To kids, there are only two kinds of dinosaurs: meat-eaters and plant-eaters. But to paleontologists, those are just diet distinctions. Paleontologists divide dinos into two different groups based largely on pelvic structure: reptile-hipped saurischians, and bird-hipped ornithischians.
Those two categories are called ‘clades’, and they’re fundamental to the study of dinosaurs. But a new study is casting doubt on those two groups, as well as moving the infamous Tyrannosaurus Rex to a new spot on the dinosaur family tree.
The study, by Matthew G. Baron, David B. Norman & Paul M. Barrett, was published in the journal Nature. If the findings in this study are accepted by paleontologists, then it will upset our understanding of the family tree that was first established in Victorian times.
The T. Rex is the most famous member of the reptile-hipped saurischians. Many other carnivorous theropods are saurischians too, like Giganotosaurus and Spinosaurus. Other famous dinosaurs, like Stegosaurus, are bird-hipped ornithischians. The distinction between the saurischians and the ornithischians has been workable for a long time. But there were always problems with the two clades of dinosaurs.
Some of the earliest ornithischian dinosaurs in the Triassic period had some theropod qualities: they were bipedal and probably meat-eaters. This clouded the separation between ornithischians and saurischians. There are also the herrerasaurids, small dinosaurs not larger than 4 meters long. They were some of the earliest dinosaurs, carnivores that look like both sauropods and theropods, and even though they appear early in the fossil record, they are not considered ancestors to any other group of dinosaurs. They show a mixture of both primitive and derived traits.
Huge plant-eating sauropods like the Brontosaurus and the Diplodocus are included in the reptile-hipped saurischians with the meat-eating theropods, even though there are some key skeletal differences between the two groups.
Another problem centers around birds. Believe it or not, birds have theropods as ancestors, even though theropods are in the reptile-hipped clade, rather than the bird-hipped clade.
Are You Confused Yet?
If this all seems kind of confusing, let’s back up for a minute.
When we think of dinosaurs, we tend to think of full-scale rebuilt skeletons of the type on display in museums around the world. But for paleontologists, the reality is much different. Many dinosaur species are known only by a few bones or teeth. These samples are studied in great detail. Any groove in a bone or slightly different shape in a tooth is analyzed, and out of this a dinosaur family tree is constructed.
It’s hard work, and our fossil record is spotty at best. Some new dinosaur taxa are proposed based only on the discovery of isolated teeth in the fossil record. With all of this in mind, you can see that the dinosaur family tree is an ongoing work in progress.
The authors of the study say that many ornithischian dinosaurs were overlooked in the past, because paleontologists didn’t really know what to do with them. Many of the ornithischians had weird traits like extra chin bones and molar-like teeth in their cheeks. These ornithischian dinos were thought of as oddities, early offshoots from other species.
The authors studied 457 traits in 74 taxa, looking at details like the shapes of tiny eye-socket bones and grooves on femurs. They found that Theropods, even though they have reptile-like hips, don’t belong in the saurischian clade. They’re suggesting that Theropods are a sister clade to the ornithischians. The revised grouping of Ornithischia and Theropoda has been named the Ornithoscelida. The authors are also proposing that the herrerasaurids did not branch off as early as previously thought, and should form a sister clade with the sauropods.
But this study does even more. It’s been long understood by paleontologists that dinosaurs appeared in the southern hemisphere first. That’s where the herrerasaurids were found, dating back to 240 million years ago. The authors remind us that there are very few Herrerasaurus skeletons and bones, and there are uncertainties in the age of the Triassic fossil beds where herrerasaurids are found. A nearly complete skeleton was found in Argentina, and less complete ones have been found in North America.
But this shuffling of the family tree moves the herrerasaurids further away from the base of the tree. Remember, the herrerasaurids look like both sauropods and theropods, and they show both derived and primitive traits. If it’s accepted that the herrerasaurids did not appear as early as thought, that might mean that dinos did not appear first in the southern hemisphere. The authors say that some enigmatic fossils found in the northern hemisphere should be re-examined in case they are earlier than the ones found in the south.
