*In a career that spanned more than half a century, Gehrels fostered new research on asteroids and comets, including those that pose a threat to Earth.*
Tom Gehrels, an internationally noted planetary scientist and astronomer at the University of Arizona, as well as a hero of the Dutch Resistance during WWII, died Monday. He was 86.
Gehrels was among the first members of the fledgling Lunar and Planetary Laboratory when he joined the UA in 1961. During a long and distinguished career Gehrels pioneered new research on asteroids and comets, especially those that pose a collision threat to Earth. He also developed and taught introductory astronomy courses that were popular with non-science undergraduates. (more…)
An international team of astronomers has identified for the first time a thick stellar disc in the Andromeda galaxy, the nearest large spiral galaxy to our own Milky Way.
The discovery of the thick disc, a major result from a five-year investigation, will help astronomers better understand the processes involved in the formation and evolution of large spiral galaxies like ours, according to the team, which includes UCLA research astronomer Michael Rich and colleagues from Europe and Australia.(more…)
A new study conducted by scientists at the Southwest Research Institute in Boulder, Colorado, has this week posited that Saturn’s rings are the remnants of a massive moon that once orbited Earth’s distant neighbour.
According to study author and astronomer Robin Canup, the moon plunged into Saturn around 4.5 billion years ago due to a giant ring of hydrogen gas responsible for creating rocky satellites but also for dragging larger moons out of orbit.
The scientific theory centres on the predominantly icy composition of Saturn’s rings, The Tech Herald reports. (more…)
The green Voorwerp in the foreground remains illuminated by light emitted up to 70,000 years ago by a quasar in the center of the background galaxy, which has since died out. Image credit: WIYN/William Keel/Anna Manning
While sorting through hundreds of galaxy images as part of the Galaxy Zoo citizen science project two years ago, Dutch schoolteacher and volunteer astronomer Hanny van Arkel stumbled upon a strange-looking object that baffled professional astronomers. Two years later, a team led by Yale University researchers has discovered that the unique object represents a snapshot in time that reveals surprising clues about the life cycle of black holes.
In a new study, the team has confirmed that the unusual object, known as Hanny’s Voorwerp (Hanny’s “object” in Dutch), is a large cloud of glowing gas illuminated by the light from a quasar-an extremely energetic galaxy with a supermassive black hole at its center. The twist, described online in the Astrophysical Journal Letters, is that the quasar lighting up the gas has since burned out almost entirely, even though the light it emitted in the past continues to travel through space, illuminating the gas cloud and producing a sort of “light echo” of the dead quasar. (more…)
Observations made with NASA’s newly refurbished Hubble Space Telescope of a nearby supernova are allowing astronomers to measure the velocity and composition of “star guts” being ejected into space following the explosion, according to a new study led by the University of Colorado at Boulder.
