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BOUNCING NEUTRONS FAIL TO FIND DARK MATTER OR ENERGY

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Earlier this year, researchers found the signal of inflation hidden in the cosmic microwave background—the radiative remnants of the Big Bang took a long time to reveal their secrets. It was a big day. Cosmologists everywhere broke out the Radler, got horrendously drunk, and rioted in front of campus administration buildings. Okay, maybe not—getting drunk while drinking Radler is difficult under the best of circumstances.

No, in reality, they went back to work. Even if those results hold up and inflation is as predicted, that still leaves cosmologists missing two pieces of their puzzle: dark matter and dark energy. While everyone else is searching the skies, a group of physicists has shown that bouncing neutrons are actually very sensitive to variations in gravity. Their research is now putting stringent limits on certain dark energy and dark matter theories.

Three forces walk into a bar

Before we crack open the door to the lab and reveal results, it is important to see how inflation, dark energy, and dark matter all fit together. When we look out into the Universe, its appearance is rather odd. It is surprisingly smooth over very large scales, containing lots of, well, bugger all. And where there is matter, it is clumped up much more than expected. So, the Universe is both smooth and lumpy. It’s also still inflating. Our observations show that the expansion of the Universe not only continues, but is getting faster.

The smoothness of the Universe can be explained by very rapid expansion—inflation. If you have the right amount of inflation to explain the size and smoothness of the Universe, however, there is not enough observable matter to get stars or galaxies. The force of gravity is simply too weak to draw matter together. This is one of a number of reasons we need dark matter. And, finally, to explain the acceleration of the expansion of the Universe, we need dark energy; ideally, that would explain both early inflation and today’s inflation. Until recently, all of these were placeholder concepts that may or may not take the form implied by their names.

Nevertheless, these names seem to have been good guesses. Observations of galactic collisions tell us that dark matter probably is some form of matter. Observations of the cosmic microwave background radiation tell us that inflation may well have taken place as predicted. Dark energy, though, is still a very open question.

Dreaming up physics

The point about placeholder concepts is that physicists can sit around dreaming up possible ways to explain the placeholder effect. Dark matter might just be a modified theory of gravity; or it could be heavy but cold particles; or light weight particles; or, well, insert your own idea here. The only requirement is that these ideas fit the available data and don’t break anything else. After coming up with an explanation, the key step is to figure out how that explanation might affect the Universe in other ways. Once you know that, the real work can begin: the search for evidence.

In amongst the many theories for dark matter, a particle family called the axion is one contender. The axion is not really a family of particles; because no one has found an axion, the particle has a range of possible properties that depend on theoretical considerations. This is much like how Higgs’ particle had a range of possible masses and could even have been a descriptor of multiple Higgs-like particles. We couldn’t tell the difference until the LHC finally found the actual Higgs particle.

In any case, the axion is a very light particle. And that is important for detecting its presence. The LHC needed protons, smashing together at very high energy, to create and detect the Higgs particle. But, when a particle has very little energy, you can use a very low energy probe to detect it. This brings particle physics back into the realm of nearly ordinary laboratory physics.

I say nearly ordinary because, although you only need a low energy probe, the changes induced by the axion will also be very small.

Hiding neutrons in a beer fridge

And this is where our intrepid group of physicists comes in. Their experiment takes the form of a very cold beam of neutrons. These neutrons float into a chamber containing two neutron mirrors. As the neutrons travel through the chamber, they bounce back and forth between the mirrors, finally exiting at the other end, where they hit a neutron detector.

If you know the angle at which the neutrons hit the first mirror, the distance between the mirrors, and the size of the mirrors, you will know exactly which direction the neutrons will be headed when they exit the chamber. By placing the detector at the right location, you will see lots of neutrons. However, if gravity is not exactly the strength that you expect, or the neutrons are slowed because they stopped to play with a passing dark matter particle, then the detector will see fewer neutrons.

This early version of the experiment saw nothing that would indicate any deviation from ordinary gravity.

This time around, however, the team has increased the sensitivity by vibrating one of the mirrors. The neutrons will keep bouncing for a long time if the mirror is stationary. By moving the mirror, we amplify the motion, speeding the neutrons up. They hit the other mirror sooner, and that changes the final trajectory of the neutrons when they exit the chamber. But the mirror must oscillate at precisely the right frequency in order to amplify the motion. That means that if dark energy is changing local gravity at all, we will see it because the vibrational frequency of the mirror will have to change to come into resonance with the bouncing neutrons.

Again, no changes to the resonance frequency were observed. This closes the window on the coupling between dark energy and ordinary matter by about five orders of magnitude. It does, however, still leave another seven orders of magnitude to be eliminated. It should also be noted that this only applies to a certain family of dark energy theories.

