Science & Technology

A house-sized asteroid grazed past Earth on Thursday, passing harmlessly inside the Moon's orbit, as predicted, to give experts a rare opportunity to rehearse for a real strike threat in future.

Dubbed 2012 TC4, the object's passing allowed scientists to practice spotting incoming objects, predicting their size and trajectory, and tracking their passage with a global network of telescopes and radars.

“We pretended that this was a critical object and exercised our communication,” said Detlef Koschny of the European Space Agency's Near-Earth Object programme.

The trial run was “a big success,” he said, despite some instruments not working as planned.

A radar system in Puerto Rico, for example, was out of service due to damage from the recent hurricane there.

“This is exactly why we do this exercise, to not be surprised by these things,” Koschny told AFP.

 

The asteroid flitted past around 0541 GMT at less than 44,000 kilometres (27.300 miles) from Earth's surface — just above the 36,000 km plane at which hundreds of geosynchronous satellites orbit our planet.

This was about an eighth of the distance between the Earth and the Moon.

Scientists had predicted that TC4 was between 10 and 30 metres (33-99 feet) wide. In the end, it measured some 10-12 metres — the smaller end of the range.

“This means it must be very bright,” to make it appear bigger, said Koschny. Observations also revealed that TC4 spins around its axis in about 12 minutes, “which is quite fast.”

When it comes back

The asteroid was about half the size of the meteoroid that exploded in the atmosphere over Chelyabinsk in central Russia in 2013 with the kinetic energy of 30 Hiroshima atom bombs.

The resulting shockwave blew out the windows of nearly 5,000 buildings and injured more than 1,200 people.

While the Chelyabinsk event caught everyone unawares, TC4 is one of thousands of space rocks whose whereabouts are known. Millions are not.

On a 609-day loop around the Sun, TC4 will return to Earth in 2050 and 2079, Koschny's colleague Ruediger Jehn has told AFP.

It will not hit Earth on its next approach but could come close in 2079 — another reason for studying its route through the Solar System.

With a one-in-750 chance of hitting in 2079, TC4 is listed at number 13 on the “risk list” of objects posing even the remotest impact threat.

As its full name suggests, the asteroid was first spotted five years ago when it called on Earth at about double the distance, before disappearing from view.

Astronomers will comb through the data they have now gathered, to learn more about the asteroid's composition.

Flybys like these are quite common — about three objects in TC4's size range graze past at a similar distance every year. What made this one special is that it was chosen to test the global warning system.

Scientists believe Earth will be hit again by a space rock of the size that wiped out the dinosaurs, though nobody knows when.

And even if we become better at predicting a strike, there is very little we can do about it.

Futuristic projects mooted to deflect or destroy incoming space rocks have come to nought so far, and the only strategy would be to evacuate people in zones at risk.

نوکیا نے خاموشی سے اپنا ایک اور اسمارٹ فون متعارف کرا دیا ہے۔

رواں سال یہ کمپنی نوکیا تھری، فائیو، سکس اور فلیگ شپ ڈیوائس 8 متعارف کراچکی تھی مگر اب اس نے نوکیا 7 بھی پیش کردیا ہے۔

دلچسپ بات یہ ہے کہ اس فون میں فلیگ شپ ڈیوائس نوکیا 8 کی طرح ڈوئل کیمرے اور بوتھی کیمرہ سافٹ ویئر دیا گیا ہے۔

مزید پڑھیں : نوکیا کا پہلا فلیگ شپ اینڈرائیڈ فون

اس فیچر کے تحت فرنٹ اور بیک کیمروں کو ایک ساتھ متحرک کرکے تصویر یا ویڈیو لی جاسکتی ہے، جبکہ ویڈیو کو فیس بک یا یوٹیوب پر لائیو نشر بھی کیا جاسکتا ہے۔

فوٹو بشکریہ ایچ ایم ڈی گلوبل
فوٹو بشکریہ ایچ ایم ڈی گلوبل

 

5.2 انچ کے نوکیا سیون میں کوالکوم اسنیپ ڈراگون 630 پراسیسر دیا گیا ہے جبکہ 4 جی بی ریم کے ساتھ 3000 ایم اے ایچ بیٹری ہے۔

اسی طرح 64 جی بی اسٹوریج ہے جس میں ایس ڈی کارڈ کے ذریعے مزید اضافہ کیا جاسکتا ہے جبکہ یہ فون سکس جی بی ریم اور 128 اسٹوریج کے آپشن کے ساتھ بھی دستیاب ہوگا۔

