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But now we need an update. While the fundamental principles set out in the treaty are vitally important to the peaceful and orderly use of outer space, the pace of development of space-related technology – which allows for activities far beyond the contemplation of those that put the treaty together – means that some activities in space may fall between the cracks.

50 years of OST

For 50 years, the OST has largely allowed for a consideration of the interests of both the space “powers” and the space “have-nots”.

In 1967, the Cold War superpowers were continuing to develop inter-continental ballistic missiles capable of destroying entire cities and taking the lives of all their inhabitants. In that context, the OST set a delicate balance between the strategic interests of the US and the USSR in space. At the same time, the OST elevated the interests of humanity in outer space above the parochial interests of individual states. Appearing in person for the signing of the treaty, US President Lyndon Johnson said:

This is an inspiring moment in the history of the human race.

Brown dwarfs, or failed stars that resemble rogue planets, are far more abundant than astronomers previously thought. A whopping 100 billion of the small, dim celestial bodies could be lurking throughout the Milky Way, new research suggests. 

Like most stars, brown dwarfs form when clouds of interstellar gas and dust collapse under their own gravity. In main-sequence stars, the heat and pressure ignite the core through nuclear fusion. But some aspiring stars never reach that point: instead, they enter a stable state before fusion can begin. Without fusion, these failed stars don't emit much light, and they can be difficult for astronomers to observe. A new study attempts to tally up how many brown dwarfs are hiding in the Milky Way, revealing a number that is much higher than expected.

Previous studies determined that there are about six stars for every brown dwarf in our cosmic neighborhood. Those studies only looked at brown dwarfs within a range of about 1,500 light-years from Earth, where such faint and tiny objects are easier to spot. However, the entire Milky Way spans a much greater distance of about 100,000 light-years, and it turns out that our neck of the woods isn't exactly representative of the entire galaxy. [Brown Dwarf Photos: Failed Stars and Stellar Misfits Revealed]

Earth’s climate is changing rapidly. We know this from billions of observations, documented in thousands of journal papers and texts and summarized every few years by the United Nations’ Intergovernmental Panel on Climate Change. The primary cause of that change is the release of carbon dioxide from burning coal, oil and natural gas.

One of the goals of the international Paris Agreement on climate change is to limit the increase of the global surface average air temperature to 2 degrees Celsius, compared to preindustrial times. There is a further commitment to strive to limit the increase to 1.5℃.

Earth has already, essentially, reached the 1℃ threshold. Despite the avoidance of millions of tons of carbon dioxide emissions through use of renewable energy, increased efficiency and conservation efforts, the rate of increase of carbon dioxide in the atmosphere remains high.

International plans on how to deal with climate change are painstakingly difficult to cobble together and take decades to work out. Most climate scientists and negotiators were dismayed by President Trump’s announcement that the U.S. will withdraw from the Paris Agreement.

NASA’s Neutron Star Interior Composition Explorer, or NICER, is an X-ray telescope launched on a SpaceX Falcon 9 rocket in early June 2017. Installed on the International Space Station, by mid-July it will commence its scientific work – to study the exotic astrophysical objects known as neutron stars and examine whether they could be used as deep-space navigation beacons for future generations of spacecraft.

What are neutron stars? When stars at least eight times more massive than the Sun exhaust all the fuel in their core through thermonuclear fusion reactions, the pressure of gravity causes them to collapse. The supernova explosion that results ejects most of the star’s material into the far reaches of space. What remains forms either a neutron star or a black hole.

I study neutron stars because of their rich range of astrophysical phenomena and the many areas of physics to which they are connected. What makes neutron stars extremely interesting is that each star is about 1.5 times the mass of the Sun, but only about 25km in diameter – the size of a single city. When you cram that much mass into such a small volume, the matter is more densely packed than that of an atomic nucleus. So, for example, while the nucleus of a helium atom has just two neutrons and two protons, a neutron star is essentially a single nucleus made up of 10⁵⁷ neutrons and 10⁵⁶ protons.

Exotic physics impossible on Earth

We can use neutron stars to probe properties of nuclear physics that cannot be investigated in laboratories on Earth. For example, some current theories predict that exotic particles of matter, such as hyperons and deconfined quarks, can appear at the high densities that are present in neutron stars. Theories also indicate that at temperatures of a billion degrees Celsius, protons in the neutron star become superconducting and neutrons, without charge, become superfluid.

Earth is estimated to be around 4.5 billion years old, with life first appearing around 3 billion years ago.