Along with not detecting dark energy, the researchers failed to find axions as well. In this case, the axions are expected to affect neutrons through the neutron spin. The neutron spins were all aligned by performing the experiment in the presence of a magnetic field. Axions are unaffected by the magnetic field because their spin is zero. But, should a neutron bounce off a passing axion, the interaction between the spins will cause the neutron to flip its spin (the spin can either be aligned to the magnetic field, or anti-aligned, but not in between), changing its resonance frequency relative to the mirror yet again. By looking at whether the change in resonance frequency depends on the orientation of the magnetic field, any interactions between an axion and the neutron beam should be made apparent.

But it wasn’t. In this case, the coupling strength between the axion and the spin of ordinary matter was shown to be at least 30 times lower than previous measurements. Unfortunately, there is no window to close on axions, because the coupling could be anywhere between the current upper limit and zero. Meaning that higher and higher precision experiments can only get closer to zero, but never exactly eliminate the possibility. Clearly, other experiments will be required for that.

I love these bouncing neutron experiments, though. They are conceptually simple and don’t require teams of hundreds of researchers to get great results. I eagerly await more results.

source:http://arstechnica.com/science/2014/04/bouncing-neutrons-fail-to-find-dark-matter-or-energy/

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Paypal to allow users to buy, hold and sell four cryptocurrencies

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Bitcoin is up $400 to $12,296 today. Part of the reason is that Paypal hass received a conditional bitlicence from the New York State Department of Financial Services and will launch a service for users to be able to buy, hold and sell cryptocurrency.
In the release the company said it “signaled its plans to significantly increase cryptocurrency’s utility by making it available as a funding source for purchases at its 26 million merchants worldwide.”
The company is introducing the ability to buy, hold and sell select cryptocurrencies, initially featuring Bitcoin, Ethereum, Bitcoin Cash and Litecoin, directly within the PayPal digital wallet. The service will be available to PayPal account holders in the U.S. in the coming weeks.
“The shift to digital forms of currencies is inevitable, bringing with it clear advantages in terms of financial inclusion and access; efficiency, speed and resilience of the payments system; and the ability for governments to disburse funds to citizens quickly,” said Dan Schulman, president and CEO, PayPal.
“Our global reach, digital payments expertise, two-sided network, and rigorous security and compliance controls provide us with the opportunity, and the responsibility, to help facilitate the understanding, redemption and interoperability of these new instruments of exchange. We are eager to work with central banks and regulators around the world to offer our support, and to meaningfully contribute to shaping the role that digital currencies will play in the future of global finance and commerce.”

This is great news for crypto but I’m told it shouldn’t have been entirely unexpected In June, there was a report that Paypal was working on direct crypto sales.

Source: https://www.forexlive.com/Cryptocurrency/!/paypal-to-enable-users-to-buy-hold-and-sell-cryptocurrencies-20201021

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Nokia awarded contract to build 4G network on the moon

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Nokia has been awarded a contract to establish a 4G network on the moon. The contract is one of several that NASA is awarding to companies as it plans a return to the moon.

The $14.1 million contract was given to Nokia’s US subsidiary and is a small part of the $370 million total awarded to companies such as SpaceX. The cellular service will allow astronauts, rovers, lunar landers, and habitats to communicate with one another according to Jim Reuter, the Associate Administrator for NASA’s Space.

Nokia Logo

The 4G network that Nokia will build will be miles superior to the form of communication that was used during the early missions to the moon.

This is not Nokia’s first attempt to launch an LTE network on the moon. It planned to do so in 2018 in collaboration with PTScientists, a German space firm, and Vodafone UK to launch an LTE network at the site of the Apollo 17 landing but the plan never came to fruition.

Source: https://www.gizmochina.com/2020/10/18/nokia-awarded-contract-to-build-4g-network-on-the-moon/

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Stripe acquires Nigeria’s Paystack for $200M+ to expand into the African continent

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When Stripe  announced earlier this year that it had picked up another $600 million in funding, it said one big reason for the funding was to expand its API-based payments services into more geographies. Today the company is coming good on that plan in the form of some M&A.

Stripe is acquiring Paystack, a startup out of Lagos, Nigeria that, like Stripe, provides a quick way to integrate payments services into an online or offline transaction by way of an API. (We and others have referred to it in the past as “the Stripe of Africa.”)

Paystack  currently has around 60,000 customers, including small businesses, larger corporates, fintechs, educational institutions and online betting companies, and the plan will be for it to continue operating independently, the companies said.

Terms of the deal are not being disclosed, but sources close to it confirm that it’s over $200 million. That makes this the biggest startup acquisition to date to come out of Nigeria, as well as Stripe’s biggest acquisition to date anywhere. (Sendwave, acquired by WorldRemit in a $500 million deal in August, is based out of Kenya.)

It’s also a notable shift in Stripe’s strategy as it continues to mature: Typically, it has only acquired smaller companies to expand its technology stack, rather than its global footprint.

The deal underscores two interesting points about Stripe, now valued at $36 billion and regularly tipped as an IPO candidate. (Note: It has never commented on those plans up to now.) First is how it is doubling down on geographic expansion: Even before this news, it had added 17 countries to its platform in the last 18 months, along with progressive feature expansion. And second is how Stripe is putting a bet on the emerging markets of Africa specifically in the future of its own growth.

