Coronal mass ejection (CME)

Definition

A Coronal Mass Ejection (CME) is a significant release of plasma and magnetic field from the Sun’s corona. These massive bursts of solar wind can impact space weather and affect Earth's magnetosphere.

5 Must Know Facts For Your Next Test

1. CMEs can cause geomagnetic storms that may disrupt satellite communications and power grids on Earth.
2. They often accompany solar flares but are distinct phenomena originating from different parts of the Sun's atmosphere.
3. The speed of a CME can range from less than 250 km/s to more than 3000 km/s.
4. CMEs are typically observed using coronagraphs, which block out the bright light of the Sun's photosphere to reveal the fainter corona.
5. The frequency of CMEs is related to the solar cycle, with more frequent occurrences during solar maximum.

Review Questions

• What are the potential effects of CMEs on Earth's technology and infrastructure?
• How do CMEs differ from solar flares in terms of origin and characteristics?
• What instruments are commonly used to observe and study CMEs?

Related terms

Solar Flare:

A sudden flash of increased brightness on the Sun, usually observed near its surface or in close proximity to a sunspot group.

Solar Wind:

A stream of charged particles released from the upper atmosphere of the Sun, known as the corona.

Magnetosphere:

The region around Earth dominated by its magnetic field, which protects against most solar wind particles.