Dinosaur asteroid hit 'worst possible place'

Scientists who drilled into the impact crater associated with the demise of the dinosaurs summarise their findings so far in a BBC Two documentary on Monday.

The researchers recovered rocks from under the Gulf of Mexico that were hit by an asteroid 66 million years ago.

The nature of this material records the details of the event.

It is becoming clear that the 15km-wide asteroid could not have hit a worse place on Earth.

https://ichef.bbci.co.uk/news/624/cpsprodpb/CA49/production/_96058715_bm_bm_eotd_02738308.jpgThe drill rig was on station in the Gulf in April and May last year / BARCROFT PRODUCTIONS/BBC

The shallow sea covering the target site meant colossal volumes of sulphur (from the mineral gypsum) were injected into the atmosphere, extending the "global winter" period that followed the immediate firestorm.

Had the asteroid struck a different location, the outcome might have been very different.

"This is where we get to the great irony of the story – because in the end it wasn’t the size of the asteroid, the scale of blast, or even its global reach that made dinosaurs extinct – it was where the impact happened," said Ben Garrod, who presents The Day The Dinosaurs Died with Alice Roberts.

https://ichef-1.bbci.co.uk/news/624/cpsprodpb/5901/production/_96058722_bm_bm_eotd_02738320.jpgThe fractured rocks were subjected to immense pressures / BARCROFT PRODUCTIONS/BBC

"Had the asteroid struck a few moments earlier or later, rather than hitting shallow coastal waters it might have hit deep ocean.

"An impact in the nearby Atlantic or Pacific oceans would have meant much less vaporised rock – including the deadly gypsum. The cloud would have been less dense and sunlight could still have reached the planet’s surface, meaning what happened next might have been avoided.

"In this cold, dark world food ran out of the oceans within a week and shortly after on land. With nothing to eat anywhere on the planet, the mighty dinosaurs stood little chance of survival."

Ben Garrod spent time on the drill rig that was stationed 30km off Mexico's Yucatan Peninsula in April/May last year, to better understand the aims of the project; Alice Roberts visited widely separated fossil beds in the Americas, to get a sense of how life was upended by the impact.

Rock cores from up to 1,300m beneath the Gulf were recovered.

The lowest sections of this material come from a feature within the crater called the peak ring.

This is made from rock that has been heavily fractured and altered by immense pressures.

By analysing its properties, the drill project team - led by Profs Jo Morgan and Sean Gulick - hope to reconstruct how the impact proceeded and the environmental changes it brought about.

Chicxulub Crater - The impact that changed life on Earth

  • A 15km-wide object dug a hole in Earth's crust 100km across and 30km deep
  • This bowl then collapsed, leaving a crater 200km across and a few km deep
  • The crater's centre rebounded and collapsed again, producing an inner ring
  • Today, much of the crater is buried offshore, under 600m of sediments
  • On land, it is covered by limestone, but its rim is traced by an arc of sinkholes
  • They know now the energy that went into making the crater when the asteroid struck - equivalent to 10 billion Hiroshima A-bombs. And they also understand how the depression assumed the structure we observe today.

    The team is also gaining insights into the return of life to the impact site in the years after the event.

    One of the many fascinating sequences in the BBC Two programme sees Alice Roberts visit a quarry in New Jersey, US, where 25,000 fossil fragments have been recovered - evidence of a mass die-off of creatures that may have been among the casualties on the day of the impact itself.

    "All these fossils occur in a layer no more than 10cm thick," palaeontologist Ken Lacovara tells Alice.

    "They died suddenly and were buried quickly. It tells us this is a moment in geological time. That's days, weeks, maybe months. But this is not thousands of years; it's not hundreds of thousands of years. This is essentially an instantaneous event."

    The Day The Dinosaurs Died is on BBC Two at 21:00, after which it will be available on the BBC iPlayer.

Full Moon, Comet Starring in Night Sky Show This Weekend

A full moon and comet share double billing in a special night sky show this weekend.

A lunar eclipse starts everything off Friday night. The moon will pass into Earth's outer shadow, or penumbra. The moon won't be blacked out like in a full eclipse. Only part of the moon will be shaded, but it should be easily visible from much of the world.

Comet 45P, meanwhile, will zoom past Earth early Saturday morning. It will be an extremely close encounter as these things go, passing within 7.7 million miles (12.4 million kilometers) of Earth. Its relative speed: 14.2 miles per second, or a breakneck 51,120 mph.

The comet, glowing green, will be visible in the constellation Hercules. Binoculars and telescopes will help in the search.

Stargazers have been tracking Comet 45P for the past couple of months. The ice ball — an estimated mile across — comes around every five years. It's officially known as Comet 45P/Honda-Mrkos-Pajdusakova, named after the Japanese, Czech and Slovak astronomers who discovered it in 1948. The letter P stands for periodic, meaning it's a recurring visitor to the inner solar system.

