Satellites measure greenhouse gases in the atmosphere, while on Earth scientists collect air samples from all over the world. Water vapour and clouds make up the majority of greenhouse gases, with carbon dioxide and other gases comprising about 25 per cent. Current samples are then compared with previous ones, including those from air bubbles that …
How Is The Greenhouse Gases Emitted Amount Measured? Read More »
Elephants do forget, but they have impressive memories. They have the largest brains of any land mammal, and some believe that their intelligence is up there with chimpanzees and dolphins. Elephants live for decades, and travel in family groups led by older females. To be successful, they need to be able to keep track of …
Europa is one of the smoothest objects in the Solar System. Although there are many surface features, including craters, these are few and far between. It is believed that Europa’s surface is a series of brittle tectonic ice plates moving on top of a warmer layer of convecting ice. Beneath that is probably a subterranean …
Just one. Out of around 40,000 spider species, Bagheera kiplingi is the only spider known to have a herbivorous diet. It lives in Mexico and Costa Rica, and feeds mostly on protein nodules of the acacia tree. But even this spider sometimes eats ant larvae, so perhaps it is closer to the sort of vegetarian …
The basic idea of using electricity to create light was first investigated over 200 years ago by the English chemist Humphrey Davy. He showed that when electric current flowed through wires, their resistance caused them to heat up to the point where they gave out light. But he also identified the key problem to creating …
It is certainly possible but highly unlikely. Typically, asteroids are travelling far too fast for Earth’s gravity to make much of an impact on their trajectories. They normally have more than enough energy to escape Earth’s influence even if they approach very close. However, if they are of the right mass, are travelling at just …
While we can’t see them, the gas and vapour molecules making up the atmosphere all have mass, and as such all feel the gravitational pull of the Earth. They could still escape if they had enough energy – for example, if the Earth was closer to the Sun, and thus hotter. Fortunately, however, our planet …
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Biologically speaking, the most important difference between the sexes is that females produce eggs that are much larger than the sperm of the male. Large eggs are an advantage because they provide more resources for the developing zygote. But making your eggs large means that you can’t produce so many of them, so another valid …
It’s called the cold shock response. When the cold receptors in your skin are all suddenly stimulated they cause an involuntary gasp and, for about a minute after that, hyperventilation. If you fall into chilly water, the cold shock response will kill you long before hypothermia does. Either that first gasping breath will fill your …
Some hackers love to break into computer systems to see what’s ‘under the hood’. It’s a big problem, so security has to constantly be improved to prevent intrusion. Several years ago, one company called Netscape Communications had a smart idea. They invited the hackers to try to break into the early versions of their software, …
They start with identical genes, because each is formed from a single fertilised egg that splits into two embryos. But from that moment onwards, their DNA begins diverging. The DNA replication mechanism introduces about one new mutation for every 100 million base pairs copied, per generation. There are around three billion base pairs in the …
When it’s sunny, it seems like people are happier – we fill the parks and beaches, and radio stations start blasting out upbeat tunes. And yet, research has repeatedly failed to find any evidence that people who live in sunnier places enjoy more positive moods. A new, massive study published this year even brought into …
Nuclear fission involves splitting atomic nuclei, and is the process used in nuclear power stations. Fusion, as its name suggests, involves fusing nuclei and is the power source of the stars. While both fission and fusion release energy, the process and amount is very different. Fission exploits the instability of nuclei of heavy elements like …
Most species of aquatic snail have a comb-like gill. The oldest groups have two gills but the majority have lost one, to make room inside their spiral shell. As snails moved to the land, they swapped gills for a primitive lung, called the pallial cavity. Some snail groups moved back to freshwater and a few …
The same bacteria that is used to ripen many cheeses, including Munster, Limburger and Port-du-Salut, also lives on our skin and eats dead skin cells. It’s called Brevibacterium; as it digests it gives off S-methyl thioesters, which smell cheesy. Another skin-munching bacterium is Staphylococcus epidermidis, which produces the cheesy, vinegary-smelling isovaleric acid. The final ingredient …