Snworld

Why aren’t our Solar System’s planets and moons made from the same material? the solar system formed from the collapse of a molecular cloud consisting mostly of hydrogen, but also containing heavier elements. As the cloud collapsed, its central region began to heat up until eventually the hot ‘proto-sun’ was formed. the planets formed by the accretion of material from within this cloud. due to their high boiling points, only metals and silicates could exist in solid form in the hot, inner regions of the early solar system. More volatile elements either remained gaseous or were blown away by the sun’s energy. since this heavy material existed mainly in the inner regions of the solar system, the planets that formed there are small and rocky. in the cold outer reaches of the solar system, compounds with low melting points could remain in solid form. these ices were also much more abundant than the heavier elements. the outer planets were therefore able to grow much larger, and he...

Could direct air capture prevent climate change ? direct air capture (dAC) is an appealing way to tackle climate change: just pass ambient air over chemicals that absorb the Co2 driving global warming, and then use or store the Co2. dAC differs from the better-known carbon capture and storage (CCs) in that it can be done anywhere, not just at big sources of Co2 such as power stations. it’s more effective than natural Co2 ‘scrubbing’ using trees and plants, and can be performed where the Co2 is most easily stored or re-used. unlike CCs at power stations, dAC must be effective at removing the far more dilute Co2 in ambient air. this demands special equipment and chemicals, plus renewable energy sources producing zero Co2. that has led to grave doubts about the economic viability of dAC. For now, it remains an intriguing but impractical remedy for global warming. 

How do we know when something is wet?  our skin contains lots of nerve endings that respond to different stimuli. there are receptors for touch, vibration, heat, cold and pain – but not for wetness. water is such a ubiquitous component of all living cells that it would be difficult for a nerve cell to avoid firing constantly in response to its own composition. instead, wetness seems to be a property that our nervous system learns to recognise, based on a mixture of cold, pressure and texture. A 2014 study at Loughborough university found that hairy skin is more sensitive to wetness than smooth skin, which may be because hairy skin has more temperature sensitive nerve endings. when you are born, you don’t feel wet or dry, you just feel cold or warm. over time we learn that the feeling of cold cloth sticking to our skin means that we’ve sat on a wet park bench.

Why do different countries use different mains voltages? the biggest disparity is between the usA on 110V and most of the rest of the world on 230V. America’s lower voltage goes all the way back to thomas edison, who introduced direct current (dC) mains electricity at 110V. edison’s rival nikola tesla showed that long power lines transmitted alternating current (AC) more efficiently than dC. His AC approach won out, but he stuck with edison’s 110V. But by the time electrification spread to europe early in the 20th Century, lamps had filaments that could give out more light and handle greater power loads. so the Berliner elektrizitätswerke company in Germany established 230V as the standard. 

Why does it feel good to scratch? studies using funCtionAL magnetic resonance imaging (fMri) have shown that scratching causes patterns of brain activity that are associated with pleasure and reward. this effect is strongest when you do the scratching yourself and when you are actually scratching an itch, rather than just an arbitrary patch of skin. But contrary to what you might expect, or might have read elsewhere, there’s no clear evidence that this pleasure comes from a release of endorphins – it happens purely in your brain and spine. this mechanism may have evolved to encourage us to dislodge skin parasites. All the evidence suggests that it’s a very ancient response, because all vertebrates scratch themselves – even fish! 

Is it best to charge your mobile battery from empty or half-full? nickel-based batteries were blighted by the ‘memory effect’, and would lose capacity unless regularly discharged completely. Most phones nowadays have lithium batteries, and these do not suffer from the memory effect. in fact, it is good for them if you top the batteries up rather than deplete them completely. therefore, it’s best to charge your phone from half-full. 

Can germs survive on a bar of soap? Yes. when you wash your hands, you  transfer a thin film of bacteria, skin flakes and oils to the bar of soap. A 2006 study of 32 dental clinics found bacteria growing on the soap in all of them – after all, standard soap doesn’t kill bacteria, it just dislodges them. A 1988 study found that washing your hands with a dirty bar of soap doesn’t transfer any of the germs onto your hands – but then the study was conducted by a us soap manufacturer.

