NASA’s Dawn spacecraft has entered an approach phase in which it will continue to close in on Ceres, a Texas-sized dwarf planet never before visited by a spacecraft. Dawn launched in 2007 and is scheduled to enter Ceres orbit in March 2015.
Dawn recently emerged from solar conjunction, in which the spacecraft is on the opposite side of the sun, limiting communication with antennas on Earth. Now that Dawn can reliably communicate with Earth again, mission controllers have programmed the maneuvers necessary for the next stage of the rendezvous, which they label the Ceres approach phase. Dawn is currently 400,000 miles (640,000 kilometers) from Ceres, approaching it at around 450 miles per hour (725 kilometers per hour).
The spacecraft’s arrival at Ceres will mark the first time that a spacecraft has ever orbited two solar system targets. Dawn previously explored the protoplanet Vesta for 14 months, from 2011 to 2012, capturing detailed images and data about that body.
The simulations took several months to run at the “Cosmology Machine” in Durham and at “Curie” in Paris, among the largest computers used for scientific research in the U.K. and France, respectively. Astronomers can now use the results to study the development of galaxies from almost 14 billion years ago until now. The results will be published in Monthly Notices of the Royal Astronomical Society on 1 January.
or years, astronomers have studied the formation of galaxies using computer simulations, but with limited success. The galaxies that formed in previous simulations were often too massive, too small, too old and too spherical.
The galaxies formed in the EAGLE-simulation (Evolution and Assembly of GaLaxies and their Environments) are a much closer reflection of real galaxies thanks to the strong galactic winds, which blow away the gas supply needed for the formation of stars. EAGLE’s galaxies are lighter and younger because fewer stars form and they form later. In the EAGLE simulation these galactic winds – which are powered by stars, supernova explosions and supermassive black holes – are stronger than in earlier simulations.
Watch Earth roll by through the perspective of ESA astronaut Alexander Gerst in this six-minute timelapse video from space. Combining 12 500 images taken by Alexander during his six-month Blue Dot mission on the International Space Station this Ultra High Definition video shows the best our beautiful planet has to offer.
Marvel at the auroras, sunrises, clouds, stars, oceans, the Milky Way, the International Space Station, lightning, cities at night, spacecraft and the thin band of atmosphere that protects us from space.
The MESSENGER spacecraft will soon run literally on fumes. After more than 10 years traveling in space, nearly four of those orbiting Mercury, the spacecraft has expended most of its propellant and was on course to impact the planet’s surface at the end of March 2015. But engineers on the team have devised a way to use the pressurization gas in the spacecraft’s propulsion system to propel MESSENGER for as long as another month, allowing scientists to collect even more data about the planet closest to the Sun.
“MESSENGER has used nearly all of the onboard liquid propellant. Typically, when this liquid propellant is completely exhausted, a spacecraft can no longer make adjustments to its trajectory. For MESSENGER, this would have meant that we would no longer have been able to delay the inevitable impact with Mercury’s surface,” explained MESSENGER Mission Systems Engineer Dan O’Shaughnessy, of the Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Md. “However, gaseous helium was used to pressurize MESSENGER’s propellant tanks, and this gas can be exploited to continue to make small adjustments to the trajectory.”
This new NASA/ESA Hubble Space Telescope image shows the galaxy IC 335 in front of a backdrop of distant galaxies. IC 335 is part of a galaxy group containing three other galaxies, and located in the Fornax Galaxy Cluster 60 million light-years away.
As seen in this image, the disk of IC 335 appears edge-on from the vantage point of Earth. This makes it harder for astronomers to classify it, as most of the characteristics of a galaxy’s morphology — the arms of a spiral or the bar across the center — are only visible on its face. Still, the 45 000 light-year-long galaxy could be classified as an S0 type.
The Milky Way, the galaxy we live in, is part of a cluster of more than 50 galaxies that make up the ‘Local Group’, a collection that includes the famous Andromeda galaxy and many other far smaller objects. Now a Russian-American team have added to the canon, finding a tiny and isolated dwarf galaxy almost 7 million light years away. Their results appear in Monthly Notices of the Royal Astronomical Society.
The team, led by Prof Igor Karachentsev of the Special Astrophysical Observatory in Karachai-Cherkessia, Russia, found the new galaxy, named KKs3, using the Hubble Space Telescope Advanced Camera for Surveys (ACS) in August 2014. Kks3 is located in the southern sky in the direction of the constellation of Hydrus and its stars have only one ten-thousandth of the mass of the Milky Way.
Despite a malfunction that ended its primary mission in May 2013, NASA’s Kepler spacecraft has discovered a new super-Earth using data collected during its “second life,” known as the K2 mission.
University of Hawaii astronomer Christoph Baranec supplied confirming data with his Robo-AO instrument mounted on the Palomar 1.5-meter telescope, and former UH graduate student Brendan Bowler, now a Joint Center for Planetary Astronomy postdoctoral fellow at Caltech, provided additional confirming observations using the Keck II adaptive optics system on Maunakea.
The Kepler spacecraft detects planets by looking for planets that transit, or cross in front of, their star as seen from the vantage of Earth. During the transit, the star’s light dims slightly. The smaller the planet, the weaker the dimming, so brightness measurements must be exquisitely precise. To enable that precision, the spacecraft must maintain a steady pointing.