اس کے بیک پر ایک سولہ میگا پکسل جبکہ دوسرا پانچ میگا پکسل کیمرہ دیا گیا ہے۔

یہ بھی پڑھیں : نوکیا 3310 کی واپسی

اس کے فرنٹ پر پانچ میگا پکسل کیمرہ ہے اور نوکیا 8 کے اہم ترین فیچر کا حامل ہونے کے باوجود یہ قیمت میں اس سے 50 فیصد سستا ہے۔

فوٹو بشکریہ ایچ ایم ڈی گلوبل
فوٹو بشکریہ ایچ ایم ڈی گلوبل

 

اس فون کو چین میں متعارف کرایا گیا جہاں یہ چوبیس اکتوبر سے 2499 یوآن (لگ بھگ چالیس ہزار پاکستانی روپے) میں دستیاب ہوگا جبکہ نوکیا 8 کی قیمت 705 ڈالرز (75 ہزار پاکستانی روپے سے زائد) رکھی گئی تھی۔

دیگر ممالک میں یہ کب تک پیش کیا جائے گا، اس کے بارے میں کمپنی نے فی الحال کوئی اعلان نہیں کیا۔

  

بیجنگ(آئی این پی ) چین کے ماہرین نے دنیا کی سب سے بڑے ٹیلی سکوپ سے خلا میں 2 نئے ستارے دریافت کرلیے،یہ ستارے زمین سے 16 ہزار نوری سال اور 4 ہزار ایک سو نوری سال کے فاصلے پر ہیں، جن کی معمول کی گردش کا عرصہ 1.83 سکینڈ اور 0.59 سیکنڈ ہے۔ ستاروں کی دریافت سے متعلق ماہرین گزشتہ ایک سال سے سر جوڑ کر بیٹھے ہوئے تھے کہ ایک سال بعد انہیں بالآخر اس میں کامیابی ملی اور انہوں نے چین کی سب سے بڑی سنگل ڈش ریڈیو ٹیلی سکوپ فاسٹ سے ستاروں کا سراغ لگالیا۔چین کی قومی خلائی رصد گاہ (آسٹرو نومیکل آبزرویٹریز) کے مطابق ان دو ستاروں کو جے 1859-01 اور جے 1931-01 کا نام دیا گیا ہے، یہ ستارے زمین سے 16 ہزار نوری سال اور 4 ہزار ایک سو نوری سال کے فاصلے پر ہیں، جن کی معمول کی گردش کا عرصہ 1.83 سکینڈ اور 0.59 سیکنڈ ہے۔ٹیلی اسکوپ پروجیکٹ کے ڈپٹی ڈائریکٹر کا کہنا ہے کہ چین کی سب سے بڑی ٹیلی اسکوپ کے حجم کے مساوی ٹیلی اسکوپس کو عمومی طور پر آزمائش کے لیے تین سے پانچ سال کا عرصہ درکار ہوتا ہے لیکن ایک سال میں ہی ایسی دریافت بہت ہی حوصلہ افزا ہے۔ چین کی قومی اجرامِ فلکی رصد گاہ کے چیف کا کہنا ہے کہ سب سے بڑی ٹیلی اسکوپ نے دو ستاروں کو جنوبی کہکشاں کی اسکیننگ کے دوران 22 اور 25 اگست کو دریافت کیا گیا۔ واضح رہے کہ چین نے خلا میں موجود ستاروں، کہکشاو¿ں اور پوشیدہ رازوں کو جاننے کے لیے دنیا کی سب سے بڑی دور بین تیار کی، فاسٹ نامی اس ٹیلی اسکوپ کی تیاری میں تقریبا 18 کروڑ ڈالر کی لاگت آئی اور اس کی تکمیل میں 5 برس کا عرصہ لگا۔ دوربین کا حجم فٹبال کے 30 اسٹیڈیم جتنا ہے جبکہ اس میں 500 میٹر قطر کے ریفلیکٹرز اور 4450 پینلز نصب کیے گئے ہیں علاوہ ازیں ٹیلی اسکوپ میں دیگر جدید آلات بھی نصب کیے گئے ہیں جس کی وجہ سے آسمان اور خلا کا نظارہ دیگر کے مقابلے میں دگنا زیادہ بہتر ہوتا ہے۔

CAPE CANAVERAL: Nasa astronauts took another spacewalk outside the International Space Station on Tuesday, this time to grease the robot arm’s new hand.

