. To begin with, I thought there was a problem with the telescope or camera.

“But as I checked more of the images, I realised it was a real feature – and it was quite a surprise.”

Damian Peach was one of the first astronomers to image the plume

The vast, bright haze lasted for about 10 days. A month later, it reappeared for the same length of time. But it has not been seen since.

An international team of scientists has now confirmed the finding, but they are struggling to find an explanation.

One theory is that the plume is a cloud of carbon dioxide or water particles.

“We know there are clouds on Mars, but clouds, up to this point, have been observed up to an altitude of 100km,” Dr Garcia Munoz said.

“And we are reporting a plume at 200km, so it is significantly different. At 200km, we shouldn’t see any clouds, the atmosphere is too thin – so the fact we see it for 20 days in total is quite surprising.”

Another explanation is that this is a Martian version of the northern or southern lights.

Dr Garcia Munoz explained: “We know in this region on Mars, there have been auroras reported before. But the intensities we are reporting are much much higher than any auroras seen before on Mars or on Earth.

“It would be 1,000 times stronger than the strongest aurora, and it is difficult to come to terms that Mars has such an intense aurora.”

If either of these theories are right, he said, it would mean our understanding of Mars’ upper atmosphere is wrong.

He hopes that by publishing the paper, other scientists might also come up with explanations.

If they cannot, astronomers will have to wait for the plumes to return.

Close-up observations from telescopes or the spacecraft that are currently in orbit around the Red Planet could help to solve this Martian mystery.

Earth’s biodiversity is helping scientist to design vehicles that will travel through space and land on Mars and other planets. It’s called ‘bio-inspiration’ as this video clip shows.


Meteorite is ‘hard drive’ from space

Meteorite is ‘hard drive’ from space

By Simon Redfern
BBC Science writer

The Esquel meteorite consists of gem-quality crystals embedded in metal.

Researchers have decoded ancient recordings from fragments of an asteroid dating back billions of years to the start of the Solar System.

They found tiny “space magnets” in meteorites which retain a memory of the birth and death of the asteroid’s core.

Like the data recorded on the surface of a computer hard drive, the magnetic signals written in the space rock reveal how Earth’s own metallic core and magnetic field may one day die.

The work appears in Nature journal.

Using a giant X-ray microscope, called a synchrotron, the team was able to read the signals that formed more than four-and-a-half billion years ago, soon after the birth of the Solar System.

The meteorites are pieces of a parent asteroid that originally came from asteroid belt, between Mars and Jupiter.

They represents the left-over fragments of a planet that failed to form. The magnetic recording within it traps a signal of the precise moments when an iron-rich core formed in the asteroid as well as when it froze, killing its magnetic field.

The new picture of metallic core solidification in the asteroid provide clues about the magnetic field and iron-rich core of Earth.

Core values

“Ideas about how the Earth’s core evolved through [our planet’s] history are really changing at the moment,” lead researcher Dr Richard Harrison, from the University of Cambridge, told BBC News.

“We believe that Earth’s magnetic field is linked to core solidification. Earth’s solid inner core may have started to form at very interesting time in terms of the evolution of life on Earth.

“By studying an asteroid we get to see this in fast forward. We can see the start of core solidification in the magnetic records as well as its end, and start to think about how these processes work on Earth.”

Magnetic field The Earth’s magnetic field will likely die off when the core completely freezes

The meteorites studied by the team originally fell to Earth in Argentina, and are composed of gem-quality crystals enclosed in a metallic matrix of iron and nickel.

Tiny particles, smaller than one thousandth the width of a human hair, trapped within the metal have retained the magnetic signature of the parent asteroid from its birth in the early Solar System.

“We’re taking ancient magnetic field measurements in nano-scale materials to the highest ever resolution in order to piece together the magnetic history of asteroids – it’s like a cosmic archaeological mission,” said Dr James Bryson, the paper’s lead author.

“Since asteroids are much smaller than Earth, they cooled much more quickly, so these processes occur on a shorter timescales, enabling us to study the whole process of core solidification.”

Don’t panic
Prof Wyn William, from the University of Edinburgh, who was not involved in the study, commented: “To be able to get a time stamp on these recordings, to get a cooling rate and the time of solidification, is fantastic. It’s a very nice piece of work.”

The key to the long-lived stability of the recording is the atomic-scale structure of the iron-nickel particles that grew slowly in the asteroid core and survived in the meteorites.

Scientists have attempted to synthesise the same iron-nickel structures in the lab, without widespread success so far. But their remarkable magnetic properties rival those of rare earth magnets, a key component of wind turbines and electric cars.

They may yet prove a route to making cheap, strong magnets without the need for scarce rare earth metals.

Making a final comment on the results, Dr Harrison said: “In our meteorites we’ve been able to capture both the beginning and end of core freezing, which will help us understand how these processes affected the Earth in the past and provide a possible glimpse of what might happen in the future.”

The Earth’s magnetic field will likely die off when the core completely freezes, and Earth will no longer be protected from the Sun’s radiation.

“There’s no need to panic” said Dr Harrison. “The core won’t completely freeze for billions of years, and chances are, the Sun will get us first.”


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