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.

Huge ‘potentially hazardous’ asteroid hurtling towards Earth

A huge 1km-wide asteroid is hurtling towards Earth, prompting astronomers to label it “potentially hazardous”. But don’t pack for Mars just yet – the giant space rock, ‘2014 JO25’, is expected to pass by our planet safely.

According to NASA the encounter on April 19 will be the closest the asteroid comes to Earth in 400 years, and no projected future encounters will be as close for at least another 480 years.

However, another fly-by is expected in 2091 and the space rock also makes regular close approaches to Mercury and Venus.

 
An asteroid of this size won't have as close an encounter with Earth for more than 10 years. "The next known flyby by an object with a comparable or larger diameter will occur when 800-meter-diameter asteroid ‘1999 AN10’ approaches within one lunar distance in August 2027," NASA said.

The asteroid was discovered by the Mt. Lemmon Survey in May 2014. Astronomers describe it as a “bright object” and believe it will be among the best targets for radar observations this year.

READ MORE: Risk of catastrophic asteroid impact ‘real’ – White House

‘2014 JO25’ has been designated as a potentially hazardous asteroid (PHA) by the Minor Planet Center. PHA’s are asteroids larger than 100 meters that can come closer to Earth than 7,495,839km (about 4,658,000 miles), which is equal to 19.5 ‘Lunar distances’.

Asteroid Hazards, Part 1: What Makes an Asteroid a Hazard?

Despite 2014 JO25’s designation as a PHA, projections predict it will pass by Earth at a safe distance of about 1.8 million km (4.57 lunar distances).

@BadAstronomer Pic of a 10-meter rock that passed inside the Moon’s orbit a couple of hours ago. Amazing we can find these things. http://www.virtualtelescope.eu/2017/04/02/near-earth-asteroid-2017-fu102-close-encounter-image-2-apr-2017/ 


 
 
 

Two other big asteroids, ‘2003 BD44’ and ‘1999 CU3’, which are both nearly 2km wide, will also pass by our planet shortly, however they won’t come as close as 2014.

Astrowatch report 1,781 PHAs were detected on Sunday, however – happily – none of them is on a projected collision course with Earth.

Oldest-ever fossils show life existed on Earth at its infancy - study

Ancient fossils discovered in Canada are “direct evidence” that life existed on Earth 4 billion years ago, scientists wrote in a newly-released study, believing the emergence of life could be simple enough to begin on other planets.

Researchers believe the microfossils – discovered in Canada's Nuvvuagittuq Supracrustal Belt, which hosts some of the oldest sedimentary rocks known on Earth – are between 3.77 billion and 4.29 billion years old.

The discovery has led scientists to believe that life was present during the infancy of the planet, which is thought to be around 4.57 billion years old.

If the dating is accurate, it would represent an “almost instantaneous emergence of life” after ocean formation, lead author Matthew Dodd said, as quoted by Reuters.

READ MORE World's oldest fossils unearthed (UCL)

The tiny microfossils were found to be half the width of a human hair and up to half-a-millimeter in length. Their appearance is of blood-red tubes and filaments, formed by ocean-dwelling bacteria that fed on iron.

The dating puts the fossils “within a few hundred million years of the acceleration of the solar system,” University College London Professor Dominic Papineau, who made the discovery, said in a video statement cited by AFP.

Even at the lower end of the range, “the microfossils we discovered are about 300 million years older” than any runners-up, Papineau said.

Locked inside white quartz structures, the microfossils were found in what were once warm-water vents on the ocean floor, most often in deep waters.

The finding has prompted scientists to hypothesize that such vents may have been some of the earliest habitable environments on the planet.

However, one of the researchers acknowledged skepticism about whether such fossils are biological in nature, or merely natural mineral formations.

“One of the big questions when it comes to early life studies is whether or not the organic carbon we find in these rocks is actually biological in origin,” Dodd said, as quoted by AFP.

Dodd and his colleagues used several methods to determine the answer to that question, including laser-imaging to analyze the minerals associated with the organic material.

They concluded that the presence of two minerals in particular – apatite and carbonite – provide strong evidence for life.

Moreover, the scientists noted that the microfossils’ structure closely resembles modern bacteria that dwell near iron-rich hydrothermal vents.