Commander Randy Bresnik ventured out for the second time in less than a week, along with Mark Vande Hei.

The pair replaced the latching mechanism on one end of the 58-foot robot arm on Thursday. The mechanism malfunctioned in August.

Tuesday’s work involved using a grease gun, which resembles a caulking gun, to keep the latching mechanism working smoothly. The two-part lube job is expected to spill into next week, in a third spacewalk.

 

These latches, or hands, are located on each end of the Canadian-built robot arm. They’re used to grab arriving US cargo ships and also allow the robot arm to move around the orbiting lab.

Launched in 2001 with the rest of the robot arm, the original latches were showing their age. Nasa plans to replace the latching mechanism on the opposite end of the arm early next year.

Published in Dawn, October 11th, 2017

A representation of the evolution of the universe over 13.8 billion years. NASA and the WMAP consortium

Different methods of studying cosmic expansion yield slightly different results, including for the age of the universe. In a new study, astronomers from the Harvard-Smithsonian Center For Astrophysics have calculated that these discrepancies could be reconciled if the dark energy that drives cosmic acceleration were not constant in time.

The universe is not only expanding – it is accelerating outward, driven by what is commonly referred to as “dark energy.” The term is a poetic analogy to label for dark matter, the mysterious material that dominates the matter in the universe and that really is dark because it does not radiate light (it reveals itself via its gravitational influence on galaxies). Two explanations are commonly advanced to explain dark energy. The first, as Einstein once speculated, is that gravity itself causes objects to repel one another when they are far enough apart (he added this “cosmological constant” term to his equations). The second explanation hypothesizes (based on our current understanding of elementary particle physics) that the vacuum has properties that provide energy to the cosmos for expansion.

For several decades cosmologies have successfully used a relativistic equation with dark matter and dark energy to explain increasingly precise observations about the cosmic microwave background, the cosmological distribution of galaxies, and other large-scale cosmic features. But as the observations have improved, some apparent discrepancies have emerged. One of the most notable is the age of the universe: there is an almost 10% difference between measurements inferred from the Planck satellite data and those from so-called Baryon Acoustic Oscillation experiments. The former relies on far-infrared and submillimeter measurements of the cosmic microwave background and the latter on spatial distribution of visible galaxies.

CfA astronomer Daniel Eisenstein was a member of a large consortium of scientists who suggest that most of the difference between these two methods, which sample different components of the cosmic fabric, could be reconciled if the dark energy were not constant in time. The scientists apply sophisticated statistical techniques to the relevant cosmological datasets and conclude that if the dark energy term varied slightly as the universe expanded (though still subject to other constraints), it could explain the discrepancy. Direct evidence for such a variation would be a dramatic breakthrough, but so far has not been obtained. One of the team’s major new experiments, the Dark Energy Spectroscopic Instrument (DESI) Survey, could settle the matter. It will map over twenty-five million galaxies in the universe, reaching back to objects only a few billion years after the big bang, and should be completed sometime in the mid 2020’s.

Publication: Gong-Bo Zhao, et al., “Dynamical Dark Energy in Light of the Latest Observations,” Nature Astronomy 1, 627–632 (2017) doi:10.1038/s41550-017-0216-z

Source: Harvard-Smithsonian Center For Astrophysics

Engineers at MIT have taken a first step in designing a computer chip that uses a fraction of the power of larger drone computers and is tailored for a drone as small as a bottlecap.

A team of engineers at MIT has developed a method for designing efficient computer chips may get miniature smart drones off the ground.

In recent years, engineers have worked to shrink drone technology, building flying prototypes that are the size of a bumblebee and loaded with even tinier sensors and cameras. Thus far, they have managed to miniaturize almost every part of a drone, except for the brains of the entire operation — the computer chip.

Standard computer chips for quadcoptors and other similarly sized drones process an enormous amount of streaming data from cameras and sensors, and interpret that data on the fly to autonomously direct a drone’s pitch, speed, and trajectory. To do so, these computers use between 10 and 30 watts of power, supplied by batteries that would weigh down a much smaller, bee-sized drone.

Now, engineers at MIT have taken a first step in designing a computer chip that uses a fraction of the power of larger drone computers and is tailored for a drone as small as a bottlecap. They will present a new methodology and design, which they call “Navion,” at the Robotics: Science and Systems conference, held this week at MIT.

