Gravity is something we all take for granted. It’s the force that holds us to the surface of the Earth and what makes things fall. But it’s much more than that, too. It’s what holds Earth together and gives the planet its roughly spherical form. It’s what keeps Earth moving in its orbit around the Sun, ensuring that we always have the heat and light we need to live. In fact, gravity is one of the most fundamental things in the universe – the force that holds everything from asteroids to galaxies together.
Gravity is one of four fundamental forces, alongside electromagnetism and the two types of nuclear force. On very small scales it’s by far the weakest of these forces, but it comes into its own at large distances. That’s because the nuclear forces have a very limited range, while electromagnetic forces tend to get cancelled out because electric charge can be either positive or negative. Gravity, on the other hand, always acts in the same direction – it’s a force of attraction, which means there’s no limit to its range. And it’s a very democratic force, operating with equal effect between any two objects having mass. For these reasons, it’s far and away the most important force governing the universe on large scales.
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Denne historien er fra Issue 179-utgaven av How It Works UK.
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RESCUE IN SPACE
Fortunately, space emergencies are a rare occurrence, but astronauts and space agencies need to be prepared for any eventuality that might arise
NEANDERTHAL LIVING
Why our prehistoric cousins were pioneers, not clueless apes
BUILDING ONE WORLD TRADE CENTER
One World Trade Center rose from the ashes of the Twin Towers. Now, as the tallest building in New York City, it looks to the skies and the future. Here's how this sustainable and secure record-breaker was built
BECOME A SMARTPHONE SCIENTIST
Amazing tips and tricks to transform your smartphone into a bug-finding, star-spotting, data-gathering device
LIFTING THE LID ON ANTARCTICA
What was the coldest continent like without ice?
URBAN WILDLIFE
How wild animals have evolved to thrive alongside humans in towns and cities
WHAT IS SUNBURN?
How solar rays can leave us red, sore and irritated
ALL ABOUT FAT
Fat is a complex, active organ. Here's how genetics, evolution, lifestyle and diet dictate how much we have beneath our skin
The Space Force is launching lasers into orbit
The Space Force aims to better pinpoint the location of Earth's true centre using lasers on GPS satellites, slated to launch in 2025. A set of Laser Retroreflector Arrays, or LRAS, will be installed onto two GPS III satellites, SV9 and SV10, as part of NASA's Space Geodesy Program. The lasers are designed to make precise sub-centimetre measurements using a technique called Satellite Laser Ranging, which will allow researchers to more accurately determine Earth's centre.
Eating too much sugar may accelerate cellular ageing
A nutrient-rich diet with few added sugars may slow the rate of biological ageing in women. Scientists found that middle-aged women who ate more foods packed with vitamins, minerals and antioxidants had 'younger looking' cells than those who consumed less nutrient-rich diets.