Tag Archives: collision

Wing.

Novel video shows what drone impacts can do to planes. Spoiler alert: it’s very, very bad

Drones: they’re small, they’re kinda cute, and they’re really cool. But these little fliers can also be very dangerous, especially to air traffic.

Wing.

Image credits University of Dayton Research Institute.

New research from the University of Dayton (UoD) Research Institute shows that these buzzing motes of technology pose a real threat to larger aircraft, with a direct impact able to cause severe structural damage to an aircraft’s frame.

Winging it

Given that planes are pretty big vehicles and civilian drones tend not to be that way, it’s easy to assume that the former would suffer only minor damage in the case of a collision. However, a new video released by researchers from the University of Dayton shows that this is far from the truth.

The team traditionally studies a similar hazard: that of mid-flight bird-airplane collisions. While such events aren’t too dangerous for planes, they can cause significant difficulties for pilots and some damage to the vehicle. Some of the most dangerous outcomes of a bird-plane collision include broken windows (and subsequent injuries to the crew), and engine damage. The team’s results are forwarded to the aircraft design industry, which uses the data to bird-proof their planes.

Given their background, the team wondered what the outcome of a drone-plane impact would be. In collaboration with researchers at the Sinclair College National UAS Training and Certification Center, they set up an experiment to find out. The test roughly followed the same layout as bird-impact tests: the team set up a target — the wing of a single-engine Mooney M20 — on a fixed mount, shot a drone at it at speeds similar to that of a flying aircraft, and filmed the whole thing. In effect, this simulates a plane hitting a drone during flight.

The footage shows that a drone can cause significant damage to an airplane, should they collide at full speed. Rather than breaking apart, bounding off, or glancing off (like birds tend to do), the drone acted like a cannonball — it tore through the vehicle’s fuselage, causing extensive internal damage. Most worryingly, it chewed right through the wing’s main spar, a key structural unit that carries the plane’s weight (i.e. it’s the part that keeps the wing from breaking off). Damage to the spar has a very high chance of making the plane incapable of flight.

Drone collisions cause greater and more severe damage to planes than birds of comparative size due to their solid motors, batteries, and other parts, the Federal Aviation Administration (FAA) reported in a study last year. These parts are much stiffer than the flesh of birds (which is mostly water), so they don’t disintegrate, and most often penetrate a vehicle’s skin. That study also says the FAA gets more than 250 sightings a month of drones posing potential risks to planes, most often near airports.

The UoD team says we need to do more extensive testing — using different sizes of drones and aircraft models — to fully understand the risks involved in such collisions. Furthermore, they point to a collision between a civilian quadcopter drone and a military helicopter that occurred last year, saying that it’s nearly certain we’ll see more such events in the future. The helicopter in that collision suffered severe damage to its rotor, but was able to make it back to base, crew unharmed.

The FAA called on drone manufacturers to develop and incorporate technology to detect and avoid planes. Judging from the UoD video, that’s a good first step. Pilots definitely shouldn’t rely on sheer luck, or current planes, to save them in a drone impact — both are flimsy defenses.

Andromeda Galaxy.

Two billion years ago, Andromeda ‘ate’ a sister-galaxy of the Milky Way

Our closest galactic neighbor, Andromeda, seems to like the taste of its brethren.

Andromeda Galaxy.

The Andromeda Galaxy imaged through a hydrogen-alpha filter.
Image credits Adam Evans.

Researchers from the University of Michigan (UoM) report that the Andromeda galaxy smote and consumed one of its brethren some two billion years ago. Although its victim was shredded almost completely, the team pieced together evidence of the collision from the thin halo of stars that spans the gap between Andromeda and its enigmatic companion, Meiser 32 (M32).

The discovery helps further our understanding of how galaxies like the Milky Way evolve, and of their behavior during large mergers.

