Science News Headlines . Earth’s close cousin: Exoplanets . How the brain purges bad memories . Forests suck up less carbon after drought . How T. Rex kept its teeth sharp . World's largest modern wooden building Read more about them below. Earth’s close cousin The Kepler Space telescope has recently (July 23, 2015) found an exoplanet orbiting the G-class star Kepler-452. It is the first potentially rocky super-Earth planet discovered orbiting within the habitable zone of a star very similar to the Sun. The planet called Kepler-452b is about 1,400 light-years away from the Solar System. At the speed of the New Horizons spacecraft, about 59,000 km/h, it would take approximately 26 million years to get there. So it is not very close by. The planet takes 385 Earth days to orbit its star. It is 60% bigger than Earth, and lies within the conservative habitable zone of its parent star. It has a probable mass five times that of Earth, and its surface gravity is twice Earth's. The clouds on the planet would be thick and misty, covering much of the surface as viewed from space. From the surface, its star Kepler-452 would look almost identical to the Sun as viewed from the Earth. The surface gravity of Kepler-452b is considerably stronger than the pull people are used to on Earth. Any hypothetical explorers would thus feel about twice as heavy on the alien world as they do on Earth. The high-gravity environment would probably lead to significant changes in the bodies of Kepler-452b colonists over longer time spans. How the Brain Purges Bad Memories A brain circuit has been found that allows us to forget fear and anxiety, according to a recent article in the journal Science. The brain is extraordinarily good at alerting us to threats. Loud noises, noxious smells, approaching predators: they all send electrical impulses buzzing down our sensory neurons, triggering our brain’s fear circuitry and, in some cases, causing us to fight or flee. The brain is also adept at knowing when an initially threatening or startling stimulus turns out to be harmless or resolved. But sometimes this system fails and unpleasant associations stick around, a malfunction thought to be at the root of post-traumatic stress disorder (PTSD). New research has identified a neuronal circuit responsible for the brain’s ability to purge bad memories, findings that could have implications for treating PTSD and other anxiety disorders. Like most emotions, fear is neurologically complicated. But research has consistently implicated two specific areas of the brain as contributing to and regulating fear responses. The amygdala, two small arcs of brain tissue deep beneath our temples, is involved in emotional reactions, and it flares with activity when we are scared. If a particular threat turns out to be harmless, a brain region behind the forehead called the prefrontal cortex steps in and the fright subsides. Our ability to extinguish painful memories is known to involve some sort of coordinated effort between the amygdala and the prefrontal cortex. The new study however, confirms that a working connection between the two brain regions is necessary to do away with fear. Until now investigators were unsure whether the amygdala–prefrontal cortex communication pathway could on its own control fear extinction. Both structures interact with many other brain regions, and so isolating their effects of on behaviour was a challenge. A technique called optogenetics has made the discovery possible, allowing scientists to precisely assess the connection between the two brain regions in real time, providing a more accurate correlation between neuronal activity and behavior. Forests Suck Up Less Carbon after Drought How do trees respond to drought? It is generally known that drought damages trees, and that it can take a while for trees to repair this damage and recover. Measuring this damage is important. According to a report in the journal Science, ecologists recently examined tree ring data from more than 1,300 sites around the world. By comparing the rings with known drought records they found that trees do not simply return to normal as soon as rains return. Drought actually puts the trees' water transport systems under a huge amount of tension, causing air bubbles to leak in, which damages or blocks those pipes. It is a sort of a heart attack for a tree. In some cases it can be lethal and in some cases that blockage can be repaired. That drought effect can cause tree growth to lag five to ten percent below normal for several years following the dry spell. This is a problem because forests currently take up about 25 percent of human emissions of carbon dioxide (CO2). The less CO2 the trees are able to take up the warmer it gets. This study makes it clear that predicting climate change is hard. These models have a challenging task of representing processes that occur from a leaf scale to a continent scale in space, and from several seconds to hundreds of years or at least a hundred years in time. Perhaps a better understanding of how much carbon trees soak up, and how much they do not, will make climate forecasting just a little bit easier. How T. rex kept its teeth sharp A group of carnivorous dinosaurs have been found to have much more complex teeth than previously expected. Known as theropods, this group includes the most well known of dinosaurs: the Tyrannosaurus rex, as well as several other equally vicious species, all of which dominated the food chain in different periods. Scientists cut open fossilised teeth from eight different species of theropod. The cut surfaces were studied using an electron microscope, which revealed a surprising level of complexity. On the outside, the teeth have large serrations – a series of bumps to help slice through flesh, like those you would find on a meat knife. Normally, these would cause the teeth to weaken and wear away over time, which would leave the animal unable to feed. To counteract this, theropods evolved unique arrangements of the two main tissues that make up teeth, dentine and enamel, to strengthen each serration and prevent erosion. Armed with this dental adaptation, the teeth maintained their flesh-tearing properties for much longer, helping the theropods to stay at the top of the food chain. Tooth structures like these had not previously been seen in meat-eating dinosaurs, although they are present in the teeth of the present-day Komodo dragon, which has a feeding pattern similar to its theropod ancestors. Herbivores, animals that eat exclusively plants, often have well-developed teeth, as chewing plant matter can otherwise cause very rapid dental erosion. However, meat is far softer and easier to chew, and so a much simpler tooth construction was expected. Unlike us, reptiles have a constant cycle of teeth, with a `spare set’ forming in their gums at all times, getting ready to replace the ones that currently being used when needed. There are still many more types of Theropod that are yet to be investigated, providing an obvious future step for scientists. However, more intriguingly, there is also potential to investigate the teeth of early birds, as they too have been found to have serrations, used for similar meat-tearing purposes. This analysis has been presented in the journal `Scientific Reports'. World's largest modern wooden building The Woodproject, a building project in Hackney in London is going to use more than 3,5000 cubic meters of wood. A method of layering wood with glue solves many of the problems with building with wood, providing a light, low carbon option. This is a laminated sort of wood, but unlike plywood, rather than just lots of thin layers, you have here strips of wood which are aligned at right angles to one another and all bonded together using an adhesive and a big press. That gives enormous strength, because wood is strong in one direction but weak in another. By putting them at 90 degrees to each other, we effectively share the benefits of both directions. Wood, in its natural state, starts to shrink in different ways and twist and bend. If you artificially bond it together, you can make flat boards stay flat for a long time. There are two important reasons for such wood based constructions. One is that we need to produce a lot of carbon dioxide when making concrete, so environmentally wood is more friendly. The other is that many such city developments are situated over many holes under the ground like the Metro, and hence need to be lightweight buildings. The builders claim that these wood buildings can last longer than concrete if treated properly. The pictures show details of the Wood Innovation and Design Centre, a 6-storey, nearly 100 foot-tall, 51,000 square foot structure built almost entirely out of engineered wood components in Prince George, British Columbia, Canada. Most appropriately, it houses the local University's wood engineering program, and was completed last October. There are other such large wooden buildings around the world, in U.K. and in Australia, and more people are getting interested in the concept. Sources: Science, Scientific Reports, Scientific American, Science News.