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Japan’s Hayabusa 2 spacecraft reaches cosmic ‘diamond’

RyuguImage copyright JAXA ET AL.
Image caption Scientists will map Ryugu with a view to choosing the best location to sample

A Japanese spacecraft has arrived at its target – an asteroid shaped like a diamond or, according to some, a spinning top.

Hayabusa 2 has been travelling toward the space rock Ryugu since launching from the Tanegashima spaceport in 2014.

It is on a quest to study the object close-up and deliver rocks and soil from Ryugu to Earth.

It will use explosives to propel a projectile into Ryugu, digging out a fresh sample from beneath the surface.

Dr Makoto Yoshikawa, Hayabusa 2’s mission manager, talked about the plan now that the spacecraft had arrived at its destination.

“At first, we will study very carefully the surface features. Then we will select where to touch down. Touchdown means we get the surface material,” he told me.

A copper projectile, or “impactor” will separate from the spacecraft, floating down to the surface of the asteroid. Once Hayabusa 2 is safely out of the way, an explosive charge will detonate, driving the projectile into the surface.

“We have an impactor which will create a small crater on the surface of Ryugu. Maybe in spring next year, we will try to make a crater… then our spacecraft will try to reach into the crater to get the subsurface material.”

“But this is a very big challenge.”

Hayabusa 2Image copyright JAXA / AKIHIRO IKESHITA
Image caption Hayabusa 2 will use a projectile to excavate fresh material from beneath Ryugu’s surface

Why is this story important?

Scientists study asteroids to gain insights into the origins and evolution of our cosmic neighbourhood, the Solar System.

Asteroids are essentially leftover building materials from the formation of the Solar System 4.6 billion years ago.

It’s also thought they may contain chemical compounds that could have been important for kick-starting life on Earth.

They contain water, organic (carbon-rich) compounds and precious metals. The last of those has tempted several companies to look into the feasibility of asteroid mining.

‘Dumpling’ space rock comes into view


DangoImage copyright GETTY IMAGES
Image caption From far away, the asteroid seemed to resemble a Japanese dango dumpling…
Spinning topImage copyright GETTY IMAGES
Image caption…but now we have close-up images, scientists are comparing its shape to that of a spinning top

Dr Yoshikawa, who is an associate professor at Japan’s Institute of Space and Astronautical Science (ISAS), said Ryugu’s shape was unexpected.

He said asteroids with this general shape tended to be fast-rotating, completing one revolution every three or four hours. But Ryugu’s spin period is relatively long – about 7.5 hours.

“Many scientists in our project think that in the past the spin period was very short – it rotated very quickly – and the spin period has slowed down. We don’t know why it slowed down, but this is a very interesting topic,” he told BBC News.

Hayabusa 2 will spend about a year and a half surveying the 900m-wide space rock, which is about 290 million km (180 million miles) from Earth.

During this time, it will aim to deploy several landing craft to the surface, including small rovers and a German-built instrument package called Mascot (Mobile Asteroid Surface Scout).

MASCOTImage copyright DLR
Image caption Hayabusa 2 is carrying a German-built lander called MASCOT

Ryugu is a so-called C-type asteroid, a kind that is thought to be relatively primitive. This means it may be rich in organic and hydrated minerals (those combined with water). Studying what Ryugu is made from could provide insights into the molecular mix that contributed to the origin of life on Earth.

The surface of the asteroid is likely to have been weathered – altered by aeons of exposure to the harsh environment of space. That’s why Hayabusa 2’s scientists want to dig down for as fresh a sample as possible.

The onboard Lidar (light detection and ranging) instrument is used partly as a navigation sensor for rendezvous, approach, and touchdown. It illuminates the target with pulsed laser light to measure variable distances between the two objects. On Tuesday, scientists successfully used the Lidar to measure the distance from Hayabusa to the asteroid for the first time.

The mission will depart from Ryugu in December 2019 with the intention of returning to Earth with the asteroid samples in 2020.

The first Hayabusa spacecraft was launched in 2003 and reached the asteroid Itokawa in 2005.

Despite being hit by a series of mishaps, it returned to Earth in 2010 with a small amount of material from the asteroid.

