Posts Tagged ‘Earth’

By Michael Marshall

Blobs of simple carbon-based compounds could have been the precursors to the first living cells. A new study suggests that such droplets could have formed quickly and easily on the young Earth.

“We were able to find these interesting microdroplet structures that could be synthesised from prebiotically available resources,” says Tony Jia of the Tokyo Institute of Technology in Japan. “Maybe they weren’t the direct precursors to modern cells, but perhaps they could have had some effect or had a role in the emergence of initial life.”

All modern cells are surrounded by an outer wall called a membrane, which is made of long chain-like molecules called lipids. Given the ubiquity of these membranes, many researchers studying how life began have made simple membrane-lined spheres, which they say could mimic the first simple cells.

The droplets Jia and his colleagues made are different. “They don’t have an outer layer,” says Jia. “In that sense they’re membrane-less.”

The first cells?
The team made them from simple chemicals called alpha-hydroxy acids. These are made by the same processes that create amino acids, suggesting they were present on the early Earth, says team member Kuhan Chandru of the National University of Malaysia. “You can find them in meteorites as well.” He showed in 2018 that alpha-hydroxy acids link up to form complex molecules at a wide range of temperatures.

In the new study, the team simply dissolved the acids in water, then left them to dry out at 80 °C for a week – mimicking the conditions near a hot volcanic pond.

The acids turned into a thick jelly, because they had again formed complex molecules. When the researchers added water, the jelly formed hundreds of droplets a few micrometres across. Further experiments showed that crucial biological molecules, including protein and RNA, could enter the droplets and still perform their functions.

Cells without walls
Membrane-less droplets were a key element of the first popular hypothesis for life’s origin, which was set out by Russian biologist Alexander Oparin in the 1920s. However, the idea fell out of favour when it emerged that all cells have membranes.

The idea is now being re-assessed, says Kate Adamala of the University of Minnesota in Minneapolis. She suspects that life went through a “membrane-less stage” and that membranes only arose later.

Both droplets and membrane-based cells are a container for life’s components. This is crucial, says Adamala, because it keeps all the parts together, creating an individual organism from what would otherwise be a mess of chemicals.

But membranes are such good barriers that the first cells would have struggled to get food in and waste out, Adamala argues. So at the very beginning, membrane-less droplets would be better. “You don’t have to be shut off from the environment, because those droplets are permeable and you can have things diffusing in and out of them.”

Journal reference: PNAS, DOI: 10.1073/pnas.1902336116

Read more: https://www.newscientist.com/article/2210671-early-life-on-earth-may-have-existed-as-miniature-droplets-of-jelly/#ixzz5uVl0RAI6

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by Alison Abbott

It had been hiding in plain sight. The original letter — long thought lost — in which Galileo Galilei first set down his arguments against the church’s doctrine that the Sun orbits the Earth has been discovered in a misdated library catalogue in London. Its unearthing and analysis expose critical new details about the saga that led to the astronomer’s condemnation for heresy in 1633.

The seven-page letter, written to a friend on 21 December 1613 and signed “G.G.”, provides the strongest evidence yet that, at the start of his battle with the religious authorities, Galileo actively engaged in damage control and tried to spread a toned-down version of his claims.

Many copies of the letter were made, and two differing versions exist — one that was sent to the Inquisition in Rome and another with less inflammatory language. But because the original letter was assumed to be lost, it wasn’t clear whether incensed clergymen had doctored the letter to strengthen their case for heresy — something Galileo complained about to friends — or whether Galileo wrote the strong version, then decided to soften his own words.

Galileo did the editing, it seems. The newly unearthed letter is dotted with scorings-out and amendments — and handwriting analysis suggests that Galileo wrote it. He shared a copy of this softened version with a friend, claiming it was his original, and urged him to send it to the Vatican.

The letter has been in the Royal Society’s possession for at least 250 years, but escaped the notice of historians. It was rediscovered in the library there by Salvatore Ricciardo, a postdoctoral science historian at the University of Bergamo in Italy, who visited on 2 August for a different purpose, and then browsed the online catalogue.

“I thought, ‘I can’t believe that I have discovered the letter that virtually all Galileo scholars thought to be hopelessly lost,’” says Ricciardo. “It seemed even more incredible because the letter was not in an obscure library, but in the Royal Society library.”

