NASA Explains How to Travel at 99.9 Percent of the Speed of Light

light, speed, light-speed
Stock photo: There are three physical processes that accelerate particles to near light-speed. Getty

Albert Einstein's special theory of relativity states that photons—or particles of light—travel at a constant speed of 670,616,629 miles per hour. As far as we know, nothing can travel faster than this.

But across the universe, particles are often accelerated to 99.99 percent the speed of light. Here's three different ways this acceleration can occur, according to NASA.

Electromagnetic fields

One of the most common ways that particles are accelerated to near light-speed is via the influence of electromagnetic fields. These are made up of two components as the name suggests—electric and magnetic fields.

Such fields accelerate charged particles by essentially pushing them along, in much the same way that gravity influences objects with mass. Given the right conditions, electromagnetic fields can propel particles close to the speed of light.

Scientists on Earth make use of these fields in laboratory settings to accelerate particles to near light-speed in facilities such as the Large Hadron Collider in Switzerland or Fermilab in Chicago. These accelerators smash particles together, creating collisions which produce vast amounts of energy, giving researchers the opportunity to study extreme physical processes.

Magnetic explosions

Space is filled with magnetic fields, some of which become entangled with one another. When this occurs, increasing tension between the crossing field lines can cause them to explosively snap in a process known as magnetic reconnection.

This leads to a rapid change in the magnetic field, which in turn creates an electric field that accelerates charged particles to high speeds. It is thought that this process is responsible for accelerating phenomena like the solar wind—the stream of charged particles emitted from the sun.

Magnetic reconnection also creates auroras on Earth when the sun's magnetic field pushes against our own planet's magnetic environment—known as the magnetosphere.

Wave-particle interactions

Finally, particles can be accelerated to near light-speed via interactions with electromagnetic waves. When electromagnetic waves collide, their fields can become compressed. As this happens, any charged particles caught in the middle of the waves may start accelerating as they bounce back and forth between them.

These kinds of interactions between waves and particles are thought to be responsible for accelerating some cosmic rays—a type of radiation that originates outside the solar system.

Wave particle interactions, which accelerate cosmic rays to 99.6 percent the speed of light, can also occur in the cataclysmic explosions which mark the deaths of some stars—known as supernovae.