Enter the Saltopus
A fossil of a cat-like creature found in Scotland, called the Saltopus, is a part of the shake-up of the dinosaur family tree. It was considered a pre-cursor to dinosaurs, rather than a true dinosaur. As part of their analysis, the Saltopus has been re-positioned in the earliest part of the dinosaur lineage, as the first true dinosaur. This supports the idea that dinosaurs appeared first in the northern hemisphere rather than the south.
If this new family tree for dinosaurs is accepted, it will change our understanding of the way dinosaurs evolved. We’ve relied on similarity in hip shape to ascertain ancestry, but that may be a little simplistic.
Our understanding of dinosaurs changes frequently. Remember when dinosaurs were slow, dim-witted creatures with tiny brains and huge bodies? Now we think of dinosaurs as feathered and fast, using cunning and perhaps teamwork to hunt in packs. Remember when the prevailing wisdom was that some dinosaurs got so large and spiny that they were doomed to extinction? That was proven false as well.
If it does stick, this new family tree will be a huge change in paleontology, a field where knowledge is overturned on a regular basis, sometimes by little more than a few teeth.
We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.
In this series we’ll look at 6 of the world’s Super Telescopes:
While the world’s other Super Telescopes rely on huge mirrors to do their work, the LSST is different. It’s a huge panoramic camera that will create an enormous moving image of the Universe. And its work will be guided by three words: wide, deep, and fast.
While other telescopes capture static images, the LSST will capture richly detailed images of the entire available night sky, over and over. This will allow astronomers to basically “watch” the movement of objects in the sky, night after night. And the imagery will be available to anyone.
At the heart of the LSST is its enormous digital camera. It weighs over three tons, and the sensor is segmented in a similar way that other Super Telescopes have segmented mirrors. The LSST’s camera is made up of 189 segments, which together create a camera sensor about 2 ft. in diameter, behind a lens that is over 5 ft. in diameter.
Each image that the LSST captures is 40 times larger than the full moon, and will measure 3.2 gigapixels. The camera will capture one of these wide-field images every 20 seconds, all night long. Every few nights, the LSST will give us an image of the entire available night sky, and it will do that for 10 years.
“The LSST survey will open a movie-like window on objects that change brightness, or move, on timescales ranging from 10 seconds to 10 years.” – LSST: FROM SCIENCE DRIVERS TO REFERENCE DESIGN AND ANTICIPATED DATA PRODUCTS
The LSST will capture a vast, movie-like image of over 40 billion objects. This will range from distant, enormous galaxies all the way down to Potentially Hazardous Objects as small as 140 meters in diameter.
There’s a whole other side to the LSST which is a little more challenging. We get the idea of an in-depth, moving, detailed image of the sky. That’s intuitively easy to engage with. But there’s another side, the data mining challenge.
The Data Challenge
The whole endeavour will create an enormous amount of data. Over 15 terabytes will have to be processed every night. Over its 10 year lifespan, it will capture 60 petabytes of data.
Once data is captured by the LSST, it will travel via two dedicated 40 GB lines to the Data Processing and Archive Center. That Center is a super-computing facility that will manage all the data and make it available to users. But when it comes to handling the data, that’s just the tip of the iceberg.
“LSST is a new way to observe, and gaining knowledge from the Big Data LSST delivers is indeed a challenge.” – Suzanne H. Jacoby, LSST
The sheer amount of data created by the LSST is a challenge that the team behind it saw coming. They knew they would have to build the capacity of the scientific community in advance, in order to get the most out of the LSST.
As Suzanne Jacoby, from the LSST team, told Universe today, “To prepare the science community for LSST Operations, the LSST Corporation has undertaken an “Enabling Science” effort which funds the LSST Data Science Fellowship Program (DSFP). This two-year program is designed to supplement existing graduate school curriculum and explores topics including statistics, machine learning, information theory, and scalable programming.”
