Friday, March 29, 2019
Thursday, March 28, 2019
Our understanding of the role water played in the history of Mars has improved greatly in the last few years, with scientists uncovering evidence of vast oceans, buried ice fields and complex networks of rivers that once sprawled across its surface. A new study has examined the lattermost of these geographical features in close detail and found these Martian waterways were far thicker and dried out far later than previously thought, suggesting that for billions of years, Mars was home to gushing rivers even wider than those on Earth today.
Today, traces of water on Mars can be found in the form of vapor in the atmosphere and stowed away underground in ice sheets and lakes. But the plentiful dried-out riverbeds filled with smooth pebbles that snake their way around the Red Planet provide useful clues about its watery past. By studying these through imagery captured by orbiting spacecraft, scientists are slowly piecing together a very complex puzzle.
While the evidence is clear that the deep, ancient channels seen on Mars were carved out by water, the type of climate that facilitated these conditions remains very much a mystery. This is because of the planet's very thin atmosphere (and therefore weak greenhouse effect), and that in the planet's early history the Sun was far fainter and weaker, providing around 25 to 30 percent of the luminosity that it does today. And less heat, presumably, means less liquid water.
"Indeed, even on ancient Mars, when it was wet enough for rivers some of the time, the rest of the data looks like Mars was extremely cold and dry most of the time," says study author Edwin Kite, assistant professor of geophysical sciences at the University of Chicago.
Looking to fill in the blanks, Kite and his team studied photographs and elevation models of more than 200 ancient Mars riverbeds. By looking at characteristics such as their width, steepness and the size of gravel chunks within them, the scientists were able to draw some conclusions about the force of water that once flowed through them.
According to the team, this provided evidence that strong and persistent water flow existed possibly as recently as two billion years ago, far beyond when the planet's last wet climate is thought to have wrapped up around 3.5 billion years ago. What's more, analysis of the catchment areas indicates that these ancient rivers were wider than the rivers found on Earth today. This adds to our understanding of the ancient climate on Mars, but it throws up a few curveballs, too.
"Our work answers some existing questions but raises a new one," says Kite. "Which is wrong: the climate models, the atmosphere evolution models, or our basic understanding of inner solar system chronology?"
India shot down one of its own low-orbit satellites in a successful test of an anti-satellite missile, Prime Minister Narendra Modi announced Wednesday.
The “historic feat” shows India has become a “global space power,” the prime minister said in a national address that was tailor-made for election season, CNN reported. Parliamentary elections will be held in seven phases from April 11 to May 19.
The US, Russia and China are the only other countries to have demonstrated similar capabilities, so the test is likely to be viewed as provocative by Beijing and Islamabad despite India’s foreign ministry’s statement that New Delhi has “no intention of entering into an arms race in outer space.”
Capable of blinding or disrupting the communications of enemies by destroying their satellites, such weapons will likely be of increasing importance in the future, and also provide a technology base for intercepting ballistic missiles, Reuters noted.
Wednesday, March 27, 2019
Monday, March 25, 2019
Friday, March 22, 2019
Digging into the surface of another planet for the first time is going to bring some surprises, you'd just hope that those surprises don't include your digging being brought to a halt before things have even begun. This is the problem scientists working on the Mars InSight mission have been forced to contend with, though they are now moving ahead with new plans to shed light on the blockage.
The digging operations of the Mars InSight lander are hoped to greatly improve our understanding of the Red Planet. By burrowing into the planet's surface further than any scientific instrument before it, its drilling device will measure thermal conductivity and subsurface materials in the soil, adding to our understanding of how rocky planets like Mars were formed.
But soon after commencing its digging operations in late February, the lander's drilling device, known as "the mole" ground to a halt during the hammering phase, only making it around three quarters of the way out of its housing structure before stopping altogether. The team resumed hammering two days later, but without success.
The data indicated that the mole was healthy and functioning properly, though it was resting at a 15-degree tilt. The operation was then paused while the team investigated the issue, suspecting that some hard rock or gravel beneath the surface is what stopped the device in its tracks.
The mole forms part of a larger instrument called the Heat and Physical Properties Package (HP3), which was built by the German Aerospace Center (DLR). Engineers there and at NASA will work with replicas of the HP3 in the lab to better understand the problem, and are planning a short hammering test on Mars to try and uncover new clues.
This test will take place over 10 to 15 minutes later in the month, and InSight's seismometer will be used to "listen" in on the hammering to try and help determine the source of the blockage. A camera mounted on the lander's robotic arm, meanwhile, will snap images of the support structure to capture any motion that might be triggered throughout.
"With a special filter applied to the short period data directly onboard the SEIS instrument, we will get a much better time resolution of the signals and should be able to diagnose whether or not the mole is stuck or even slowly moving forward or is rebounding," writes DLR's Tilman Spohn, instrument lead. "Knowing this will help us greatly in designing our