Official "Science News" Thread

[ewmayer]

New Evidence Reveals a 17,000-Year-Old Coastal Route Into North America | Gizmodo ... discusses research article in Science Advances (bolds mine):

During the 20th century, it was conventionally assumed that North America’s first peoples travelled through a narrow, ice-free corridor, but recent evidence has thrown a rather large wrench into this long-standing hypothesis. The retreating ice sheets didn’t yield an interior pathway until about 14,000 years ago, and the strip of land that suddenly became accessible wasn’t suitable for animals and humans until about 13,000 to 12,600 years ago. This presents a huge chronological problem, because archaeological evidence places humans in Chile around 15,000 years ago, and in Florida some 14,500 years ago.

Hence the Coastal Migration Theory, also known as the Kelp Highway Hypothesis. Instead of traveling through an interior route, it’s counterargued, human migrants hugged the Siberian, Beringian, and Alaskan coastlines, eventually making their way into North and South America. There’s practically no archaeological evidence to support this theory, but the recent discovery of 29 footprints on the shoreline of Calvert Island in British Columbia, dated at 13,000 years old, teases at the possibility. Complicating matters, scientists aren’t even sure if the glaciers completely blocked the coastal route, or when the ice sheets retreated to make the route available for human migration.

If the hypothesis is right, the lack of evidence would be expected, since such a coast-hugging migration route would now be under water, and if boats were used (in conjunction with landings where favorable), the odds of the kinds of small craft used surviving to leave traces are [a] tiny, and [b] any remains would similarly now be under water. A lot of (very expensive and difficult) submarine archaeology is likely going to be needed to settle the issue one way or another.

[Dr Sardonicus]

Originally Posted by rogue

A Chemist Shines Light on a Surprising Prime Number Pattern

Not so surprising, it would seem. From the article:

The chemist told de Courcy-Ireland that he could use his formula to predict the frequency of “twin primes,” which are pairs of primes separated by two, like 17 and 19. The mathematician replied that Torquato could in fact predict all other separations as well. The formula for the Bragg peaks was mathematically equivalent to the Hardy-Littlewood k-tuple conjecture, a powerful statement made by the English mathematicians Godfrey Hardy and John Littlewood in 1923 about which “constellations” of primes can exist. One rule forbids three consecutive odd-numbered primes after {3, 5, 7}, since one in the set will always be divisible by three, as in {7, 9, 11}. This rule illustrates why the second-brightest peaks in the primes’ diffraction pattern come from pairs of primes separated by six, rather than four.

[rogue]

A New Genetic Clue to How Humans Got Such Big Brains

Quantum Physics May Be Even Spookier Than You Think

The top 10 new species of 2018, from deep-sea fish to tree-climbing lions

Discover Fascinating Vintage Maps From National Geographic's Archives

Study Reveals Brain Activity Patterns Underlying Fluent Speech

3D-printed corneas are real and they’re spec-tacular

This Is Your Brain Detecting Patterns

What's Going On In Your Child's Brain When You Read Them A Story?

[rogue]

A Shot against Cancer Slated for Testing in Massive Dog Study

Incredible NASA Video Crams 20 Years of Earth's Weather Into 2 Minutes

Life on Mars? Rover’s Latest Discovery Puts It ‘On the Table’

Bookworms More Prone to Be Nearsigted

Jurassic World: Can We Really Resurrect a Dinosaur?

Evidence Found for a New Fundamental Particle

Researchers Get a Peek at How Other Animals See the World

[Dr Sardonicus]

Originally Posted by rogue

Evidence Found for a New Fundamental Particle

Neutrinos are tiny particles that pass through our bodies by the billions each second but seldom interact. They constantly oscillate between three known types, or “flavors,” called electron, muon and tau. The MiniBooNE experiment shoots a beam of muon neutrinos toward a giant oil tank. On the way to the tank, some of these muon neutrinos should transform into electron neutrinos at a rate determined by the difference in mass between the two. MiniBooNE then monitors the arrival of electron neutrinos, which produce characteristic flashes of radiation on the rare occasions when they interact with oil molecules. In its 15-year run, MiniBooNE has registered a few hundred more electron neutrinos than expected.
[snip]
The Liquid Scintillator Neutrino Detector (LSND) in Los Alamos detected a similar anomaly in the 1990s, prompting the construction of MiniBooNE. However, other neutrino experiments that work differently from LSND and MiniBooNE have failed to produce a clear sign of the putative sterile neutrino. “It is a curse of this business that some experiments see something while others don’t,” said Werner Rodejohann of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany.

Hmm. Once upon a time, long long ago, there was a mysterious shortage of electron neutrinos in detectors looking for neutrinos coming out of Mr. Sun. Year after year, only about a third of the expected number were showing up. This was called the "solar neutrino problem."

The problem was solved when it was found that neutrinos "oscillated" between electron neutrinos, muon neutrinos, and tau neutrinos -- and the detectors being used could only detect electron neutrinos. Three kinds of neutrinos coming through the detector, only one of which was detectable. How 'bout that!

This oscillation also settled another neutrino mystery, namely whether neutrinos have mass. Only particles with mass can "oscillate" between different types of particle, so ipso facto, neutrinos have mass!

Now it seems to me that having three types of neutrino solves the "solar neutrino problem" quite neatly. Adding a fourth type would appear to raise the question, "why were we detecting a third, rather than a fourth, the number of solar neutrinos we originally expected?"

[science_man_88]

Originally Posted by Dr Sardonicus

Now it seems to me that having three types of neutrino solves the "solar neutrino problem" quite neatly. Adding a fourth type would appear to raise the question, "why were we detecting a third, rather than a fourth, the number of solar neutrinos we originally expected?"

Maybe the don't happen equally often

[kladner]

@Dr Sardonicus:
Thanks very much for the physics and history in your post. It is stimulating me to look up and read about neutrinos at greater length.

I thought that neutrino detectors involved deep water-filled caverns? The techniques described are new to me.

[Dr Sardonicus]

Originally Posted by kladner

I thought that neutrino detectors involved deep water-filled caverns? The techniques described are new to me.

Tanks of extremely pure heavy water situated deep underground are a well known type of neutrino detector. IIRC another favorite liquid is perchloroethylene (a common cleaning fluid), whose chlorine atoms emit a flash of light if struck by an electron neutrino.

One solar neutrino detector (the Sudbury Neutrino Observatory) is in Sudbury, Ontario, deep, deep underground in a nickel mine. The locale shields the heavy-water detector from cosmic rays, which would otherwise swamp the neutrinos.

[xilman]

https://authors.elsevier.com/a/1XEx4LWHFnnfU is live for 50 days (ish) It's about interstellar communication and I'm one of the cow-riters.

[chalsall]

Originally Posted by xilman

https://authors.elsevier.com/a/1XEx4LWHFnnfU is live for 50 days (ish) It's about interstellar communication and I'm one of the cow-riters.

Extreme coolness. Although I wasn't able to view anything more than the Abstract without enabling Javascript...

I'm reminded of this What If?

[retina]

Originally Posted by xilman

https://authors.elsevier.com/a/1XEx4LWHFnnfU is live for 50 days (ish) It's about interstellar communication and I'm one of the cow-riters.

I guess the assumption is that v is in units of c?

Penetration depth is a strong function of velocity with a minimum requirement of 10 m of titanium shielding at v = 0.995 .

Edit:

Originally Posted by chalsall

Although I wasn't able to view anything more than the Abstract without enabling Javascript...

I didn't need any JS. I had a couple of manual redirect links, that is all.