The Nature of Dark Matter and Understanding Dark Energy
Contributing to our understanding Dark Energy and Dark Matter is a goal of all of the Super Telescopes. The LSST will map several billion galaxies through time and space. It will help us understand how Dark Energy behaves over time, and how Dark Matter affects the development of cosmic structure.
Cataloging the Solar System
The raw imaging power of the LSST will be a game-changer for mapping and cataloguing our Solar System. It’s thought that the LSST could detect between 60-90% of all potentially hazardous asteroids (PHAs) larger than 140 meters in diameter, as far away as the main asteroid belt. This will not only contribute to NASA’s goal of identifying threats to Earth posed by asteroids, but will help us understand how planets formed and how our Solar System evolved.
Exploring the Changing Sky
The repeated imaging of the night sky, at great depth and with excellent image quality, should tell us a lot about supernovae, variable stars, and possible other events we haven’t even discovered yet. There are always surprising results whenever we build a new telescope or send a probe to a new destination. The LSST will probably be no different.
Milky Way Structure & Formation
The LSST will give us an unprecedented look at the Milky Way. It will survey over half of the sky, and will do so repeatedly. Hundreds of times, in fact. The end result will be an enormously detailed look at the motion of millions of stars in our galaxy.
Perhaps the best part of the whole LSST project is that the all of the data will be available to everyone. Anyone with a computer and an internet connection will be able to access LSST’s movie of the Universe. It’s warm and fuzzy, to be sure, to have the results of large science endeavours like this available to anyone. But there’s more to it. The LSST team suspects that the majority of the discoveries resulting from its rich data will come from unaffiliated astronomers, students, and even amateurs.
It was designed from the ground up in this way, and there will be no delay or proprietary barriers when it comes to public data access. In fact, Google has signed on as a partner with LSST because of the desire for public access to the data. We’ve seen what Google has done with Google Earth and Google Sky. What will they come up with for Google LSST?
The Sloan Digital Sky Survey (SDSS), a kind of predecessor to the LSST, was modelled in the same way. All of its data was available to astronomers not affiliated with it, and out of over 6000 papers that refer to SDSS data, the large majority of them were published by astronomers not affiliated with SDSS.
We’ll have to wait a while for all of this to come our way, though. First light for the LSST won’t be until 2021, and it will begin its 10 year run in 2022. At that time, be ready for a whole new look at our Universe. The LSST will be a game-changer.
We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.
In this series we’ll look at 6 of the world’s Super Telescopes:
The Giant Magellan Telescope (GMT) is being built in Chile, at the Las Campanas Observatory, home of the GMT’s predecessors the Magellan Telescopes. The Atacama region of Chile is an excellent location for telescopes because of its superb seeing conditions. It’s a high-altitude desert, so it’s extremely dry and cool there, with little light pollution.
The GMT is being built by the USA, Australia, South Korea, and Brazil. It started facility construction in 2015, and first light should be in the early 2020’s.
Segmented mirrors are the peak of technology when it comes to super telescopes, and the GMT is built around this technology.
The GMT’s primary mirror consists of 7 separate mirrors: one central mirror surrounded by 6 other mirrors. Together they form an optical surface that is 24.5 meters (80 ft.) in diameter. That means the GMT will have a total light collecting area of 368 square meters, or almost 4,000 square feet. The GMT will outperform the Hubble Space Telescope by having a resolving power 10 times greater.
There’s a limit to the size of single mirrors that can be built, and the 8.4 meter mirrors in the GMT are at the limits of construction methods. That’s why segmented systems are in use in the GMT, and in other super telescopes being designed and built around the world.
These mirrors are modern feats of engineering. Each one is made of 20 tons of glass, and takes years to build. The first mirror was cast in 2005, and was still being polished 6 years later. In fact, the mirrors are so massive, that they need 6 months to cool when they come out of casting.
