Dino Doomsday Asteroid Baked Earth For 100,000 Years

By Eric Betz | May 24, 2018 1:00 pm
Home»October»Drilling to Doomsday FROM THE OCTOBER 2016 ISSUE Drilling to Doomsday An expedition in the Gulf of Mexico gets to the core of the most important event in the past 100 million years. By Eric Betz|Tuesday, May 09, 2017 RELATED TAGS: NATURAL DISASTERS 60 doomsday A 9-mile-wide asteroid smashed into a shallow sea off Mexico’s Yucatan Peninsula 66 million years ago. Some 75 percent of life on Earth died in the aftermath (Credit: Mark Garlick)

A 9-mile-wide asteroid smashed into a shallow sea off Mexico’s Yucatan Peninsula 66 million years ago. Some 75 percent of life on Earth died in the aftermath (Credit: Mark Garlick)

Some 66 million years ago, a city-sized asteroid set fire to the planet and began what was likely the worst day in history. Decades of research have helped illuminate the actual impact. But scientists are still figuring out what happened over the years that followed.

Based on studies of the impact site, it’s likely that sulfur vaporized from the crater would have choked our atmosphere and blocked the sun for years or decades. So Earth likely cooled into a kind of nuclear winter, with land temps plummeting as much as 28 degrees Celsius (50 degrees Fahrenheit). And after that debris settled, the lingering carbon dioxide probably pushed our planet into an epic period of global warming. But most of the specifics — like just how hot is hellish? — have come from models rather than the rock record.

Now, a study published Friday in the journal Science attempts to change that. By examining many millennia worth of tiny fossils, the researchers estimate that Earth’s global average temps rose by a whopping 5 degrees Celsius (9 degrees Fahrenheit) after the impact and stayed at that level for some 100,000 years. That’s roughly in line with what some models had previously projected.

Nonetheless, it’s still a dramatic change. For comparison, climate change researchers are currently investigating the impact of a 1.5 degree Celsius increase over the next century. So the study not only illuminates what killed off the world of the dinosaurs, it can also offer hints about what could happen as human-caused greenhouse gasses drive up temperatures in the centuries to come.

Fishy Bits

University of Missouri geologist Ken MacLeod has spent years trying to better understand this ancient period of Earth’s history. He’s traveled the world studying sites where a thin layer of sediment separates the final dinosaur days from the first years of the era that followed. This rock layer, called the Cretaceous-Paleogene boundary, or K/Pg, is easy to identify because it’s rich in iridium — an element common in asteroids but rare on Earth.

For this most recent study, MacLeod’s team excavated a site just outside El Kef, Tunisia, that boasts one of the most important sections of this K/Pg boundary. On a nondescript hillside, they dug a small trench and kept the relevant dirt so they could search it for sand-grain sized fossils laid down before and after the impact. It was a time when this region was underwater.

Once the team had their samples back at the University of Missouri, they washed the slurry though a sieve. Then, using a binocular microscope, they picked out tiny fish bits — teeth, scales, bone. These microfossils were deposited during the last 50,000 years of the Cretaceous, the age of the dinosaurs, and the first several hundred thousand years that followed the impact.

“While rare, there was enough fish debris in virtually all samples to make measurements,” MacLeod says.

And by dividing those fishy bits into three bins — one before, one just after and another immediately after that — they were able to spot distinct changes.

Signatures of isotopic oxygen inside the fish fossils act like a thermometer, storing a record of the time that creature lived. And changes in those signatures imply that the global temperature climbed by 5 degrees Celsius after the impact and didn’t cool to prior levels for some 100,000 years.

The authors do admit it’s possible that changing local conditions could have caused the temperature variations if, say, ocean circulation or some other factor changed nearby for a time. However they also say that other finds within their fossils would seem to rule out such a temporary local change.

Overall, the level of global warming they described matches what some other scientists have suggested based on studying fossilized leaves. But, if they’re right, it would mean that global carbon dioxide levels rose to a truly insane 2,300 parts per million (ppm). That’s significantly higher than some other estimates. For comparison, thanks to human emissions, global CO2 levels have now climbed above 410ppm for the first time in millions of years.