The possibility that the microfossils were formed by temperature and pressure changes as the sediment formed were also examined and excluded.

Perhaps the most intriguing piece of the research is that Dodd believes there’s no reason to rule out similar evidence of early life being found on other planets.

READ MORE: 500mn years old & boasting 30 legs: ‘Worm’ fossil offers insight into ancient species (VIDEO)

“We could expect to find evidence for past life on Mars 4 billion years ago,” Dodd said, stating that Earth and Mars had liquid on their surfaces at the same time.

“If life happened so quickly on Earth, then could we expect it to be a simple process that could start on other planets?” he said.

He admitted, however, that Earth could be “just a special case.”

The discovery represents a significant milestone, as the oldest microfossils previously reported were found in Western Australia and dated to 3.46 billion years old. However, some scientists say they are not biological in origin.

Researchers from various institutions, including the US Geological Survey, took part in the study. The results were published in the journal Nature on Wednesday.

NASA has discovered 7 Earth-like planets orbiting a star just 40 light-years away

This tiny star has 7 planets that potentially could be suitable for life.

The first step in finding life outside our own planet is to find a planet like our own: small, rocky, and at just the right distance from the star that liquid water could exist on its surface.

That’s why an announcement today from NASA is so exciting: The space agency, along with partners around the world, has found seven potentially Earth-like planets orbiting a star 40 light-years away.

“It’s the first time that so many planets of this kind are found around a same star,” Michaël Gillon, the lead author of the Nature paper announcing the discovery, said in a press conference. “The seven planets … could have some liquid water and maybe life on the surface.”

Three of the planets are directly in the star’s habitable zone, meaning water can mostly likely exist on the surface of them. One of them, Gillon said, has a mass “strongly to suggest a water-rich composition.” And it’s possible that the other four could have liquid water, too, depending on the composition of their atmospheres, the astronomers said.

 The planets “e,” “f,” and “g” — marked in green are directly in the “habitable zone” of this star system. NASA

The exoplanets orbit a star in the constellation Aquarius called Trappist-1. And it’s a solar system very different from our own.

For one, Trappist-1 is a tiny, “ultra-cool” dwarf star. It’s cool because it’s small: just about a tenth of the mass of our sun and about one-thousandth as bright. But its low mass allows its planets to orbit it very closely and remain in the habitable zone.

The distance at which the planets orbit Trappist-1 is comparable to the distance of Jupiter to its moons. All the planets are believed to be rocky, and are all believed to be around the size of Earth, give or take 10 to 20 percent.

The star’s dimness is actually what led to the discoveries of these planets. When astronomers search for exoplanets, they typically look for a temporary dimming of a star — an indication that a planet has passed in front of it. This method makes it hard to find small, rocky worlds orbiting big, bright stars. If the planets are too small, they’ll get washed out.

“Maybe the most exciting thing here is that these seven planets are very well suited for detailed atmospheric study,” Gillon said. The James Webb Space Telescope, set to launch in 2018, will have the ability to measure the chemical composition of exoplanet atmospheres. If the atmospheres contain telltale gases like ozone, oxygen, or methane, life could exist there. “We can expect that in a few years, we will know a lot more about these [seven] planets,” Amaury Triaud, another of the paper’s co-authors, said.

If this all sounds a bit familiar, it’s because astronomers announced three potentially habitable planets around Trappist-1 in May. Today’s reveal adds four more to the mix.

Right now, the astronomers are beginning to study the planets’ atmospheres with the telescopes they have. And from these observations, they feel fairly confident that the worlds are rocky. “For detailed characterization, we will need James Webb,” Triaud said.

In the meantime, we just have our imaginations to fill in the gap. This is an artist’s rendition of what the fifth planet in this bizarre solar system might look like. These planets are believed to be tidally locked to the star, each has a permanent day side and a permanent nice side. And because the planets are so close together, they’d appear in the sky like moons.

 This artist's concept allows us to imagine what it would be like to stand on the surface of the exoplanet Trappist-1f. Dream vacation? NASA/JPL-Caltech

The more Earth-like exoplanets astronomers find in the galaxy, the more they update their estimates of how many Earth-like planets could be out there. “For every transiting planet found, there should be a multitude of similar planets (20–100 times more) that, seen from Earth, never pass in front of their host star,” Nature reporter Ignas Snellen explains in a feature article. And the more exoplanets there are, the more likely it is that life exists on at least one of them.

