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Zircon in a meteorite opens the door on Mars’ past
Zircons in a Martian meteorite widens the possible timeframe for life on Mars.
- A meteorite from Mars unexpectedly contains zircons that reveal the planets history.
- The rock likely comes from one of the solar system's tallest volcanoes.
- Analyzing the zirconium required smashing some very expensive rock.
Just last week, we wrote about one lab's conclusion that water may be a common byproduct in the formation of rocky planets. This week, the same lab has announced that the very same Martian meteorite that led to that earlier finding has yet another secret to reveal: It contains lots of zircons, minerals thought to be scarce on Mars. Having so many now is "like opening a time window into the geologic history of planet ," according to senior author of both studies Martin Bizzarro from the GLOBE Institute at the University of Copenhagen.
Zirconian time capsules
Earth zircon in gem form atop calcite
Credit: Rob Lavinsky, iRocks.com/Wikimedia
"We were quite surprised and excited when we found so many zircons in this Martian meteorite," says Bizzarro. "Zircon are incredible durable crystals that can be dated and preserve information that tell us about their origins." Zircons are a rarity on Mars' surface — which resembles the crust beneath Earth's ocean floors — and so scientists have not been expecting to find much of the mineral.
What makes this so intriguing, Bizzarro explains to the Danish National Research Foundation, is that zircon "functions as a small time capsule because it obtains and saves information about the environment as well as when it was created. In this case a time capsule with hafnium, which comes from Mars' early crust, which existed around 100 million years before the oldest zircon in Black Beauty was created. Thus, Mars got an early start in comparison with Earth, whose solid crust was created much later."
Breaking Black Beauty
Big Think readers may recall that the meteorite — known as "Black Beauty," though its official name is "Northwest Africa 7533" — cost the university $500,000 dollars for 50 grams of its 319.8-gram volume. As such, deciding to perform any sort of analysis that requires damaging the precious rock is not a decision taken lightly, as when, say, zircons are found in the stone.
"One of the big challenges," says Bizzarro, "has been that the zircons in Black Beauty are extremely small. This called for a courageous strategy: We crushed our precious meteorite. Or to be precise: We crushed 5 grams."
The decision paid off, says Bizzarro: "Today, I'm glad we chose that strategy. It released seven zircons, one of which is the oldest known zircon from Mars. And from the zircons and their content of hafnium, we can now conclude that the crystallization of the surface of Mars went extremely fast: already 20 million years after the formation of the solar system, Mars had a solid crust that could potentially could house oceans and perhaps also life."
Eventually, the team would crush 15 grams of Black Beauty, extracting 60 zircons.
Old and young zircons
The oldest Martian zircon found so far
Credit: Martin Bizzarro/University of Copenhagen
"Zircon is a very solid mineral that is ideal for making such an absolute dating of time. In this regard, zircon can be used as a portal to pinpoint a time frame for the history of crust formation on Mars." Dating of Black Beauty's zircons shed new light on the planet's history. Most of the minerals were dated back to roughly 4.5 billion years ago, the earliest days of the planet.
Unexpectedly, though, some of the zircons were more recently formed, a period from about 1,500 million years ago to 300 million years. "These young ages were a great surprise," recalls Bizzarro.
That finding may have to do with where the rock came from. "The Black Beauty meteorite is believed to come from the southern hemisphere of Mars, which does not have any young volcanic terrains. The only possible source for these young zircons is the Tharsis volcanic province located in the northern hemisphere of the planet, which contains large volcanoes that were recently active," Martin Bizzarro adds.
That province, known as the Tharsis bulge, is a huge volcanic area that's got the largest volcanoes, up to 21 kilometers (13 miles) high, yet seen anywhere in the solar system. It's believed that since Mars lacks plate tectonics, volcanoes gather in a single area, beneath which a massive reservoir of magma is likely located.
First author of the study is Mafalda Costa , who says, "Having samples of the deep interior of Mars is key. This means that we can now use these zircons to probe the origin of the volatile elements on Mars, including its water, and see how it compares with Earth and other planets in the Solar System."
The most important element the zircons contain for the purpose of looking into Mars history is hafnium. Bizzarro explains that hafnium "retains a memory of where the zircon formed. We found that the hafnium isotope composition of the young zircons is unlike any of the known Martian meteorites, which indicates that the young zircons come from a primitive reservoir that we did not know existed in the interior of Mars."
What is human dignity? Here's a primer, told through 200 years of great essays, lectures, and novels.
- Human dignity means that each of our lives have an unimpeachable value simply because we are human, and therefore we are deserving of a baseline level of respect.
- That baseline requires more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose.
- We look at incredible writings from the last 200 years that illustrate the push for human dignity in regards to slavery, equality, communism, free speech and education.