They aren’t just flat, simple mirrors. They’re described as potato chips, rather than being flat. They’re aspheric, meaning the mirrors’ faces have steeply curved surfaces. The mirror’s have to have exactly the same curvature in order to perform together, which requires leading-edge manufacturing. The mirrors’ paraboloidal shape has to be polished to an accuracy greater than 25 nanometers. That’s about 1/25th the wavelength of light itself!
In fact, if you took one of the GMT’s mirrors and spread it out from the east coast to the west coast of the USA, the height of the tallest mountain on the mirror would be only 1/2 of one inch.
The plan is for the Giant Magellan Telescope to begin operation with only four of its mirrors. The GMT will also have an extra mirror built, just for contingencies.
The construction of the GMT’s mirrors required entirely new testing methods and equipment to achieve these demanding accuracies. The entire task fell on the University of Arizona’s Richard F. Caris Mirror Lab.
But GMT is more than just its primary mirror. It also has a secondary mirror, which is also segmented. Each one of the secondary mirror’s segments must work in concert with its matching segment on the primary mirror, and the distance from secondary mirror to primary mirror has to be measured within one part in 500 million. That requires exacting engineering for the steel structure of the body of the telescope.
The engineering behind the GMT is extremely demanding, but once it’s in operation, what will it help us learn about the Universe?
“I think the really exciting things will be things that we haven’t yet though of.” -Dr. Robert Kirshner
The GMT will help us tackle multiple mysteries in the Universe, as Dr. Robert Kirshner, of the Harvard-Smithsonian Center for Astrophysics, explains in this video.
The scientific aims of the GMT are well laid out, and there aren’t really any surprises. The goals of the GMT are to increase our understanding of some fundamental aspects of our Universe:
Star, planet, and disk formation
Extrasolar planetary systems
Stellar populations and chemical evolution
Galaxy assembly and evolution
First light and reionization
The GMT will collect more light than any other telescope we have, which is why its development is so keenly followed. It will be the first ‘scope to directly image extrasolar planets, which will be enormously exciting. With the GMT, we may be able to see the color of planets, and maybe even weather systems.
We’re accustomed to seeing images of Jupiter’s storm bands, and weather phenomena on other planets in our Solar System, but to be able to see something like that on extra-solar planets will be astounding. That’s something that even the casual space-interested person will immediately be fascinated by. It’s like science fiction come to life.
Of course, we’re still a ways away from any of that happening. With first light not anticipated until the early 2020’s, we’ll have to be very patient.
Isn’t modern society great? With all this technology surrounding us in all directions. It’s like a cocoon of sweet, fluffy silicon. There are chips in my fitness tracker, my bluetooth headset, mobile phone, car keys and that’s just on my body.
At all times in the Cain household, there dozens of internet devices connected to my wifi router. I’m not sure how we got to the point, but there’s one thing I know for sure, more is better. If I could use two smartphones at the same time, I totally would.
And I’m sure you agree, that without all this technology, life would be a pale shadow of its current glory. Without these devices, we’d have to actually interact with each other. Maybe enjoy the beauty of nature, or something boring like that.
It turns out, that terrible burning orb in the sky, the Sun, is fully willing and capable of bricking our precious technology. It’s done so in the past, and it’s likely to take a swipe at us in the future.
I’m talking about solar storms, of course, tremendous blasts of particles and radiation from the Sun which can interact with the Earth’s magnetosphere and overwhelm anything with a wire.
In fact, we got a sneak preview of this back in 1859, when a massive solar storm engulfed the Earth and ruined our old timey technology. It was known as the Carrington Event.
Follow your imagination back to Thursday, September 1st, 1859. This was squarely in the middle of the Victorian age.
And not the awesome, fictional Steampunk Victorian age where spectacled gentleman and ladies of adventure plied the skies in their steam-powered brass dirigibles.
