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Scientists find 'smoking gun' proof of a recent supernova near Earth
A supernova exploded near Earth about 2.5 million years ago, possibly causing an extinction event.
- Researchers from the University of Munich find evidence of a supernova near Earth.
- A star exploded close to our planet about 2.5 million years ago.
- The scientists deduced this by finding unusual concentrations of isotopes, created by a supernova.
If you wanted some more shattering news, we now know that a supernova exploded very close to Earth about 2.5 million years ago. That might sound like a long time ago, but in the life of our 4.5 billion-year-old planet, that's just yesterday.
Supernovas are amazingly bright explosions of stars at the end of their lives. A recent study found a blast 4.5 million light-years away could release as much as 10 times the amount of energy that a sun can emit in its lifetime. It also spreads a tremendous amount of chemicals all throughout the cosmos. Just-released research looked at such a spread and found that concentrations of particular elements point to a supernova near Earth just 2.5 million years ago.
The scientists found an unusual amount of 53Mn, a radioisotope made by supernovas. Previous studies looked for such traces in concentrations of 60Fe, an isotope of iron.
The scientists, led by Dr. Gunther Korschinek from the Technical University of Munich, focused their study on ferromanganese crusts. These marine sediments, composed mainly of iron and manganese oxides, grow in time and jut out from the water. This makes them great record-keepers of chemicals in the water around them. While examining these ferromanganese crusts from locations in the Pacific Ocean, the team found not only the isotope 60Fe, but also 53Mn. The samples came from 1,589 meters (5,213 feet) down to 5,120 meters (3.18 miles) down.
What does the presence of 60Fe tell the researchers? It's half-life of 2.6 million years indicates that it was created in a nearby supernova explosion in relatively recently times. Otherwise, 60Fe would have decayed into nickel.
One other explanation for the presence of the isotope is its possible creation in the death throes of asymptotic giant branch (AGB) stars. But the presence of 53Mn, which cannot be produced by such stars, clearly points to supernovae as the origin, think the scientists.
This Manganese crust started to form about 20 million years ago. Growing layer by layer, it resulted in minerals precipitated out of seawater.
Elevated concentrations of 60 Fe and 56 Mn in layers from 2.5 million years ago hints at a nearby supernova explosion around that time. Credit: Dominik Koll/ TUM
"The increased concentrations of manganese-53 can be taken as the 'smoking gun' – the ultimate proof that this supernova really did take place," shared Dr. Korschinek in a press release.
The researchers used accelerator mass spectrometry to locate the 53Mn atoms in the crust that looks like hardened chocolate cake.
"This is investigative ultra-trace analysis," said Korschinek. "We are talking about merely a few atoms here." He explained further that the technique is also very useful in figuring out the sizes of the original stars, adding "accelerator mass spectrometry is so sensitive that it even allows us to calculate from our measurements that the star that exploded must have had around 11 to 25 times the size of the sun."
If there was a supernova in Earth's relatively recent history, what effect did it have on the planet? The scientists think it likely caused cosmic ray showers and affected the climate. It might have also caused a partial extinction event – the Pliocene marine megafauna extinction
Check out the study "Supernova-Produced 53Mn on Earth" in the journal Physical Review Letters.
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The finding is remarkably similar to the Dunning-Kruger effect, which describes how incompetent people tend to overestimate their own competency.
- Recent studies asked participants to rate the attractiveness of themselves and other participants, who were strangers.
- The studies kept yielding the same finding: unattractive people overestimate their attractiveness, while attractive people underrate their looks.
- Why this happens is unclear, but it doesn't seem to be due to a general inability to judge attractiveness.
There's no shortage of disparities between attractive and unattractive people. Studies show that the best-looking among us tend to have an easier time making money, receiving help, avoiding punishment, and being perceived as competent. (Sure, research also suggests beautiful people have shorter relationships, but they also have more sexual partners, and more options for romantic relationships. So call it a wash.)
Now, new research reveals another disparity: Unattractive people seem less able to accurately judge their own attractiveness, and they tend to overestimate their looks. In contrast, beautiful people tend to rate themselves more accurately. If anything, they underestimate their attractiveness.
The research, published in the Scandinavian Journal of Psychology, involved six studies that asked participants to rate the attractiveness of themselves and other participants, who were strangers. The studies also asked participants to predict how others might rate them.
In the first study, lead author Tobias Greitemeyer found that the participants who were most likely to overestimate their attractiveness were among the least attractive people in the study, based on average ratings.
Ratings of subjective attractiveness as a function of the participant's objective attractiveness (Study 1)
"Overall, unattractive participants judged themselves to be of about average attractiveness and they showed very little awareness that strangers do not share this view. In contrast, attractive participants had more insights into how attractive they actually are. [...] It thus appears that unattractive people maintain illusory self‐perceptions of their attractiveness, whereas attractive people's self‐views are more grounded in reality."