The Slooh network of observatories will provide a live broadcast from the Canary Islands for both big events.

The eclipse will last more than four hours, beginning at 5:32 p.m. EST. The action will unfold early Saturday in Europe, Africa and western Asia.

Early Mars didn’t have enough CO2 to keep water liquid, Curiosity finds

Liquid water on Mars' surface, but not enough CO2 above to keep it there.

Even though Mars is currently too cold and has too little pressure to prevent water from freezing, the planet had liquid water on its surface in the distant past. That could happen if the ancient Martian atmosphere, thicker than its present-day counterpart, had enough greenhouse gasses to keep the planet warm and the water liquid. So over the past decades of our observations and robotic visitations of Mars, researchers have been looking for evidence for Mars' past carbon dioxide levels.

The evidence we've gathered indicates there was some CO2 present but not nearly enough to keep water liquid, especially given that the early Sun was less active than it is at present. So far, these estimates contained large uncertainties, so it remained possible that there was enough carbon in the atmosphere to allow the ancient water to flow.

A team of researchers has created a new estimate of Mars' ancient carbon levels using data collected by the Curiosity rover. They've also concluded that there was nowhere near enough CO2 to warm the planet to the point where water on the surface would remain liquid.

https://cdn.arstechnica.net/wp-content/uploads/2013/07/MSL-self-portrait-pia16239-20121101-300x417.jpgEnlarge / A "selfie" taken by Curiosity (actually assembled from a mosaic of selfies). The rover captured the public's imagination with its daring, Rube Goldberg-ian skycrane touchdown on Mars.

During its trip towards Aeolis Mons (the peak at the center of the Gale crater), Curiosity came upon what looked to be the remains of an ancient lake. This was a region of about 70 meters with mudstones, siltstones, and sandstones left behind by ancient water, somewhere between 3.8 and 3.1 billion years ago. The rover analyzed these materials as it passed, but there were no carbonate minerals, which would have made assessing past carbon levels easier. However, certain clays could provide a way to estimate the ancient carbon concentration.

When these clays formed, CO2 would have dissolved into their structure. While we can't measure them, we can infer their presence indirectly, as dissolved carbon limits the solubility of iron-bearing olivine. The amount of this olivine in the clays puts a limit on the amount of CO2 that could be in the water that the clays formed in.

This technique is also used to estimate Earth’s early atmosphere, but here it’s actually less reliable because the presence of life contaminates the process. The Martian rocks have been comparatively undisturbed, making them prime targets for science. “In many ways, deriving [CO2] estimates from Gale Crater sedimentary rocks is more straightforward than doing so in their terrestrial equivalents,” the authors write in their paper.

The researchers made a detailed analysis of the compounds involved in the clays, comparing them to those found in thousands of lakebeds on Earth. The time it takes for various chemicals to mix in with the clays is an important factor as well, as it affects how much of them we’d observe now.

The researchers conclude that the Martian atmosphere at the time the clays were formed had a lot more CO2 than the lower limits of previous estimates. But the numbers are still fall far short of what's needed to keep the temperature above freezing.

This doesn't definitively rule out the greenhouse explanation; certain environmental processes the researchers are not considering could have changed the composition of the clays. Where does that leave things? It's largely the same predicament as before. This study adds more evidence that Mars didn’t have enough CO2 in its atmosphere to have kept water liquid from 3.8 to 3.1 billion years ago. So either warming was driven by some other mechanism, or somehow the water was able to flow despite temperatures that were typically below. Either conclusion would be interesting.

The data also provides more information about a critical period in the history of Mars—around the time these clays were formed, Mars was rapidly losing its atmosphere. This site is among the youngest of the now-dry sites of surface water yet discovered, meaning these clays were probably formed during the tail end of this process. Those were essentially the last days of the wet Mars.

Fall armyworm 'threatens African farmers' livelihoods'

Scientists are calling for urgent action to halt the spread of a pest that is destroying maize crops and spreading rapidly across Africa.

The fall armyworm poses a major threat to food security and agricultural trade, warns the Centre for Agriculture and Biosciences International (Cabi).

It says farmers' livelihoods are at risk as the non-native insect threatens to reach Asia and the Mediterranean.

The Food and Agriculture Organization plans emergency talks on the issue.

The fall armyworm, so called because it eats its way through most of the vegetation in its way as it marches through crops, is native to North and South America but was identified for the first time in Africa last year.

Cabi chief scientist Dr Matthew Cock said: "This invasive species is now a serious pest spreading quickly in tropical Africa and with the potential to spread to Asia.

"Urgent action will be needed to prevent devastating losses to crops and farmers' livelihoods."

Scientists think the caterpillar or its eggs may have reached the continent through imported produce.

Once established in an area, the adult moths can fly large distances and spread rapidly.

