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Three ways to travel at (almost) the speed of light



Three ways to travel at (almost) the speed of light

Credit: NASA

One hundred years ago today, on May 29, 1919, measurements of a solar eclipse offered verification of Einstein's theory of general relativity. Even before that, Einstein had developed the theory of special relativity, which revolutionized the way we understand light. To this day, it provides guidance in understanding how particles move through space, a key area of ​​research to keep spacecraft and astronauts safe from radiation.

The theory of special relativity showed that light particles, photons, travel through a vacuum at a constant rate of 670,616,629 miles per hour, a speed that is immensely difficult to achieve and impossible to overcome in that environment. However, in all space, from black holes to our environment close to Earth, the particles, in fact, accelerate at incredible speeds, some even reach 99.9% of the speed of light.

One of NASA's jobs is to better understand how these particles accelerate. The study of these super-fast particles, or relativists, can help protect missions that explore the solar system, travel to the moon, and can teach us more about our galactic neighborhood: many at the same time could have negative radiation effects on astronauts. who travel to the Moon or beyond.

Here are three ways acceleration occurs.

1. Electromagnetic fields

Most processes that accelerate particles at relativistic speeds work with electromagnetic fields, the same force that keeps the magnets in your refrigerator. The two components, the electric and magnetic fields, like two sides of the same coin, work together to beat particles at relativistic speeds throughout the universe.


Electric and magnetic fields can add and remove energy from the particles, changing their velocities. Credit: NASA's scientific visualization study.

In essence, electromagnetic fields accelerate the charged particles because the particles feel a force in an electromagnetic field that pushes them, similar to how gravity attracts objects with mbad. Under the right conditions, electromagnetic fields can accelerate the particles at a speed close to that of light.

On Earth, electric fields are often used specifically at smaller scales to accelerate particles in laboratories. Particle accelerators, such as the Large Hadron Collider and Fermilab, use pulsed electromagnetic fields to accelerate charged particles to 99.99999896% of the speed of light. At these speeds, the particles can break together to produce collisions with immense amounts of energy. This allows scientists to search for elementary particles and understand what the universe was like in the first fractions of a second after the Big Bang.

2. Magnetic explosions

Magnetic fields are everywhere in space, surrounding the Earth and encompbading the solar system. They even guide the charged particles that move through space, which spiral around the fields.

When these magnetic fields collide with each other, they can become entangled. When the tension between the crossed lines becomes too large, the lines break and line up explosively in a process known as magnetic reconnection. The rapid change in the magnetic field of a region creates electric fields, which causes all the charged particles to move at high speeds. Scientists suspect that magnetic reconnection is a way in which particles, for example, the solar wind, which is the constant flow of charged particles from the sun, accelerate at relativistic speeds.

Those fast particles also create a variety of side effects near the planets. Magnetic reconnection occurs near us at points where the sun's magnetic field pushes against Earth's magnetosphere, its protective magnetic environment. When a magnetic reconnection occurs on the side of the Earth that is away from the sun, the particles can be released into the upper atmosphere of the Earth, where they produce auroras. It is also thought that magnetic reconnection is responsible around other planets such as Jupiter and Saturn, albeit in slightly different ways.

Three ways to travel at (almost) the speed of light

Enormous and invisible explosions occur constantly in the space around the Earth. These explosions are the result of twisted magnetic fields that fit and realign, firing particles through space. Credit: NASA's Goddard Space Flight Center.

NASA's Magnetospheric Multiscale spacecraft was designed and built to focus on the understanding of all aspects of magnetic reconnection. Using four identical spacecraft, the mission flies around the Earth to capture the magnetic reconnection in action. The results of the data badyzed can help scientists understand the acceleration of particles at relativistic speeds around the Earth and throughout the universe.

3. Wave-particle interactions

Particles can be accelerated by interactions with electromagnetic waves, called wave-particle interactions. When electromagnetic waves collide, their fields can be compressed. Charged particles that bounce between waves can gain energy similar to a ball that bounces between two fusing walls.

These types of interactions occur constantly in the near-Earth space and are responsible for accelerating the particles at speeds that can damage the electronics of spacecraft and satellites in space. NASA missions, such as the Van Allen probes, help scientists understand wave-particle interactions.

It is also thought that wave-particle interactions are responsible for accelerating some cosmic rays that originate outside our solar system. After a supernova explosion, a dense, hot layer of compressed gas called an expansive wave is ejected from the stellar core. Filled with magnetic fields and charged particles, the wave-particle interactions in these bubbles can release high-energy cosmic rays at 99.6% of the speed of light. Wave-particle interactions may also be partly responsible for accelerating the solar wind and the cosmic rays of the sun.


Studying the explosions of magnetic space with NASA missions.


Provided by
NASA Goddard Space Flight Center




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Three ways to travel at (almost) the speed of light (2019, May 31)
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