An American asteroid sample return mission, Osiris-Rex, will rendezvous with the object 101955 Bennu in August.

Space debris or an alien satellite: Unraveling the mysteries behind the “Black Knight”

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What most people don’t realize is that 6,000 satellites have been launched into Earth’s orbit since the Soviet Union sent Sputnik 1 into space back in 1957. These man-made satellites have served various purposes, such as means of communication, navigation, and exploration. Estimates suggest that around 3,600 so far have remained in orbit, out of which far fewer are still operational. Once these satellites fulfill their purpose and reach life expectancy, they become nothing more than a space debris.

It is very easy to spot some of them, orbiting in the skies, including the largest one of all, the International Space Station. However, none of them match the Black Knight, a highly mysterious and much-debated satellite, in the power of storytelling.

While some argue the Black Knight has been in orbit for some five decades already, others say it is less time than that–and there are those who argue it was there 13,000 years ago. Its purpose and origin have remained well hidden, although there are claims it has already beamed signals to the Earth. Who gave this object its ominous name adds to the spine-tingling nature of the enigma, and it is uncertain who was the first to discover it, either.

Unsurprisingly, conspiracy theorists have come to the table. As they explain it, the Black Knight’s origin is linked to extra-terrestrials. The scientific and academic community dismiss all such talk. So how to explain the buzz surrounding the Black Knight?

The root of the story begins with Nikola Tesla, who supposedly had heard sounds from space back in 1899. He deemed the sounds were possibly from intelligent life not on Earth, perhaps inhabitants of Mars. Decades later, in 1968, astronomers confirmed that he indeed heard radio signals, but they came via other natural objects in space.

Tesla never claimed he heard signals coming from a satellite orbiting the Earth, but there are those who still believe he was listening to transmissions from an orbiting satellite, one that was none other than the Black Knight.

In 1954, some newspapers, including The San Francisco Examiner and the St. Louis Post-Dispatch, published certain opinions, made by Donald Edward Keyhoe, a former Marine Corps naval aviator and famed UFO researcher. Keyhoe continually published stories in various magazines such as Weird TalesFlying AcesThe Saturday Evening Post and Reader’s Digest.

Published in the newspapers was Keyhoe’s belief that extra-terrestrials had visited the Earth. He also wrote a couple of books in which he stated that the U.S. Air Force detected two satellites orbiting the Earth in 1954, when in fact, no such technology existed.

On the other hand, the mid-1950s were times when science fiction was moving towards its peak in popularity.

Keyhoe’s books were rivalled by those written by H.G. Wells, Arthur C. Clarke, and Issac Asimov. Along with a range of movies and television shows, these stories fueled the public imagination about space travel and possible alien life encounters. Skeptics decided that much of what Keyhoe wrote was to help the promotion of his own books.

However, in 1960, during the Cold War, Time Magazine further claimed the U.S. Navy was aware of a satellite that had an unusual orbit. Initially, the magazine claimed it was a Soviet spy, but later it stated concern that a U.S. satellite broke out of orbit.

Over the years, reports of the Black Knight satellite have accumulated, but according to many, they are the result of unverified stories, overzealous reporters, and over-interpreted photographs. As NASA astronaut Jerry Ross says, the object and all the speculations about it are simply the results of a mistake.

Furthermore, senior education support officer Martina Redpath of the Armagh Planetarium in Norther Ireland doubts that the Black Knight is anything but a “jumble of completely unrelated stories.” Redpath had also claimed that many of the related reports on the matter are “unusual science observation” that have nurtured the myth of the Black Knight.

A possible explanation to the mystery can be found in December 1998, when a space shuttle mission was conducted at the International Space Station (ISS). During the mission, which involved spacewalks, Colonel Ross and Dr. James Newman were attempting to install thermal blankets to make adjustments that would reduce heat loss and save energy at the ISS. As the blankets were fastened to Col. Ross’ spacesuit, one of them was lost. Once he had realized it was gone, it was already far away from the astronauts and they were unable to retrieve it.

As NASA explains, debris regardless of its size escapes the stations at missions that require a spacewalk. Such was the case in December 1998, when a few more items had ended up as space debris. Usually, the majority of those objects are officially cataloged by the US SSN (Space Surveillance Network) too.