THE TOP 5 BIGGEST HACKS IN RECENT MEMORY MACRON EMAIL LEAK Just 48 hours before the run-off poll between Emmanuel Macron and Marine Le Pen, a 9GB cache of emails from Macron’s En Marche! party was posted on PasteBin, a filesharing platform. They were spread to WikiLeaks. “The attacks were so simple and generic that it could have been practically anyone,” France’s cybersecurity chief said. BANGLADESH BANK HEIST In February 2016, hackers got the login credentials used by Bangladesh Central Bank for the international banking transfer system SWIFT. They tried to transfer $951m to accounts in Sri Lanka and the Philippines. Most transactions were flagged, but $101m was removed. A Trojan known as Dridex was used, which hides in MS Word or Excel attachments. WANNACRY ATTACK On May 12, 2017, a global ransomware attack affected more than 2,30,000 computers, including PCs in the NHS, FedEx and Deutsche Bahn. The malware was leaked from the NSA, and targeted machines running Wi...

TYPES OF HACK VIRUSES AND WORMS Most malware tends to be either a virus or a worm. The difference comes down to the software’s ability to propagate. Like their biological namesakes, computer viruses require a host body, whereas worms can spread from one machine to the next unaided. DDOS Short for distributed denial of service, a DDOS attack is basic yet effective. It works on the principle that, if a website’s DNS server can be overwhelmed by traffic requests, the site will crash. Hackers run botnets – networks of zombie computers or devices – to besiege a server from multiple fronts simultaneously. TROJANS As its name suggests, a Trojan is a form of malware that sneaks into your computer under an innocuous guise (like an email attachment). Its cargo can be any form of malware. A Trojan’s specific ability is getting in, then leaving a backdoor open for others to follow undetected. RANSOMWARE This subset of malware made the headlines for the WannaCry atta...

At the recent Paris Air Show, Airbus was showing off its new Racer concept helicopter, which has both a main rotor and a pair of propellersporting wings. Racer (an acronym for ‘RApid “Destroy all mosquitoes!” and Cost-Effective Rotorcraft’) would take off and land vertically, just like a normal helicopter, but would boast a top speed of 400km/h (250mph), which is nippier than traditional choppers. If you’re getting a sense of déjà vu here, that’s because the Racer is essentially an updated take on the X3 concept that Eurocopter (now Airbus) took to the Paris Air Show in 2011. The craft is designed for the operation of high-speed passenger services, particularly between urban centres (such as London and Berlin) where its vertical takeoff and landing capabilities eliminate the need to travel to and from airports. But it could also find a role in military or search-and-rescue operations. Airbus hopes to have a commercial craft based on the Racer concept available by 2020.

Farmers under pressure to reduce chemical pesticides can take heart from the news that the US Department of Agriculture is about to start trialling a device that can kill insects with a laser. Developed by Seattle company Intellectual Ventures Lab (IVL), the ‘Photonic Fence’ isn’t really a fence at all, but a small box containing lasers, cameras and an AI computer system. The cameras scan the air around the device for 100 metres, and the AI system measures the shape, speed, acceleration and wingbeat frequency of any bugs detected, to establish which are potentially harmful. Any insects identified as a threat can be zapped by the lasers, with a ‘kill rate’ of up to 20 insects per second. By deploying several such devices, farmers could effectively create a virtual fence around their crops that kills harmful pests but leaves bees and other beneficial or harmless insects unharmed. As well as protecting crops, it’s hoped the Photonic Fence could also prove useful in the fight agai...

To kick off the ‘Summer of Mars’ events programme at the Kennedy Space Center in Florida, NASA recently unveiled an 8.5m-long concept Martian rover that wouldn’t look out of place in the Batcave. The vehicle consists of a detachable rear section housing a science laboratory, and a front section that’s equipped with radio and GPS. Sadly, it is only a concept: according to the latest information on NASA’s website, the actual rover used in the Mars 2020 mission is likely to be similar in size and appearance to Curiosity, the 3m-long rover that’s been busy exploring the Red Planet’s surface since 2012.

Do video games affect behaviour? Video games are likely able to affect the way we behave in a number of ways. For instance, there’s concern about whether violence in games makes young people more violent. It’s not uncommon for news outlets to blame games every time a crime happens, but how true is that claim? This is controversial even within the scientific community. Yes, exposure to violence seems to affect the brain, but studies have also found that we’re good at distinguishing between real and virtual violence, and aggressive behaviour is better explained by other, mainly socio-economic factors. Numerous studies about the effects of games on the brain had been published, but all that information had not been put together until now. How did you review the research?  We gathered all scientific articles to date and compared results. In total, we found 116 experiments, the first from the 1980s. Many compared regular video game players with people who had never played; other...

