The US space agency's robotic Mars explorer Opportunity has completed 90 days on the Red Planet, bringing its primary mission to an end. But Opportunity is not finished yet: the rover will carry on investigating the Red Planet for at least another 240 sols, or Martian days. The rover has uncovered evidence that its landing site was once the shoreline of a salty lake or sea. Its "twin", Spirit, passed the 90 sol landmark earlier this month. Opportunity is exploring Meridiani Planum, a flat plain rich in the mineral grey haematite – which usually forms in water. "We have full mission success on the project," said mission manager Matt Wallace. "It's a remarkable milestone."
Molecular rings could shelter Venus bugs
(Apr 29, 2004)
The idea that microbes may be alive and well in Venus's clouds is controversial. But some scientists are becoming more convinced that microorganisms could survive, thanks to the shelter from ultraviolet radiation provided by molecular rings of sulphur. Venus might once have been warm and wet, and a potential breeding ground for life, but at some point a runaway greenhouse effect dried the planet out and heated its surface to more than 480°C. A few scientists have argued that if Venus's climate change was slow enough for life to adapt, microbes could survive there today, living in acidic clouds at altitudes of about 50 kilometres. The temperature there is only about 50 to 70°C – conditions some terrestrial microbes can endure.
Super-hot star caught in death throes
(Apr 29, 2004)
The Hubble Space Telescope has imaged the death throes of a searingly hot, Sun-like star that has cast off its outer layers in a form resembling the opalescent wings of a giant butterfly. Gas in the Bug Nebula, officially called NGC 6302, is being ionised by an unseen star – one of the hottest known – at the intersection of the wings. Hubble's Wide Field and Planetary Camera 2 made this composite image from exposures of ionised hydrogen and nitrogen in the nebula. The gas is expanding outward, rippling into finger shapes where it collides with slower-moving gas. But what excites astronomers most is not the shimmer of the wings but a dark band that bisects them. A dense ring of gas and dust girdles and obscures the dying star and contains most of the star's ejected gas.
Too many males may have been the reason the dinosaurs died out 65 million years ago, say Leeds University scientists. They believe the dinosaurs could have been like modern-day reptiles such as crocodiles whose sex depends upon the temperature before they are born. The idea is that the asteroid which struck changed the world's climate, causing it to be cooler and leading to the birth of a preponderance of males. The male-female imbalance would have led to the dinosaurs' extinction.
Scientists say a new lunar mineral has been found in a meteorite from the Moon that crashed to Earth in 2000. The mineral is called hapkeite after the scientist Bruce Hapke who predicted the existence of the iron and silicon compound on the Moon 30 years ago. Hapkeite is probably made when tiny particles impact the Moon at very high speeds, say Mahesh Anand and colleagues Their investigation of meteorite Dhofar 280 is reported in the Proceedings of the National Academy of Sciences.
New images of unsurpassed clarity have been obtained with the ESO Very Large Telescope (VLT) of formations on the surface of Titan, the largest moon in the Saturnian system. They were made by an international research team during recent commissioning observations with the "Simultaneous Differential Imager (SDI)", a novel optical device, just installed at the NACO Adaptive Optics instrument. The images show a number of surface regions with very different reflectivity. Of particular interest are several large "dark" areas of uniformly low reflectivity. One possible interpretation is that they represent huge surface reservoirs of liquid hydrocarbons.
A robotic rescue mission to repair and upgrade the Hubble Space Telescope may be feasible, according to NASA's Associate Administrator, Dr Ed Weiler. In January, the US space agency said there would be no more risky astronaut visits to the telescope, which would probably limit its life to a few years. But Dr Weiler says there are now some promising ideas about how Hubble could be visited without the space shuttle. A small spacecraft could be built to attach itself to Hubble, he believes. "There is a lot of optimism about the robotic possibilities," Dr Weiler told BBC News Online. He added that NASA should be able to be more definitive about the options in June.
Geologists have discovered microscopic burrows where some of Earth's earliest lifeforms bored their way into volcanic glass 3.5 billion years ago. The tubes, from rocks in South Africa's Barberton Greenstone Belt, retain traces of organic carbon left behind by the microorganisms, the authors say. The microbes etched their way into rocks that formed as lava oozed out across a sea floor in Archaean times. An international team published details of the work in the journal Science.
'Weird' meteorite may be from Mars moon
(Apr 22, 2004)
A unique meteorite that fell on a Soviet military base in Yemen in 1980 may have come from one of the moons of Mars. Several meteorites from the Red Planet have been found on Earth, but this could be the only piece of Martian moon rock. Andrei Ivanov, who is based at the Vernadsky Institute of Geochemistry and Analytical Chemistry in Moscow, Russia, spent two decades puzzling over the fist-sized Kaidun meteorite before he decided that it must be a chip off Phobos, the larger of the two Martian moons. "I can't find a better candidate," Ivanov told New Scientist. The Kaidun meteorite is like no other in the world – and 23,000 of them have been catalogued. It is made of many small chunks of material, including minerals never seen before.
A Russian spacecraft carrying a Russian-American-Dutch crew has docked smoothly with the international space station. The Soyuz TM-4, working on autopilot, docked three minutes ahead of schedule at 9:01 a.m. local time, approximately two days after blasting off on a rocket from Russia's Baikonur cosmodrome in Kazakhstan. Carrying three astronauts, it was the third Russian spacecraft to fill in for the U.S. space shuttle, which has been suspended since the Columbia disaster.