The inherent worth of all human beings<p>Human dignity is the inherent worth of each individual human being. Recognizing human dignity means respecting human beings' special value—value that sets us apart from other animals; value that is intrinsic and cannot be lost.</p> <p>Liberalism—the broad political philosophy that organizes society around liberty, justice, and equality—is rooted in the idea of human dignity. Liberalism assumes each of our lives, plans, and preferences have some unimpeachable value, not because of any objective evaluation or contribution to a greater good, but simply because they belong to a human being. We are human, and therefore deserving of a baseline level of respect. </p> <p>Because so many of us take human dignity for granted—just a fact of our humanness—it's usually only when someone's dignity is ignored or violated that we feel compelled to talk about it. </p> <p>But human dignity means more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose—a freedom that can be hampered by restrictive social institutions or the tyranny of the majority. The liberal ideal of the good society is not just peaceful but also pluralistic: It is a society in which we respect others' right to think and live differently than we do.</p>
From the 19th century to today<p>With <a href="https://books.google.com/ngrams/graph?year_start=1800&year_end=2019&content=human+dignity&corpus=26&smoothing=3&direct_url=t1%3B%2Chuman%20dignity%3B%2Cc0" target="_blank" rel="noopener noreferrer">Google Books Ngram Viewer</a>, we can chart mentions of human dignity from 1800-2019.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg0ODU0My9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1MTUwMzE4MX0.bu0D_0uQuyNLyJjfRESNhu7twkJ5nxu8pQtfa1w3hZs/img.png?width=980" id="7ef38" class="rm-shortcode" data-rm-shortcode-id="9974c7bef3812fcb36858f325889e3c6" data-rm-shortcode-name="rebelmouse-image" />
American novelist, writer, playwright, poet, essayist and civil rights activist James Baldwin at his home in Saint-Paul-de-Vence, southern France, on November 6, 1979.
Credit: Ralph Gatti/AFP via Getty Images
The future of dignity<p>Around the world, people are still working toward the full and equal recognition of human dignity. Every year, new speeches and writings help us understand what dignity is—not only what it looks like when dignity is violated but also what it looks like when dignity is honored. In his posthumous essay, Congressman Lewis wrote, "When historians pick up their pens to write the story of the 21st century, let them say that it was your generation who laid down the heavy burdens of hate at last and that peace finally triumphed over violence, aggression and war."</p> <p>The more we talk about human dignity, the better we understand it. And the sooner we can make progress toward a shared vision of peace, freedom, and mutual respect for all. </p>
With just a few strategical tweaks, the Nazis could have won one of World War II's most decisive battles.
- The Battle of Britain is widely recognized as one of the most significant battles that occurred during World War II. It marked the first major victory of the Allied forces and shifted the tide of the war.
- Historians, however, have long debated the deciding factor in the British victory and German defeat.
- A new mathematical model took into account numerous alternative tactics that the German's could have made and found that just two tweaks stood between them and victory over Britain.
Two strategic blunders<p>Now, historians and mathematicians from York St. John University have collaborated to produce <a href="http://www-users.york.ac.uk/~nm15/bootstrapBoB%20AAMS.docx" target="_blank">a statistical model (docx download)</a> capable of calculating what the likely outcomes of the Battle of Britain would have been had the circumstances been different. </p><p>Would the German war effort have fared better had they not bombed Britain at all? What if Hitler had begun his bombing campaign earlier, even by just a few weeks? What if they had focused their targets on RAF airfields for the entire course of the battle? Using a statistical technique called weighted bootstrapping, the researchers studied these and other alternatives.</p><p>"The weighted bootstrap technique allowed us to model alternative campaigns in which the Luftwaffe prolongs or contracts the different phases of the battle and varies its targets," said co-author Dr. Jaime Wood in a <a href="https://www.york.ac.uk/news-and-events/news/2020/research/mathematicians-battle-britain-what-if-scenarios/" target="_blank">statement</a>. Based on the different strategic decisions that the German forces could have made, the researchers' model enabled them to predict the likelihood that the events of a given day of fighting would or would not occur.</p><p>"The Luftwaffe would only have been able to make the necessary bases in France available to launch an air attack on Britain in June at the earliest, so our alternative campaign brings forward the air campaign by three weeks," continued Wood. "We tested the impact of this and the other counterfactuals by varying the probabilities with which we choose individual days."</p><p>Ultimately, two strategic tweaks shifted the odds significantly towards the Germans' favor. Had the German forces started their campaign earlier in the year and had they consistently targeted RAF airfields, an Allied victory would have been extremely unlikely.</p><p>Say the odds of a British victory in the real-world Battle of Britain stood at 50-50 (there's no real way of knowing what the actual odds are, so we'll just have to select an arbitrary figure). If this were the case, changing the start date of the campaign and focusing only on airfields would have reduced British chances at victory to just 10 percent. Even if a British victory stood at 98 percent, these changes would have cut them down to just 34 percent.</p>
A tool for understanding history<p>This technique, said co-author Niall Mackay, "demonstrates just how finely-balanced the outcomes of some of the biggest moments of history were. Even when we use the actual days' events of the battle, make a small change of timing or emphasis to the arrangement of those days and things might have turned out very differently."</p><p>The researchers also claimed that their technique could be applied to other uncertain historical events. "Weighted bootstrapping can provide a natural and intuitive tool for historians to investigate unrealized possibilities, informing historical controversies and debates," said Mackay.</p><p>Using this technique, researchers can evaluate other what-ifs and gain insight into how differently influential events could have turned out if only the slightest things had changed. For now, at least, we can all be thankful that Hitler underestimated Britain's grit.</p>
We’ve mapped a million previously undiscovered galaxies beyond the Milky Way. Take the virtual tour here.
See the most detailed survey of the southern sky ever carried out using radio waves.
Astronomers have mapped about a million previously undiscovered galaxies beyond the Milky Way, in the most detailed survey of the southern sky ever carried out using radio waves.
A new study shows our planet is much closer to the supermassive black hole at the galaxy's center than previously estimated.
Credit: NAOJ<p><em>Arrows on this map show position and velocity data for the 224 objects utilized to model the Milky Way Galaxy. The solid black lines point to the positions of the spiral arms of the Galaxy. Colors reflect groups of objects that are part of the same arm, while the background is a simulation image.</em></p>
Apple sold its first iPod in 2001, and six years later it introduced the iPhone, which ushered in a new era of personal technology.