SPACE & SCIENCE NEWS: August 2004Home > Space & Science News > Space & Science News: August 2004: 1 | 2 | 3
Remnants of 1994 comet impact leave puzzle at Jupiter
(Aug 24, 2004)
Jupiter's atmosphere still contains remnants of a comet impact from a decade ago, but scientists said last week they are puzzled by how two substances have spread into different locations. The new study also discovered two previously undetected chemicals in Jupiter's air. Grasping what chemical compounds are in and above the Jovian clouds and how they move about could help scientists understand planets outside our solar system, too, said the researchers who produced the work.
Scientists have mapped enormous impact craters hidden under the Antarctic ice sheet using satellite technology. The craters may have either come from an asteroid between 5 and 11km across that broke up in the atmosphere, a swarm of comets or comet fragments. The space impacts created multiple craters over an area of 2,092 km (1300 miles) by 3,862 km (2,400 miles). The scientists told a conference this week that the impacts occurred roughly 780,000 years ago during an ice age.
The US space agency's robotic rover Spirit has found more evidence that water washed and altered the rocks it has been studying on the Red Planet. The vehicle is examining the geology of an outcrop at Columbia Hills named Clovis, which shows chemical and physical signs of alteration by water. Sprit's twin, Opportunity, has now completed its transect of rocks in a large crater on the other side of Mars. NASA says both rovers continue to work well as they move into Mars' winter.
The mystery surrounding Sedna – the most distant object ever seen in the Solar System – deepened as astronomers calculated that the planetoid's "missing" moon must belong to an entirely new class of celestial object, and is possibly the darkest body in the Solar System. When Sedna was spotted in November 2003 it was the largest object found since the discovery of Pluto. It has puzzled astronomers because it rotates just once every 20 days. Slow rotation usually indicates the presence of a moon, which would put a brake on the planetoid's rotation by exerting tidal forces on it.
Five new satellites – and one candidate moon – have been discovered orbiting the giant planet Neptune, bringing its tally of moons to 13. Two orbit in the same direction as the planet rotates, while the orbits of the others are opposite to Neptune's spin. The tiny outer satellites are probably captured asteroids, astronomers say. Cataclysmic events connected to the capture of Neptune's moon Triton were thought to have destroyed any outer satellites the planet once had.
Astronomers have used measurements from two distant stars to come up with an age for our galaxy, the Milky Way. A team working with the Very Large Telescope (VLT) in Chile report that our galaxy is 13,600 million years old, give or take 800 million years. This was determined by measuring the amount of the element beryllium in two stars in a so-called globular cluster.
The Cassini-Huygens mission in orbit around Saturn has discovered two new moons around the ringed planet. The new discoveries take Saturn's total tally of natural satellites to 33. The moons are about 3 km (2 miles) and 4 km (2.5 miles) across and located 194,000km (120,000 miles) and 211,000 km (131,000 miles) from Saturn's centre. They are provisionally named S/2004 S1 and S/2004 S2 though one of the new moons may have been spotted before in a single image from the Voyager probe.
The Chandra X-ray Observatory has caught enormous hot gas clouds in space in the act of merging to form a single massive galaxy cluster. The clouds, which are many millions of degrees Celsius in temperature, each contain hundreds of galaxies. The gas complex, known as Abell 2125, is about three billion light-years from Earth and is seen at a time about 11 billion years after the Big Bang.
An astronomer in the US has taken the sharpest ever image of the dust disk around a nearby star and seen "clumps" of material that could be evidence for new planets forming. Michael Liu of the University of Hawaii used the Keck II telescope in Hawaii to observe a young star called AU Microscopii, and says that the results could help shed light on the formation of planets (M Liu 2004 Sciencexpress 1102929).
The Hubble Space Telescope has peered inside a bubble of interstellar gas and dust that being inflated by a hurricane of particles emitted from a young star. This nearby star, which has no name, is losing 100 million times more mass per second than our own Sun, generating a torrent of speeding particles. Because the star is surrounded by an envelope of gas the particle train, or stellar wind, collides with the gas. This pushes it out forming a bubble of the type seen in the Hubble image.