“There is enormous opportunity,” said Patrick Collison, Stripe’s co-founder and CEO, in an interview with TechCrunch. “In absolute numbers, Africa may be smaller right now than other regions, but online commerce will grow about 30% every year. And even with wider global declines, online shoppers are growing twice as fast. Stripe thinks on a longer time horizon than others because we are an infrastructure company. We are thinking of what the world will look like in 2040-2050.”

For Paystack, the deal will give the company a lot more fuel (that is, investment) to build out further in Nigeria and expand to other markets, CEO Shola Akinlade said in an interview.

“Paystack was not for sale when Stripe approached us,” said Akinlade, who co-founded the company with Ezra Olubi (who is the CTO). “For us, it’s about the mission. I’m driven by the mission to accelerate payments on the continent, and I am convinced that Stripe will help us get there faster. It is a very natural move.”

Paystack had been on Stripe’s radar for some time prior to acquiring it. Like its U.S. counterpart, the Nigerian startup went through Y Combinator — that was in 2016, and it was actually the first-ever startup out of Nigeria to get into the world-famous incubator. Then, in 2018, Stripe led an $8 million funding round for Paystack, with others participating, including Visa and Tencent. (And for the record, Akinlade said that Visa and Tencent had not approached it for acquisition. Both have been regular investors in startups on the continent.)

In the last several years, Stripe has made a number of investments into startups building technology or businesses in areas where Stripe has yet to move. This year, those investments have included backing an investment in universal checkout service Fast, and backing the Philippines-based payment platform PayMongo.

Collison said that while acquiring Paystack after investing in it was a big move for the company, people also shouldn’t read too much into it in terms of Stripe’s bigger acquisition policy.

“When we invest in startups we’re not trying to tie them up with complicated strategic investments,” Collison said. “We try to understand the broader ecosystem, and keep our eyes pointed outwards and see where we can help.”

That is to say, there are no plans to acquire other regional companies or other operations simply to expand Stripe’s footprint, with the interest in Paystack being about how well they’d built the company, not just where they are located.

“A lot of companies have been, let’s say, heavily influenced by Stripe,” Collison said, raising his eyebrows a little. “But with Paystack, clearly they’ve put a lot of original thinking into how to do things better. There are some details of Stripe that we consider mistakes, but we can see that Paystack ‘gets it,’ it’s clear from the site and from the product sensibilities, and that has nothing to do with them being in Africa or African.”

Stripe, with its business firmly in the world of digital transactions, already has a strong line in the detection and prevention of fraud and other financial crimes. It has developed an extensive platform of fraud protection tools, but even with that, incidents can slip through the cracks. Just last month, Stripe was ordered to pay $120,000 in a case in Massachusetts after failing to protect users in a $15 million cryptocurrency scam.

Now, bringing on a business from Nigeria could give the company a different kind of risk exposure. Nigeria is the biggest economy in Africa, but it is also one of the more corrupt on the continent, according to research from Transparency International.

And related to that, it also has a very contentious approach to law and order. Nigeria has been embroiled in protests in the last week with demonstrators calling for the disbanding of the country’s Special Anti-Robbery Squad, after multiple accusations of brutality, including extrajudicial killings, extortion and torture. In fact, Stripe and Paystack postponed the original announcement in part because of the current situation in the country.

But while those troubles continue to be worked through (and hopefully eventually resolved, by way of government reform in response to demonstrators’ demands), Paystack’s acquisition is a notable foil to those themes. It points to how talented people in the region are identifying problems in the market and building technology to help fix them, as a way of improving how people can transact, and in turn, economic outcomes more generally.

The company got its start back when Akinlade, for fun (!) built a quick way of integrating a card transaction into a web page, and it was the simplicity of how it worked that spurred him and his co-founder to think of how to develop that into something others could use. That became the germination of the idea that eventually landed them at YC and in the scope of Stripe.

“We’re still very early in the Paystack payments ecosystem, which is super broken,” said Akinlade. The company today provides a payments API, and it makes revenue every time a transaction is made using it. He wouldn’t talk about what else is on Paystack’s radar, but when you consider Stripe’s own product trajectory as a template, there is a wide range of accounting, fraud, card, cash advance and other services to meet business needs that could be built around that to expand the business. “Most of what we will be building in Africa has not been built yet.”

Last month, at Disrupt, we interviewed another successful entrepreneur in the country, Tunde Kehinde, who wisely noted that more exits of promising startups — either by going public or getting acquired — will help lift up the whole ecosystem. In that regard, Stripe’s move is a vote of confidence not just for the potential of the region, but for those putting in the efforts to build tech and continue improving outcomes for everyone.

Source: https://techcrunch.com/2020/10/15/stripe-acquires-nigerias-paystack-for-200m-to-expand-into-the-african-continent/?tpcc=ECTW2020

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