Guide

# Will We Ever Figure Out How to Defy Gravity?

The Gravity is by far the weakest of the four forces of nature. Defying gravity is easy: just lift something in the air. But the annoying thing about gravity is that it’s both tenacious and has an infinite range that takes a surprising amount of work to overcome.

Gravity is so weak that it would do it even if it were a billion times stronger than it is now quiet be the weakest of all forces. All of the earth’s mass is pulling at you, but you can reach over and grab a pencil and overcome all of that gravitational force. Of course, eventually you’ll get tired and put down the pencil, but we have other methods to magically defy the power of gravity.

Continue reading: What is the fifth force?

## Defy gravity in space

The magnetic force can keep an item hanging on the side of your fridge for eternity. Even stronger magnets, using superconductors, can levitate entire train cars, enabling super-fast transport that levitates above the tracks.

In addition, defying gravity and going into space is not too difficult. After all, the edge of space is only 100 kilometers (or about 62 miles) away, and shooting something straight up that distance isn’t the hardest thing in the world.

But gravity has a superpower. Even at the edge of the atmosphere and in the beginnings of space, the Earth’s gravitational pull is not much weaker than it is on the surface. So if you don’t keep accelerating, gravity will eventually pull you back.

Most of the energy we put into rockets doesn’t go to space, it goes to space remain in space. If you want to completely escape Earth’s gravity, you need to reach a speed of at least 11.2 kilometers (or about 7 miles) per second, which is about 33 times the speed of sound.

Continue reading: How to understand Einstein’s theory of gravitation

Once in space, we have a few methods at our disposal to simulate the effects of gravity. This is important because constant attraction is vital to maintaining a healthy body. Without gravity, our hearts weaken, our bones thin, and our entire cardiovascular system weakens. Without constant movement, astronauts who spend too much time in Zero-G could not survive a return to earth.

Engineers have developed concepts for rotating space habitats to replicate the effects of gravity. Instead of a massive object on Earth pulling on you, a spacecraft’s wall would spin and slam you against the outer wall. The centrifugal force would give you the exact same sense of gravity you have on our planet and save you from the ravages of zero-g.

All of these technologies are still in the world of science fiction, but space agencies around the world are interested in developing such habitats for long-term missions in space.

## Anti-Gravity Devices and Dark Energy

Speaking of sci-fi, writers and authors love to dream up all sorts of gravity-defying gizmos, whether it’s adding artificial gravity to their ships or propelling their spaceship through the universe. Unfortunately, it seems that these types of anti-gravity devices will remain in the realm of fiction.

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To operate these devices would require the use of negative matter, which is a form of negative-mass matter (not to be confused with antimatter, which is like normal matter but with an opposite charge). We’ve never observed negative matter in the universe, and we strongly suspect it can never exist because it would violate our understanding of conservation of momentum, which is a pretty big deal.

However, at the largest scales in space, we are already observing an antigravity effect. We know from the observations of Edwin Hubble, about a hundred years ago, that our universe is expanding – over time, the average distance between galaxies increases. But in the late 1990s, two independent teams of astronomers discovered something remarkable: not only is the universe expanding, but that expansion is accelerating. The universe is expanding faster and faster every day.

Continue reading: The universe may be more unstable than you think

The name we give to this phenomenon is dark energy, and it appears to be an antigravity force that repels all matter in the universe. Antigravity isn’t actually all that strange in Einstein’s general theory of relativity, the set of equations we use to understand how gravity works. In general relativity, any kind of tension, like the tension in a stretched rubber band, creates an antigravity effect. But usually this anti-gravity effect is completely overpowered by the normal, attractive gravity that we are used to.