No, it was the regular crappy Victorian age of cholera and child labor. Technology was making huge leaps and bounds, however, and the first telegraph lines and electrical grids were getting laid down.
Imagine a really primitive version of today’s electrical grid and internet.
On that fateful morning, the British astronomer Richard Carrington turned his solar telescope to the Sun, and was amazed at the huge sunspot complex staring back at him. So impressed that he drew this picture of it.
While he was observing the sunspot, Carrington noticed it flash brightly, right in his telescope, becoming a large kidney-shaped bright white flare.
Carrington realized he was seeing unprecedented activity on the surface of the Sun. Within a minute, the activity died down and faded away.
And then about 5 minutes later. Aurora activity erupted across the entire planet. We’re not talking about those rare Northern Lights enjoyed by the Alaskans, Canadians and Northern Europeans in the audience. We’re talking about everyone, everywhere on Earth. Even in the tropics.
In fact, the brilliant auroras were so bright you could read a book to them.
The beautiful night time auroras was just one effect from the monster solar flare. The other impact was that telegraph lines and electrical grids were overwhelmed by the electricity pushed through their wires. Operators got electrical shocks from their telegraph machines, and the telegraph paper lit on fire.
What happened? The most powerful solar flare ever observed is what happened.
A solar flare occurs because the Sun’s magnetic field lines can get tangled up in the solar atmosphere. In a moment, the magnetic fields reorganize themselves, and a huge wave of particles and radiation is released.
Flares happen in three stages. First, you get the precursor stage, with a blast of soft X-ray radiation. This is followed by the impulsive stage, where protons and electrons are accelerated off the surface of the Sun. And finally, the decay stage, with another burp of X-rays as the flare dies down.
These stages can happen in just a few seconds or drag out over an hour.
Remember those particles hurled off into space? They take several hours or a few days to reach Earth and interact with our planet’s protective magnetosphere, and then we get to see beautiful auroras in the sky.
This geomagnetic storm causes the Earth’s magnetosphere to jiggle around, which drives charges through wires back and forth, burning out circuits, killing satellites, overloading electrical grids.
Back in 1859, this wasn’t a huge deal, when our quaint technology hadn’t progressed beyond the occasional telegraph tower.
Today, our entire civilization depends on wires. There are wires in the hundreds of satellites flying overhead that we depend on for communications and navigation. Our homes and businesses are connected by an enormous electrical grid. Airplanes, cars, smartphones, this camera I’m using.
Everything is electronic, or controlled by electronics.
Think it can’t happen? We got a sneak preview back in March, 1989 when a much smaller geomagnetic storm crashed into the Earth. People as far south as Florida and Cuba could see auroras in the sky, while North America’s entire interconnected electrical grid groaned under the strain.
The Canadian province of Quebec’s electrical grid wasn’t able to handle the load and went entirely offline. For 12 hours, in the freezing Quebec winter, almost the entire province was without power. I’m telling you, that place gets cold, so this was really bad timing.
Satellites went offline, including NASA’s TDRS-1 communication satellite, which suffered 250 separate glitches during the storm.
And on July 23, 2012, a Carrington-class solar superstorm blasted off the Sun, and off into space. Fortunately, it missed the Earth, and we were spared the mayhem.
If a solar storm of that magnitude did strike the Earth, the cleanup might cost $2 trillion, according to a study by the National Academy of Sciences.
It’s been 160 years since the Carrington Event, and according to ice core samples, this was the most powerful solar flare over the last 500 years or so. Solar astronomers estimate solar storms like this happen twice a millennium, which means we’re not likely to experience another one in our lifetimes.
But if we do, it’ll cause worldwide destruction of technology and anyone reliant on it. You might want to have a contingency plan with some topic starters when you can’t access the internet for a few days. Locate nearby interesting nature spots to explore and enjoy while you wait for our technological civilization to be rebuilt.
