It has long been thought that somewhere out there, the Sun has a twin - born not just in the same stellar nursery, but an almost identical twin, a binary companion made of the same star-stuff. And now astronomers think they might have found it. Located roughly 184 light-years away, it's called HD 186302, and it's almost certainly a long-lost sibling of our home star.

Most stars are born in groups that can number in the thousands, in what are known as stellar nurseries. The Sun's life is thought to have started this way, 4.57 billion years ago. Recent research suggests that over 50 percent of all Sun-like stars are in binary pairs.

HD186302 is not just a stellar sibling, but a special one, uncannily similar to the Sun. It's a G-type main-sequence star just a bit bigger than the Sun, and around about the same surface temperature and luminosity. It also has extremely similar chemical abundances, and is around the same age - about 4.5 billion years old. It's an even closer match than F-type star HD162826, identified as a stellar sibling in 2014.

That means the size, age, temperature, luminosity and chemical composition of the Sun are all compatible with life “as we know it.” It is plausible that planets orbiting other stars with these same qualities - stellar siblings - could host life-forms similar to ours… and a stellar twin represents an even more hopeful option. If our sibling candidate has a planet, and the planet is a rocky type, in the habitable zone, and if this planet was 'contaminated' by the life seeds from Earth, then we have a dream scenario - an Earth 2.0, orbiting a Sun 2.0.

That's a lot of ifs, but however slim the chance, all these things could plausibly have come to pass. IA astronomers are now making plans to look very hard for signs of any planets that may be orbiting HD186302.

The team's research has been published in the journal Astronomy & Astrophysics.

Image credit: CDS Portal/Simbad
Source: https://www.sciencealert.com/we-may-have-found-our-sun-s-long-lost-identical-twin-star

Chinese nuclear scientists have reached an important milestone in the global quest to harness energy from nuclear fusion - a process that occurs naturally in the Sun. The team from China's Institute of Plasma Physics announced this week that plasma in their Experimental Advanced Superconducting Tokamak (EAST) - dubbed the "Artificial Sun" - reached a whopping 100 million degrees Celsius, temperature required to maintain a fusion reaction that produces more power than it takes to run.

To put that in perspective, the temperature at the core of the actual Sun is said to be about 15 million degrees Celsius, making the plasma in China's artificial Sun more than six times hotter than the original. While current nuclear power plants rely on nuclear fission - a chain reaction where uranium atoms are split to release energy - nuclear fusion effectively does the opposite by forcing atoms to merge. One way of achieving this on Earth is by using what's known as a tokamak, a device designed to replicate the nuclear fusion process that occurs naturally in the Sun and stars to generate energy.

Source: https://www.abc.net.au/news/2018-11-15/china-attempts-to-create-an-artificial-sun/10495536

No matter how abundant or renewable, solar power has one great hurdle to overcome: there is still no cheap and efficient long-term storage for the energy that it generates. This year, a series of four papers has ushered in an intriguing new solution. Scientists in Sweden have developed a specialised fluid, called a solar thermal fuel, that can store energy from the Sun for well over a decade.

They explain that it is like a rechargeable battery, but instead of electricity, you put sunlight in and get heat out, triggered on demand. The fluid is actually a molecule in liquid form composed of carbon, hydrogen and nitrogen, and when it is hit by sunlight, it does something unusual: the bonds between its atoms are rearranged and it turns into an isomer.

Energy from the Sun stays there even when the molecule cools down to room temperature. When the energy is needed the fluid is simply drawn through a catalyst that returns the molecule to its original form, releasing energy in the form of heat. The energy in this isomer can now be stored for up to 18 years.

The renewable, emissions-free energy device is made up of a concave reflector with a pipe in the centre, which tracks the Sun like a sort-of satellite dish. The system works in a circular manner. Pumping through transparent tubes, the fluid is heated up by the sunlight, turning the molecule norbornadiene into its heat-trapping isomer, quadricyclane. The fluid is then stored at room temperature with minimal energy loss.

When the energy is needed, the fluid is filtered through a special catalyst that converts the molecules back to their original form, warming the liquid by 63 degrees Celsius (113 degrees Fahrenheit). The researchers claim their fluid can now hold 250 watt-hours of energy per kilogram, which is double the energy capacity of Tesla's Powerwall batteries. They think they can get even more heat out of this system, at least 110 degrees Celsius (230 degrees Fahrenheit) more.

The hope is that this warmth can be used for domestic heating systems, powering a building's water heater, dishwasher, clothes dryer and much more, before heading back to the roof once again. The technology could be available for commercial use within 10 years.

Source: https://www.sciencealert.com/scientists-develop-liquid-that-sucks-up-sun-s-energy
CARLY CASSELLA 6 NOV 2018
 Image credit: Chalmers University of Technology