Posts Tagged ‘national astronomy meeting’

Galaxy Distribution When Universe Was Half Its Age

At the UK-Germany National Astronomy Meeting NAM2012, the Baryon Oscillation Spectroscopic Survey (BOSS) team today announced the most accurate measurement yet of the distribution of galaxies between five and six billion years ago. This was the key ‘pivot’ moment at which the expansion of the universe stopped slowing down due to gravity and started to accelerate instead, due to a mysterious force dubbed ”dark energy”. The nature of this ”dark energy” is one of the big mysteries in cosmology today, and scientists need precise measurements of the expansion history of the universe to unravel this mystery – BOSS provides this kind of data. In a set of six joint papers presented today, the BOSS team, an international group of scientists with the participation of the Max Planck Institute of Extraterrestrial Physics in Garching, Germany, used these data together with previous measurements to place tight constraints on various cosmological models.

The BOSS survey, which is a part of the Sloan Digital Sky Survey (SDSS-III), was started in 2009 to probe the universe at a time when dark energy started to dominate. The survey will continue until 2014, collecting data for 1.35 million galaxies with a custom-designed new spectrograph on the 2.5-metre Sloan Telescope at the Apache Point Observatory in New Mexico, USA. In the first year-and-a-half, it has already mapped the three-dimensional positions of more than a quarter of a million galaxies spread across about one tenth of the sky, yielding the most accurate and complete map of the galaxy distribution up to a distance of about 6 billion light years.

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Measuring the Cosmic Dust Swept Up by the Earth

Although we think of space as being empty, there is more out there than meets the eye – dust, for example, is everywhere. If all the material between the Sun and Jupiter were compressed together it would form a moon 25 km across. Now a new research programme will try to see how much of this dust enters the Earth’s atmosphere. Metals from the cosmic dust play a part in various phenomena that affect our climate. An accurate estimate of dust would also help us understand how particles are transported through different layers of the Earth’s atmosphere. Professor John Plane of the University of Leeds will present the Cosmic Dust in the Terrestrial Atmosphere (CODITA) project on Friday 30 March at the National Astronomy Meeting in Manchester.

CODITA has received a EUR 2.5 million grant from the European Research Council to investigate the dust input over the next 5 years. The international team, led by Professor Plane, is made up of 11 scientists in Leeds and a further 10 research groups in the US and Germany.

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When Dark Energy Turned On

The Sloan Digital Sky Survey (SDSS-III) today announced the most accurate measurements yet of the distances to galaxies in the faraway universe, giving an unprecedented look at the time when the universe first began to expand at an ever-increasing rate. Scientists from the University of Portsmouth and the Max-Planck Institute for Extraterrestrial Physics will present the new results in a press conference at 1000 BST on Friday 30 March at the National Astronomy Meeting in Manchester.

The results are available in six related papers posted to the arXiv preprint server and are the culmination of more than two years of work by the team of scientists and engineers behind the Baryon Oscillation Spectroscopic Survey (BOSS), one of the SDSS-III’s four component surveys.

“There’s been a lot of talk about using galaxy maps to find out what’s causing accelerating expansion,” says David Schlegel of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, the principal investigator of BOSS. “We’ve been making a map, and now we’re using it – starting to push our knowledge out to the distances when dark energy turned on.”

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Interstellar Beacons Could Help Future Astronauts Find Their Way

The use of stars, planets and stellar constellations for navigation was of fundamental importance for mankind for thousands of years. Now a group of scientists at the Max-Planck Institute for Extraterrestrial Physics in Garching, Germany have developed a new technique using a special population of stars to navigate not on Earth, but in voyages across the universe. Team member Prof. Werner Becker will present their work at the National Astronomy Meeting in Manchester on Friday 30 March.

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How Comets Fizzle Out or Survive a Flight Through the Sun’s Atmosphere

Since the 1980s astronomers have seen thousands of comets falling towards the Sun, most of them too small to survive a close approach, let alone to re-emerge. Until recently no such objects had been seen very close to the Sun as the glare of sunlight made them impossible to observe. Now a team of scientists led by Professor Emeritus John Brown, Astronomer Royal for Scotland and former Regius Professor of Astronomy at Glasgow University, have worked out which comets make it through this fiery journey, which fizzle out high up and which explode just above the surface. Prof. Brown will present this new work in a paper at the National Astronomy Meeting in Manchester on Friday 30 March.

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Solar Eruptions Cause Sunquakes

April 2, 2012 1 comment

A study led by UCL’s Mullard Space Science Laboratory has shown for the first time that sunquakes can be produced during eruptions of magnetic field and charged particles, as the immense magnetic structure blasts off into the Solar System. The results will be presented by Dr Sergei Zharkov at the National Astronomy Meeting 2012 in Manchester on Friday 30th March 2012.

