Premium - Gist of Science Reporter: December 2013
OPPORTUNITY COMPLETES TEN YEARS ON MARS
When NASA’s Mars rover Opportunity blasted c from Cape
Canaveral in 2003, many observers expected the rover to survive not more than a
few months. It was designed only for a three-month mission on the hostile
Martian surface. On 7 July 2013, Opportunity celebrated the tenth anniversary of
its launch and had spent nine years roving the red sands of Mars - and still
According to a recent NASA report, after nineplus years of
traveling, Opportunity recently set the US space program’s all-time record for
mileage on another planet. The milestone occurred on 15 May 2013, when the rover
drove 80 metres, bringing its total odometry 35.760 kilometres or 22.220 miles.
The previous mark had been held by the Apollo 17 moon rover, which astronauts
Gene Cernan and Harrison Schmitt drove for 35.74 km (22.21 miles) across the
lunar surface in December 1972.
Over the years, Opportunity has been photographing and
sampling the Martian landscape. The surface of Mars of today is bone dry and
hostile to life as we know it. Opportunity’s mission is to hunt for places where
it wasn’t always so, places where ancient water might have nourished life forms
native to Mars. The rover has found abundant evidence that liquid water was once
present. For the past 20 months, Opportunity has been “working” the rim of
Endeavour Crater. There, Opportunity found deposits of gypsum probably formed
from groundwater seeping up through cracks in Martian soil. It has also found
signs of clay minerals in a rock
The rover is currently en route to “Selander Point”, a place on
the rim of Endurance Crater where a treasure-trove of geological layers is
exposed for investigation.
A visit to Solander Point will be like reading a Martian
history book. Besides, there are north-facing slopes at Solander Point where the
rover can tilt its solar panels toward the sun and ride out the coming winter.
The minimum-sunshine days of this sixth Martian winter for Opportunity will come
in February 2014.
If Opportunity survives another year, the rover might yet break
the all-time extraterrestrial driving record set by Lunokhod 2, a Soviet robotic
vehicle that traveled an estimated 26 miles (42 km) across the Moon in 1973.
THYROID CANCER RISK FROM DENTAL XRAY DIAGNOSTICS
Concerns have recently been raised regarding triggering of
thyroid cancer due to X-ray-based diagnostic procedures. It is being recommended
that patients should insist on a leaded collar, also called a Thyroid Guard,
wearing it over the thyroid to protect it from radiation.
Most people in the developing world, including India, may not
even be aware that a thyroid guard exists. A Thyroid Guard is a collar that is
placed around the neck, covering the thyroid gland, to assure maximum protection
for the patient. It may be a separate unit or a little flap on the top of the
Lead Apron that can be lifted up and wrapped around the neck. The American
Dental Association recommends that a Thyroid Guard be placed for all dental
X-rays to reduce exposure to radiation. These concerns do not appear to be
entirely unfounded. X-ray based diagnostics might actually be causing greater
damage, than hitherto considered, to the thyroid gland and other tissues in the
vicinity, including parathyroid glands and brain. People do not bother to ask
for the Thyroid Guard during Xrays, especially during dental X-rays. The Thyroid
Guard should be used to protect the technologist as well as anyone that has to
be in the room with the patient being X-rayed.