May 22, 2013 9:34 am
Heinrich Rohrer, winner of the 1986 Nobel Prize in Physics, passed away last week at the age of 79. Rohrer is widely regarded as one of the founding scientists of the nanotechnology field.
In his Nobel Prize announcement, the Nobel Prize committee called out “his fundamental work in electron optics and for the design of the first electron microscope.” The electron microscope is what let scientists see viruses and IBM make this little animation. Here’s Physics World on how the Scanning Tunneling Microscope (STM) works:
An STM creates an image of the surface of a sample by scanning an atomically sharp tip over its surface. The tip is held less than one nanometre from the surface and a voltage is applied so that electrons can undergo quantum-mechanical tunnelling between tip and surface. The tunnelling current is strongly dependent on the tip–surface separation and this is used in a feedback loop to keep the tip the same distance from the surface. An image is obtained by scanning the tip across the surface to create a topographical map in which individual atoms can be seen.
The scientists’ colleagues at I.B.M. were skeptical of the project. As Dr. Rohrer recalled, “They all said, ‘You are completely crazy — but if it works you’ll get the Nobel Prize.’ ”
For inventing the STM, Rohrer didn’t just get the Nobel Prize. He was also awarded the German Physics Prize, the Otto Klung Prize, the Hewlett Packard Europhysics Prize, the King Faisal Prize and the Cresson Medal. His invention also got him inducted into the U.S. National Inventors Hall of Fame. That’s because the STM allows scientists to look at the arrangement of the atoms on a surface and move atoms around. Seeing this atomic level and being able to study and manipulate it allowed scientists to develop modern forms of nanotechnology.
Rohrer was born in Buchs, Switzerland, on June 6th, 1933, half an hour after his twin sister. Rohrer wasn’t planning on going into physics, he writes in his autobiography:
My finding to physics was rather accidental. My natural bent was towards classical languages and natural sciences, and only when I had to register at the ETH (Swiss Federal Institute of Technology) in autumn 1951, did I decide in favor of physics.
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May 10, 2013 1:49 pm
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.
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May 9, 2013 12:55 pm
You would think that we’d know how thunder and lightning work by now. But researchers still puzzle over what, exactly, causes those bright flashes of electrostatic discharge. Lightning electrifies the sky about 100 times per second in various locations around the world, yet the electric fields within thunderclouds seem to have only about a tenth of the strength required for producing a lightning bolt, LiveScience reports.
As it turns out, lightning may have extraterrestrial origins. This idea is not new:
More than 20 years ago, physicist Alex Gurevich at the Russian Academy of Sciences in Moscow suggested lightning might be initiated by cosmic rays from outer space. These particles strike Earth with gargantuan amounts of energy surpassing anything the most powerful atom smashers on the planet are capable of.
Cosmic rays slamming into air molecules may split those molecules into many electrons, which collide in turn with additional molecules, snowballing into more and more electrons zipping around. Gurevich called this “a runaway breakdown,” LiveScience writes.
In a new paper, Gurevich and colleagues analyzed radio pulses from around 3,800 lightning strikes. They hypothesize that thunderclouds’ highly electrically charged water droplets and ice nuggets allow even the most un-energetic cosmic rays to spark a bolt of lightning if it comes into contact with such a cloud. Researchers know that cosmic rays hit the planet about as frequently as lightning strikes, LiveScience writes, so the theory at least makes sense.
Unfortunately, Gurevich and a number of other scientific groups are still in the process of taking simultaneous measurements of cosmic ray’s energetic particles and the radio pulses lightning produces, which should help determine whether or not the two phenomenon are indeed linked. At least for now, Gurevich’s idea—long ignored by science—is at least being given the attention needed to prove once and for all whether lightning does have extraterrestrial origins.
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May 7, 2013 1:54 pm
A star being ripped to shreds in a violent supernova is one of the most powerful explosions in the universe. The largest supernovae can produce gamma-ray bursts: a tightly concentrated lance of light that streams out into space. Gamma-ray bursts, says NASA, “are the most luminous and mysterious explosions in the universe.”
The blasts emit surges of gamma rays — the most powerful form of light — as well as X-rays, and they produce afterglows that can be observed at optical and radio energies.
Two weeks ago, says NASA, astronomers saw the longest and brightest gamma-ray burst ever detected. It was the biggest shot of energy we’ve ever seen, streaming from the universe’s most powerful class of explosions. NASA:
“We have waited a long time for a gamma-ray burst this shockingly, eye-wateringly bright,” said Julie McEnery, project scientist for the Fermi Gamma-ray Space Telescope at NASA’s Goddard Space Flight Center in Greenbelt, Md.
“The event, labeled GRB 130427A, was the most energetic gamma-ray burst yet seen, and also had the longest duration,” says Matthew Francis for Ars Technica. “The output from GRB 130427A was visible in gamma ray light for nearly half a day, while typical GRBs fade within a matter of minutes or hours.”
There are a few different of classes of gamma-ray bursts in the world. Astrophysicists think that some—short gamma-ray bursts—form when two neutron stars merge and emit a pulse of energy. Huge ones like the one just detected are known as long gamma-ray bursts, and they form when huge stars collapse, often leading to the formation of a black hole.
Gamma-ray bursts focus their energy in a tightly-concentrated spire of energy. A few years ago, says Wired, researchers calculated what would happen if a gamma-ray burst went off nearby, and was pointed at the Earth.
Steve Thorsett of Princeton University has calculated the consequences if such a merger were to take place within 3,500 light-years of Earth, with its energy aimed at the solar system. The blast would bathe Earth in the equivalent of 300,000 megatons of TNT, 30 times the world’s nuclear weaponry, with the gamma-ray and X-ray radiation stripping Earth of its ozone layer.
While scientists cannot yet predict with any precision which nearby stars will go supernova, the merger of neutron star binaries is as predictable as any solar eclipse. Three such binary systems have been discovered, and one, PSR B1534+12, presently sits about 3,500 light-years away and will coalesce in a billion years.
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May 1, 2013 10:59 am
In November 1999, Don Eigler proved that man had truly mastered the atom: not by way of a devastating explosion or constrained reaction, but with art. The physicist, working for IBM, spelled out the company’s name using 35 individual atoms of the element xenon using a scanning tunneling microscope.
Now, scientists use scanning tunneling microscopes “for more than just imaging surfaces. Physicists and chemists are able to use the probe to move molecules, and even individual atoms, around in a controlled way,” says physicist Jim Al-Khalili in a 2004 book. Fourteen years ago, Don Eigler was the first person to do so, an achievement that helped to open the door on the then-nascent field of nanotechnology.
Now IBM is back, and with fourteen more years playing with these techniques, scientists have moved from precisely positioning individual atoms to making them dance. In a new short stop-motion film, A Boy and His Atom, scientists manipulated thousands of individual atoms to make the “world’s smallest movie.” The movie exists on a plane 100,000,000 times smaller than the world as we know and experience it. The boy and his ball are made from molecules of carbon monoxide, and yet gives an image reminiscent of the video games of the early 1980s.
“Though the technology that the team discusses isn’t new,” says the Verge, “they were able to use it in a new way: the black-and-white images and playful music form a strong artistic style that’s reminiscent of early film, but at an entirely different scale.”
For more information about how the movie was made, IBM has released a behind-the-scenes video to accompany their animation.
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