What is a filament?

Solar filaments are clouds of ionized gas above the solar surface squeezed between magnetic regions of opposite polarity. Being cooler and denser than the plasma underneath and their surroundings, they appear as dark lines when seen on the solar disk. When a solar filament is seen near the solar limb with the blackness of space as background it is called a "prominence" instead.

A filament as seen by NASA’s Solar Dynamics Observatory which is suspended between two areas of opposite magnetic polarity.

Image: A filament as seen by NASA’s Solar Dynamics Observatory which is suspended between two areas of opposite magnetic polarity.

Solar filaments can last a long time before they disappear. Some survive for weeks! When solar filaments become unstable they can either fall back onto the Sun or erupt into space, sending a coronal mass ejection away from the Sun which can come towards Earth if the solar filament was well positioned. Just like coronal mass ejections produced by solar flares, a coronal mass ejection from a solar filament could also very well cause a geomagnetic storm on Earth. Space weather forecasters keep an eye on these filaments as they can be just as important as solar flares!

A gorgeous filament eruption as seen by NASA’s Solar Dynamics Observatory

Image: A gorgeous filament eruption as seen by NASA’s Solar Dynamics Observatory.

<< Go to previous page

Current data suggest that it is not possible to see aurora now at middle latitudes
The solar wind speed is currently moderately high (503.1 km/sec.)

Latest news

Today's space weather

Auroral activity Minor Severe
High latitude 20% 20%
Middle latitude 5% 1%
Predicted Kp max 3
Solar activity
M-class solar flare 1%
X-class solar flare 1%
Moon phase
Waning Crescent

Support SpaceWeatherLive.com!

A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!

17%

Get instant alerts!

Space weather facts

Last X-flare:2015/05/05X2.7
Last M-flare:2017/04/03M5.8
Last geomagnetic storm:2017/04/23Kp6 (G2)
Number of spotless days in 2017:37
Last spotless day:2017/05/15

This day in history*

Solar flares
12000C9.5
22000C5.6
32000C5.4
42000C4.3
52013C3.9
ApG
1200278G4
2200734G1
3200029G3
4199520G2
5201417G1
*since 1994