Ricciardo, together with his supervisor Franco Giudice at the University of Bergamo and science historian Michele Camerota of the University of Cagliari, describe the letter’s details and implications in an article in press at the Royal Society journal Notes and Records. Some science historians declined to comment on the finding before they had scrutinized the article. But Allan Chapman, a science historian at the University of Oxford, UK, and president of the Society for the History of Astronomy, says “it’s so valuable — it will allow new insights into this critical period”.

Mixed messages
Galileo wrote the 1613 letter to Benedetto Castelli, a mathematician at the University of Pisa in Italy. In it, Galileo set out for the first time his arguments that scientific research should be free from theological doctrine (see ‘The Galileo affair’).

He argued that the scant references in the Bible to astronomical events should not be taken literally, because scribes had simplified these descriptions so that they could be understood by common people. Religious authorities who argued otherwise, he wrote, didn’t have the competence to judge. Most crucially, he reasoned that the heliocentric model of Earth orbiting the Sun, proposed by Polish astronomer Nicolaus Copernicus 70 years earlier, is not actually incompatible with the Bible.

Galileo, who by then was living in Florence, wrote thousands of letters, many of which are scientific treatises. Copies of the most significant were immediately made by different readers and widely circulated.

His letter to Castelli caused a storm.

Of the two versions known to survive, one is now held in the Vatican Secret Archives. This version was sent to the Inquisition in Rome on 7 February 1615, by a Dominican friar named Niccolò Lorini. Historians know that Castelli then returned Galileo’s 1613 letter to him, and that on 16 February 1615 Galileo wrote to his friend Piero Dini, a cleric in Rome, suggesting that the version Lorini had sent to the Inquisition might have been doctored. Galileo enclosed with that letter a less inflammatory version of the document, which he said was the correct one, and asked Dini to pass it on to Vatican theologians.

His letter to Dini complains of the “wickedness and ignorance” of his enemies, and lays out his concern that the Inquisition “may be in part deceived by this fraud which is going around under the cloak of zeal and charity”.

At least a dozen copies of the version Galileo sent to Dini are now held in different collections.

The existence of the two versions created confusion among scholars over which corresponded to Galileo’s original.

Beneath its scratchings-out and amendments, the signed copy discovered by Ricciardo shows Galileo’s original wording — and it is the same as in the Lorini copy. The changes are telling. In one case, Galileo referred to certain propositions in the Bible as “false if one goes by the literal meaning of the words”. He crossed through the word “false”, and replaced it with “look different from the truth”. In another section, he changed his reference to the Scriptures “concealing” its most basic dogmas, to the weaker “veiling”.

This suggests that Galileo moderated his own text, says Giudice. To be certain that the letter really was written in Galileo’s hand, the three researchers compared individual words in it with similar words in other works written by Galileo around the same time.

Chance discovery
Ricciardo uncovered the document when he was spending a month this summer touring British libraries to study any handwritten comments that readers might have left on Galileo’s printed works. When his one day at the Royal Society was finished, he idly flicked through the online catalogue looking for anything to do with Castelli, whose writings he had recently finished editing.

One entry jumped out at him — a letter that Galileo wrote to Castelli. According to the catalogue, it was dated 21 October 1613. When Ricciardo examined it, his heart leapt. It appeared to include Galileo’s own signature, “G.G.”; was actually dated 21 December 1613; and contained many crossings out. He immediately realized the letter’s potential importance and asked for permission to photograph all seven pages.

“Strange as it might seem, it has gone unnoticed for centuries, as if it were transparent,” says Giudice. The misdating might be one reason that the letter has been overlooked by Galileo scholars, says Giudice. The letter was included in an 1840 Royal Society catalogue — but was also misdated there, as 21 December 1618.Another reason might be that the Royal Society is not the go-to place in the United Kingdom for this type of historical document, whose more natural home would have been the British Library.

The historians are now trying to trace how long the letter has been in the Royal Society library, and how it arrived there. They know that it has been there since at least the mid-eighteenth century, and they have found hints in old catalogues that it might even have been there a century or more earlier. The researchers speculate that it might have arrived at the society thanks to close connections between the Royal Society and the Academy of Experiments in Florence, which was founded in 1657 by Galileo’s students but fizzled out within a decade or so.

