Kepler discovers first Earth-size planets beyond our solar system
NASA’s Kepler mission has discovered the first Earth-size planets orbiting a sun-like star outside our solar system. The planets, called Kepler-20e and Kepler-20f, are too close to their star to be in the so-called habitable zone where liquid water could exist on a planet’s surface, but they are the smallest exoplanets ever confirmed around a star like our sun.
The new planets are thought to be rocky. Kepler-20e is slightly smaller than Venus, measuring 0.87 times the radius of Earth. Kepler-20f is a bit larger than Earth, measuring 1.03 times its radius. Both planets reside in a five-planet system called Kepler-20, approximately 1,000 light-years away in the constellation Lyra.
Kepler-20e orbits its parent star every 6.1 days and Kepler-20f every 19.6 days. These short orbital periods mean very hot, inhospitable worlds. Kepler-20f, at 800 degrees Fahrenheit, is similar to an average day on the planet Mercury. The surface temperature of Kepler-20e, at more than 1,400 degrees Fahrenheit, would melt glass.
The Kepler-20 system includes three other planets that are larger than Earth but smaller than Neptune. Kepler-20b, the closest planet, Kepler-20c, the third planet, and Kepler-20d, the fifth planet, orbit their star every 3.7, 10.9 and 77.6 days. All five planets have orbits lying roughly within Mercury’s orbit in our solar system. The host star belongs to the same G-type class as our sun, although it is slightly smaller and cooler.
The system has an unexpected arrangement. In our solar system, small, rocky worlds orbit close to the sun and large, gaseous worlds orbit farther out. In comparison, the planets of Kepler-20 are organized in alternating size: large, small, large, small and large. The planets formed farther from their star and then migrated inward, likely through interactions with the disk of material from which they originated. This allowed the worlds to maintain their regular spacing despite alternating sizes.
Above: (1) Artist’s conception of Kepler-20e. (2) Artist’s conception of Kepler-20f. (3) This chart compares the first Earth-size planets found around a sun-like star to planets in our own solar system, Earth and Venus. | Watch an animation of the Kepler-20 system »
How to replicate the squishy sophistication of the human brain in hard metal and silicon? IBM thinks it’s found a way, and to prove it has built and tested two new “cognitive computing” microchips whose design is inspired by the human brain.
In the mammalian brain, neurons send chemical signals to each other across tiny gaps called synapses. A neuron’s long “tail”, the axon, sends the signals from its multiple terminals; the receptive parts of other neurons – the dendrites – collect them.
Each of IBM’s brain-mimicking silicon chips is a few square millimetres in size and holds a grid of 256 parallel wires that represent dendrites of computational “neurons” crossed at right angles by other wires standing in for axons. The “synapses” are 45-nanometre transistors connecting the criss-crossing wires and act as the chips’ memory; one chip has 262,144 of them and the other 65,536. Each electrical signal crossing a synapse consumes just 45 picajoules – a thousandth of what typical computer chips use.
Because the neurons and synapses are so close together, the pieces of hardware responsible for computation and memory are also much closer than in ordinary computer chips. Conventionally, the memory sits to the side of the processor, but in the new chips the memory – the synapses – and the processors – the neurons – are on top of each other, so they don’t need to use as much energy sending electrons back and forth. That means the chips can perform parallel processing far more efficiently than conventional computers.
In preliminary tests, the chips were able to play a game of Pong, control a virtual car on a racecourse and identify an image or digit drawn on a screen. These are all tasks computers have accomplished before, but the new chips managed to complete them without needing a specialised program for each task. The chips can also “learn” how to complete each task if trained.
Fewer watts than Watson
Eventually, by connecting many such chips, Dharmendra Modha of IBM Research – Almaden, in San Jose, California, hopes to build a shoebox-sized supercomputer with 10 billion neurons and 100 trillion synapses that consumes just 1 kilowatt of power. That may still sound a lot – a standard PC uses only a few hundred watts – but a supercomputer like IBM’s Watsonuses hundreds of kilowatts. By contrast, the ultra-efficient human brain is estimated to have 100 billion neurons and at least 100 trillion synapses but consumes no more than 20 watts.
Kwabena Boahen of Stanford University, California, says scale is one of the key issues. Until the chips contain as many synapses as the human brain, it will be difficult to distinguish their accomplishments from those of other computers.
The chips are sponsored by a US Defense Advanced Research Projects Agency (DARPA) project to create computers whose abilities rival those of the human brain.
Calling all couch potatoes. You can live an extra three years if you exercise for just 15 minutes a day – half the 30-minute minimum prescribed by the World Health Organization.
That’s the heart-warming news from an eight-year study on 400,000 people of all ages in Taiwan. “Halving the daily exercise requirement still yielded significant benefits for men and women, young and old, smokers and non-smokers, and even for high-risk groups such as diabetics and people with high blood pressure,” says Chi-Pang Wen of the National Health Research Institutes in Taipei, Taiwan, head of the research team.
