The strange orbits of some objects in the farthest reaches of our solar system, hypothesized by some astronomers to be shaped by an unknown ninth planet, can instead be explained by the combined gravitational force of small objects orbiting the sun beyond Neptune, say researchers.
Saturn's distinctive rings were observed in unprecedented detail by NASA's Cassini spacecraft, and scientists have now used those observations to probe the interior of the giant planet and obtain the first precise determination of its rotation rate. The length of a day on Saturn, according to their calculations, is 10 hours 33 minutes and 38 seconds.
An international team of researchers including Chryssa Kouveliotou, a professor of physics at the George Washington University, discovered the missing link connecting hypernovae to GRBs in the form of a hot cocoon around the jets of matter expelled by the central engine as these spread through the outer layers of the progenitor star.
In its last days, the Cassini spacecraft looped between Saturn and its rings so that Earth-based radio telescopes could track the gravitational tug of each. Scientists in Italy and the U.S. have now used these measurements to determine the mass of the rings and estimate its age, which is young: 10-100 million years. This supports the hypothesis that the rings are rubble from a comet or Kuiper Belt object captured late in Saturn's history.
A team of scientists has determined the number of asteroid impacts on the moon and Earth increased by two to three times starting around 290 million years ago. Previous theories held that there were fewer craters on both objects dating back to before that time because they had disappeared due to erosion. The new findings claim that there were simply fewer asteroid impacts during that earlier period.
Using images and thermal data collected by NASA's Lunar Reconnaissance Orbiter (LRO), Southwest Research Institute scientists and their collaborators have calculated the ages of large lunar craters across the moon to be less than 1 billion years. By comparing the impact history of the moon with Earth's craters over this interval, they discovered that the rate of sizable asteroid collisions has increased by a factor of two to three on both bodies over the last 290 million years.
The number of asteroids colliding with the Earth and moon has increased by up to three times over the past 290 million years, according to a major new study involving the University of Southampton. These findings, published in Science challenge our previous understanding of Earth's history.
An international team of researchers, including the University of Leicester, found evidence for the much theorized 'hot cocoon'.
A team of scientists has, for the first time, used a single, cohesive computer model to simulate the entire life cycle of a solar flare: from the buildup of energy thousands of kilometers below the solar surface, to the emergence of tangled magnetic field lines, to the explosive release of energy in a brilliant flash.
An image from the international Cassini spacecraft provides evidence of rainfall on the north pole of Titan, the largest of Saturn's moons. The rainfall would be the first indication of the start of a summer season in the moon's northern hemisphere.