Army worm caterpillar The caterpillar can march like an army across the landscape / Image copyright CABI

Dr Jayne Crozier, of Cabi, said the fall armyworm's presence had now been confirmed in west Africa and was thought to be present in the south and east of the continent, many parts of which rely on maize for their staple diet.

"It's possibly been there for some time and it's causing a lot of damage now," she told BBC News.

"The recent discovery of fall armyworm in Africa will be a huge threat to food security and also to trade in the region."

The FAO is to hold an emergency meeting in Harare between 14 and 16 February to decide emergency responses to the fall armyworm threat.

It says the pest has been confirmed in Zimbabwe and preliminary reports suggest it may also be present in Malawi, Mozambique, Namibia, South Africa and Zambia.

An investigation by Cabi has found that the fall armyworm is established in Ghana.

Experts at Cabi say it could take several years to develop effective methods to control the pest.

And they say there is confusion over the identity of the fall armyworm as it is similar to other types of armyworm, which are already present in Africa.

Zambia has used army planes to spray affected areas with insecticides.

Mission To Build Better Tomatoes Has Begun

WASHINGTON (CBSMiami/AP) — The mission to build a better tomato has begun, as scientists are working on some new techniques hoping to make flavorless a tomatoes a thing of the past.

Bite into a supermarket tomato and you’ll probably notice something missing: taste.

Scientists think they can put the yum back into the grocery tomato by tinkering with its genetic recipe.

Researchers are reinstalling five long-lost genetic traits that add much of the sweet-yet-acidic taste that had been bred out of mass-produced tomatoes for the past 50 years. They’re using mostly natural breeding methods, not genetic modification technology.

“We know what’s wrong with modern tomatoes and we have a pretty good idea how to fix it,” said University of Florida horticultural scientist Harry Klee , co-author of a study in Thursday’s journal Science.

Yield of tomatoes has tripled since 1960, but there’s been a slow decline in taste quality as tomatoes have been bred for size and sturdiness at the expense of flavor. Klee said a tastier supermarket tomato could be ready within three years.

“Nobody deliberately set out to make tomatoes that don’t have flavor,” Klee said. “Basically it was a process of neglect.”

One key issue is size. Growers keep increasing individual tomato size and grow more per plant. The trouble is that there is a limit to how much sugar each tomato plant can produce. Bigger tomatoes and more of them means less sugar per tomato and less taste, Klee said.

So Klee and colleagues looked at the genomes of the mass-produced tomato varieties and heirloom tomatoes to try to help the grocery tomatoes catch up to their backyard garden taste.

Good tiny heirloom tomatoes “are like eating candy,” said New York University nutrition professor Marion Nestle, who wasn’t part of the study. “For people who care about how food tastes, it’s a very big deal.”

Klee isolated some sugar genes and ones that were more geared to pure taste, but figured those won’t work as well because they clash against growers’ shipping and size needs. So he found areas that affect the aroma of tomatoes but not size or heartiness. Reintroducing those into mass-produced tomatoes should work because smell is a big factor in taste, he said.

Altering genes in a lab would make the process faster, but because of consumer distrust and regulations, Klee is opting for natural breeding methods — with help from an electric toothbrush to spread pollen. He’s not quite there yet, but is close.

Jose Ordovas, a nutrition professor at Tufts University, applauds the work, but cautions: “It is possible that some traits are not compatible and you cannot make the plant to behave exactly the way that you want.”

Reggie Brown of growers’ Florida Tomato Committee praised the study, saying it could help make supermarket tomatoes taste better.

No matter how much tinkering scientists do to mass-produced tomatoes, picking them too early and refrigerating them can make them bland. And consumers do have to be willing to pay more to have fresher, unrefrigerated tomatoes, said Klee, who generally doesn’t do the taste testing in his lab.

“I don’t like raw tomatoes very much at all. You know, I’m kind of tired of them,” he said.

(TM and © Copyright 2017 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2017 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.

New Study Shows No Global Warming Pause

UNITED STATES—There has not been a pause in global warming according to newly published findings. A new study in the journal “Science Advances” back an earlier NOAA study that came to similar conclusions.

According to The Washington Post, a 2015 NOAA study contradicted an argument questioning the scientific consensus on climate change.

“The skeptics had for years suggested that following the then-record warm year of 1998 and throughout the beginning of the 21st century, global warming had slowed down or ‘paused,’” the article states. “But the 2015 paper, led by NOAA’s Thomas Karl, employed an update to the agency’s influential temperature dataset, and in particular to its record of the planet’s ocean temperatures, to suggest that really, the recent period was perfectly consistent with the much longer warming trend.”

The article goes on to explain that the study caused controversy in Congress.

“It actually led to a congressional subpoena from Rep. Lamar Smith, chair of the House Committee on Science, who charged that ‘NOAA’s decision to readjust historical temperature records has broad national implications’ and requested more information on why NOAA had made the dataset adjustment, including data and communications from the scientists involved,” the article says.