Family dinner

Our own galaxy, the Milky Way, and our closest neighbor, Andromeda, are the two largest members of a group known as the Local Group (of galaxies). The extended family includes some 54 different galaxies — most of them dwarf galaxies acting as satellites for their larger relatives — all orbiting around a point roughly between Andromeda and the Milky Way.

It may sound idyllic, but researchers have found that at least one member of this group found its demise at the hands of Andromeda. This once-galaxy, christened M32p, was the third-largest member of the Local Group — a distinction that now falls on the galaxy Triangulum.

The team started their research using data pertaining to the halo of stars around Andromeda. It’s not a unique feature; many galaxies harbor such wispy-thin groupings of stars around their bulk, the final remnants of smaller galaxies that they absorbed over time. Since Andromeda is so large and rich in matter (it has over double the diameter of the Milky Way and double its number of stars), the researchers expected it to have consumed hundreds of smaller galaxies — which they thought would make it impossible to study a single such meal.

M32.

Size comparison between M32p and today’s M32.
Image credits Richard D’Souza; for the image of M64: NOAO/AURA/NSF.

However, the team’s computer simulations revealed that although Andromeda did dine on many of its companion galaxies, most stars in the outer halo originate from a single, large galaxy. Piecing the evidence together to peer back in time, the team found that M32p would have been massive — likely the third-largest in the Local Group, after Andromeda and the Milky Way. The paper adds that M32p was at least 20 times larger than any galaxy the Milky Way ever merged with.

“The stars in Andromeda are very metal-rich and considerably young,” Richard D’Souza, lead author of the paper, explained in an e-mail. “In general, the larger the galaxy the more metal rich the stars are. We suspected that since the stars in the halo of Andromeda were so metal-rich, it must have come from a large metal-rich galaxy.”

One big bite

A metal-rich halo large enough to encompass a galaxy such as Andromeda could only be formed “through a single large merger,” he adds, noting that “there are not many smaller galaxies in the Universe to build up to the mass of the halo”.

“In terms of a business analogy, galaxies also grow through mergers and acquisitions. In order for a major company to grow at a very fast pace, it would need to acquire a similar large company into its business. Such was the case with Andromeda,” D’Souza adds.

The findings call into question our models of how mergers between two massive galaxies play out. Until now, astronomers believed that such an event would flatten the disk of a spiral galaxy into an elliptical one, but Andromeda’s disk evidently pulled through still very spiral-shaped. Some effects of this collision can still be seen, D’Souza told me. Among them are the thickness of Andromeda’s disk and the higher speeds its stars travel at (90 km/s compared to around 30 km/s in the Milky Way).

Collision path.

The process of shredding of the large galaxy M32p by the Andromeda (M31) galaxy which eventually resulted in M32 and a giant halo of stars.
Image credits Richard D’Souza; M31, courtesy of Wei-Hao Wang; Stellar halo of M31: AAS/IOP.

Still, he admits that it came as “a major surprise” that Andromeda could retain its spiral shape following this collision. One explanation could be that the particular angle of the collision between the two galaxies helped keep Andromeda spiral-like, “but we need to run more computer simulations to see which set of orbits helps preserve the disk”.

Beyond this, it helps us better understand Andromeda’s evolution over time. The timing of the merger coincides with a burst of intense star formation in Andromeda two billion years ago. All this star-forming activity also suggests that M32p must have been gas-rich in order to supply enough building blocks.

Finally, the findings point to Andromeda’s mysterious, compact, and very dense, satellite galaxy M32 (the one today) as the last sliver of the once-mighty galaxy — the naked core. This piece of data could help explain why we see so few galaxies similar to M32 zipping around in the universe.

“M32 is a weirdo,” co-author Eric Bell, UoM professor of astronomy, said in a press release. “While it looks like a compact example of an old, elliptical galaxy, it actually has lots of young stars. It’s one of the most compact galaxies in the universe. There isn’t another galaxy like it.”

