WHAT IS THE EVIDENCE FOR A BIG BANG?
The Universe has not existed forever. It was born. Around 13.82 billion years ago, matter, energy, space – and time – erupted into being in a fireball called the Big Bang. It expanded and, from the cooling debris, there congealed galaxies – islands of stars of which our Milky Way is one among about two trillion. This is the Big Bang theory.
A universe popping into existence out of nothing is so bonkers that scientists had to be dragged kicking and screaming to the idea. But the evidence is compelling. The galaxies are flying apart like pieces of cosmic shrapnel. And the heat of the Big Bang is still around us. Greatly cooled by cosmic expansion, this ‘afterglow’ appears not as visible light but principally as microwave radiation – the ‘cosmic background radiation’, which was discovered by radio astronomers in 1965.
WHERE DID THE BIG BANG HAPPEN?
When a stick of dynamite explodes, the detonation occurs in one place and shrapnel flies into the void. In the Big Bang, there was no centre and no pre-existing void, so it didn’t happen at any ‘location’. Space itself popped into existence and began expanding everywhere at once.
Astronomy books often liken the Universe to a rising cake, with raisins representing galaxies. As the cake grows, raisins recede from each other, with no centre of expansion – just like the Big Bang. But of course, a cake has an edge, unlike the Universe, which may go on forever. No analogy is perfect!
Diese Geschichte stammt aus der December 2020-Ausgabe von BBC Focus - Science & Technology.
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Diese Geschichte stammt aus der December 2020-Ausgabe von BBC Focus - Science & Technology.
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COULD MARINE CLOUD BRIGHTENING HELP US FIGHT CLIMATE CHANGE?
The theory behind marine cloud brightening is that brighter or whiter clouds reflect more sunlight back into space.
IS IT SAFE TO RUN EVERY DAY, OR SHOULD I DITCH MY RUN STREAK TO SAVE MY KNEES?
A running streak, where you run every day without taking rest days, can be highly motivating and beneficial for overall fitness. Running is great cardiovascular exercise and isn't to be discouraged (and finding a routine with some consistency is great). Getting a bit of exercise as often as possible is also hugely beneficial for your mental health.
WHAT MAKES THE MEDITERRANEAN DIET SO GOOD FOR US?
The Mediterranean diet may help you live longer, especially if you also adopt the lifestyle of people living near the Med during the 1950s.
WHAT IS MEXICO'S BLUE HOLE?
The world's deepest blue hole (marine sinkhole) lies off the coast of Mexico's Yucatán Peninsula. It's at least 420m (1,378ft) deep, but explorers still haven't found its bottom.
HOW CAN I TELL IF I'VE GOT HIGH CORTISOL LEVELS?
Cortisol is a hormone produced by glands in our bodies called the adrenal glands, which sit above the kidneys. It plays a critical role in various bodily functions, including regulating metabolism, reducing inflammation and helping the body respond to stress. While essential for our health, chronic elevation of cortisol levels can lead to several issues.
THE LUNGFISH
In 1836, European scientists discovered a peculiar animal from the River Amazon that they struggled to identify. Its eel-like body was a few feet long and its air-filled lungs persuaded anatomists it must be a reptile.
ARE WE THE ONLY SPECIES TO HAVE BEEN THROUGH A STONE AGE?
The Stone Age might conjure up images of early humans, sitting around a campfire or hunting prehistoric beasts, but evidence shows that we're not the only species that has learned how to work with stone tools. Wild chimpanzees (Pan troglodytes) use stone tools to crack open nuts.
Should we scrap daylight saving time?
Most of us look forward to the extra hour we get in bed every October, but researchers argue that changing the clocks twice a year harms our health
THE INTERNET OF ANIMALS
SCIENTISTS ARE USING ELECTRONIC TAGS AND SATELLITES TO TRACK WILD ANIMALS AND CREATE A DATA NETWORK THAT COULD HELP US ADDRESS THE BIODIVERSITY CRISIS
MUSIC FOR A DISTRACTED GENERATION
The number of things competing for our attention is often overwhelming. Can dreamy soundscapes created with neuroscience help our bewildered brains to concentrate?