We are smack bang in the middle of a second industrial revolution. 3D printing, or “additive manufacturing” as it is more properly known, is about to transform every single aspect of our lives.
Machines today can print objects out of almost any material - from nylon to glass, from chocolate to titanium - and with any complex geometry. This is transforming not just engineering, but many other fields, including education, archaeology, bio-printing and even food printing. Look online and you will see thousands of objects ready to be printed on demand, from custom-shaped hearing aids to authentic-looking replicas of ancient cuneiform tablets.
More importantly, soon anyone will be able to make complex products quickly and cheaply, something that will democratise innovation and unleash human creativity.
The next stage of this journey, which we are just beginning to experience, is control over the composition of such printed matter - going beyond shaping geometry, to shaping the internal structure of materials - with unprecedented fidelity. Forget the traditional limitations imposed by conventional manufacturing, in which each part is made of a single material. Instead, we are talking about specifying microstructure with micrometre-scale precision.
We are making materials within materials, and embedding and weaving multiple materials into complex patterns. We can print hard and soft materials in patterns that create bizarre and new structural behaviours, like materials that expand laterally when pulled longitudinally.
This flexibility means you will soon be able to print a custom tennis racket that cleverly compensates for your unique weaknesses, or a replacement spinal-disc implant exactly tailored for your bad back.
The third and final episode of this journey, of which we have only seen the early signs so far, is the control over behaviour. Here we will go beyond controlling just the shape of matter and its composition. We will then be able to program these materials to function in arbitrary ways - to sense and react, to compute and behave - moving from an object’s mechanical functionality to controlling how it processes information and energy as well.
When this day arrives, you will be able to print virtually anything - from a cellphone to a robot that will walk out of the printer, batteries included. But that robot will not look at all like today’s robots, because it will not be limited by the constraints imposed by conventional manufacturing. The ability to construct systems like this will create a new paradigm of engineering, one that is not unlike biology.
Viral pathogens pose serious health threats worldwide. For clinical viruses such as HIV or hepatitis, emerging viruses such as avian or swine influenza, and highly lethal viruses such as Ebola or smallpox that might be used in bioterrorist attacks, relatively few therapeutics or prophylactics (preventatives) exist. Most therapeutics that do exist are highly specific for one virus, are ineffective against virus strains that become resistant to them, or have adverse effects on patients.
As part of the PANACEA (for Pharmacological Augmentation of Nonspecific Anti-pathogen Cellular Enzymes and Activities) project, researchers from MIT Lincoln Laboratory have developed and demonstrated a novel broad-spectrum antiviral approach, called DRACO (for Double-stranded RNA [dsRNA] Activated Caspase
Oligomerizer). DRACO selectively induces apoptosis, or cell suicide, in cells containing any viral dsRNA, rapidly killing infected cells without harming uninfected cells. As a result, DRACO should be effective against virtually all viruses, rapidly terminating a viral infection while minimizing the impact on the patient.
More than 30 years after they left Earth, NASA’s twin Voyager probes are now at the edge of the solar system. Not only that, they’re still working. And with each passing day they are beaming back a message that, to scientists, is both unsettling and thrilling.
The message is, “Expect the unexpected.”
“It’s uncanny,” says Ed Stone of Caltech, Voyager Project Scientist since 1972. “Voyager 1 and 2 have a knack for making discoveries.”
Today, April 28, 2011, NASA held a live briefing to reflect on what the Voyager mission has accomplished—and to preview what lies ahead as the probes prepare to enter the realm of the Milky Way itself.
Black Hole May Have Ripped Star Apart Causing Unprecedented Explosion
NASA’s Swift, Hubble Space Telescope and Chandra X-ray Observatory have teamed up to study one of the most puzzling cosmic blasts yet observed. More than a week later, high-energy radiation continues to brighten and fade from its location.
Astronomers say they have never seen anything this bright, long-lasting and variable before. Usually, gamma-ray bursts mark the destruction of a massive star, but flaring emission from these events never lasts more than a few hours.
Although research is ongoing, astronomers say that the unusual blast likely arose when a star wandered too close to its galaxy’s central black hole. Intense tidal forces tore the star apart, and the infalling gas continues to stream toward the hole. According to this model, the spinning black hole formed an outflowing jet along its rotational axis. A powerful blast of X- and gamma rays is seen if this jet is pointed in our direction.
On March 28, Swift’s Burst Alert Telescope discovered the source in the constellation Draco when it erupted with the first in a series of powerful X-ray blasts. The satellite determined a position for the explosion, now cataloged as gamma-ray burst (GRB) 110328A, and informed astronomers worldwide. read more