- Distant planetoid Sedna still has no equal
- Nasa delays its next Mars mission
- Researchers find ancient climate cycles recorded in Mars rocks
- China, Russia to send probes to Mars next year
The size of the object, called 2005 QU182 based on its distance and apparent brightness, it appears to be about 900 kilometres in diameter. It also has a very elongated orbit that takes it from 37 to 188 astronomical units from the Sun.
That looked neat enough to call Mike Brown, the Caltech astronomer whose team first spotted 2005 QU182 three years ago.
"It is a pretty large one," he admitted. Brown checked his files and found that 2005 QU182 is the eighth largest of the heliopause, the boundary between the solar wind and interplanetary space. Yet the elongated shapes of those orbits aren't mysterious - all the objects come close enough to Neptune for its gravity to have distorted their paths.
But the real mystery is what Brown didn't find after two years of searching with giant telescopes - objects like Sedna, the 1300- to 1800-kilometre-wide body with the largest known orbit around the Sun. Its nearest approach to the Sun is 76 AU, so far away that no known object in the solar system could have put it there.
"Sedna is really interesting because it's a fossil record of something we no longer see," Brown said, referring to the object that must have kicked it into such a strange path.source
My comment: It's hard to get the information from this blog entry, but why I posted it is the last sentence. Sedna was put on extra elongated orbit by an unknown object! This is weird enough, right?
Nasa delays its next Mars mission
The US space agency (Nasa) has delayed the launch of its Mars Science Laboratory rover mission.
MSL was scheduled to fly next year, but the mission has been dogged by testing and hardware problems.
The rover's launch would now be postponed until late 2011, agency officials said.
The mission is using innovative technologies to explore whether microbial life could ever have existed on the Red Planet.
The delay could add $400m to the price tag, which is likely to top $2bn.
"Trying for '09 would require us to assume too much risk, more than I think is appropriate for a flagship mission," said Nasa's administrator Michael Griffin.
The launch date was changed following an assessment by the mission's scientists and engineers of the progress it has made in the past three months.
MSL will use novel technologies to adjust its flight while descending through the Martian atmosphere, and to set the rover on the surface by lowering it on a tether from a hovering platform.
It is engineered to drive longer distances over rougher terrain than previous rovers and contains a science payload 10 times the mass of instruments on Nasa's Spirit and Opportunity Mars rovers.
Engineers have struggled with the development of MSL's complex actuators - the motors that drive and turn the rover's wheels, and operate its robotic arm.
The window for a 2009 launch ends in late October. The relative positions of Earth and Mars are favourable for flights to the Red Planet only a few weeks every two years.
The next launch opportunity after 2009 is in 2011. The window in 2011 runs through October to December.
Dr Ed Weiler, chief scientist at Nasa, announced he had held discussions with the European Space Agency (Esa) about conducting joint missions to Mars in future. He said the cost of such missions meant collaboration was inevitable.
Dr Weiler told reporters that preliminary discussions with his opposite number at Esa, David Southwood, had led to an informal agreement that in future they would adopt a joint architecture for all missions to the Red Planet.
Both agencies are likely to combine their efforts in the early 2020s to return rocks from Mars for study in Earth laboratories.
Europe has already made a decision to delay the launch of its own Mars rover, ExoMars, from 2013 to 2016.
Dr Weiler said there was a possibility this mission could also now become a joint venture with Nasa even though ExoMars is quite advanced in its design.
At its Ministerial Council meeting last week, Esa said it was actively seeking the participation of both the US and Russia on ExoMars as a means of limiting the mission's 1.2bn-euro cost.
David Southwood told the BBC that international cooperation at Mars was the only way forward. source
My comment: Eh, I can't help but be sad about the delay of ExoMars, but what the hell, if we manage to pull a cooperation with other countries, it might even get nice. After the major success of the latest Mars missions, I can't wait to see what the next ones will do.
Researchers find ancient climate cycles recorded in Mars rocks
Based on a pattern of layers within layers measured at one location, known as Becquerel crater, the scientists propose that each layer was formed over a period of about 100,000 years and that these layers were produced by the same cyclical climate changes.
In addition, every 10 layers were bundled together into larger units, which were laid down over an approximately one-million-year period; in the Becquerel crater, the 10-layer pattern is repeated at least 10 times. This one-million-year cycle corresponds to a known pattern of change in Mars's obliquity caused by the dynamics of the solar system.
"Due to the scale of the layers, small variations in Mars's orbit are the best candidate for the implied climate changes. These are the very same changes that have been shown to set the pacing of ice ages on the Earth and can also lead to cyclic layering of sediments," says Lewis.
The tilt of Earth on its axis varies between 22.1 and 24.5 degrees over a 41,000-year period.
Mars's tilt varies by tens of degrees over a 100,000-year cycle, producing even more dramatic variation. When the obliquity is low, the poles are the coldest places on the planet, while the sun is located near the equator all the time. This could cause volatiles in the atmosphere, like water and carbon dioxide, to migrate poleward, where they'd be locked up as ice.
When the obliquity is higher, the poles get relatively more sunlight, and those materials would migrate away. "That affects the volatiles budget. If you move carbon dioxide away from the poles, the atmospheric pressure would increase, which may cause a difference in the ability of winds to transport and deposit sand," Aharonson says. This is one effect that could change the rate of deposition of layers such as those seen by the researchers in the four craters.
Another effect of the changing tilt would be a change in the stability of surface water, which alters the ability of sand grains to stick together and cement in order to form the rock layers.
"The whole climate system would be different," Aharonson says. source
My comment: Ok, not too much to comment appart from my previous comment. I don't understand how people decide not to fund Mars missions when we saw so many discoveries. And what's even more fun is how we start to understand our own planet better thanks to the knowledge about other planets.
China, Russia to send probes to Mars next year
BEIJING (Reuters) – China will team up with Russia to launch two satellite probes to take pictures of Mars and one of its small moons in October next year as it seeks to cement its place in the select ranks of global space powers.
A Chinese-built probe will piggy-back on a Russian-built rocket which would also be carrying a Russian satellite, the Beijing News said, quoting a Chinese lead designer on the project.
The Chinese probe, called "Yinghuo 1," would "carry two cameras to take photos of Mars and(Mars 1)," the paper quoted Chen Changya, the mission's deputy design chief, as saying.
The two countries' satellites would travel together for 11 months, with the Chinese probe powered by Russia's, before separating on entering Mars' orbit, the paper said.
The mission planned for the Chinese probe to spend a year in orbit taking pictures, Chen said, but designers were still puzzling over how to keep the solar-powered probe functioning during seven "long shadow periods."
The probe would have to pass through seven periods of 8.8 hours in darkness when the sun would be obscured by the, with temperatures plunging to 200 degrees below Celsius, the paper said.
While it could turn itself off to conserve energy, the concern was that it might "freeze to death" and not be able to turn itself back on. source
My comment: Hm, I wonder what the Russian mission will do. In any case, it's worrying how European and US missions get delayed and Russian and Chineese get launched.