Therefore, the object photographed during the mission in 1998 known as STS-88, widely claimed to be the Black Knight satellite, is, according to the space journalist James Oberg, probably the thermal blanket that has been reported lost during the extravehicular activity conducted by Col. Ross and Dr. Newman.

In an interview given in 2014, Col. Ross has also stated that “conspiracy theories are fun for those working on them, but a waste of valuable brain power,” in the context of all the surrounding Black Knight theories.

Will these statements put an end to the intrigue of the Black Knight? The answer is: probably not.

 Stefan Andrews

Dozen black holes found at galactic centre

Black holeImage copyrightSCIENCE PHOTO LIBRARY

A dozen black holes may lie at the centre of our galaxy, the Milky Way, researchers have said.

A new analysis provides support for a decades-old prediction that “supermassive” black holes at the centres of galaxies are surrounded by many smaller ones.

However, previous searches of the Milky Way’s centre, where the nearest supermassive black hole is located, have found little evidence for this.

Details appear in the journal Nature.

Charles Hailey from Columbia University in New York and colleagues used archival data from Nasa’s Chandra X-ray telescope to come to their conclusions.

They report the discovery of a dozen inactive and low-mass “binary systems”, in which a star orbits an unseen companion – the black hole.

The supermassive black hole at the centre of the Milky Way, known as Sagittarius A* (Sgr A*), is surrounded by a halo of gas and dust that provides the perfect breeding ground for the birth of massive stars. These stars live, die and could turn into black holes there.

In addition, black holes from outside the halo are believed to fall under the influence of Sgr A* as they lose their energy, causing them to be pulled into its vicinity, where they are held captive by its force.

Some of these bind – or “mate” – to passing stars, forming binary systems.

Previous attempts to detect this population of black holes have looked for the bright bursts of X-rays that are sometimes emitted by black hole binaries.

Faint and steady

“The galactic centre is so far away from Earth that those bursts are only strong and bright enough to see about once every 100 to 1,000 years,” said Prof Hailey.

Instead, the Columbia University astrophysicist and his colleagues decided to look for the fainter but steadier X-rays emitted when these binaries are in an inactive state.

“Isolated, unmated black holes are just black – they don’t do anything,” said Prof Hailey.

“But when black holes mate with a low mass star, the marriage emits X-ray bursts that are weaker, but consistent and detectable.”

A search for the X-ray signatures of low-mass black hole binaries in the Chandra data turned up 12 within three light-years of Sgr A*.

By extrapolating from the properties and distribution of these binaries, the team estimates that there may be 300-500 low-mass binaries and 10,000 isolated low-mass black holes surrounding Sgr A*.

Prof Hailey said the finding “confirms a major theory”, adding: “It is going to significantly advance gravitational wave research because knowing the number of black holes in the centre of a typical galaxy can help in better predicting how many gravitational wave events may be associated with them.”

Gravitational waves are ripples in the fabric of space-time. They were predicted by Albert Einstein’s general theory of relativity and detected by the Ligo experiment in 2015. One way these ripples arise is through the collision of separate black holes.

By BBC Science

What is Mercury in Retrograde, and Why Do We Blame Things On It?

NASA

NASA

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding for the first time this year on Friday, March 23. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

“We don’t know of any physical mechanism that would cause things like power outages or personality changes in people,” Dr. Mark Hammergren, an astronomer at Chicago’s Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?

THE HISTORY

Mercury retrograde—as it’s technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an “ill omen” also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

“Don’t start anything when Mercury is retrograde,” an April 1979 issue of The Baltimore Sun instructed its readers. “A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication.” The power attributed to the event has become so overblown that today it’s blamed for everything from digestive problems to broken washing machines.

WHAT IS IT ACTUALLY?