The team, led by Sertac Karaman, the Class of 1948 Career Development Associate Professor of Aeronautics and Astronautics at MIT, and Vivienne Sze, an associate professor in MIT’s Department of Electrical Engineering and Computer Science, developed a low-power algorithm, in tandem with pared-down hardware, to create a specialized computer chip.

The key contribution of their work is a new approach for designing the chip hardware and the algorithms that run on the chip. “Traditionally, an algorithm is designed, and you throw it over to a hardware person to figure out how to map the algorithm to hardware,” Sze says. “But we found by designing the hardware and algorithms together, we can achieve more substantial power savings.”

“We are finding that this new approach to programming robots, which involves thinking about hardware and algorithms jointly, is key to scaling them down,” Karaman says.

The new chip processes streaming images at 20 frames per second and automatically carries out commands to adjust a drone’s orientation in space. The streamlined chip performs all these computations while using just below 2 watts of power — making it an order of magnitude more efficient than current drone-embedded chips.

Karaman, says the team’s design is the first step toward engineering “the smallest intelligent drone that can fly on its own.” He ultimately envisions disaster-response and search-and-rescue missions in which insect-sized drones flit in and out of tight spaces to examine a collapsed structure or look for trapped individuals. Karaman also foresees novel uses in consumer electronics.

“Imagine buying a bottlecap-sized drone that can integrate with your phone, and you can take it out and fit it in your palm,” he says. “If you lift your hand up a little, it would sense that, and start to fly around and film you. Then you open your hand again and it would land on your palm, and you could upload that video to your phone and share it with others.”

Karaman and Sze’s co-authors are graduate students Zhengdong Zhang and Amr Suleiman, and research scientist Luca Carlone.

From the ground up

Current minidrone prototypes are small enough to fit on a person’s fingertip and are extremely light, requiring only 1 watt of power to lift off from the ground. Their accompanying cameras and sensors use up an additional half a watt to operate.

“The missing piece is the computers — we can’t fit them in terms of size and power,” Karaman says. “We need to miniaturize the computers and make them low power.”

The group quickly realized that conventional chip design techniques would likely not produce a chip that was small enough and provided the required processing power to intelligently fly a small autonomous drone.

“As transistors have gotten smaller, there have been improvements in efficiency and speed, but that’s slowing down, and now we have to come up with specialized hardware to get improvements in efficiency,” Sze says.

The researchers decided to build a specialized chip from the ground up, developing algorithms to process data, and hardware to carry out that data-processing, in tandem.

Tweaking a formula

Specifically, the researchers made slight changes to an existing algorithm commonly used to determine a drone’s “ego-motion,” or awareness of its position in space. They then implemented various versions of the algorithm on a field-programmable gate array (FPGA), a very simple programmable chip. To formalize this process, they developed a method called iterative splitting co-design that could strike the right balance of achieving accuracy while reducing the power consumption and the number of gates.

A typical FPGA consists of hundreds of thousands of disconnected gates, which researchers can connect in desired patterns to create specialized computing elements. Reducing the number gates with co-design allowed the team to chose an FPGA chip with fewer gates, leading to substantial power savings.

“If we don’t need a certain logic or memory process, we don’t use them, and that saves a lot of power,” Karaman explains.

Each time the researchers tweaked the ego-motion algorithm, they mapped the version onto the FPGA’s gates and connected the chip to a circuit board. They then fed the chip data from a standard drone dataset — an accumulation of streaming images and accelerometer measurements from previous drone-flying experiments that had been carried out by others and made available to the robotics community.

“These experiments are also done in a motion-capture room, so you know exactly where the drone is, and we use all this information after the fact,” Karaman says.

Memory savings

For each version of the algorithm that was implemented on the FPGA chip, the researchers observed the amount of power that the chip consumed as it processed the incoming data and estimated its resulting position in space.

The team’s most efficient design processed images at 20 frames per second and accurately estimated the drone’s orientation in space, while consuming less than 2 watts of power.

The power savings came partly from modifications to the amount of memory stored in the chip. Sze and her colleagues found that they were able to shrink the amount of data that the algorithm needed to process, while still achieving the same outcome. As a result, the chip itself was able to store less data and consume less power.

“Memory is really expensive in terms of power,” Sze says. “Since we do on-the-fly computing, as soon as we receive any data on the chip, we try to do as much processing as possible so we can throw it out right away, which enables us to keep a very small amount of memory on the chip without accessing off-chip memory, which is much more expensive.”

