Scientists have long tried to explain the origin of a mysterious, large and anomalously cold region of the sky. In 2015, they came close to figuring it out as a study showed it to be a “supervoid” in which the density of galaxies is much lower than it is in the rest of the universe. However, other studies haven’t managed to replicate the result.
Low energy efficiency is already a major problem for petrol and diesel vehicles. Typically, only 20% of the overall well-to-wheel energy is actually used to power these vehicles. The other 80% is lost through oil extraction, refinement, transport, evaporation, and engine heat. This low energy efficiency is the primary reason why fossil fuel vehicles are emissions-intensive, and relatively expensive to run.
Most of us don’t have any memories from the first three to four years of our lives – in fact, we tend to remember very little of life before the age of seven. And when we do try to think back to our earliest memories, it is often unclear whether they are the real thing or just recollections based on photos or stories told to us by others.
We’ve all been there: waiting for a boring meeting to finish or for a bus to arrive and time just seems to drag on far more slowly than usual. Yet our most enjoyable moments seem to whizz by at lightning speed. It seems obvious that more boring events appear to take longer than the ones that stimulate us. But there’s another reason we sometimes experience time differently.
Most of us know eating fruit daily is a great way to try to stay healthy, with the Australian Guide to Healthy Eating encouraging us to eat two serves a day. This is because they are relatively low in energy content and rich in fibre, antioxidants and some phytochemicals that may have beneficial health effects.
You may have heard of graphene, a sheet of pure carbon, one atom thick, that’s all the rage in materials-science circles, and getting plenty of media hype as well. Reports have trumpeted graphene as an ultra-thin, super-strong, super-conductive, super-flexible material. You could be excused for thinking it might even save all of humanity from certain doom.
Around four decades ago, astronomers became aware that our galaxy, the Milky Way, was moving through space at a much faster rate than expected. At 2.2-million kilometres an hour, the speed of the Milky Way through the Cosmos is 2,500 times faster than a cruising airliner; 55 times more than the escape velocity from Earth; and a factor of two greater than even the galaxy’s own escape velocity! But where this motion comes from is a mystery.
One of the moon’s greatest mysteries has long been whether it has any water. During the Apollo era in 1960s and 70s, scientists were convinced it was dry and dusty – estimating there was less than one part in a billion water. However, over the last decade, analyses of lunar samples have revealed that there is a considerable amount of water inside the moon – up to several hundred parts per million – and that it’s been there since the satellite was very young.
Despite massive government, medical and individual efforts to win the war on obesity, 71 percent of Americans are overweight. The average adult is 24 pounds heavier today than in 1960. Our growing girth adds some US$200 billion per year to our health care expenditure, amounting to a severe health crisis.
It was only a matter of 700m years or so after Earth formed and its surface cooled and solidified that life began to flourish on Earth. All studies suggest that life requires water – and we know from rocks on Earth that the climate in this distant past was sufficiently warm for liquid water to be present. But therein lies a mystery.
Given how much they can actually do, computers have a surprisingly simple basis. Indeed, the logic they use has worked so well that we have even started to think of them as analogous to the human brain. Current computers basically use two basic values – 0 (false) and 1 (true) – and apply simple operations like “and”, “or” and “not” to compute with them. These operations can be combined and scaled up to represent virtually any computation.
