Medical Mysteries Revealed

Do sunglasses cause sunburn? Or can sun lotion hurt our bones?

Wearing sunglasses increases the risk of getting sunburned. The reason for this is that our pituitary gland only knows how much melanin (pigment that protects our skin from ultraviolet light) to produce from the signals that it receives from the eyes.

If our eyes indicate that it is sunny outside, the gland produces a lot of pigment. However, sunglasses trick the gland into thinking it’s less sunny, meaning less melanin and a higher risk of burning.

Similarly, sun lotion can hurt our bones. Vitamin D is vital for healthy bones. If we don't have enough, then adults can develop osteoporosis and children rickets.

But unlike most vitamins, we don't need to eat vitamin D. Our bodies can make it by themselves when exposed to the right kind of sunlight.

Ultraviolet B (UVB) rays are strongest when the sun is directly overhead and helps the body to convert cholesterol into vitamin D. But suntan lotion blocks UVB and our body is not able to create vitamin D.

Read more about all such medical mysteries.

Longest Egg Drop

On August 22 1994 David Donoghue threw an egg out of a helicopter onto a golf course in the UK, from a height of 700 feet. Apparently the trick was to get the egg moving forward at the same speed it's falling, and then have it land on a grassy slope. Looks like it worked as he now has the record for the longest egg drop without breaking in the world.

Read more.

Dickin Medal

The Dickin Medal was instituted in 1943 in the United Kingdom by Maria Dickin to honour the work of animals in war. It is a bronze medallion, bearing the words "For Gallantry" and "We Also Serve" within a laurel wreath, carried on ribbon of striped green, dark brown and pale blue. It is awarded to animals that have displayed "conspicuous gallantry or devotion to duty while serving or associated with any branch of the Armed Forces or Civil Defence Units". The award is commonly referred to as "the animals' Victoria Cross".

The first recipients of the award, in December 1943, were three pigeons, serving with the Royal Air Force, all of whom contributed to the recovery of air crew from ditched aircraft during the Second World War. The most recent animal to be honoured is Treo, a black Labrador, honoured for his "heroic actions as an arms and explosives search dog in Afghanistan". As of March 2010, the Dickin Medal has been awarded 63 times.

View the complete list of Dickin Medal recipients.

Neutron Stars

A neutron star is about 20 km in diameter and has the mass of about 1.4 times that of our Sun. This means that a neutron star is so dense that on Earth, one teaspoonful would weigh a billion tons! Because of its small size and high density, a neutron star possesses a surface gravitational field about 2 x 1011 times that of Earth. Neutron stars can also have magnetic fields a million times stronger than the strongest magnetic fields produced on Earth.

The density of a neutron star is 7 x1014g/cm3. Here are some other densities for comparison.

• The Sun - 1.41 g/cm3

• White Dwarf - 2 x 106 g/cm3

• Water - 1.0 g/cm3

• Irons - 7.86 g/cm3

Neutron stars are one of the possible ends for a star. They result from massive stars which have mass greater than 4 to 8 times that of our Sun. After these stars have finished burning their nuclear fuel, they undergo a supernova explosion. This explosion blows off the outer layers of a star into a beautiful supernova remnant. The central region of the star collapses under gravity. It collapses so much that protons and electrons combine to form neutrons. Hence the name "neutron star".

More about neutron stars.