In this way, the team was able to reduce the chip’s memory storage to 2 megabytes without using off-chip memory, compared to a typical embedded computer chip for drones, which uses off-chip memory on the order of a few gigabytes.

“Any which way you can reduce the power so you can reduce battery size or extend battery life, the better,” Sze says.

This summer, the team will mount the FPGA chip onto a drone to test its performance in flight. Ultimately, the team plans to implement the optimized algorithm on an application-specific integrated circuit, or ASIC, a more specialized hardware platform that allows engineers to design specific types of gates, directly onto the chip.

“We think we can get this down to just a few hundred milliwatts,” Karaman says. “With this platform, we can do all kinds of optimizations, which allows tremendous power savings.”

This research was supported, in part, by Air Force Office of Scientific Research and the National Science Foundation.

Publication:

Source: Jennifer Chu, MIT News

Because the system is built on a flexible polymer film, it could be adapted for devices with complex curvature or with moving surfaces.

A team of researchers has made the first demonstration of a solid state cooling device based on the electrocaloric effect. This thin flexible device that could keep smartphones and laptop computers cool and prevent overheating.

Engineers and scientists from the UCLA Henry Samueli School of Engineering and Applied Science and SRI International, a nonprofit research and development organization based in Menlo Park, California, have created a thin flexible device that could keep smartphones and laptop computers cool and prevent overheating.

The system’s flexibility also means it could eventually be used in wearable electronics, robotic systems and new types of personalized cooling systems. It is the first demonstration of a solid state cooling device based on the electrocaloric effect — a phenomenon in which a material’s temperature changes when an electric field is applied to it. The research was published September 15 in Science.

The method devised by UCLA and SRI researchers is very energy-efficient. It uses a thin polymer film that transfers heat from the heat source (a battery or processor, typically) to a “heat sink,” and alternates contact between the two by switching on and off the electric voltage. Because the polymer film is flexible, the system could be adapted for devices with complex curvature or with moving surfaces.

“We were motivated by the idea of devising a personalized cooling system,” said Qibing Pei, UCLA a professor of materials science and engineering and the study’s principal investigator. “For example, an active cooling pad could keep a person comfortable in a hot office and thus lower the electricity consumption for building air conditioning. Or it could be placed in a shoe insole or in a hat to keep a runner comfortable in the hot Southern California sun. It’s like a personal air conditioner.”

A major application could be in mobile and wearable electronics. As most smartphone and tablet users know, devices tend to heat up when they are used, particularly with power-intensive applications like video streaming. So although the devices are made with interior metal radiators designed to pull heat away from the battery and computer processors, they can still overheat, which can even cause them to shut down. And excessive heat can damage the devices’ components over time.

That tendency to overheat remains a major challenge for engineers, and with the anticipated introduction of more flexible electronic devices, it’s an issue that researchers and device manufacturers are working hard to address. The cooling systems in larger devices like air conditioners and refrigerators, which use a process called vapor compression, are simply too large for mobile electronics. (They’re also impractical for smartphones and wearable technology because they use a chemical coolant that is an environmental hazard.)

“The development of practical efficient cooling systems that do not use chemical coolants that are potent greenhouse gases is becoming even more important as developing nations increase their use of air conditioning,” said Roy Kornbluh, an SRI research engineer.

The UCLA–SRI system also has certain advantages over another advanced type of cooling system, called thermoelectric coolers, which require expensive ceramic materials and whose cooling capabilities don’t yet measure up to vapor compression systems.

Pei said the invention’s other potential applications could include being used in a flexible pad for treating injuries, or reducing thermal “noise” in thermographic cameras, which are used by scientists and firefighters, and in night-vision devices, among other uses.

The study’s lead authors are UCLA postdoctoral scholar Rujun Ma and doctoral student Ziyang Zhang, both members of Pei’s research group. Other authors are Kwing Tong, a UCLA graduate student; David Huber, a research engineer at SRI; and Yongho Sungtaek Ju, a UCLA professor of mechanical and aerospace engineering.

The research was supported by the Department of Energy’s Advanced Research Projects Agency–Energy and by the Air Force Office of Scientific Research. The researchers have submitted a U.S. patent application for the device.

Publication: Rujun Ma, et al., “Highly efficient electrocaloric cooling with electrostatic actuation,” Science 15 Sep 2017: Vol. 357, Issue 6356, pp. 1130-1134; DOI: 10.1126/science.aan5980

Source: Matthew Chin, UCLA News

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