For now, the researchers are stunned by their find. “Galileo’s letter to Castelli is one of the first secular manifestos about the freedom of science — it’s the first time in my life I have been involved in such a thrilling discovery,” says Giudice.

TIMELINE: THE GALILEO AFFAIR
1543 Polish astronomer Nicolaus Copernicus publishes his book On the Revolutions of the Heavenly Spheres, which proposes that the planets orbit the Sun.

1600 The Inquisition in Rome convicts Dominican friar and mathematician Giordano Bruno of heresy on multiple counts, including supporting and extending the Copernican model. Bruno is burnt at the stake.

1610 Galileo publishes his book The Starry Messenger (Sidereus nuncius), describing discoveries made with his newly built telescope that provide evidence for the Copernican model.

1613 Galileo writes a letter to his friend Benedetto Castelli, arguing against the doctrine of the Roman Catholic Church in matters of astronomy. Copies of this letter are circulated.

1615 Dominican friar Niccolò Lorini forwards a copy of the letter to the inquisition in Rome. Galileo asks a friend to forward what he claims to be a copy of his original letter to Rome; this version is less inflammatory than Lorini’s.

1616 Galileo is warned to abandon his support of the Copernican model. Books supporting the Copernican model are banned. On the Revolutions of the Heavenly Spheres is withdrawn from circulation pending correction to clarify that it is only a theory.

1632 Galileo publishes Dialogue Concerning the Two Chief World Systems, in which he lays out the various evidence for and against the Church’s Ptolemaic model of the Solar System, and the Copernican model. The Inquisition summons Galileo to Rome to stand trial.

1633 Galileo is convicted on “vehement suspicion of heresy” and the book is banned. He is issued with a prison sentence, later commuted to house arrest, under which lived the last nine years of his life.

Nature 561, 441-442 (2018)

https://www.nature.com/articles/d41586-018-06769-4


A NASA artist visualized what Earth would look like if it entered the “snowball state” predicted by new research from the University of Washington

By Chelsea Gohd

Earth-like planets with severe tilts and orbits could enter abrupt “snowball states,” in which entire oceans freeze and surface life cannot survive, according to new research.

Researchers at the University of Washington (UW) have found a new reason why, just because a planet is located in a “habitable zone” — meaning it’s close enough to its host star to sustain liquid water — it isn’t necessarily habitable. The team found that the axial tilt and orbital dynamics of planets in the habitable zone around “G dwarf” stars like our own sun can lead to “snowball states,” which are essentially extreme ice ages.

This new research looked at how a planet’s obliquity, or the angle at which a planet’s rotation axis tilts, and its orbital eccentricity, a parameter that determines the amount that an orbit deviates from a perfect circle, could affect that planet’s potential to be habitable.

Previous research suggested that planets in a habitable zone with a sun-like star that had a severe axial tilt or tilting orbit would be warmer, according to the statement. The team’s research found that the opposite holds true, which was quite a shock, they said.”We found that planets in the habitable zone could abruptly enter ‘snowball’ states if the eccentricity or the semi-major axis variations — changes in the distance between a planet and star over an orbit — were large or if the planet’s obliquity increased beyond 35 degrees,” Russell Deitrick, lead author of the new work and a postdoctoral researcher at the University of Bern who completed this research at UW, said in a statement.

Luckily, Earth’s axial tilt varies ever so slightly, leaving Earth “a relatively calm planet, climate-wise,” co-author Rory Barnes, an astronomer at UW, said in the statement. But, as it pertains to exoplanets, Deitrick “has essentially shown that ice ages on exoplanets can be much more severe than on Earth, that orbital dynamics can be a major driver of habitability and that the habitable zone is insufficient to characterize a planet’s habitability,” Barnes said.

A planet’s position in the habitable zone is typically a major factor in considering whether it may be habitable. However, this new research shows that even if a planet seems Earth-like and is orbiting at the right distance from its star, if “its orbit and obliquity oscillate like crazy, another planet might be better for follow-up with telescopes of the future,” Deitrick said.

With this research in mind, orbital dynamics should be considered an important part of determining a planet’s habitability, Deitrick added.

The work will be published in The Astronomical Journal, according to the statement.

https://www.space.com/40606-exoplanets-sudden-ice-age-snowball-states.html


Most believers in a flat Earth think the planet is a flat disk surrounded by an ice wall.