Though hysteria around Mercury retrograde is stronger than ever, there’s still zero evidence that it’s something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. “A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does,” Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the Sun is retrograde, it appears to move “backwards” (east to west rather than west to east) across the sky. This apparent reversal in Mercury’s orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the Sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the Sun, Mercury looks like it’s moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it’s just a trick of perspective. “Same thing if you were passing a car on a highway, maybe going a little bit faster than they are,” he says. “They’re not really going backwards, they just appear to be going backwards relative to your motion.”

https://giphy.com/embed/gidFS64MBFZNC

Embedded from GIFY

Earth’s orbit isn’t identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the Sun than Earth have even more noticeable retrograde patterns because they’re visible at night. But thanks to astrology, it’s Mercury’s retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: “[Believers] will say, ‘Aha! See, there’s a shake-up in my workplace because Mercury’s retrograde.'” He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They’ll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn’t retrograde, “we don’t get that hashtag. It’s called Monday.”

(This story originally ran in 2017)  BY MICHELE DEBCZAK  MARCH 21, 2018

Nasa spacecraft reveals Jupiter’s interior in unprecedented detail

Juno mission paints dramatic picture of the turbulence within the solar system’s largest planet

Jupiter's south pole
 This image of Jupiter’s south pole is a mosaic of many images acquired by the Jovian InfraRed Auroral Mapper. Photograph: NASA/SWRI/JPL/ASI/INAF/IAPS

Jupiter’s interior has been revealed in unprecedented detail in observations by Nasa’s Juno spacecraft that show it to be as strange and turbulent as the planet’s surface.

Despite extensive studies of Jupiter’s surface, including its distinctive dark and light bands and “great red spot”, little had previously been known about what lies at the interior of the solar system’s largest planet.

The new findings, based on high-precision gravitational measurements, show that Jupiter’s iconic striped bands, caused by immensely powerful winds, extend to a depth of about 3,000km below the surface. The mission has also produced a partial answer to the question of whether the planet has a core, showing that the inner 96% of the planet rotates “as a solid body”, even though technically it is composed of an extraordinarily dense mixture of hydrogen and helium gas.

The findings are published in four separate papers in the journal Nature, describing the planet’s gravitational field (surprisingly asymmetrical), atmospheric flows, interior composition and polar cyclones.

Jonathan Fortney, an astronomer at the University of California Santa Cruz who wrote an analysis of the findings, said: “The big deal is that this tells us how the interior of Jupiter works. People have been fighting about this since before I was born.”

A crucial question was whether the bands on Jupiter, caused by air currents that are five times as strong as the most powerful hurricanes on Earth, were a “weather” phenomenon comparable to the Earth’s jet streams or part of a deep-seated convection system. Juno’s latest observations point to the latter, showing the jets continued to around 3,000km beneath the surface – deep enough to cause ripples and asymmetries in the planet’s gravitational field that were perceptible to detectors on the spacecraft.

A composite image of Jupiter’s south pole.
Pinterest
 A composite image of Jupiter’s south pole. Photograph: NASA/SWRI/MSSS/Gerald Eichstädt/John Rogers

“It’s a 50-year-old problem that is basically solved thanks to Juno – that is really something to be proud of,” said Tristan Guillot of Côte d’Azur University in Nice, France, lead author of one of two papers on the depth of the atmosphere.

On Earth, the atmosphere represents about a millionth of the mass of the whole planet. The latest work suggests that on Jupiter the figure is closer to 1%. “The concept that an atmosphere can be so heavy and contain so much of the planet is surprising,” said Yohai Kaspi, a planetary scientist at the Weizmann Institute of Science in Israel and the other lead author on this topic.

It is not yet clear whether these findings also apply to the “great red spot”, a storm that has been visible on Jupiter’s surface for centuries, and the mission is expected to make further observations this year that could reveal the depth of its roots.

The new findings, based on extremely sensitive gravitational measurements, also begin to paint a picture of the internal structure of the planet.

On an imagined journey from the outside to the centre, one would first encounter a cloud layer of 99% hydrogen and helium, with traces of methane and ammonia. The density at the surface is about 10 times less than that of air, but the gas becomes denser and denser towards the centre of the planet. At about 10% towards the centre, the gas becomes so dense that hydrogen becomes ionised, turning into a metallic hydrogen gas approaching the density of water. About 20% towards the centre, helium condenses into rain. And in the deep interior, where pressures are about 10 million times higher than at the Earth’s surface, scientists think the gas exists as a dense soup speckled with rocks of heavy metal.

“There may be a small hard [solid] core very, very deep, but we’re thinking it’s just dense gas enriched in heavy elements … it’s not a solid that you can imagine,” said Kaspi. “The normal concept of gas, liquid and solid don’t really hold at these pressures.”