Have you ever seen an aurora in your lifetime? Give me the details of your experience in the comments.
The wonderful thing about science is that it’s constantly searching for new evidence, revising estimates, throwing out theories, and sometimes discovering aspects of the Universe that we never realized existed.
The best science is skeptical of itself, always examining its own theories to find out where they could be wrong, and seriously considering new ideas to see if they better explain the observations and data.
What this means is that whenever I state some conclusion that science has reached, you can’t come back a few years later and throw that answer in my face. Science changes, it’s not my fault.
I get it, VY Canis Majoris isn’t the biggest star any more, it’s whatever the biggest star is right now. UY Scuti? That what it is today, but I’m sure it’ll be a totally different star when you watch this in a few years.
What I’m saying is, the science changes, numbers update, and we don’t need to get concerned when it happens. Change is a good thing. And so, it’s with no big surprise that I need to update the estimate for the number of galaxies in the observable Universe. Until a couple of weeks ago, the established count for galaxies was about 200 billion galaxies.
But a new paper published in the Astrophysics Journal revised the estimate for the number of galaxies, by a factor of 10, from 200 billion to 2 trillion. 200 billion, I could wrap my head around, I say billion all the time. But 2 trillion? That’s just an incomprehensible number.
Does that throw all the previous estimates for the number of stars up as well? Actually, it doesn’t.
The observable Universe measures 13.8 billion light-years in all directions. What this means is that at the very edge of what we can see, is the light left that region 13.8 billion years ago. Furthermore, the expansion of the Universe has carried to those regions 46 billion light-years away.
Does that make sense? The light you’re seeing is 13.8 billion light-years old, but now it’s 46 billion light-years away. What this means is that the expansion of space has stretched out the light from all the photons trying to reach us.
What might have been visible or ultraviolet radiation in the past, has shifted into infrared, and even microwaves at the very edge of the observable Universe.
Since astronomers know the volume of the observable Universe, and they can calculate the density of the Universe, they know the mass of the entire Universe. 3.4 x 10^54 kilograms including regular matter and dark matter. They also know the ratio of regular matter to dark matter, so they can calculate the total amount of regular mass in the Universe.
In the past, astronomers divided that total mass by the number of galaxies they could see in the original Hubble data and determined there were about 200 billion galaxies.
Now, astronomers used a new technique to estimate the galaxies and it’s pretty cool. Astronomers used the Hubble Space Telescope to peer into a seemingly empty part of the sky and identified all the galaxies in it. This is the Hubble Ultra Deep Field, and it’s one of the most amazing pictures Hubble has ever captured.
Astronomers painstakingly converted this image of galaxies into a 3-dimensional map of galaxy size and locations. Then, they used their knowledge of galaxy structure closer to home to provide a more accurate estimate of what the galaxies must look like, out there, at the very edge of our observational ability.
For example, the Milky Way is surrounded by about 50 satellite dwarf galaxies, each of which has a fraction of the mass of the Milky Way.
By recognizing which were the larger main galaxies, they could calculate the distribution of smaller, dimmer dwarf galaxies that weren’t visible in the Hubble images.
In other words, if the distant Universe is similar to the nearby Universe, and this is one of the principles of modern astronomy, then the distant galaxies have the same structure as nearby galaxies.
It doesn’t mean that the Universe is bigger than we thought, or that there are more stars, it just means that the Universe contains more galaxies, which have less stars in them. There are the big main galaxies, and then a smooth distribution curve of smaller and smaller galaxies down to the tiny dwarf galaxies. The total number of stars comes out to be the same number.
The galaxies we can see are just the tip of the galactic iceberg. For every galaxy we can see, there are another 9, smaller fainter galaxies that we can’t see.
Furthermore, James Webb is an infrared telescope, a specialized tool for looking at cooler objects, and galaxies which are billions of light-years away. The kinds of galaxies that Hubble can only hint at, James Webb will be able to see directly.