By Jeanna Bryner

More than 200 flat-Earth enthusiasts descended on West Midlands, England, this past weekend to “engage freely in deep and meaningful discussions,” according to the Flat Earth Convention UK.

The Earth’s glorious globular-ness was proved more than 2,000 years ago by the ancient Greeks, but there’s a small subset of people who think the planet is a disk despite enjoying the downward pull of gravity that could only result from living on a sphere.

At this conference, they were presenting their scientific evidence for such a disk. One of the more interesting pieces of evidence came from speaker Darren Nesbit, who referred to the “Pac-Man effect” as the reason why planes don’t fall off the edge of a flat Earth, according to the science news website Physics-Astronomy.org. When a plane or other object reaches the edge of the horizon, such as when Pac-Man reaches the end of the screen, that object will teleport from one side of the planet to the other, a la Pac-Man entering from the other side of the screen.

According to the group that put on the convention, the gathering also included some “alternative viewpoints.”

MORE
Flat-Earthers Explain Why We Don’t Fall Off the Edge of Our Planet, and It Involves Pac-Man
Most believers in a flat Earth think the planet is a flat disk surrounded by an ice wall.
Credit: Getty
More than 200 flat-Earth enthusiasts descended on West Midlands, England, this past weekend to “engage freely in deep and meaningful discussions,” according to the Flat Earth Convention UK.

The Earth’s glorious globular-ness was proved more than 2,000 years ago by the ancient Greeks, but there’s a small subset of people who think the planet is a disk despite enjoying the downward pull of gravity that could only result from living on a sphere.

At this conference, they were presenting their scientific evidence for such a disk. One of the more interesting pieces of evidence came from speaker Darren Nesbit, who referred to the “Pac-Man effect” as the reason why planes don’t fall off the edge of a flat Earth, according to the science news website Physics-Astronomy.org. When a plane or other object reaches the edge of the horizon, such as when Pac-Man reaches the end of the screen, that object will teleport from one side of the planet to the other, a la Pac-Man entering from the other side of the screen. [7 Ways to Prove the Earth Is Round]

According to the group that put on the convention, the gathering also included some “alternative viewpoints.” (You think?)

“In conjunction with a select number of well-known flat-earth speakers, we have also provided some alternative viewpoints. We truly hope that new friendships are forged, ideas and experiments are brain stormed and future actions are set in motion,” they state on their website.

Among the nine speakers were Nesbit, a musician who became interested in flat-Earth beliefs in 2014; Dave Marsh, a manager with England’s National Health Service; and Gary John, an independent flat-Earther who put on the convention.

Marsh was one of four speakers who are associated with the flat-Earth research group called FEcore. His research focuses on the moon, “as he believes it is the key to unlocking the globe earth deception,” according to the convention website: https://www.flatearthconventionuk.co.uk/home.html

He studies the speed of the moon across the night sky. (Flat-Earthers believe the moon and sun orbit around Earth’s North Pole.) “My research destroys big bang cosmology,” he said, according to Physics-Astronomy.org. “It supports the idea that gravity doesn’t exist and the only true force in nature is electromagnetism.”

Another speaker, Martin Kenny, purports to have broader views of a flat Earth than other believers. “It is my innerstanding that there are other lands, dimensions and civilizations yet to be discovered across and within the plane of our Earth. The whole earth consists of 4 concentric rings of land, each ring having its own sun and moon, which would be our wandering stars,” he says on the convention website.

Flat-Earthers like Kenny agree that the planet is a flat plane, though they have varied ideas for the disk’s particular layout. Many seem to think the Earth is a disk surrounded by an ice wall and that those who show evidence to the contrary — including NASA, with its many satellite pics beamed down of our blue marble — are fakes. These conspiracy theorists believe NASA and others are trying to keep this secret from the public.

As for how many people buy into this clearly mistaken belief, that is unknown. However, the oldest flat-Earth organization, the Flat Earth Society, claims to have 555 registered members as of August 2016. According to the society’s website, the group was founded by an English inventor named Samuel Birley Rowbotham in the 1800s.

