NASA has announced that they have detected a coronal mass ejection (CME) from the sun directed towards earth, an event in which millions of tons of solar material can be launched away from the sun. The particles, travelling at around 575 miles per second - about 2.07 million miles per hour - will reach earth in one to three days. Historically, and based on NASA's predictive models, this is an average CME and will have very mild effects. NASA doesn't expect there to be any interference with satellites or electrical systems on earth, but there may be some increased aurora activity near the poles.
A coronal mass ejection is caused by the strong magnetic fields which make up the outer solar atmosphere. When those fields are closed, the confined and violent solar atmosphere can violently eject bubbles of gas and magnetic fields in a massive explosion. The largest CMEs eject several billion tons of solar matter, which streams outwards from the sun to impact planets and spacecraft. CMEs are occasionally associated with solar flares, but this one occurred independently of flare activity. When particles from a CME near earth they can cause a very specific form of space weather called a geomagnetic storm, where they connects with the earth's magnetic envelope for an extended period of time. Geomagnetic storms can cause damage to communications and GPS satellites, but realistically their effects are usually limited to slight signal disruptions and increased aurora activity.
The Solar and Helioscopic Observatory (SOHO) was used to capture the images of the CME as it was moving away from the sun and into space. NASA routinely monitors and releases news updates on space weather events through the NOAA's Space Weather Prediction Center.