To unravel this incredible history, scientists use a range of different techniques to determine when and where continents moved, how life evolved, how climate changed over time, when our oceans rose and fell, and how land was shaped. Tectonic plates – the huge, constantly moving slabs of rock that make up the outermost layer of the Earth, the crust – are central to all these studies.

Along with our colleagues, we have published the first whole-Earth plate tectonic map of half a billion years of Earth history, from 1,000 million years ago to 520 million years ago.

The time range is crucial. It’s a period when the Earth went through the most extreme climate swings known, from “Snowball Earth” icy extremes to super-hot greenhouse conditions, when the atmosphere got a major injection of oxygen and when multicellular life appeared and exploded in diversity.

The measures by which we judge scientists are always under intense scrutiny. For those who hit the peak of their field, there’s the Nobel Prize. But across all levels of career progression, we publish research papers in journals whose importance or rank can be communicated via a number known as the Journal Impact Factor.

The much respected Nobel Prize Twitter site @NobelPrize recently tweeted an impressive video with four Nobel Laureates speaking out against Journal Impact Factors.

My view is that the Nobel Laureates are right in theory. But I cannot advise the junior researchers I mentor to ignore Impact Factors.

For decades, while astronomers have detected black holes equal in mass either to a few suns or millions of suns, the missing-link black holes in between have eluded discovery. Now, a new study suggests such intermediate-mass black holes may not exist in the modern-day universe because of the rate at which black holes grow.

Scientists think stellar-mass black holes — up to a few times the sun's mass — form when giant stars die and collapse in on themselves. Over the years, astronomers have detected a number of stellar-mass black holes in the nearby universe, and in 2010, researchers detected the first such black hole outside the local cluster of nearby galaxies known as the Local Group.

As big as stellar-mass black holes might seem, they are tiny in comparison to the so-called supermassive black holes that are millions to billions of times the sun's mass, which form the hearts of most, if not all, large galaxies. The oldest supermassive black holes found to date include one found in 2015 — with a mass of about 12 billion solar masses — that existed when the universe was only about 875 million years old. This finding and others suggest that many black holes were born in the dawn of time, back when the universe was smaller and matter was more concentrated, making it easier for them to form and grow. [No Escape: Dive into a Black Hole (Infographic)]

Scientists have spent decades debating whether asteroids and comets hit the Earth at regular intervals. At the same time, a few studies have found evidence that the large extinction events on Earth – such as the one that wiped out the dinosaurs 66m years ago – repeat themselves every 26m to 30m years. Given that there’s good evidence that an asteroid triggered the dinosaur extinction, it makes sense to ask whether showers of asteroids could be to blame for regular extinction events.

The question is extremely important – if we could prove that this is the case, then we might be able to predict and even prevent asteroids causing mass extinctions in the future. We have tried to find out the answer.

Today, there are approximately 190 impact craters from asteroids and comets on Earth. They range in size from only a few meters to more than 100km across. And they formed anywhere between a few years ago and more than two billion years ago. Only a few, like the famous “Meteor crater” in Arizona, are visible to the untrained eye, but scientists have learned to recognise impact craters even if they are covered by lakes, the ocean or thick layers of sediment.

But have these craters formed as a result of regular asteroid collisions? And if so, why? There have been many suggestions, but most prominently, some scientists have suggested that the sun has a companion star (called “Nemesis”) on a very wide orbit, which approaches the solar system every 26m to 30m years and thereby triggers showers of comets.

Paleontologists like us are used to working with fossils that would seem bizarre to many biologists accustomed to living creatures. And as we go farther back in Earth’s history, the fossils start to look even weirder. They lack tails, legs, skeletons, eyes…any characteristics that would help us understand where these organisms fit in the tree of life. Under these circumstances, the science of paleontology becomes significantly harder.

Nowhere is this issue more apparent than in the Ediacaran period, which lasted from 635 million to 541 million years ago. A peculiar and entirely soft-bodied suite of fossils from this era are collectively referred to as the Ediacara biota. Despite nearly 70 years of careful study, paleontologists have yet to identify key features among them that would allow us to understand how these organisms are related to modern animals. The forms evident among Ediacaran organisms are, for the most part, truly unique – and we are no closer to understanding their place in evolutionary history.

Rather than looking for characteristics that would allow us to shoehorn some of these organisms into known animal groups, we’ve taken a different approach. It relies on a technique called computational fluid dynamics that lets us reverse engineer how these organisms lived in their ocean environment.