“Galaxies like M32 are considerably rare in the Universe,” D’Souza adds. “The term used for them in the literature is called ‘compact ellipticals’, and they are one of the most rarest galaxies in the Universe. We do know a dozen or so compact ellipticals in the nearby Universe, and we have inferred that further out (where we cannot resolve them), the number is equally low.”

As part of the paper, the team also found that the merger scenario could help explain the scarcity of M32-like objects. It seems the secret is not just in the merging process itself, but also in the particular makeup of the galaxies involved. “What one really needs is a galaxy with a high central surface density of stars comparable to M32,” D’Souza explains. It seems to be quite a rare occurrence — the team only identified 8 potential progenitors for M32-like objects.

Their study may alter the traditional understanding of how galaxies evolve, the researchers say. The realization that Andromeda’s disk survived an impact with a massive galaxy flies in the face of our current models, which suggests that such large interactions would destroy disks and form an elliptical galaxy.

It went so fundamentally against the grain of our understanding of galaxy-formation that, previously, we didn’t even consider the possibility that this scenario could have ever occurred.

“Astronomers have been studying the Local Group–the Milky Way, Andromeda and their companions–for so long. It was shocking to realize that the Milky Way had a large sibling, and we never knew about it,” Bell concludes.

Such investigative methods can be applied to other galaxies as well, the team explains, to help us tease out the merger history of other galaxies besides Andromeda.

The paper “The Andromeda galaxy’s most important merger about 2 billion years ago as M32’s likely progenitor” has been published in the journal Nature Astronomy.

Earth may actually be 2 planets, new study finds

A new study that compared the chemical make-up of the Earth to that of the Moon concluded that our planet may be the result of a head-on collision between two planetary bodies: a proto-Earth and another planet called Theia.

Artistic depiction of the collision between Earth and Theia. Copyright William K. Hartmann

Artistic depiction of the collision between Earth and Theia. Copyright William K. Hartmann

The idea of a planetary collision in our planet’s early history is not new. It is generally accepted that the Moon formed as the result of a violent collision between Earth and a “planetary embryo” called Theia approximately 100 million years after the Earth formed – some 4.4 billion years ago. But the prevalent theory was that it was only a swiping collision, taking place at a small angle. UCLA researchers believe this was not the case.

A head-o collision was first proposed in 2012, by Matija Ćuk, now a research scientist with the SETI Institute, and Sarah Stewart, now a professor at UC Davis. In the same year, Robin Canup of the Southwest Research Institute reached the same conclusion. This new study analyzed rocks brought back from the Moon during the Apollo missions. Specifically, they looked at the rocks’ oxygen atoms. Oxygen makes up 90% of their volume and 50% of their weight, so there’s plenty of it to look at. Now, just like many other elements, oxygen also has some isotopes – atoms with the same structure but one or more extra neutron. For example, regular oxygen has an atomic number of 16: it has 8 protons and 8 neutrons. Let’s call it O16. But there’s also O17 and O18, that have one and two extra neutrons respectively. All the planets have a unique ratio of these isotopes, their own “isotopic fingerprint” – but the Moon and the Earth seem to have the same ratio.

“We don’t see any difference between the Earth’s and the moon’s oxygen isotopes; they’re indistinguishable,” said Edward Young, lead author of the new study and a UCLA professor of geochemistry and cosmochemistry.

Paul Warren, Edward Young (holding a sample of a rock from the moon) and Issaku Kohl. Credits: Christelle Snow/UCLA

Paul Warren, Edward Young (holding a sample of a rock from the moon) and Issaku Kohl. Credits: Christelle Snow/UCLA

This fact is very telling. If Earth and Theia would have collided marginally, then the Earth would retain most of its initial make-up, and the Moon would have most of Theia’s make-up. A head-on collision would have mixed the two much more, up to the point where they would have a similar isotopic ratio.

“Theia was thoroughly mixed into both the Earth and the moon, and evenly dispersed between them,” Young said. “This explains why we don’t see a different signature of Theia in the moon versus the Earth.”

Theia did not survive the collision, but it is believed that it now makes large parts of the Moon and even some parts of the Earth.

