What is Plasma?

Narration: Beth Anthony (KBRwyle)


Out in space, particles play by a different set of rules than we are familiar with at home. The expanse beyond Earth is almost entirely filled with a mysterious state of matter.

This matter is the least understood. It’s rarely encountered on Earth. Yet it triggers auroras and even impacts our exploration of space.

This, is plasma.

After solid, liquid, and gas, plasma is the fourth state of matter. It is made of particles that have been ionized.

This means the particles have been given so much energy that electrons separate from their atoms, making a subatomic soup.

Unlike gas, plasma easily conducts electricity. This allows it to move along invisible pathways charted by the electromagnetic fields that fill space.

While plasma is rare on Earth, it makes up 99.9% of the visible universe, including the Sun and other stars.

It’s also spread out across the universe in the space separating planets and stars. This space is not empty. It’s filled with a weak soup of plasma.

Those vast expanses of space are also filled with electromagnetic fields, such as those created by the Sun and Earth.

In these places where plasma and electromagnetic fields play, plasma can undergo a unique explosive phenomenon called magnetic reconnection.

Magnetic reconnection occurs where magnetic field lines are constantly shifting. When the lines become tangled, they explosively snap and realign. This transfers energy and sends nearby plasma particles flying through space.

Magnetic reconnection triggers solar flares on the surface of the Sun, creates shockwaves near supernovae, and violently twists plasma around black holes.

Closer to home, magnetic reconnection between the Sun and Earth’s magnetic fields is a critical way energy is transferred around our planet.

For example, when magnetic reconnection occurs the nightside of Earth, it can push particles down towards the poles, triggering auroras.

Near-Earth space is the easiest place to study magnetic reconnection -- and NASA does that with its Magnetospheric Multiscale mission, or MMS.

MMS uses four identical spacecraft to measure magnetic fields and particles in 3D one hundred times faster than previous missions. This has revealed new insights on the small-scale details of magnetic reconnection and the nature of plasma itself.

Other NASA missions like Parker Solar Probe, THEMIS-ARTEMIS, and Voyager also study plasma across our solar system.

From the surface of the Sun to the space between the planets, NASA continues to unravel the mysteries of plasma that help us as we venture beyond Earth.