So, why don’t we see galaxies in all directions with our eyeballs? This is actually an old conundrum, proposed by Wilhelm Olbers in the 1700, appropriately named Olber’s Paradox. We did a whole article on it, but the basic idea is that if you look in any direction, you’ll eventually hit a star. It could be close, like the Sun, or very far away, but whatever the case, it should be stars in all directions. Which means that the entire night sky should be as bright as the surface of a star. Clearly it isn’t, but why isn’t it?
In fact, with 10 times the number of galaxies, you could restate the paradox and say that in every direction, you should be looking at a galaxy, but that’s not what you see.
Except you are. Everywhere you look, in all directions, you’re seeing galaxies. It’s just that those galaxies are red-shifted from the visible spectrum into the infrared spectrum, so your eyeballs can’t perceive them. But they’re there.
When you see the sky in microwaves, it does indeed glow in all directions. That’s the Cosmic Microwave Background Radiation, shining behind all those galaxies.
It turns out the Universe has 10 times more galaxies than previously estimated – 2 trillion galaxies. Not 10 times the stars or mass, those numbers have stayed the same.
And, once James Webb launches, those numbers will be fine-tuned again to be even more precise. 1.5 trillion? 3.4 trillion? Stay tuned for the better number.
In 2003, the Japanese Aerospace Exploration Agency (JAXA) launched the Hayabusa probe. Its mission was to rendezvous with asteroid 25143 Itokawa in 2005. Once there, it studied a number of things about Itokawa, including its shape, topography, composition, colour, spin, density, and history. But the most exciting part of its mission was to collect samples from the asteroid and return them to Earth.
The mission suffered some complications, including the failure of Minerva, Hayabusa’s detachable mini-lander. But Hayabusa did land on the asteroid, and it did collect some samples; tiny grains of material from the surface of Itokawa. This was the first time a mission had landed somewhere and returned samples, other than missions to the Moon.
Once the collected grains made it back to Earth in 2010, and were confirmed to be from the asteroid, scientists got excited. These grains would be key to helping understand the early Solar System when the planetary bodies were formed. And they have revealed a sometimes violent history going back 4.5 billion years.
The grains themselves are truly microscopic, at just over 10 micrometers in size. The marks and surface patterns on them are measured in nanometers. Initially, all the marks on the surfaces of the particles were thought to be of one type. But the team behind the study used electron microscopes and X-Ray Microtomography to reveal four different types of patterns on their surfaces.
One 4.5 billion year old pattern shows crystallization from intense heat. At this time period, Itokawa was part of a larger asteroid. The second pattern indicates a collision with a meteor about 1.3 billion years ago. Another pattern was formed by exposure to the solar wind between 1 million and 1,000 years ago. A fourth pattern detected by scientists shows that the particles have been rubbing against each other.
The team has concluded that Itokawa didn’t always exist in its current shape and form. When it was formed over 4 billion years ago, it was about 40 times bigger than it is now. That parent body was destroyed, and the researchers think that Itokawa re-formed from fragments of the parent body.
If there is still any lingering doubt about the violent nature of the Solar System’s history, the grains from Itokawa help dispel it. Collision, fragmentation, bombardments, and of course solar wind, seem to be the norm in our Solar System’s history.
The return of these samples was a bit of a happy accident. The sample collection mechanism on Hayabusa suffered a failure, and the returned dust grains were actually kicked up by the landing of the probe, and some ended up in the sample capsule.
For their part, JAXA has already launched Hayabusa’s successor, Hayabusa 2. It was launched in December 2014, and is headed for asteroid 162173 Ryugu. It should reach its destination in July 2018, and spend a year and a half there. Hayabusa 2 is also designed to collect asteroid samples and return them to Earth, this time using an explosive device to dig into the asteroid’s surface for a sample. Hayabusa 2 should return to Earth in December 2020.