Juno has also taken a series of images of Jupiter’s poles, in visible and infrared light, showing that the cyclones known to exist there create striking polygonal patterns, with eight cyclones rotating around a single cyclone at the north pole and five cyclones circling a central one in the south. Where the cyclones come from and why they don’t merge is not yet clear.

The Juno spacecraft arrived at Jupiter in 2016 after a journey of five years and nearly 1.8 billion miles. Working out what is going on beneath the planet’s surface is a central goal of the $1.1bn mission, which is aiming to understand how the gas giant formed and evolved. Nasa is currently deciding whether to extend the mission beyond its original planned ending in July, when controllers are due to send the craft into a destructive dive into Jupiter’s atmosphere.

The ancient Peruvian mystery solved from space

In one of the most arid regions in the world a series of carefully constructed, spiralling holes form lines across the landscape. Known as puquios, their origin has been a puzzle – one that could only be solved from space.

The holes are from the Nasca region of Peru – an area famous for the Nasca lines, several enormous geometric images carved into the landscape; immaculate archaeological evidence of ceremonial burials; and the rapid decline of this once flourishing society.

What adds to the intrigue in the native ancient people of Nasca is how they were able to survive in an area where droughts can last for years at a time.

The puquios were a “sophisticated hydraulic system constructed to retrieve water from underground aquifers,” says Rosa Lasaponara of the Institute of Methodologies for Environmental Analysis, in Italy. And they transformed this inhospitable region.

(Credit: Ab5602/Wikimedia/Public Domain)

The funnel-like shape helped to draw the wind down into the underground canals (Credit: Ab5602/Wikimedia/Public Domain)

The puquio system must have been much more developed than it appears today

Lasaponara and her team studied the puquios using satellite imaging. From this, the team were able to better understand how the puquios were distributed across the Nasca region, and where they ran in relation to nearby settlements – which are easier to date.

“What is clearly evident today is that the puquio system must have been much more developed than it appears today,” says Lasaponara. “Exploiting an inexhaustible water supply throughout the year the puquio system contributed to an intensive agriculture of the valleys in one of the most arid places in the world.”

A series of canals brought the water, trapped underground, to the areas where it was needed; anything left was stored in surface reservoirs. To help keep it moving, chimneys were excavated above the canals in the shape of corkscrewing funnels. These funnels let wind into the canals, which forced the water through the system.

Like many other South American cultures the Nasca had no writing system

“The puquios were the most ambitious hydraulic project in the Nasca area and made water available for the whole year, not only for agriculture and irrigation but also for domestic needs,” says Lasaponara, who has written about her satellite studies in Ancient Nasca World: New Insights from Science and Archaeology, which is due to be published later this year.

The origin of the puquios has remained a mystery to researchers because it was not possible to use traditional carbon dating techniques on the tunnels. Nor did the Nasca leave any clues as to their origin. Like many other South American cultures they had no writing system.

(Credit: Getty Images)

Some think the famous ‘Nasca lines’ related to the presence of water (Credit: Getty Images)

Their existence tells us something remarkable about the people who lived in the Nasca region from before 1,000 BC to AD750. “The construction of the puquios involved the use of particularly specialised technology,” says Lasaponara. Not only did the builders of the puquios need a deep understanding of the geology of the area and annual variations in water availability, maintaining the canals was a technical challenge as they spread across tectonic faults.

What makes them even more remarkable is that they still function today

“What is really impressive is the great efforts, organisation and cooperation required for their construction and regular maintenance,” she says. That meant a regular dependable water supply for centuries, in an area that’s one of the most arid places on Earth.

“Maintenance was likely based on a collaborative and socially organised system, similar to that adopted for the construction of the famous ’Nasca lines‘ which in some cases are clearly related to the presence of water.” The quality of construction was so good, that some of the puquios still function today.

These structures show the native people of the Nasca basin were not only highly organised, but that their society was structured in a hierarchy, says Lasaponara. She says the puquios were vital in “controlling water distribution by those in power over the communities that came under their influence.” Knowing how to bring water to one of the driest places on earth means that you hold the very key to life itself.

By William Park

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