In addition to the Q&A’s with the nine speakers at the three-day convention, there was apparently a talk entitled “Heliocentric v Geocentric experts Debate.” The convention’s site doesn’t indicate who was debating these two views, one proved ages ago, and the other suggesting Earth is fixed in space with the universe revolving around it.

This isn’t the first flat-Earth convening. In November 2017, the Flat Earth International Conference was held in Raleigh, North Carolina. That convention hosted some big-name (in flat-Earth circles, at least) speakers, such as founder of the Flat Earth Clues series on YouTube, Mark Sargent, who thinks we are all locked inside a “Truman Show”-like dome structure. The next FEIC is scheduled for Nov. 15 -16 in Denver.

https://www.livescience.com/62454-flat-earthers-explain-pac-man-effect.html?utm_source=notification

By Rafi Letzter

Russian scientists have a plan to deal with a hypothetical asteroid threat that’s straight out of the movie “Armageddon.”

A team of government scientists has proposed that nuclear weapons well within the power of those already developed could be used to break up incoming asteroids, protecting the planet from a major asteroid strike. They then demonstrated, in a paper published online March 8 in the Journal of Experimental and Theoretical Physics, the effect of a nuclear strike on an asteroid, using scale model “asteroids” and powerful lasers.

Striking a tiny model asteroid with a powerful laser on Earth is obviously not the exact same thing as striking a full-size asteroid with a laser out in space. But there’s a reasonable degree of comparison between the two situations.

MORE
Russian Scientists Tested Their Asteroid-Nuking Plan with Powerful Lasers
This photo of the asteroid Eros was taken during the NEAR Shoemaker mission.
Credit: NASA
Russian scientists have a plan to deal with a hypothetical asteroid threat that’s straight out of the movie “Armageddon.”

A team of government scientists has proposed that nuclear weapons well within the power of those already developed could be used to break up incoming asteroids, protecting the planet from a major asteroid strike. They then demonstrated, in a paper published online March 8 in the Journal of Experimental and Theoretical Physics, the effect of a nuclear strike on an asteroid, using scale model “asteroids” and powerful lasers.

Striking a tiny model asteroid with a powerful laser on Earth is obviously not the exact same thing as striking a full-size asteroid with a laser out in space. But there’s a reasonable degree of comparison between the two situations. [Crash! The 10 Biggest Impact Craters on Earth]

The researchers took careful steps to make sure the scale models were created from the same materials and had similar structures to chondrites (common, stony asteroids). And the immense energy deposited by a pulsed laser onto a single point on the model was reasonably similar to the effect of a nuclear blast on a single point on the asteroid’s surface. They wrote that their experiment showed they could use a a 3-megaton bomb to blast a 656-foot-wide (200 meters) asteroid — 10 times wider than the asteroid that detonated over Russia in 2013 — to harmless bits that would spread out and miss Earth.

The first thermonuclear weapon ever detonated had a strength of about 10.4 megatons, according to the Nuclear Weapon Archive. That bomb was detonated on Elugelab Island, Enewetak Atoll, in the Pacific Ocean in 1952.

There are other methods for diverting incoming asteroids, the researchers acknowledged, like the gravity tug— using the force of gravity to move the space rock to a better orbit. But they require more advanced knowledge of the incoming strike and planning. The advantage of a nuclear strike, they wrote, is that it can work against even surprise asteroids discovered late.

Russia isn’t alone in considering the possibility of a nuclear strike on an asteroid. U.S. government researchers also raised the possibility in a February paper.

https://www.livescience.com/62057-asteroid-nuclear-bomb-russia-laser.html?utm_source=notification


Chunks of clay excavated from Iron Age grain bins in South Africa. Early farmers burnt their clay huts and grain storage buildings in times of drought as part of a cleansing ritual, unknowingly locking the magnetic properties of the minerals in the clay into place.

A flip in Earth’s magnetic field may be brewing. And if it is, an electromagnetic blob deep under southern Africa is likely to be ground zero for the change.

New research using clays burned in cleansing rituals by Iron Age farmers finds that over the past 1,500 years, an electromagnetic anomaly in the Southern Hemisphere has waxed and waned, with the magnetic field in the region weakening and strengthening. This weirdness may presage a gradual reversal in the magnetic field, so that magnetic north moves to the South Pole and vice versa. (A flip-flop of this sort last occurred 780,000 years ago.)