So, if CO2 levels were truly that high after the impact, it might suggest even more widespread wildfires than expected or some other carbon sources not previously predicted that would have contributed to emissions. Either way, the new study provides one more data point in the effort to understand some of the worst times on planet Earth.

CATEGORIZED UNDER: Environment, Living World

A Billion-dollar Shipwreck Finally Comes to Light

By Amber Jorgenson | May 24, 2018 12:59 pm
(Credit: Samuel Scott)

(Credit: Samuel Scott)

Buried treasure doesn’t just exist in the movies.

The Woods Hole Oceanographic Institution (WHOI) recently announced new details of the discovery of the San José — a Spanish galleon carrying a treasure of gold, silver and emeralds that went down in the War of Spanish Succession in 1708. You could quite literally say that its cargo is worth a boat-load — valued in the billions of dollars today.

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CATEGORIZED UNDER: Living World
MORE ABOUT: archaeology, ocean

The Aftermath of Michael Jackson’s Antigravity Lean

By Mark Barna | May 22, 2018 1:03 pm
The infamous lean.

The infamous lean.

In Michael Jackson’s 1987 music video “Smooth Criminal,” the legendary performer leans forward 45 degrees from a straight-up position — and comes back. It’s a feat that seemingly defies both physics and physiology, and the move has become another element of MJ’s aura of mystery.

Some type of cinematic or mechanical trick must be responsible, since most people can manage only a 20-degree forward tilt before toppling headlong. Yet Jackson performed the move live on tours around the world for years. Read More

CATEGORIZED UNDER: Health & Medicine

Giant Flatworms Invade France

By Lauren Sigfusson | May 22, 2018 11:13 am
giant-flatworm-invasive

This giant invasive flatworm, a Diversibipalium ‘blue,’ made its way to a French territory off Africa. (Credit: Laurent Charles – CCBY 4.0)

Worms have a way of appearing in strange, unwanted places: Inside feet, eyeballs and stomachs. Turns out some are even invading countries.

Giant predatory flatworms have inched their way into France and its overseas territories on four continents, according to a study released Tuesday in PeerJ. The invasive flatworms were documented by citizen scientists and managed to stay under the radar for more than two decades. This is the first study to cover the invasion. Read More

CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: animals

Astronomers Find First Interstellar Immigrant

By Jake Parks | May 21, 2018 11:50 am
New research suggests the asteroid 2015 BZ509 may have originally traveled to the solar system from another star. (Credit: NASA/JPL)

New research suggests the asteroid 2015 BZ509 may have originally traveled to the solar system from another star. (Credit: NASA/JPL)

Less than a year ago, astronomers discovered ‘Oumuamua, the first known object from another star system to pass through our own. Now, in a new study published today in the Monthly Notices of the Royal Astronomical Society: Letters, astronomers announced the discovery of the first interstellar object known to have taken up permanent residence around the Sun. Read More

CATEGORIZED UNDER: Space & Physics, top posts

Physicists See Quantum Effects in Photosynthesis

By Bill Andrews | May 21, 2018 10:26 am
(Credit: Shutterstock)

With photosynthesis, scientists show for the first time that there are quantum effects in living systems. This could lead to better solar panels, energy storage or even quantum computers.  (Credit: Shutterstock)

We all probably learned about photosynthesis, how plants turn sunlight into energy, in school. It might seem, therefore, that we figured out this bit of the world. But scientists are still learning new things about even the most basic stuff (see also the sun and moon), and photosynthesis is no different.