But not everyone agrees with this finding. A previous study from 2014 found that the isotopic ratio differs so I’d still wait for a tertiary confirmation. Both studies used precise measurements and state-of-the-art equipment.

Gold doesn’t fall out of the sky – but it’s created in the heavens

For thousands of years gold has been the embodiment of wealth. Its chemical stability and scarcity make it ideal for coinage. In the USA, the link between gold and currency has only been weakened in 1933 when the gold standard fell out of use, and was fully separated from the dollar in 1971. While currently no country uses the gold standard any longer, money deriving its value from government regulation or law  (called fiat currency), for much of human history gold has been the basis of most economic structures: everything had a corresponding value relative to the metal.

It is found in economy as a carrier of value, in art as a symbol of grandeur and in social interactions as a sign of high status. Religions across the globe reinforce this key place for gold, using it either literally – in contexts linked with divinity – or metaphorically, as mark of purity. But for the central role it played in human society, we know surprisingly little about how gold came into being. Research by the Harvard-Smithsonian Center for Astrophysics (CfA) may help us better understand the processes which create this soft, shiny and precious metal.

Gold rules the world. Powerful dark magic helps too.
Image credit to vincentxyooj, via: deviantart.com

While we’ve previously wrote on the importance and creation of gold here, research based on recent observations of a nearby gamma-ray burst, GRB 130603B, helps to explain how gold and silver atoms are created.

These bursts are flashes of high-energy light (gamma rays), associated with explosions. Researchers believe that the immense energy released in the GRB 130603B event resulted from the collision of two neutron stars–deceased cores of stars that have exhausted their fuel and exploded. Gamma-ray bursts come in two varieties – long and short – depending on how long the flash of gamma rays lasts. GRB 130603B, detected by NASA’s Swift satellite on June 3rd, lasted for less than two-tenths of a second, followed by a glow dominated by infrared light that radiated from the area for several days after the explosion, exhibiting unusual behavior.

Its brightness and behavior didn’t match a typical ‘afterglow,’ which is created when a high-speed jet of particles slams into the surrounding environment. Instead, the glow behaved like it came from exotic radioactive elements. The neutron-rich material ejected by colliding neutron stars can generate such elements, which then undergo radioactive decay, emitting a glow that’s dominated by infrared light – exactly what the team observed.

“We’ve been looking for a ‘smoking gun’ to link a short gamma-ray burst with a neutron star collision. The radioactive glow from GRB 130603B may be that smoking gun,” explains Wen-fai Fong, a graduate student at the CfA and a co-author of the paper.

In this high-energy event, two neutron stars collide. Scientists believe the glowing aftermath is the origin of elements such as gold. Image via: popsci.com

In this high-energy event, two neutron stars collide. Scientists believe the glowing aftermath is the origin of elements such as gold.
Image via: popsci.com

The team believes that significant quantities of gold and other heavy elements were created and released in that area during the collision.

“We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 moon masses–quite a lot of bling!” lead author Edo Berger said in a statement.

“To paraphrase Carl Sagan, we are all star stuff, and our jewelry is colliding-star stuff,” says Berger.

As gamma-ray burst events are quite frequent, Berger and his colleagues hypothesize that all the gold in our universe could have been created this way.

The team’s results have been submitted for publication in The Astrophysical Journal Letters and are available online. Berger’s co-authors are Wen-fai Fong and Ryan Chornock, both of the CfA.

Giant Radio telescope spots colliding galaxies

A new radio telescope array built in the world’s highest and driest desert in the world has just photographed two colliding galaxies for its first public test shots.

The Atacama Large Millimeter/submillimeter Array, a joint project between Canada, Chile, the European Union, Japan, Taiwan and the United States was officially opened for business after a decade of planning and building. The world’s largest astronomy project, ALMA is described as the most powerful millimeter/submillimeter-wavelength telescope ever and the most complex ground-based observatory, and these first images are a perfect description of what it has to give.