Why do unattractive people overestimate their attractiveness? Could it be because they want to maintain a positive self-image, so they delude themselves? After all, previous research has shown that people tend to discredit or "forget" negative social feedback, which seems to help protect a sense of self-worth.
To find out, Greitemeyer conducted a study that aimed to put participants in a positive, non-defensive mindset before rating attractiveness. He did that by asking participants questions that affirmed parts of their personality that had nothing to do with physical appearance, such as: "Have you ever been generous and selfless to another person?" Yet, this didn't change how participants rated themselves, suggesting that unattractive people aren't overestimating their looks out of defensiveness.
The studies kept yielding the same finding: unattractive people overestimate their attractiveness. Does that bias sound familiar? If so, you might be thinking of the Dunning-Kruger effect, which describes how incompetent people tend to overestimate their own competency. Why? Because they lack the metacognitive skills needed to discern their own shortcomings.
Greitemeyer found that unattractive people were worse at differentiating between attractive and unattractive people. But the finding that unattractive people may have different beauty ideals (or, more plainly, weaker ability to judge attractiveness) did "not have an impact on how they perceive themselves."
In short, it remains a mystery exactly why unattractive people overestimate their looks. Greitemeyer concluded that, while most people are decent at judging the attractiveness of others, "it appears that those who are unattractive do not know that they are unattractive."
Unattractive people aren't completely unaware
The results of one study suggested that unattractive people aren't completely in the dark about their looks. In the study, unattractive people were shown a set of photos of highly attractive and unattractive people, and they were asked to select photos of people with comparable attractiveness. Most unattractive people chose to compare themselves with similarly unattractive people.
"The finding that unattractive participants selected unattractive stimulus persons with whom they would compare their attractiveness to suggests that they may have an inkling that they are less attractive than they want it to be," Greitemeyer wrote.
Every star we can see, including our sun, was born in one of these violent clouds.
This article was originally published on our sister site, Freethink.
An international team of astronomers has conducted the biggest survey of stellar nurseries to date, charting more than 100,000 star-birthing regions across our corner of the universe.
Stellar nurseries: Outer space is filled with clouds of dust and gas called nebulae. In some of these nebulae, gravity will pull the dust and gas into clumps that eventually get so big, they collapse on themselves — and a star is born.
These star-birthing nebulae are known as stellar nurseries.
The challenge: Stars are a key part of the universe — they lead to the formation of planets and produce the elements needed to create life as we know it. A better understanding of stars, then, means a better understanding of the universe — but there's still a lot we don't know about star formation.
This is partly because it's hard to see what's going on in stellar nurseries — the clouds of dust obscure optical telescopes' view — and also because there are just so many of them that it's hard to know what the average nursery is like.
The survey: The astronomers conducted their survey of stellar nurseries using the massive ALMA telescope array in Chile. Because ALMA is a radio telescope, it captures the radio waves emanating from celestial objects, rather than the light.
"The new thing ... is that we can use ALMA to take pictures of many galaxies, and these pictures are as sharp and detailed as those taken by optical telescopes," Jiayi Sun, an Ohio State University (OSU) researcher, said in a press release.
"This just hasn't been possible before."
Over the course of the five-year survey, the group was able to chart more than 100,000 stellar nurseries across more than 90 nearby galaxies, expanding the amount of available data on the celestial objects tenfold, according to OSU researcher Adam Leroy.
New insights: The survey is already yielding new insights into stellar nurseries, including the fact that they appear to be more diverse than previously thought.
"For a long time, conventional wisdom among astronomers was that all stellar nurseries looked more or less the same," Sun said. "But with this survey we can see that this is really not the case."
"While there are some similarities, the nature and appearance of these nurseries change within and among galaxies," he continued, "just like cities or trees may vary in important ways as you go from place to place across the world."
Astronomers have also learned from the survey that stellar nurseries aren't particularly efficient at producing stars and tend to live for only 10 to 30 million years, which isn't very long on a universal scale.
Looking ahead: Data from the survey is now publicly available, so expect to see other researchers using it to make their own observations about stellar nurseries in the future.
"We have an incredible dataset here that will continue to be useful," Leroy said. "This is really a new view of galaxies and we expect to be learning from it for years to come."
Tiny specks of space debris can move faster than bullets and cause way more damage. Cleaning it up is imperative.
- NASA estimates that more than 500,000 pieces of space trash larger than a marble are currently in orbit. Estimates exceed 128 million pieces when factoring in smaller pieces from collisions. At 17,500 MPH, even a paint chip can cause serious damage.
- To prevent this untrackable space debris from taking out satellites and putting astronauts in danger, scientists have been working on ways to retrieve large objects before they collide and create more problems.
- The team at Clearspace, in collaboration with the European Space Agency, is on a mission to capture one such object using an autonomous spacecraft with claw-like arms. It's an expensive and very tricky mission, but one that could have a major impact on the future of space exploration.
This is the first episode of Just Might Work, an original series by Freethink, focused on surprising solutions to our biggest problems.
Catch more Just Might Work episodes on their channel: https://www.freethink.com/shows/just-might-work