In particular, according to a study released Monday in Nature Chemistry, an international team of scientists showed that molecules involved in photosynthesis display quantum mechanical behavior. Even though we’d suspected as much before, this is the first time we’ve seen quantum effects in living systems. Not only will it help us better understand plants, sunlight and everything in between, but it could also mean cool new tech in the future. Read More

Mosquito Bites Leave A Lasting Impression On Our Immune System

By Roni Dengler | May 17, 2018 1:06 pm
(Credit: Kokhanchikov/Shutterstock)

(Credit: Kokhanchikov/Shutterstock)

Mosquito bites are like a gross form of French kissing — the insects swap your blood with their saliva, and leave a trail of salivary secretions behind like mosquito cooties. Some of those compounds prevent clotting as the insects slurp up your blood. Now researchers find mosquito spit aggravates your immune system for days afterward. The findings could help scientists develop vaccines for mosquito-born diseases like Zika.

Rebecca Rico-Hesse, a virologist at Baylor College of Medicine in Houston, Texas, wanted to know how mosquitoes exploit our immune systems with their drool. So, she and her team exposed mice with human-like immune systems to live mosquitoes. Then, they sized up the mice’s immune response as it reacted to the mosquito spittle. Read More

CATEGORIZED UNDER: Health & Medicine, Living World

Your Emergency Contact Does More Than You Think

By Lauren Sigfusson | May 17, 2018 12:57 pm
(Credit: Shutterstock)

(Credit: Shutterstock)

You know when you’re filling out your medical paperwork and it asks for your emergency contact? Sure, the process might be annoying, but that emergency contact could actually be put to good use by researchers.

Since many of us use a family member, those contacts can help scientists create family trees. And they can also be used for genetics and disease research, according to a study released Thursday in Cell. Read More

CATEGORIZED UNDER: Health & Medicine, top posts

Uncovering Roman History With Ice Cores and Lead

By Nathaniel Scharping | May 16, 2018 4:58 pm
(Credit: Bukhta Yurii/Shutterstock)

(Credit: Bukhta Yurii/Shutterstock)

Scientists today are searching for the “Golden Spike,” evidence for the presence of man that will show up even hundreds of thousands of years from now. Such a marker would officially kick off the Anthropocene, the epoch of man, and candidates include the presence of radiation from nuclear bomb tests in geological samples and elevated levels of CO2 preserved in ice cores.

But even today, we can look back into the layers of Earth’s past and see evidence of humanity. Researchers have peered into an ice core from Greenland and found that they can track the fortunes of the Roman Empire over a period of almost 2,000 years. Elevated levels of lead gave the Romans away — a byproduct of the silver smelting used to make their unique coinage. The Romans, by proxy of lead, show up clearly in the ice, and fluctuations in the lead levels match up with periods of good fortune and bad luck for the empire. Read More

CATEGORIZED UNDER: Environment, Living World

Researchers Close In On Birthdate of First Stars

By Jake Parks | May 16, 2018 1:15 pm
With the help of the Atacama large Millimeter/submillimeter Array, astronomers have detected the earliest signs of oxygen (red) distributed in the galaxy MACS1149-JD1. The discovery provides the strongest evidence yet that stars in the fledgling universe started forming earlier than previously thought — when it was less than 2 percent its current age. (Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, W. Zheng (JHU), M. Postman (STScI), the CLASH Team, Hashimoto et al.)

With the help of the Atacama large Millimeter/submillimeter Array, astronomers have detected the earliest signs of oxygen (red) distributed in the galaxy MACS1149-JD1. The discovery provides the strongest evidence yet that stars in the fledgling universe started forming earlier than previously thought — when it was less than 2 percent its current age. (Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, W. Zheng (JHU), M. Postman (STScI), the CLASH Team, Hashimoto et al.)

The Atacama Large Millimeter/submillimeter Array (ALMA) is not your standard, run-of-the-mill telescope. Instead, ALMA, which is located in the high-and-dry Atacama Desert of northern Chile, is a radio telescope made up of 66 high-precision antennas that operate in perfect harmony. When ALMA’s antennas (which range from 7 to 12 meters in diameter) are configured in different ways, the array is capable of zooming in on some of the most distant cosmic objects in the universe, as well as capturing images that are clearer than those produced by the Hubble Space Telescope.
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CATEGORIZED UNDER: Space & Physics
MORE ABOUT: stars
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