Mystery fossils

The Ediacaran period marks a pivotal interval in Earth’s history; at its start are the last of the so-called “Snowball Earth” events – episodes lasting millions of years when the entire surface of our planet was covered in ice. It segues into the succeeding Cambrian geological period, which saw the first appearance of many of the animal groups we recognize in the present day. This is what’s commonly referred to as the Cambrian explosion.

The dinosaurs may have volcanoes to thank for their domination of the planet, at least according to one theory. Most scientists think that a severe bout of volcanic activity 200m years ago may have led to the mass extinction that cleared the way for the dinosaurs’ rise. Now we – with a team of colleagues – have discovered new evidence that strengthens this idea: a global geological “fingerprint” indicating volcanic gases were affecting the whole world at the time of the extinction.

Geologists have previously discovered that the Earth’s crust hosts massive amounts of volcanic rock from the end of the Triassic period, 200m years ago. We know from the fossil record that, at about the same time, a very large proportion of Earth’s species died out, which made space for the remaining dinosaurs (and other species) to flourish. As volcanoes can produce large amounts of carbon dioxide (CO₂), it’s possible that the volcanic activity that left these massive lava flows behind also provoked global climate change that led to this mass extinction.

What was missing was evidence that the volcanic activity really had such a worldwide impact. By examining geological records from all over the world, we discovered that large amounts of mercury were released into the atmosphere at around the same time as the extinction. As mercury is also released by volcanoes, this suggests the volcanic eruptions really were severe enough to affect the whole world and potentially cause the mass extinction.

The volcanic rocks cover a huge area, across four present-day continents. They are the remains of a huge episode of heightened volcanic activity that lasted about a million years known as the Central Atlantic Magmatic Province (CAMP).

Sometimes you run across a grimy, tattered dollar bill that seems like it’s been around since the beginning of time. Assuredly it hasn’t, but the history of human beings using cash currency does go back a long time – 40,000 years.

Scientists have tracked exchange and trade through the archaeological record, starting in Upper Paleolithic when groups of hunters traded for the best flint weapons and other tools. First, people bartered, making direct deals between two parties of desirable objects.

Money came a bit later. Its form has evolved over the millennia – from natural objects to coins to paper to digital versions. But whatever the format, human beings have long used currency as a means of exchange, a method of payment, a standard of value, a store of wealth and a unit of account.

As an anthropologist who’s made discoveries of ancient currency in the field, I’m interested in how money evolved in human civilization – and what these archaeological finds can tell us about trade and interaction between far-flung groups.

Why do people need currency?

Editor's Note: This article was originally published at ScienceNordic.

In a Viking settlement on Stevns in Denmark, archaeologists have excavated a two metre deep hole. But it is not just any old hole. This hole, it seems, may be the oldest toilet in Denmark.

Radiocarbon dating of the faeces layer dates back to the Viking Age, making it quite possibly the oldest toilet in Denmark.

“It was a totally random find. We were looking for pit houses—semi-subterrenean workshop huts—and it really looked like that from the surface. But we soon realised that it was something totally different,” says PhD student Anna Beck from the Museum Southeast Denmark.

Humans are the only ultrasocial creature on the planet. We have outcompeted, interbred or even killed off all other hominin species. We cohabit in cities of tens of millions of people and, despite what the media tell us, violence between individuals is extremely rare. This is because we have an extremely large, flexible and complex “social brain”.

To truly understand how the brain maintains our human intellect, we would need to know about the state of all 86 billion neurons and their 100 trillion interconnections, as well as the varying strengths with which they are connected, and the state of more than 1,000 proteins that exist at each connection point. Neurobiologist Steven Rose suggests that even this is not enough – we would still need know how these connections have evolved over a person’s lifetime and even the social context in which they had occurred. It may take centuries just to figure out basic neuronal connectivity.

Many people assume that our brain operates like a powerful computer. But Robert Epstein, a psychologist at the American Institute for Behavioural Research and Technology, says this is just shoddy thinking and is holding back our understanding of the human brain. Because, while humans start with senses, reflexes and learning mechanisms, we are not born with any of the information, rules, algorithms or other key design elements that allow computers to behave somewhat intelligently. For instance, computers store exact copies of data that persist for long periods of time, even when the power is switched off. Our brains, meanwhile, are capable of creating false data or false memories, and they only maintain our intellect as long as we remain alive.

