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A fresh look at data collected by NASA's Cassini spacecraft during its 2001 flyby of Jupiter shows that Europa's tenuous atmosphere is even thinner than previously thought and also suggests that the thin, hot gas around the moon does not show evidence of plume activity occurring at the time of the flyby. The new research provides a snapshot of Europa's state of activity at that time, and suggests that if there is plume activity, it is likely intermittent.
NASA's planet-hunting Kepler spacecraft makes a comeback with the discovery of the first exoplanet found using its new mission -- K2. The discovery was made when astronomers and engineers devised an ingenious way to repurpose Kepler for the K2 mission and continue its search of the cosmos for other worlds.
Scientists have solved a long-standing space mystery -- the origin of the 'theta aurora'. Auroras are the most visible manifestation of the Sun's effect on Earth. They are seen as colorful displays in the night sky, known as the Northern or Southern Lights. They are caused by the solar wind, a stream of plasma -- electrically charged atomic particles -- carrying its own magnetic field, interacting with the earth's magnetic field. Normally, the main region for this impressive display is the 'auroral oval', which lies at around 65-70 degrees north or south of the equator, encircling the polar caps. However, auroras can occur at even higher latitudes. One type is known as a 'theta aurora' because seen from above it looks like the Greek letter theta -- an oval with a line crossing through the center.
To paraphrase Mark Twain, the report of the Kepler spacecraft's death was greatly exaggerated. Despite a malfunction that ended its primary mission in May 2013, Kepler is still alive and working. The evidence comes from the discovery of a new super-Earth using data collected during Kepler's 'second life.'
An examination of middle-aged star clusters reveals an unexpectedly narrow age range among their stars, suggesting that large groups of stars evolve differently than previously understood.
Astronomers have discovered that modest black holes can shut down star formation by producing turbulence. High-energy jets powered by supermassive black holes can blast away a galaxy's star-forming fuel, resulting in so-called "red and dead" galaxies: those brimming with ancient red stars yet containing little or no hydrogen gas to create new ones.
Messier 47 is located approximately 1600 light-years from Earth, in the constellation of Puppis (the poop deck of the mythological ship Argo). It was first noticed some time before 1654 by Italian astronomer Giovanni Battista Hodierna and was later independently discovered by Charles Messier himself, who apparently had no knowledge of Hodierna's earlier observation. Although it is bright and easy to see, Messier 47 is one of the least densely populated open clusters. Only around 50 stars are visible in a region about 12 light-years across, compared to other similar objects which can contain thousands of stars.
The closest planet to the sun appears to get hit by a periodic meteor shower, possibly associated with a comet that produces multiple events annually on Earth. The clues pointing to Mercury's shower were discovered in the very thin halo of gases that make up the planet's exosphere, which is under study by NASA's MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft.
The Voyager 1 spacecraft has experienced three shock waves. The most recent shock wave, first observed in February 2014, still appears to be going on. One wave, previously reported, helped researchers determine that Voyager 1 had entered interstellar space.
Early discoveries by NASA's newest Mars orbiter are starting to reveal key features about the loss of the planet's atmosphere to space over time. The findings are among the first returns from NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission, which entered its science phase on Nov. 16. The observations reveal a new process by which the solar wind can penetrate deep into a planetary atmosphere. They include the first comprehensive measurements of the composition of Mars' upper atmosphere and electrically charged ionosphere. The results also offer an unprecedented view of ions as they gain the energy that will lead to their to escape from the atmosphere.
Astronomers could soon be able to find rocky planets stretched out by the gravity of the stars they orbit. Since the first discovery in 1993, more than 1800 planets have been found in orbit around stars other than our Sun. These ‘exoplanets’ are incredibly diverse, with some gaseous like Jupiter and some mostly rocky like the Earth. The worlds also orbit their stars at very different distances, from less than a million km to nearly 100 billion km away.
Scientists working on the three newest dark matter experiments are hopeful that we’ll soon understand a quarter of the universe -- but they’re making no promises.
Astronomers may have detected the dusty hallmarks of an entire family of Pluto-size objects swarming around an adolescent version of our own Sun. By making detailed observations of the protoplanetary disk surrounding the star known as HD 107146, the astronomers detected an unexpected increase in the concentration of millimeter-size dust grains in the disk's outer reaches. This surprising increase, which begins remarkably far -- about 13 billion kilometers -- from the host star, may be the result of Pluto-size planetesimals stirring up the region, causing smaller objects to collide and blast themselves apart.
An interstellar mystery of why stars form has been solved thanks to the most realistic supercomputer simulations of galaxies yet made. Theoretical astrophysicists found that stellar activity -- like supernova explosions or even just starlight -- plays a big part in the formation of other stars and the growth of galaxies.
Scientists are preparing to unveil a new, miniature portable solar observatory for use onboard a commercial, manned suborbital spacecraft.
Scientists have picked up an atypical photon emission in X-rays coming from space, and say it could be evidence for the existence of a particle of dark matter. If confirmed, it could open up new perspectives in cosmology.
ESA's Rosetta spacecraft has found the water vapor from its target comet to be significantly different to that found on Earth. The discovery fuels the debate on the origin of our planet's oceans. One of the leading hypotheses on Earth's formation is that it was so hot when it formed 4.6 billion years ago that any original water content should have boiled off. But, today, two thirds of the surface is covered in water, so where did it come from? In this scenario, it should have been delivered after our planet had cooled down, most likely from collisions with comets and asteroids.
NASA regularly watches the Sun in numerous wavelengths because different wavelengths provide information about different temperatures and processes in space. Looking at all the wavelengths together helps to provide a complete picture of what's occurring on the sun over 92 million miles away -- but no one has been able to focus on high energy X-rays from the Sun until recently.
Titan, Saturn's largest moon, is a peculiar place. Unlike any other moon, it has a dense atmosphere. It has rivers and lakes made up of components of natural gas, such as ethane and methane. It also has windswept dunes that are hundreds of yards high, more than a mile wide and hundreds of miles long -- despite data suggesting the body to have only light breezes. Winds on Titan must blow faster than previously thought to move sand. The discovery may explain how the dunes were formed.
Some like it hot, but for creating new stars, a cool cosmic environment is ideal. As a new study suggests, a surge of warm gas into a nearby galaxy -- left over from the devouring of a separate galaxy -- has extinguished star formation by agitating the available chilled gas.