“With this discovery we’ve made a giant, accelerated leap forward in our search for habitable worlds and life on other worlds potentially,” Sara Seager, a leading exoplanet expert at MIT, said during the announcement. This one star system, she said, gives astronomers many chances to look for life, and refine their understanding of exoplanets in small-star systems.

Also promising: Tiny, cool stars like Trappist-1 are some of the most common in the galaxy. Investigating them will likely yield more exoplanet discoveries. Which will help get us closer to finding places like Earth.

As NASA associate administrator Thomas Zurbuchen said, “Finding another Earth-like planet isn't a matter of if but when.“

Antarctica found amplifying effects of climate change during last global warming

SAN FRANCISCO -- A a new study indicates that the Antarctic warmed about 11 degrees Celsius between about 20,000 and 10,000 years ago while the average temperature worldwide rose about 4 degrees Celsius following Earth's last ice age.

The disparity, that the Antarctic warmed nearly three times the average temperature increase worldwide after the peak of last ice age 20,000 years ago, highlights the fact that the poles, both the Arctic in the north and the Antarctic in the south, amplify the effects of a changing climate, whether it gets warmer or cooler.

As the calculations are in line with estimates from most climate models,"the result is not a surprise, but if you look at the global climate models that have been used to analyze what the planet looked like 20,000 years ago, the same models used to predict global warming in the future, they are doing, on average, a very good job reproducing how cold it was in Antarctica," said Kurt Cuffey, a glaciologist at the University of California, Berkeley.

The models predict that as a result of current global climate change, Antarctica will warm twice as much as the rest of the planet and reach its peak in a couple of hundred years. Given business-as-usual greenhouse gas emissions, a global average increase of 3 degrees Celsius by 2100 and a rise of around 6 degrees in the Antarctic is predicted.

During the last period of global warming, the ice deep inside the Antarctic glaciers warmed more slowly than Earth's surface. By measuring the remaining difference, that the 20,000-year old ice deep in the West Antarctic ice sheet is about 1 degree Celsius cooler than the surface, the researchers were able to estimate the original temperature based on how fast pure ice warms up.

Gary Clow of the U.S. Geological Survey in Lakewood, Colorado, measured in 2011 and again in 2014 the temperature in a 3.4-kilometer-deep borehole from which the West Antarctic Sheet Divide ice core had been drilled during an eight-year project that ended in 2011. Ice at the bottom of the borehole was deposited about 70,000 years ago; ice about one-sixth of the way up about 50,000 years ago; and ice about one-third of the way to the surface 20,000 years ago.

Cuffey, first author of the study recently published in the Proceedings of the National Academy of Sciences, developed a technique to combine these temperature measurements with isotopic measurements of old ice to come up with an estimated temperature of 11.3 degrees, plus or minus 1.8 degrees Celsius, warming since the depths of the ice age.

The Antarctic temperature rose much more rapidly than did Arctic temperatures after the glacial maximum. By 15,000 years ago, Antarctica had warmed to about 75 percent of its temperature today. The Arctic took another 3,000-4,000 years to warm this much, primarily because the Northern Hemisphere had huge ice sheets to buffer warming, and changes in ocean currents and Earth's orbital configuration accelerated warming in the south.

Antarctica was also more sensitive to global carbon dioxide levels, Cuffey was quoted as saying in a news release from UC Berkeley, adding that the situation today, with global warming driven primarily by human emissions of carbon dioxide from burning fossil fuels, is different from natural cycles. The ability of the oceans to take up carbon dioxide cannot keep up with the rising levels of greenhouse gases in the atmosphere, meaning carbon dioxide and global temperatures will continue to increase unless humans cut their emissions.

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.”

Humans Are Totally Unprepared For A Potential Asteroid Strike, NASA Scientist Warns

Speaking at the annual meeting of the American Geophysical Union in San Francisco, Nuth said: “The biggest problem, basically, is there’s not a hell of a lot we can do about it at the moment,” according to The Guardian.