“Today marks the recognition of the successful coalition of thousands of people from all over the world all working with the same goal: to build the world’s most advanced radio telescope to see into the universe’s coldest, darkest places, where galaxies and stars and perhaps the building blocks of life are created,” said ALMA director Thijs de Graauw.

What ALMA photographed isn’t visible in normal light, because the murky material that leads to star birth blocks visible wavelengths of light.

“In the past we couldn’t study them because they were behind the dust. The thing that’s been missing is the youngest stars, which are the most interesting,” said astronomer Brad Whitmore of the Space Telescope Science Institute in a webcast. “This is a beautiful example where we’ll be able to see the full life histories of star clusters.”

What happens is that gas and dust absorb the light of stars and then re-emit the energy, but in different wavelengths of light. However, like black out curtains the thickest molecular dust clouds trap almost all wavelengths, making them extremely hard to spot.

Radio waves are an exception; in the same way that radio frequencies pass even through the thickest of walls, so do they pass through these dust clouds; and ALMA is capable of not only noticing the presence of hot young stars, but also determine rich chemical information about them.

 

“For the last 25 years, we have really only relied on being able to see carbon monoxide or hydrogen cyanide,” said astronomer Kartik Sheth of the National Radio Astronomy Observatory in the webcast. “For the first time, we can see the entire chemical spectrum.”

“We will use ALMA to image the ‘birth ring’ of planetesimals that we believe orbits this young star,” he said. “We hope to discover clumps in these dusty asteroid belts, which can be the markers of unseen planets.”

Via Wired

NASA to collect samples from near-Earth asteroid

NASA announced that it will launch an unmaned ship to a nearby asteroid, in an attempt to figure out more about both the asteroid itself, and how life started on our planet.

The mission, named Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer – or, as always, with an easier more manageable name, Osiris-Rex was chosen to take place from a number of other missions, which included a trip to the far side of Venus.

“This is a critical step in meeting the objectives outlined by President Obama to extend our reach beyond low-Earth orbit and explore into deep space,” said NASA administrator Charlie Bolden. “It’s robotic missions like these that will pave the way for future human space missions to an asteroid and other deep space destinations.”

After a four year travel, Osiris-Rex will approach the near-Earth asteroid 1999 RQ36 in 2020; once it is there, it will remain at a three mile distance for six months, during which it will map the surface of the asteroid. After that, it will draw closer allowing a robotic arm to collect more than two ounces of material for return to Earth in 2023 at the NASA space center in Houston.

Ths mission will help understand the ‘Yarkovsky effect’ for the first time – a small push caused by the sun on an asteroid as it absorbs sunlight and re-emits that energy as heat, an effect that plays a crucial role in avoiding collisions with asteroids.

“This asteroid is a time capsule from the birth of our solar system and ushers in a new era of planetary exploration,” said Jim Green, director of NASA‘s Planetary Science Division. “The knowledge from the mission also will help us to develop methods to better track the orbits of asteroids.”

Via TG Daily

A fifth of Florida’s pumas were killed in car collisions

panther_next_2_mi

There are less than 100 pumas left in Florida’s wilds, and 17 were killed in collisions with cars, which is even more than in 2008 (when 10 such magnificent creatures found their death after being hit by a car) and 2007 (15). For me, it’s absolutely heart breaking to see this happening.

You’d expect people to learn, after panther numbers were down to just 20-30 in 1990. It took some serious efforts to raise their numbers by almost 10 times, but the future is once again looking dire for the felines.

florida_panther_with_cub

“If we don’t do something quickly to reduce the risks to Florida’s panthers as they move around in search of food, mates and territory, then we are facing loss of this iconic species,” said a member from Defenders of Wildlife. “The panther found dead yesterday should serve as a sobering reminder that we all have to do our part to protect the Florida panther and watch out for wildlife while we drive through their habitat.”

They also proposed some good ideas on how this could be stopped, which you can read on their site.