The study suggests that the magnetic field under southern Africa may not just be weird today, study co-author John Tarduno, who researches the Earth’s magnetism at the University of Rochester in New York, told Live Science. It may be a longstanding hotspot for changes in the global magnetic field.

WEAKENING FIELD

The planet’s magnetic field is generated by the churning of liquid iron in the core. Without the field, life on the planet would be much different, if not impossible: This invisible shield protects the Earth’s surface from deadly cosmic radiation.

Right now, the field is undergoing a weakening, and no one is sure why. The South Atlantic Anomaly, a region of the magnetic field that stretches from South Africa to Chile, is particularly weak, Tarduno said, so scientists have become interested in figuring out what might be going on in the core underneath that area.

The problem is that before about 160 years or so ago, with the advent of magnetic observatories and (eventually) satellite observations, there weren’t many records of what the magnetic field looked like in the Southern Hemisphere, Tarduno said. Ninety percent of the data that does exist comes from the northern half of the planet. To start to rectify that disparity, Tarduno and his team excavated clays from the Limpopo River Valley of Zimbabwe, South Africa, and Botswana. In times of drought hundreds to thousands of years ago, Bantu-speaking farmers would burn down their clay huts and grain bins in ritualistic ceremonies. Unbeknown to these ancient farmers, the fire heated the magnetic minerals in the clay and locked into place a record of the strength and orientation of the field at that time. Now, researchers can study those properties to find out what the magnetic field was doing at that moment in time.

LOCKED IN CLAY

The excavations unearthed these burnt clays as long ago as A.D. 425, Tarduno said, providing the longest record yet of the magnetic field in southern Africa. The data show that the magnetic field experienced sudden directional shifts between A.D. 400 and 450, and then again between A.D. 750 and 800. Between about A.D. 1225 and 1550, the field noticeably weakened. The first two shifts might also indicate a weakened field, Tarduno said, but more research is needed to determine the magnetic intensity in those time frames. The researchers reported their findings Feb. 15 in the journal Geophysical Research Letters.

What these shifts suggest is that what is going on in the Southern Hemisphere’s magnetic field today may have happened before, Tarduno said.

The field shifts may have to do with underlying processes churning deep beneath the Earth’s surface, Tarduno said. In recent years, scientists have documented a weird patch of magnetic field below southern Africa at the boundary between the core and the mantle, where the polarity of the field is reversed.

“That patch may be largely responsible for the decreasing magnetic field,” Tarduno said.

The patch is like an eddy in a stream, he said. As for what causes the eddy, it may be something odd about the mantle right above the core in that location, he said. The mantle under southern Africa is unusual, and possibly both hotter and denser than surrounding mantle, he said.

“We think that is causing there to be changes in the flow of the iron [in the core] as it enters this region,” Tarduno said.

That could mean that southern Africa is the origin for magnetic field reversals, Tarduno said, though there’s no guarantee that the field will flip now — the weakening could also dissipate, as it has in centuries past.

Even if the field doesn’t reverse, though, the weakening itself could have societal implications, Tarduno said.

“These are not of the nature of disaster movies. That’s not the point,” he said. Instead, a weakening field could let more cosmic radiation hit the Earth, making infrastructure like the power grid more susceptible to geomagnetic storms and even changing atmospheric chemistry so that more UV rays could sneak through, causing increased risk for skin cancer in humans.

“It’s definitely something that we need to keep an eye on,” Tarduno said.

https://www.livescience.com/61958-africa-blob-earth-magnetic-flip.html?utm_source=notification

The universe has some added sparkle — now that a shiny, spherical satellite is traveling around our planet.

The newly launched satellite, dubbed the Humanity Star, resembles a disco ball. Its mission: to serve as a focal point for humanity and reminder about our fragile place in the universe.
“No matter where you are in the world, or what is happening in your life, everyone will be able to see the Humanity Star in the night sky,” said Peter Beck, founder of the private company Rocket Lab, in a statement.

“My hope is that all those looking up at it will look past it to the vast expanse of the universe and think a little differently about their lives, actions and what is important for humanity.”
The satellite is made from carbon fiber and has 65 reflective panels that reflect sunlight back to Earth. The Humanity Star spins rapidly, creating a blinking flashing effect.

https://www.cnn.com/2018/01/25/world/humanity-star-launch-trnd/index.html