Despite the NASA planetary defence office having been established – with the aim to observe the skies for possible asteroid strikes – this will supposedly not give us a large enough window to begin a preventative mission.

In fact, it takes years to complete a ‘deflection’ operation – five to launch a spacecraft - and the most recent ‘near miss’ with Mars in 2014 was only noticed 22 months before impact.

Admittedly there is a very low chance of an earth impact in the next 100 years, approximately 0.01% according to NASA themselves, but Nuth said: “On the other hand they are the extinction-level events, things like dinosaur killers, they’re 50 to 60 million years apart, essentially.

“You could say, of course, we’re due, but it’s a random course at that point.”

The current plan of action is mass evacuation, but Nuth recommend that NASA build an interceptor rocket with periodic testing, alongside an observer spacecraft to stop catastrophic fireballs from hitting us.

However even if we were able to cut the action time in half, Nuth still says this would be a “hail-mary pass”.

Back in August, NASA sent a probe to an asteroid, Bennu, that could one day hit Earth and bring about our downfall. 

Speaking to the Sunday Times, Principal Investigator Dante Lauretta confirmed that in 2135 its believed Bannu will pass between the Earth and the moon, and could potentially leave a wake of destruction.

2016 'very likely' to be world's warmest year

2016 looks poised to be the warmest year on record globally, according to preliminary data.

With data from just the first nine months, scientists are 90% certain that 2016 will pass the mark set by 2015.

Temperatures from January to September were 1.2C above pre-industrial levels, according to the World Meteorological Organization (WMO).

The body says temperatures should remain high enough for the rest of the year to break the previous record.

El Nino has had an impact, but the most significant factor driving temperatures up continues to be CO2 emissions.

What is climate change?

The provisional statement on the status of the global climate in 2016 has been released early this year to help inform negotiators meeting in Morocco, who are trying to push forward with the Paris Climate Agreement.

The document says the year to September was 0.88 above the average for the period between 1961-90, which the WMO uses at its baseline.

The whole of 2015, which broke the previous record by a significant amount, was 0.77 above the 1961-90 average.

http://ichef-1.bbci.co.uk/news/624/cpsprodpb/112FF/production/_92399307_mediaitem92399306.jpg

While there are still a couple of months to go this year, a preliminary analysis of the October data indicates that 2016 is very much on track to surpass the 2015 level, which in turn broke the previous high mark set in 2014.

"Another year. Another record. The high temperatures we saw in 2015 are set to be beaten in 2016," said WMO secretary-general Petteri Taalas.

"In parts of Arctic Russia, temperatures were 6C to 7C above the long-term average. Many other Arctic and sub-Arctic regions in Russia, Alaska and north-west Canada were at least 3C above average. We are used to measuring temperature records in fractions of a degree, and so this is different," said Mr Taalas.

The report highlights the fact that other long-term climate change indicators are also breaking records. The amount of greenhouse gas in the atmosphere continued on its upward march in 2016.

Arctic sea ice continued to melt in significant amounts, while the Greenland ice sheet displayed very early melting this year.

Experts believe that the El Nino weather phenomenon played a role in the record warm temperatures seen in 2015 and 2016.

They quantify it as roughly 0.2 of a degree - but the bulk of the warming is coming from the accumulation of greenhouse gases. And the impacts of that warming are being widely felt.

"Because of climate change, the occurrence and impact of extreme events has risen," said Petteri Taalas.

"'Once in a generation' heatwaves and flooding are becoming more regular. Sea level rise has increased exposure to storm surges associated with tropical cyclones," he said.

The surprise election of Donald Trump as president of the US has increased expectations that he will bring a more sceptical view of climate change to the White House.

Scientists are stressing that the evidence for the reality of climate change is getting stronger all the time.

"We are seeing the impacts of climate change on extreme weather," said Dr Peter Stott, who leads the climate attribution team at the UK Met Office.

"One degree may sound a relatively small number but in the context of such a stable climate that we've had over the past millennia, and the rapidity of that warming, we are seeing this real world evidence that doesn't come from a model or a projection."

According to the WMO analysis, 16 of the 17 warmest years have been recorded this century. The only exception was 1998.

 

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