Video footage requires much higher data transmission rates than still images, and it can take several hours for NASA to receive just one high-resolution colour image from Mars. Engineers are looking at switching from radio to infrared communication, because the much shorter wavelength offers far higher data rates. The next generation of Mars landers may …
IT DEPENDS ON THE GUN – Experiments using ballistic gelatine to mimic the human body suggest that a 9mm bullet from a handgun will penetrate about 60cm through human fat tissue. A fully jacketed bullet from an assault rifle, such as an AK-47, will go much further and can easily shoot through a brick wall. …
Garlic contains a chemical called allyl cysteine sulphoxide or ‘alliin’. When a raw garlic clove is crushed or chopped, an enzyme in the garlic cells is released that reacts in a matter of seconds with the alliin to produce a chemical called allicin. This breaks down into lots of other chemicals, most of them stinky. …
There is virtually none there to begin with. Only the white blood cells have a nucleus, so they are the only that carry any of the donor’s DNA. Red blood cells and platelets lose their nucleus during production in the bone marrow. Donated blood is spun in a centrifuge to separate it into plasma, platelets, …
What Happens To The Donor’s DNA In A Blood Transfusion? Read More »
It’s all to do with the shape of the pelvis. Dinosaurs are divided into two groups: the Saurischia, or lizard-hipped’ dinosaurs, have a pubis bone that points forward; the Ornithischia (‘bird-hipped’) have a backwards-pointing pubis. Any fossil with either of these pelvis types is classified as a dinosaur. Ironically, birds are actually descended from the …
Hair growth in humans is complicated and influenced by several different genes and hormones. The prevailing theory is that we evolved to have less hair than primates because our ancestors evolved sweating as a strategy to keep cool on the African Savannah, and too much hair gets in the way of sweating. But the evolutionary …
Most commercial fruit isn’t grown from seed. Even fruits that still have seeds, like apples and cherries, are grown from cuttings because this guarantees that the plant will be genetically identical to the parent plant from which they are cloned. Seedless grapes were originally a natural mutation that prevented the young seeds from maturing and …
When we are sleeping, there is a brain mechanism that stops the neural activity associated with dreaming from triggering speech or body movements. But this system isn’t perfect, and sometimes signals can get through. This can lead to mumbling and groaning and sometimes even proper speech (and sleep walking). The content of sleep talking can …
One hypothesis is that the iron sulphide spewing from deep-sea volcanic vents precipitated into a solid mass with lots of tiny chambers where simple biological molecules could become concentrated and assemble, using energy from iron redox reactions. The ‘panspermia hypothesis’, on the other hand, suggests that living cells or spores may have arrived fully formed …
Our brains have obviously evolved to work in Earth’s gravity. Experiments on the International Space Station suggest that our brains have an internal model of how gravity works that we use to accurately predict where a ball will be when we move to catch it. In a weightless environment, the ball moves at a constant …
As a species, humans actually show remarkably little genetic diversity. The DNA of two unrelated people only differs by about one in every 1,000 base pairs; orangutans differ by more than double this amount. Even so, there are three billion base pairs in the human genome, so that’s an average of three million genetic differences …
Could Two People Who Aren’t Twins Have The Same DNA? Read More »
To make computers learn, we use software that simulates neurons connected in networks like in a brain. These networks are trained with data until they can learn patterns or make predictions about what data might come next. Methods like these help computers understand speech or recognise car number plates, so in this respect computers can …
When we’re up high, the lack of nearby visual anchors makes our bodies sway automatically – this contributes to the dizzying sensation of vertigo. But most people aren’t afraid of heights, not in the sense of having ‘acrophobia’, which is when the mere thought of falling can bring on a panic attack. The rest of …
The absence of air resistance and gravity would make a speeding bullet travel very differently in space. Although there would be no oxygen, bullets contain their own oxidiser, which would allow the gunpowder to ignite and fire the gun. With no air to slow it down, a bullet could in theory travel forever through deep …
It was extremely difficult. The street lighting of towns and major roads would have provided some clues but during World War II, with blackouts over Europe, night bombers flew with a navigator who used the airspeed and compass bearing to plot a course on a map. Over water, some planes were fitted with a calibrated …