Hayabusa suffered several failures, including the failure of its mini-lander, problems with sample collection, and it even suffered damaged to its solar panels caused by a solar flare, which reduced its power and delayed its arrival at Itokawa. Yet it still ended up being a success in the end.
If Hayabusa 2 can avoid some of these problems, who knows what we may learn from more intentional samples. Sample missions are tricky and complex. If Hayabusa can return samples, it would be only the fourth body to have samples successfully returned to Earth, including the Moon, asteroid Itokawa, and comet Wild 2.
We’ve had an abundance of news stories for the past few months, and not enough time to get to them all. So we are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!
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The spread of metallurgy in different civilizations is a keen point of interest for historians and archaeologists. It helps chart the rise and fall of different cultures. There are even names for the different ages corresponding to increasingly sophisticated metallurgical technologies: the Stone Age, the Bronze Age, and the Iron Age.
But sometimes, a piece of evidence surfaces that doesn’t fit our understanding of a civilization.
Probably the most iconic ancient civilization in all of history is ancient Egypt. Its pyramids are instantly recognizable to almost anyone. When King Tutankhamun’s almost intact tomb was discovered in 1922, it was a treasure trove of artifacts. And though the tomb, and King Tut, are most well-known for the golden death mask, it’s another, little-known artifact that has perhaps the most intriguing story: King Tut’s iron dagger.
King Tut’s iron-bladed dagger wasn’t discovered until 1925, three years after the tomb was discovered. It was hidden in the wrappings surrounding Tut’s mummy. It’s mere existence was a puzzle, because King Tut reigned in 1332–1323 BC, 600 years before the Egyptians developed iron smelting technology.
It was long thought, but never proven, that the blade may be made of meteorite iron. In the past, tests have produced inconclusive results. But according to a new study led by Daniela Comelli, of the Polytechnic University of Milan, and published in the Journal of Meteoritics and Planetary Science, there is no doubt that a meteorite was the source of iron for the blade.
The team of scientists behind the study used a technique called x-ray fluorescence spectrometry to determine the chemical composition of the blade. This technique aims x-rays at an artifact, then determines its composition by the spectrum of colors given off. Those results were then compared with 11 other meteorites.
In the dagger’s case, the results indicated Fe plus 10.8 wt% Ni and 0.58 wt% Co. This couldn’t be a coincidence, since iron meteorites are mostly made of Fe (Iron) and Ni (Nickel), with minor quantities of Co (Cobalt), P (Phosphorus), S (Sulphur), and C (Carbon). Iron found in the Earth’s crust has almost no Ni content.
Testing of Egyptian artifacts is a tricky business. Egypt is highly protective of their archaeological resources. This study was possible only because of advances in portable x-ray fluorescence spectrometry, which meant the dagger didn’t have to be taken to a lab and could be tested at the Egyptian Museum of Cairo.
Iron objects were rare in Egypt at that time, and were considered more valuable than gold. They were mostly decorative, probably because ancient Egyptians found iron very difficult to work. It requires a very high heat to work with, which was not possible in ancient Egypt.
Even without the ability to heat and work iron, a great deal of craftsmanship went into the blade. The dagger itself had to be hammered into shape, and it features a decorated golden handle and a rounded rock crystal knob. It’s golden sheath is decorated with a jackal’s head and a pattern of feathers and lilies.
Ancient Egyptians probably new what they were working with. They called meteorite iron from the sky in one hieroglyph. Whether they knew with absolute certainty that their iron meteorites came from the sky, and what that might have meant, they did value the iron. As the authors of the study say, “…our study confirms that ancient Egyptians attributed great value to meteoritic iron for the production of precious objects.”
The authors go on to say, “Moreover, the high manufacturing quality of Tutankhamun’s dagger blade, in comparison with other simple-shaped meteoritic iron artifacts, suggests a significant mastery of ironworking in Tutankhamun’s time.”