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Archive for March, 2012

Solar ‘Climate Change’ Could Cause Rougher Space Weather

March 29, 2012 1 comment

Recent research shows that the space age has coincided with a period of unusually high solar activity, called a grand maximum. Isotopes in ice sheets and tree rings tell us that this grand solar maximum is one of 24 during the last 9300 years and suggest the high levels of solar magnetic field seen over the space age will reduce in future. This decline will cause a reduction in sunspot numbers and explosive solar events, but those events that do take place could be more damaging. Graduate student Luke Barnard of the University of Reading will present new results on ‘solar climate change’ in his paper at the National Astronomy Meeting in Manchester.

The level of radiation in the space environment is of great interest to scientists and engineers as it poses various threats to man-made systems including damage to electronics on satellites. It can also be a health hazard to astronauts and to a lesser extent the crew of high-altitude aircraft.

The main sources of radiation are galactic cosmic rays (GCRs), which are a continuous flow of highly energetic particles from outside our solar system and solar energetic particles (SEPs), which are accelerated to high energies in short bursts by explosive events on the sun. The amount of radiation in the near-Earth environment from these two sources is partly controlled in a complicated way by the strength of the Sun’s magnetic field.

There are theoretical predictions supported by observational evidence that a decline in the average strength of the Sun’s magnetic field would lead to an increase in the amount of GCRs reaching near-Earth space. Furthermore there are predictions that, although a decline in solar activity would mean less frequent bursts of SEPs, the bursts that do occur would be larger and more harmful.

Full Story: http://www.jodrellbank.manchester.ac.uk/meetings/nam2012/pressreleases/nam12.html

Spacecraft Observe Impact of Powerful Solar Storm

March 28, 2012 Leave a comment

For the first time, instrumentation aboard two NASA missions operating from complementary vantage points watched as a powerful solar storm spewed a two million-mile-per-hour stream of charged particles and interacted with the invisible magnetic field surrounding Earth, according to a paper published today in the Journal of Geophysical Research.

The spacecraft, NASA’s Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) and Interstellar Boundary Explorer (IBEX), observed the impact from inside and outside the Earth’s magnetosphere, respectively. The energetic neutral atom (ENA) cameras aboard each spacecraft enabled global imaging of the magnetosphere, the invisible bubble that protects Earth from the majority of charged particles from the Sun, as it compressed in response to sharply faster solar wind.

The storm, observed April 5, 2010, also is thought to have caused an important communications satellite, Galaxy-15, to founder and drift, taking almost a year to return to its station.

Full Story: http://www.swri.org/press/2012/twins-ibex.htm#axzz1qT8kzuQ2

Vast Amounts of Gas & Dust Around Black Hole in Early Universe

March 28, 2012 Leave a comment

Using the IRAM array of millimetre-wave telescopes in the French Alps, a team of European astronomers from Germany, the UK and France have discovered a large reservoir of gas and dust in a galaxy that surrounds the most distant supermassive black hole known. Light from the galaxy, called J1120+0641, has taken so long to reach us that the galaxy is seen as it was only 740 million years after the Big Bang, when the universe was only 1/18th of its current age. Team leader Dr. Bram Venemans of the Max-Planck Institute for Astronomy in Heidelberg, Germany will present the new discovery on Wednesday 28 March at the National Astronomy Meeting in Manchester.

The Institut de Radioastronomie Millimetrique (IRAM) array is made up of six 15-m size telescopes that detect emission at millimetre wavelengths (about ten thousand times as long as visible light) sited on the 2550-m high Plateau de Bure in the French Alps. The IRAM telescopes work together to simulate a single much larger telescope in a so-called interferometer that can study objects in fine detail.

A recent upgrade to IRAM allowed the scientists to detect the newly discovered gas and dust that includes significant quantities of carbon. This is quite unexpected, as the chemical element carbon is created via nuclear fusion of helium in the centres of massive stars and ejected into the galaxy when these stars end their lives in dramatic supernova explosions.

Full Story: http://www.jodrellbank.manchester.ac.uk/meetings/nam2012/pressreleases/nam10.html

Billions of Rocky Planets in Habitable Zones Around Red Dwarfs

March 28, 2012 Leave a comment

Image Credit: ESO/L. Calçada

Image Credit: ESO/L. Calçada

A new result from ESO’s HARPS planet finder shows that rocky planets not much bigger than Earth are very common in the habitable zones around faint red stars. The international team estimates that there are tens of billions of such planets in the Milky Way galaxy alone, and probably about one hundred in the Sun’s immediate neighbourhood. This is the first direct measurement of the frequency of super-Earths around red dwarfs, which account for 80% of the stars in the Milky Way.

This first direct estimate of the number of light planets around red dwarf stars has just been announced by an international team using observations with the HARPS spectrograph on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile. A recent announcement (eso1204), showing that planets are ubiquitous in our galaxy used a different method that was not sensitive to this important class of exoplanets.

The HARPS team has been searching for exoplanets orbiting the most common kind of star in the Milky Way — red dwarf stars (also known as M dwarfs). These stars are faint and cool compared to the Sun, but very common and long-lived, and therefore account for 80% of all the stars in the Milky Way.

Full Story: http://www.eso.org/public/news/eso1214/

Earth Usually Has More Than One Moon

March 27, 2012 Leave a comment

Earth usually has more than one moon, according to a team of astronomers from the University of Helsinki, the Paris Observatory and the University of Hawaii at Manoa.

Our 2,000-mile-diameter Moon, so beloved by poets, artists and romantics, has been orbiting Earth for over 4 billion years. Its much smaller cousins, dubbed “minimoons,” are thought to be only a few feet across and to usually orbit our planet for less than a year before resuming their previous lives as asteroids orbiting the Sun.

Mikael Granvik (formerly at UH Manoa and now at Helsinki), Jeremie Vaubaillon (Paris Observatory) and Robert Jedicke (UH Manoa) calculated the probability that at any given time Earth has more than one moon. They used a supercomputer to simulate the passage of 10 million asteroids past Earth. They then tracked the trajectories of the 18,000 objects that were captured by Earth’s gravity.

They concluded that at any given time there should be at least one asteroid with a diameter of at least one meter orbiting Earth. Of course, there may also be many smaller objects orbiting Earth, too.

Full Story: http://www.ifa.hawaii.edu/info/press-releases/minimoons/

Join the 2012 Hubble’s Hidden Treasures Competition

March 27, 2012 Leave a comment

Over two decades in orbit, the Hubble Space Telescope has made a huge number of observations. Every week, we publish new images on the ESA/Hubble website.

But hidden in Hubble’s huge data archives are still some truly breathtaking images that have never been seen in public. We call them Hubble’s Hidden Treasures — and we’re looking for your help to bring them to light.

We’re inviting the public into Hubble’s vast science archive to dig out the best unseen Hubble images. Find a great dataset in the Hubble Legacy Archive, adjust the contrast and colours using the simple online tools and submit to our Hubble’s Hidden Treasures Contest Flickr group, and you could win an iPod Touch in our Hubble’s Hidden Treasures Competition.

Full Story: http://www.spacetelescope.org/announcements/ann1203/

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.

Full Story: http://www.jodrellbank.manchester.ac.uk/meetings/nam2012/pressreleases/nam19.html