The first observation of a sunquake was reported by Kosovichev & Zharkova in the late 1990s. During the last decade it has become well established that explosions in the Sun’s atmosphere, known as solar flares, can create sunquakes through the impact of powerful beams of particles which travel into the Sun. This new study shows that eruptions of material known as coronal mass ejections are also able to produce sunquakes.

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Milky Way Image Reveals a Billion Stars

March 29, 2012 Leave a comment

More than one billion stars in the Milky Way can be seen together in detail for the first time in an image captured by an international team of astronomers. Scientists created the colour picture by combining infra-red light images from telescopes in the northern and southern hemispheres. Large structures of the Milky Way galaxy, such as gas and dust clouds where stars have formed and died, can be seen in the image. Dr Nick Cross of the University of Edinburgh will present the new work on Thursday 29 March at the National Astronomy Meeting in Manchester.

The picture represents part of a 10-year project involving scientists from the UK, Europe and Chile, who gathered data from the two telescopes. The information has been processed and archived by teams at the Universities of Edinburgh and Cambridge, who have made it available to astronomers around the world for further studies.

Archived information from the project – known as the VISTA Data Flow System – is expected to enable scientists to carry out groundbreaking research in future years without the need to generate further data.

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Space Weather Warnings for Earth & Forecasts for Exoplanets

March 29, 2012 Leave a comment

The UK Met Office’s weather and climate model is being adapted to help understand space weather at Earth and the atmospheres of planets orbiting other stars. Two teams of scientists will present their work at the National Astronomy Meeting in Manchester.

The Met Office plans to expand its services to provide operational space weather forecasts for the UK. It is pooling skills with the UK’s space weather research community to extend its ‘Unified Model’ upwards to include the Earth’s thermosphere, a region about 90-600km above the Earth surface. The impact of space weather events is very commonly seen in this region.

“Space weather can affect the aviation and power industries, as well as a whole range of activities that rely on GPS timing and positioning, radio communication or satellite-based observations,” said the Met Office’s Dr David Jackson, who will present the project on Friday 30th March.

“To develop a more accurate and useful advanced-warning system for space weather, we need to develop a system of interconnected models that describe the whole domain – the conditions on the Sun, interplanetary space, the layers of the Earth’s atmosphere, all the way down to the Earth’s surface. The more accurate we can be in representing interactions between the lower atmosphere and thermosphere, the more we can enhance thermospheric forecasts, and thus improve space weather forecast products for users,” Jackson continued.

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Comet Wild 2 – First Evidence of Space Weathering

March 27, 2012 Leave a comment

The traditional picture of comets as cold, icy, unchanging bodies throughout their history is being reappraised in the light of analyses of dust grains from Comet Wild2. A team led by the University of Leicester has detected the presence of iron in a dust grain, evidence of space weathering that could explain the rusty reddish colour of Wild2’s outer surface. The results were presented by Dr John Bridges at the National Astronomy Meeting in Manchester on Tuesday 27th March.

The Wild2 grains were collected by the NASA Stardust mission and returned to Earth in 2006. The fast-moving dust grains were collected in arrays of aerogel, a silicon-based foam that is 99 per cent empty space, which slowed the particles from velocities of 6 kilometres a second to a halt over just a few millimetres. Since then, an international team of scientists has been analysing the samples and the carrot-shaped tracks that they left in the aerogel. Microscopic samples dissected from the grains have been analysed at facilities around the UK, and in particular this work was performed at the Diamond Light Source synchrotron in Oxfordshire and Leicester University. Through a range of analytical techniques, scientists in the UK have been able to fully analyse the mineralogy and isotopes of the samples.

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Cassini Measures Saturn’s Nightside Aurora & Electric Currents

March 27, 2012 Leave a comment

Since the NASA / ESA Cassini-Huygens spacecraft arrived at Saturn in 2004, astronomers and space scientists have been able to study the ringed planet and its moons in great detail. Now, for the first time, a team of planetary scientists have made simultaneous measurements of Saturn’s nightside aurora, magnetic field, and associated charged particles. Together the fields and particle data provide information on the electric currents flowing that produce the emissions. Team leader Dr Emma Bunce of the University of Leicester will present the new work at the National Astronomy Meeting in Manchester on 27 March 2012.

Generally, images of the aurora (equivalent to the terrestrial ‘northern lights’) provide valuable information about the electromagnetic connection between the solar wind, the planet’s magnetic field (magnetosphere) and its upper atmosphere. Variations in the aurora then provide information on changes in the associated magnetosphere. But viewing the aurora (best done at a large distance) at the same time as measuring the magnetic field and charged particles at high latitudes (where the aurora is found, best done close to the planet) is hard

In 2009, Cassini made a crossing of the magnetic field tubes that connect to the aurora on the night side of Saturn. Because of the position of the spacecraft, Dr Bunce and her team were able to obtain ultraviolet images of the aurora (which manifests itself as a complete oval around each pole of the planet) at the same time.

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