We are organisms, not computers

Of course, we can see many advantages in having a large brain. In my recent book on human evolution I suggest it firstly allows humans to exist in a group size of about 150. This builds resilience to environmental changes by increasing and diversifying food production and sharing.

WASHINGTON — By some estimates, the known universe may contain as many as 2 trillion galaxies, with the average galaxy holding approximately 100 million stars and untold numbers of planets. But could there be multiple copies of the entire universe as we understand it?

The concept of a multiverse — worlds that invisibly coexist alongside us, perhaps representing versions of reality that are near-identical to our own — is a pervasive idea in sci-fi, and one that has intrigued generations of physicists as well as science-fiction creators and fans.

While scientists have yet to find any evidence that multiverses exist, there are a number of hypotheses that use the laws of physics to explore the possibility of multiple universes, sometimes challenging our understanding of reality itself in the process, Erin Macdonald, astrophysicist and self-proclaimed "massive sci-fi nerd," explained during a panel on Saturday (June 17) at Future Con, a festival that highlighted the intersection between science, technology and science fiction in Washington, D.C. [Top 5 Reasons We May Live in a Multiverse]
 
Our universe exists within the fabric of space-time — 3D space combined with time, to create a 4D continuum, explained Macdonald, who is now a science educator at the Denver Museum for Nature and Science. But scientists can't say for sure what space-time looks like, which means it might hold countless universes that are invisible to us, she said.

In some Ebola survivors, the virus leaves a unique scar at the back of the eye that can be seen long after they are cured of the disease, according to a new study.

Researchers analyzed information from 82 Ebola survivors in Sierra Leone and 105 people who lived in the area but never had Ebola. All participants took a vision test and had the back of their eyes examined with an ophthalmoscope. Among Ebola survivors, more than a year had passed, on average, between the time they were cured of the disease and the time of the eye exam.

When asked to read letters on an eye chart, the Ebola survivors tended to perform just as well as those who'd never had the disease, meaning their infection didn't seem affect their vision. [27 Devastating Infectious Diseases]
 
But about 15 percent of Ebola survivors had a unique scar on their retina — the light-sensitive tissue at the back of the eye. The people who had never contracted Ebola did not have this particular type of scar, the study found.

Iron is not commonly famous for its role as a micronutrient for tiny organisms dwelling in the cold waters of polar oceans. But iron feeds plankton, which in turn hold carbon dioxide in their bodies. When they die, the creatures sink to the bottom of the sea, safely storing that carbon.

How exactly the iron gets to the Southern Ocean is hotly debated, but we do know that during the last ice age huge amounts of carbon were stored at the bottom of the Southern Ocean. Understanding how carbon comes to be stored in the depth of the oceans could help abate CO₂ in the atmosphere, and Antarctica has a powerful role.

Icebergs and atmospheric dust are believed to have been the major sources of this micronutrient in the past. However, in research published in Nature Communications, my colleagues and I examined calcite crusts from Antarctica, and found that volcanoes under its glaciers were vital in delivering iron to the ocean during the last ice age.

Today, glacial meltwaters from Greenland and the Antarctic peninsula supply iron both in solution and as tiny particles (less than 0.0001mm in diameter), which are readily consumed by plankton. Where glaciers meet bedrock, minute organisms can live in pockets of relatively warm water. They are able to extract “food” from the rock, and in doing so release iron, which then can be carried by underwater rivers to the sea.

The satellite Micius, launched from Jiuquan, China, in August last year, is unlike any other in the sky. While other satellites communicate with Earth using physics worked out by James Clerk Maxwell 150 years ago, Micius is the world’s first quantum-enabled satellite. And now, it has conclusively proved its quantum credentials.

For the first time, scientists have transmitted photons, or particles of light, that are “entangled” with one another from space to Earth. This entanglement, dubbed “spooky action at a distance” by Albert Einstein, is a uniquely quantum-mechanical phenomenon in which the behaviour of one particle is mysteriously choreographed with another – even though the particles can be at opposite ends of the universe. Manipulating one will instantly affect its entangled partner.

These new results pave the way for space-based quantum communication, a technology that promises to provide truly secure communication across the globe.

Every time we interact with our online bank, for example, the messages sent back and forth between computers are encrypted. People are essentially relying on the extreme unwieldiness of large numbers to keep their messages safe. But being able to encode and decode encrypted messages requires the sharing of secret keys – certain specific numbers that are used in the scrambling and unscrambling process.