YOU’VE BEEN WORKING AT TANIS, A TOP-SECRET FOSSIL LOCATION IN NORTH DAKOTA. WHEN WAS THIS SITE LAID DOWN?
We worked out the site was deposited during the fallout of coarse ejecta material [debris] from an asteroid impact. To give it probably the broadest span possible, we can say the site is constrained [dated] to the first one to two hours [after asteroid impact], maximum, because that’s how long ejecta would have been falling for.
HAVE YOU FOUND ANY OTHER EVIDENCE THAT THIS SITE WAS CREATED RIGHT AFTER THE ASTEROID IMPACT?
We have constrained the site in multiple different ways, using plants, pollen, marine dinoflagellates and different organisms. In addition to that, we have physics. When the asteroid hit, material was thrown out of the crater [as vaporised and molten rock] and out of the atmosphere, where it cooled and solidified, then fell back to Earth in a rain of glowing glass droplets, or spherules. These spherules would have started to arrive at Tanis tens of minutes after impact, raining down for around an hour, two at most. The impact glass has been radiometrically dated, and it dates to the very end of the Cretaceous. Basically, it correlates exactly with the Chicxulub impact event [the moment the asteroid that wiped out the dinosaurs hit Earth in Mexico].
WHAT IS THE SIGNIFICANCE OF THE SPHERULES?
You’re dealing with stuff that was molten by the impact, and they therefore contain contamination from the impactor itself.
この記事は BBC Science Focus の May 2022 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
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この記事は BBC Science Focus の May 2022 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
すでに購読者です? サインイン
COULD MARINE CLOUD BRIGHTENING HELP US FIGHT CLIMATE CHANGE?
The theory behind marine cloud brightening is that brighter or whiter clouds reflect more sunlight back into space.
IS IT SAFE TO RUN EVERY DAY, OR SHOULD I DITCH MY RUN STREAK TO SAVE MY KNEES?
A running streak, where you run every day without taking rest days, can be highly motivating and beneficial for overall fitness. Running is great cardiovascular exercise and isn't to be discouraged (and finding a routine with some consistency is great). Getting a bit of exercise as often as possible is also hugely beneficial for your mental health.
WHAT MAKES THE MEDITERRANEAN DIET SO GOOD FOR US?
The Mediterranean diet may help you live longer, especially if you also adopt the lifestyle of people living near the Med during the 1950s.
WHAT IS MEXICO'S BLUE HOLE?
The world's deepest blue hole (marine sinkhole) lies off the coast of Mexico's Yucatán Peninsula. It's at least 420m (1,378ft) deep, but explorers still haven't found its bottom.
HOW CAN I TELL IF I'VE GOT HIGH CORTISOL LEVELS?
Cortisol is a hormone produced by glands in our bodies called the adrenal glands, which sit above the kidneys. It plays a critical role in various bodily functions, including regulating metabolism, reducing inflammation and helping the body respond to stress. While essential for our health, chronic elevation of cortisol levels can lead to several issues.
THE LUNGFISH
In 1836, European scientists discovered a peculiar animal from the River Amazon that they struggled to identify. Its eel-like body was a few feet long and its air-filled lungs persuaded anatomists it must be a reptile.
ARE WE THE ONLY SPECIES TO HAVE BEEN THROUGH A STONE AGE?
The Stone Age might conjure up images of early humans, sitting around a campfire or hunting prehistoric beasts, but evidence shows that we're not the only species that has learned how to work with stone tools. Wild chimpanzees (Pan troglodytes) use stone tools to crack open nuts.
Should we scrap daylight saving time?
Most of us look forward to the extra hour we get in bed every October, but researchers argue that changing the clocks twice a year harms our health
THE INTERNET OF ANIMALS
SCIENTISTS ARE USING ELECTRONIC TAGS AND SATELLITES TO TRACK WILD ANIMALS AND CREATE A DATA NETWORK THAT COULD HELP US ADDRESS THE BIODIVERSITY CRISIS
MUSIC FOR A DISTRACTED GENERATION
The number of things competing for our attention is often overwhelming. Can dreamy soundscapes created with neuroscience help our bewildered brains to concentrate?