A new study published on January 4 supports the findings of the earlier NOAA study. The study’s lead authors, Kevin Cowtan and Zeke Hausfather, wrote a blog post for Scientific American on their study and the political controversy around the older NOAA findings.

“Our results suggests that the new NOAA record is likely the most accurate of the various sea surface temperature records during the past two decades, and should help resolve some of the criticism that accompanied the original NOAA study,” the Washington Post said.

“However the scientific question of how fast the Earth has been warming over the past two decades can be answered by replication from the scientific community, not by a political investigation. And the best evidence we have says that NOAA got it right,” the post says.

The new study can be found here.

Researchers Discover Jet Stream in Earth’s Molten Iron Core

A jet stream within the Earth’s core has been discovered by researchers using data from ESA’s Swarm satellite mission.

Launched in 2013, the three Swarm satellites are measuring and untangling the different magnetic fields that stem from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere.

Together, these signals form the magnetic field that protects us from cosmic radiation and charged particles that stream towards Earth in solar winds.

The field exists because of an ocean of superheated, swirling liquid iron that makes up the outer core. Like a spinning conductor in a bicycle dynamo, this moving iron creates electrical currents, which in turn generate our continuously changing magnetic field.

Tracking changes in the magnetic field can, therefore, tell researchers how the iron in the core moves.

“We know more about the Sun than Earth’s core because the Sun is not hidden from us by about 1,870 miles (3,000 km) of rock,” noted Dr. Chris Finlay, a senior scientist in the Division of Geomagnetism at DTU Space at the Technical University of Denmark and senior author of a paper published in the journal Nature Geoscience.

The accurate measurements by Swarm satellites allow the different sources of magnetism to be separated, making the contribution from the core much clearer.

Previous research had found that changes in the magnetic field indicated that iron in the outer core was moving faster in the northern hemisphere, mostly under Alaska and Siberia.

But the new Swarm data have revealed these changes are actually caused by a jet stream moving at more than 25 miles (40 km) per year — three times faster than typical outer-core speeds and hundreds of thousands of times faster than Earth’s tectonic plates move.

“We can explain it as acceleration in a band of core fluid circling the pole, like the jet stream in the atmosphere,” said lead author Dr. Phil Livermore, from the University of Leeds.

So, what is causing the jet stream and why is it speeding up so quickly?

The jet flows along a boundary between two different regions in the core. When material in the liquid core moves towards this boundary from both sides, the converging liquid is squeezed out sideways, forming the jet.

“Of course, you need a force to move the fluid towards the boundary. This could be provided by buoyancy, or perhaps more likely from changes in the magnetic field within the core,” said co-author Prof. Rainer Hollerbach, also from the University of Leeds.

As for what happens next, the Swarm team is watching and waiting.

“Further surprises are likely,” said ESA’s Swarm mission manager Dr. Rune Floberghagen, who was not involved in the current study.

“The magnetic field is forever changing, and this could even make the jet stream switch direction.”

How bacteria survive antibiotic treatment

Multiresistant bacteria Scientists around the world are working hard to win the battle against multi-resistant bacteria. A new publication from the BASP Centre, University of Copenhagen now presents how even sensitive bacteria often manage to survive antibiotic treatment as so-called 'persister cells'. The comprehensive perspective on this phenomenon may help to improve current options of drug treatment and could even inspire the discovery of novel antibiotics targeting these notoriously difficult-to-treat persister bacteria.

In the current issue of the journal Science, Alexander Harms and colleagues from the BASP Centre, Department of Biology, University of Copenhagen summarise newly discovered molecular mechanisms explaining how bacteria manage to survive antibiotic treatment and cause chronic and recurrent infections.

Post-Doc Alexander Harms explains: "This amazing resilience is often due to hibernation in a physiological state called persistence where the bacteria are tolerant to multiple antibiotics and other stressors. Bacterial cells can switch into persistence by activating dedicated physiological programs that literally pull the plug of important cellular processes. Once they are persisters, the bacteria may sit through even long-lasting antibiotic therapy and can resuscitate to cause relapsing infections at any time after the treatment is abandoned."

Using novel detection methods, recent work in the field has uncovered the molecular architecture of several cellular pathways underlying the formation of bacterial persisters -- and these results confirmed the long-standing notion that persistence is intimately connected to slow growth or dormancy. Bacterial persistence can therefore be compared to hibernation of animals or the durable spores produced by many mushrooms and plants.

Across many different bacteria, these programs are controlled by a regulatory compound known as "magic spot" that plays a central role in the persistence phenomenon. These important discoveries, many of which were accomplished by the BASP Centre, may in the future facilitate the development of improved drug treatment regimens and eventually lead to the development of novel antibiotics.


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