That’s the temperature of your core. Your skin is usually around 34°C, and your face, fingers and toes can be much colder. The receptors in your skin react to differences in temperature, so, when you put your hand on your bare stomach, your hand registers warmth but your belly shrieks ‘cold!’, even though both are ‘skin temperature’. Similarly, the inside of your mouth feels warm to your finger, but not to your tongue.

Mercury levels in the oceans have tripled since the Industrial Revolution, thanks to mining and the burning of fossil fuels. All sea creatures absorb some of this heavy metal directly, and, once it’s in the body, there’s no way of getting rid of it. The amount of mercury in fish varies between species. Long-lived predators like tuna and swordfish tend to contain the most, because they also absorb mercury from their prey and they’ve had a long time to accumulate it. The lowest levels are found in short-lived species lower down the food chain, such as oysters and shrimp.

Sleep consists of two radically different physiological states. There is rapid eye movement sleep (REM) and non-rapid eye movement sleep (NREM). The sleep stages seem to have different functions, but why we sleep is still not completely understood. Babies spend half of their sleep in REM, but this drops to a quarter by the age of two. It is therefore thought that REM sleep is particularly vital for the developing brain. In NREM sleep, brain activity slows and a person woken at this stage may feel groggy. 1. Pituitary gland During non-REM sleep, the pituitary gland produces growth hormone and secretes prolactin. This counteracts dopamine, to lower general arousal levels. 2. Mouth You produce less saliva, which reduces the need to swallow. Five per cent of adults also grind their teeth at night, mostly during the early stages of sleep. 3. Lungs The throat muscles relax so your airway narrows when inhaling. This can cause snoring, or temporarily halt your breathing for a few ...

You can still have a fairly normal life without one of your lungs, a kidney, your spleen, appendix, gall bladder, adenoids, tonsils, plus some of your lymph nodes, the fibula bones from each leg and six of your ribs. Losing your uterus, ovaries and breasts, or your testicles and prostate, is also quite survivable, although you might need hormone therapy to avoid other long-term problems, such as brittle bones. If you allow yourself artificial replacements and medication, we can go further and remove your stomach, colon, pancreas, salivary glands, thyroid, bladder and your other kidney. Still not enough for you? Theoretically, surgeons could amputate all of your limbs, and remove your eyes, nose, ears, larynx, tongue, lower spine and rectum. Supported by machines in an intensive care unit, they could also take away your skull, heart and your remaining lung, at least for a short while. This adds up to a theoretically survivable loss of around 45 per cent of your total body mass. But a...

Even after passing through water treatment plants, small quantities of chemical compounds from cleaning products can find their way into rivers, ponds and lakes and have adverse effects on aquatic life. Phosphates in laundry and dishwasher detergent have a fertilising effect, triggering the widespread growth of algae that saps away the water’s oxygen, reducing biodiversity. By reducing water tension, surfactants allow other pollutants in water bodies to be absorbed more easily by plants and animals. Many other compounds can be toxic to wildlife, or affect growth and reproduction, for instance by mimicking the effects of hormones in mammals and fish

At -269°C, helium gas condenses to become a liquid. Cool it even further and it becomes a state of matter called a superfluid. In this state it has no measurable viscosity and so does some odd things, such as climbing up the walls of a dish, leaking through apparently solid materials and staying motionless while its container is spun. To create the liquid and superfluid states, you cool down helium gas to a few degrees above absolute zero. This is achieved by compressing the gas, and then expelling it through a small nozzle. As the gas expands, it rapidly cools (you’ll have noticed this effect if you’ve ever used an aerosol deodorant). The process is repeated until the gas that rushes out of the nozzle is cold enough to condense to a liquid, then if you repeat the cycle a few more times the helium will become cold enough to turn to a superfluid.

Since the Martian atmosphere is about 100 times less dense than Earth’s, the ‘lift’ a frisbee experiences would also be about 100 times less. But the gravitational force on Mars is about a third of that on Earth, so a frisbee on Mars would act as if it is about 33 times heavier (100/3). Since the lift depends on the size of the frisbee, the angle of attack and the velocity it is thrown (as well as the air density), it would still be possible to make a frisbee glide, but it would require much more effort on the part of the thrower.