Physicists Find Way to Measure Earth’s Rarest Element

A fundamental property of the rarest element on Earth, astatine, has been discovered for the first time, scientists say.

Astatine occurs naturally; however, scientists estimate much less than an ounce in total exists worldwide. For a long time, the characteristics of this elusive element were a mystery, but physicists at the CERN physics laboratory in Switzerland have now measured its ionization potential — the amount of energy needed to remove one electron from an atom of astatine, turning it into an ion or a charged particle.

The measurement fills in a missing piece of the periodic table of elements, because astatine was the last naturally occurring element for which this property was unknown. Astatine, which has 85 protons and 85 electrons per atom, is radioactive, and half of its most stable version decays in just 8.1 hours, a time called half-life. In 1953, Isaac Asimov estimated the worldwide total of astatine in nature was 0.002 ounces (0.07 grams).

Full Article

Barns Are Painted Red Because of the Physics of Dying Stars

Have you ever noticed that almost every barn you have ever seen is red? There’s a reason for that, and it has to do with the chemistry of dying stars. Seriously.

Yonatan Zunger is a Google employee who decided to explain this phenomenon on Google+ recently. The simple answer to why barns are painted red is because red paint is cheap. The cheapest paint there is, in fact. But the reason it’s so cheap? Well, that’s the interesting part.

Red ochre—Fe2O3—is a simple compound of iron and oxygen that absorbs yellow, green and blue light and appears red. It’s what makes red paint red. It’s really cheap because it’s really plentiful. And it’s really plentiful because of nuclear fusion in dying stars. Zunger explains:

The only thing holding the star up was the energy of the fusion reactions, so as power levels go down, the star starts to shrink. And as it shrinks, the pressure goes up, and the temperature goes up, until suddenly it hits a temperature where a new reaction can get started. These new reactions give it a big burst of energy, but start to form heavier elements still, and so the cycle gradually repeats, with the star reacting further and further up the periodic table, producing more and more heavy elements as it goes. Until it hits 56. At that point, the reactions simply stop producing energy at all; the star shuts down and collapses without stopping.

As soon as the star hits the 56 nucleon (total number of protons and neutrons in the nucleus) cutoff, it falls apart. It doesn’t make anything heavier than 56. What does this have to do with red paint? Because the star stops at 56, it winds up making a ton of things with 56 neucleons. It makes more 56 nucleon containing things than anything else (aside from the super light stuff in the star that is too light to fuse).

The element that has 56 protons and neutrons in its nucleus in its stable state? Iron. The stuff that makes red paint.

And that, Zunger explains, is how the death of a star determines what color barns are painted.

New Plasma Device Considered Holy Grail of Energy Generation

Scientists at the University of Missouri have devised a new way to create and control plasma that could transform American energy generation and storage.

Randy Curry, professor of electrical and computer engineering at the University of Missouri’s College of Engineering, and his team developed a device that launches a ring of plasma at distances of up to two feet. Although the plasma reaches a temperature hotter than the surface of the sun, it doesn’t emit radiation and is completely safe in proximity to humans.

While most of us are familiar with three states of matter – liquid, gas and solid – there is also a fourth state known as plasma, which includes things such as fire and lightning. Life on Earth depends on the energy emitted by plasma produced during fusion reactions within the sun.

The secret to Curry’s success was developing a way to make plasma form its own self-magnetic field, which holds it together as it travels through the air.

“Launching plasma in open air is the ‘Holy Grail’ in the field of physics,” said Curry.

“Creating plasma in a vacuum tube surrounded by powerful electromagnets is no big deal; dozens of labs can do that. Our innovation allows the plasma to hold itself together while it travels through regular air without any need for containment.”

The plasma device could also be enlarged to handle much larger amounts of energy, he said.

Ask a grown-up: is there anything smaller than an atom?

Cern scientist Jon Butterworth answers eight-year-old Adam’s question

Yes, and we use them every day. Electrons are one of the things inside atoms and we are very used to seeing them move around when an electric current flows. They have been known about for more than 100 years.

We have something called the standard model of physics, which is a list of things that are not made of anything else – in other words, the smallest things we know of. That list includes quarks, gluons, electrons and neutrinos. Then there are the forces that join those things up: light is one of them. Light is carried by little particles called photons. And there is the Higgs boson particle, which we found last year, which is also smaller than an atom.

It does still boggle my mind. You know the maths of particle physics but while the maths is elegant and beautiful, it feels completely other to everyday life. When we built the Large Hadron Collider and actually saw the Higgs boson particle in action, it was amazing.

Detectors zero in on Earth’s heat: Geoneutrinos paint picture of deep-mantle processes.

A window on the deep Earth opened unexpectedly in 2011, when Japan’s nuclear reactors were shut down after the Fukushima disaster. Before the closure, an underground particle detector called KamLAND based in Kamioka, Japan, was monitoring a torrent of neutrinos streaming from dozens of nearby nuclear reactors, seeking clues to the nature of these hard-to-catch subatomic particles. After those plants fell silent, KamLAND scientists could see more clearly a signal that had largely been obscured: a faint trickle of neutrinos produced inside the planet.

Neutrinos are generated in stars, reactors, and deep in Earth’s crust and mantle by the radio­active decay of elements such as uranium and thorium. KamLAND reported the first tentative detections of these ‘geoneutrinos’ in 2005 (ref.1). But last month at a conference in Takayama, Japan, KamLAND scientists reported seeing them in meaningful quantities — as did a team at the Borexino neutrino detector at the Gran Sasso National Laboratory near L’Aquila, Italy.

These detections are not just curiosities. Geoneutrinos offer the only way to measure one of Earth’s internal heat sources. The total heat flow, measured with sensors in deep mines and amounting to 47 terawatts (TW) of power, drives everything from plate tectonics to Earth’s magnetic field. Some of it comes from the decay of radioactive elements, the rest is primordial heat left over from when Earth was formed by the violent collision of planetary building blocks.

But no one knows the proportions. Geologists assume that Earth contains the same amount of radioactive elements as certain primitive meteorites, but they aren’t sure. “We’re after trying to understand how Earth was built,” says William McDonough, a geologist at the University of Maryland in College Park.

Ultimately, geoneutrino researchers would like multiple detectors spaced around Earth, so that they could perform a sort of tomography on the mantle. That could help scientists to discern between models that favour the uranium and thorium being spread throughout the mantle, versus those in which the elements are concentrated near the core–mantle boundary. Such a difference could help to determine where and how long heat will continue to flow to drive geological processes such as plate tectonics — and how long it will take Earth to cool.

Full Article