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Dinosaur killing meteor hit Earth at 'worst possible angle'
You think you've had a day where everything that went wrong could? T-Rex has you beat.
- A new study suggests that the object that brought about the end of the dinosaurs crashed into the Earth at a 60-degree angle.
- This is about the worst possible angle for such an impact.
- The findings also help explain the nature of the impact crater in Yucatan.
A new study out of the Imperial College in London and published in Nature Communications suggests that the asteroid impact that wiped out the dinosaurs struck just the right place at just the right angle to be as utterly catastrophic as it was for the three-quarters of the planet's species that it wiped out.
Talk about bad luck
The angle of an asteroid impact can have effects on the aftermath every bit as dramatic as increasing or decreasing the size of the asteroid itself.
According to the findings of this study, the asteroid struck Earth at around sixty degrees. At that angle, the amount of climate-changing gas released by the impact is up to three times higher than the amount released by an impact at a lower one. The result of this was a global impact winter that doomed the dinosaurs and took a fair amount of other plant and animal life down with them.
Had it struck at a lower angle, the force of the impact would have been dispersed more widely in more shallow layers of rock, sending fewer gasses into the air. A review of most craters suggests that impactors tend to come in at low angles. The odds of one coming in at sixty degrees or above is just one in four.
This was made worse by the location, just off the coast of what is now Yucatan. Gypsum deposits at the impact site would have released vast amounts of sulfur gas into the atmosphere, as described above. If the impact site had been somewhere else with a different geological makeup, fewer climate-altering gasses would have been released by the impact.
Sometimes, you just can't win.
The result of this perfect storm of high impact angle and sulfate laden location was apocalyptic. The impactor, assumed in this study to be a 12 kilometers (7 miles) wide asteroid made of granite, slammed into the Earth at terminal velocity. It blew a hole in the crust perhaps 30 kilometers (19 miles) deep, and sent up mountains of fluidized rocks to rival the Himalayas before they collapsed.
Endless supplies of vaporized sulfur were released into the atmosphere, severely reducing the amount of solar radiation reaching the Earth. Some estimates suggest this was severe enough to make photosynthesis impossible.
How do we know all this? I mean, it was 65 million years ago, and the dinosaurs didn't leave notes.
We do know what the impact crater looks like; you can see it for yourself in the Yucatan. The part that is on land is known for its sinkholes, which map out the impact site. If you know that you can model a variety of scenarios and compare them to the conditions we see. If they match, we have a winner. This is what the scientists did.
Professor Collins of the Imperial College of London and the lead author of this study explained the results: "If you run the model at different impact angles, at 30 degrees and at 45 degrees, say, you can't match the observations - you get centres of mantle uplift and of the peak ring on the downrange side of the crater centre. And for a straight overhead impact, at 90 degrees, the centres are all on top of each other. So, that's doesn't match the observations, either."
As a result, we know that if the angle of impact was flatter it would have produced different effects, and the people reading this might be advanced dinosaurs rather than intelligent apes. Likewise, Yucatan might not have its famous, beautiful sinkholes.
Now that would be a tragedy.
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A Mercury-bound spacecraft's noisy flyby of our home planet.
- There is no sound in space, but if there was, this is what it might sound like passing by Earth.
- A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
- Yes, in space no one can hear you scream, but this is still some chill stuff.
First off, let's be clear what we mean by "hear" here. (Here, here!)
Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.
All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.
Image source: European Space Agency
The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.
Into and out of Earth's shadow
In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.
The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."
In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."
When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.
The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.
BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.
MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.
Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.
Research suggests that aging affects a brain circuit critical for learning and decision-making.
As people age, they often lose their motivation to learn new things or engage in everyday activities. In a study of mice, MIT neuroscientists have now identified a brain circuit that is critical for maintaining this kind of motivation.
Researchers develop the first objective tool for assessing the onset of cognitive decline through the measurement of white spots in the brain.
- MRI brain scans may show white spots that scientists believe are linked to cognitive decline.
- Experts have had no objective means of counting and measuring these lesions.
- A new tool counts white spots and also cleverly measures their volumes.
White spots and educated guesses<p>The white spots, or "hyperintensities," are brain lesions—fluid-filled holes in the brain believed to have been left behind by the breaking down of blood vessels that had previously provided nourishment to brain cells.</p><p>Prior to the new research, the quantity of white spots was assessed using an imprecise three-point scale indicating ascending likelihoods of dementia: A minimal number of spots was considered as level 1, a medium number of spots level 2, and a great number of them level 3.</p>
How the new measurements were derived<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDYwMTc1OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNDQ1ODExNX0.vqhQJSvL99KjOe24TOs4E8R7c6-pprbXYSrGcIqbVps/img.jpg?width=980" id="c64d9" class="rm-shortcode" data-rm-shortcode-id="002d9b8ef47b5a86c3a387ad2cd90629" data-rm-shortcode-name="rebelmouse-image" />
Credit: sfam_photo/Shutterstock<p>The team of researchers from NYU's Langone's <a href="https://med.nyu.edu/departments-institutes/neurology/divisions-centers/center-cognitive-neurology" target="_blank">Center for Cognitive Neurology</a> and <a href="https://med.nyu.edu/departments-institutes/neurology/divisions-centers/center-cognitive-neurology/alzheimers-disease-research-center" target="_blank">Alzheimer's Disease Research Center</a> were led by <a href="https://med.nyu.edu/faculty/jingyun-chen" target="_blank">Jingyun "Josh" Chen</a>. They analyzed 72 MRI scans from a national database of older people taken as part of the <a href="http://adni.loni.usc.edu" target="_blank">Alzheimer's Disease Neuroimaging Initiative</a> (ADNI). The scans were mostly of white people over age 70, and there were a roughly equivalent number of men and women. Some had normal brain function, some were presenting moderate cognitive decline, and some had severe dementia.</p><p>Without knowing each individual's diagnosis, the researchers analyzed the white spots in their scans. While the team counted each scan's lesions, the innovation they introduced was the production of a 3D measurement for each lesion's fluid volume. The measurement was derived by measuring a lesion's distance from opposite sides of the brain.</p><p>Measurements of 0 milliliters (mL) were assessed for areas without white spots, with other white spots coming up as containing 60 mL of fluid. Chen's team predicted that volumes over 100 mL could signify severe dementia.</p><p>"Amounts of white matter lesions above the normal range should serve as an early warning sign for patients and physicians," Chen told <a href="https://nyulangone.org/news/white-matter-lesion-mapping-tool-identifies-early-signs-dementia" target="_blank">NYU Langone Health NewsHub</a>.</p><p>When the team compared the likely diagnoses derived from their calculations against the individuals' medical records, they found that their predictions were correct about 7 out of 10 times.</p><p>The researchers compiled their formulas into an online tool that's available to physicians for free via <a href="https://github.com/jingyunc/wmhs" target="_blank" rel="noopener noreferrer">GitHub</a>. The researchers plan to further refine and test it using an additional 1,495 brain scans representing a more diverse group of individuals from the ADNI database.</p>