The Sun is heating up, and in 4 billion years from now it will swell up to become a red giant – Earth and the rest of the inner planets will be destroyed. But the deadly conditions that destroy the Earth will mean warmer temperatures in the outer Solar System, possibly supporting life. The region from Saturn to Pluto will warm up to the point that frozen water will melt on moons and planets. Scientists think the best chances for life will be found on Pluto and its moon Charon as well as Neptune’s moon Triton because they’re rich in organic chemicals.
After 15 years of observation, over the course of more than 1,000 nights, a European team of astronomers has collected the most thorough survey of our local stellar neighborhood. The team performed an analysis of more than 14,000 stars to calculate their distance, age, chemical analysis, velocity and orbit around the Milky Way. Each star was measured 4 times over the course of this period. It turns out that the motion of stars through the Milky Way is much more chaotic and turbulent than previously thought.
An international team of astronomers have mapped a sizable region of space around the Andromeda Galaxy (M31) and have found the wreckage of many galaxies, torn apart by its massive gravity. One stream of stars has been found stretching back 50,000 to a satellite galaxy which is in the process of being consumed. They also found 14 globular star clusters floating far from Andromeda’s centre; the remnants of destroyed galaxies. By studying these galactic fossils, astronomers can better understand the evolution of Andromeda.
Radio astronomers have successfully measured an object that surrounds the supermassive black hole at the heart of our Milky Way galaxy. The centre of our galaxy lies 26,000 light-years from Earth, but it’s normally obscured by gas and dust, so visible light telescopes can’t see it. By focusing on the object, called Sagittarius A, with high radio wavelengths, the astronomers were determine that its size is as about the same as the orbit of the Earth around the Sun. The supermassive black hole at the centre is likely the size of the orbit of Mercury, but it contains 4 million solar masses.
A survey with the Anglo-Australian Telescope (AAT) has revealed dozens of miniature galaxies the nearby Fornax galaxy cluster. These are a class of galaxies known as “ultra compact dwarfs” (UCDs). These objects were completely unknown until a few years ago, and now astronomers believe that they are very common. Perhaps they are leftover primordial building blocks that merged together to form larger galaxies. They are incredibly small, only about 120 light-years across, but they can contain tens of millions of stars.
Venus, currently the brightest “star” in the sky, will spend the next few days passing through the Pleiades star cluster, making for a beautiful sky show. Venus is easy to see, it’s that blazingly bright “star” high in the Western sky after sunset. Pleiades is much dimmer; a collection of young stars that looks like a miniature dipper that’s hard to see in polluted city skies. On April 2, Venus will be right below the cluster; on April 3 it will be in the handle; and then April 4 it will have passed completely through. Find some dark skies over the next few nights to really appreciate the view – it won’t happen again for another 8 years.
In order the represent the Universe mathematically, physicists use a handful of constants, such as the speed of light, or the gravitational constant. One called the “fine structure constant”, or alpha, helps describe how the forces hold atoms together and interact with light. Researchers recently revealed that alpha might have changed over the history of the Universe, but a new study from the European Southern Observatory refutes this evidence. By studying the light from a distant quasar with a high degree of precision, they found that alpha doesn’t seem to have changed over time.
NASA’s Chandra X-Ray Observatory has found unexpectedly large quantities of magnesium in an exploded star called N49B. N49B exploded as a supernova approximately 10,000 years ago, and it seems to have ejected a mass of magnesium equal to the mass of our Sun – this would make the original star 1,000 times larger than the Sun. High concentrations of magnesium usually correspond to high concentrations of oxygen in a star, but this wasn’t the case with N49B. So how did the extra magnesium get there?
Dark matter is a mystery. Astronomers know it’s there because they can measure the effect of its gravity on stars and galaxies, but they can’t see it. One theory about the nature of dark matter is that it’s composed of theoretical subatomic particles called Weakly Interacting Massive Particles (WIMPS). A team from Italy believed they detected these WIMPs back in 1998, but other scientists were skeptical. A researcher from the University of Utah has proposed that the Italians search for different streams of particles coming from different galaxies to validate their original experiment.
Astronomers have measured the light from a supernova, and believe that it was inside a very unusual star system when it exploded. The team used the European Southern Observatory’s Very Large Telescope in Chile to analyze the light from supernova 2002ic, and determined that it was inside a flat, dense, clumpy disk of dust and gas that was previously blown out by a companion star. It seems similar to objects known as protoplanetary nebulae, which are found in our own Milky Way.