Science news digest – 19th November 2012
In the science news this week, dust-devils surround Curiosity, touchscreens that can tell your knuckles from your nails, the origins of the great white shark, and finally… a 500-year-old murder case is under investigation.
Curiosity glimpses dust-devils on Mars
The NASA rover, Curiosity, has detected whirlwinds of dust skirting around the edges of the vehicle on Mars, reported the BBC.
So far, the cameras are yet to glimpse the dust clouds, also known as dust-devils, but NASA scientists believe the whirlwinds may even have travelled over the top of the Mars-based laboratory.
This isn’t the first time dust-devils have been spotted on Mars – previous Mars rovers have detected the phenomena as well.
"A dust-devil looks essentially like what you would expect from the movies - a tiny tornado that is lifting dust," explained Manuel de la Torre Juarez of Nasa's Jet Propulsion Laboratory (JPL) and a scientist on the Rover Environmental Monitoring Station (Rems) instrument.
"Understanding these phenomena is very important because the Martian climate is driven largely by its dust cycle."
The Rems instrument was the only part of the rover that was damaged when it landed on the surface earlier this year. It’s likely that a piece of grit flew up and knocked out one of the two wind probes during the rover’s descent into the crater.
However, despite the damage, the Rems instrument is still returning useful data, and the scientists are learning to cope with its deficiencies.
Surprisingly, the rover has established that the winds blow in an east-to-west direction on the floor of the crater, but it was originally thought that the prevailing winds would be north-westerly because of the rover’s position near the northern slopes of crater’s central mountain.
Also, barometric readings have shown that the air pressure has been slowly increasing since the rover landed on the surface. This is consistent with the southern hemisphere moving into summer, because as the temperatures increase the southern ice cap, made of frozen carbon dioxide, begins to evaporate. This increases the mass of the atmosphere, thus raising the air pressure.
"Each year, the Martian atmosphere basically shrinks and grows by about 30% because a portion of the atmosphere is freezing out to the poles in [autumn] and then vaporising again in spring; and that of course is unlike anything we see on Earth," said Claire Newman, a Rems investigator at Ashima Research in California.
Touchscreens that can tell your knuckle from your fingernail
The latest step in touchscreen technology could see smartphones that can distinguish between a person’s fingertip, their knuckle or even their fingernail, reported New Scientist.
Chris Harrison, a computer scientist at Carnegie Mellon University in Pittsburg, Pennslyvania has built a prototype smartphone that has been fitted with a small vibration sensor that can identify the acoustic and vibrational differences between the three different types of touch.
The development could mean that a knuckle touch could work as a right-click on a desktop mouse, for example, increasing the capabilities of software and websites viewed on a touchscreen device.
"A big problem with touchscreens right now is that they are very simplistic, relative to the capability of our hands," Harrison says. "We could do so much more."
"The more ways you have of expressing input into smartphones the better," says Joseph Paradiso at the MIT Media Lab in Boston, who has worked on similar technology.
Harrison says that the sensor is a standard piece of electronics that can easily be added to the main circuit board of any smartphone, and then the user just needs to download the software program he has created to interpret the sound and vibrational data.
Great whites did not evolve from megashark
A new fossil discovery has finally put to bed a debate that has been raging for the past 150 years – whether or not great white sharks evolved from huge megasharks.
US scientists have described the fossil of the species Carcharodon hubbelli showing that the shark has intermediate features, somewhere between present day predators and smaller, prehistoric mako sharks.
This find supports the theory that the great white shark has evolved from a smaller mako shark, rather than from the giant megatooth sharks, such as Megalodon (Carcharocles megalodon), found in the oceans millions of years ago.
"When the early palaeontologists put together dentitions of Megalodon and the other megatooth species, they used the modern white shark to put them together, so of course it's going to look like a white shark because that's what was used as a model," explained Professor Dana Ehret of Monmouth University in New Jersey who lead the new research.
Present day great whites have similar teeth serrations to those of the megasharks, which led researchers to believe the sharks were closely related.
"But we actually see the evolution of serrations occurring many times in different lineages of sharks and if you look at the shape and size of the serrations in the two groups you see that they are actually very different from each other," Professor Ehret told BBC News. "White sharks have very large, coarse serrations whereas megalodon had very fine serrations."
"A big issue in shark palaeontology is that we tend to only have isolated teeth, and even when you find associated teeth very, very rarely are they articulated in a life position," continued Professor Ehret.
"The nice thing about this new species is that we have an articulated set of jaws which almost never happens and we could see that the third anterior tooth is curved out, just like in the tooth row of mako sharks today," he said.
Astronomer’s ‘murder’ investigation is revisited
The untimely death of Tycho Brahe over 400 years ago, has led to much speculation in recent years over the circumstances of his sudden demise.
The Danish scientist laid much of the groundwork for modern astronomy, but his death in 1601, which was originally put down to a bladder infection, was widely disputed due to a worryingly high level of mercury in a sample taken from his grave in 1901.
However, to finally put these rumours to bed, scientists have exhumed the astronomer’s grave once again. This time, they say that if he was murdered, it certainly wasn’t from mercury poisoning, reported the Guardian.
"We measured the concentration of mercury using three different quantitative chemical methods in our labs," said Kaare Lund Rasmussen, associate professor of chemistry at the University of Southern Denmark. "All tests revealed the same result: that mercury concentrations were not sufficiently high to have caused his death. In fact, chemical analyses of the bones indicate that Tycho Brahe was not exposed to an abnormally high mercury load in the last five to 10 years of his life."
However, this doesn’t completely rule out foul-play and until a formal cause of death can be established, the investigation will continue. Currently, further tests are still being conducted on the remains.