Excellent Questions

The excitement surrounding the Northern Lighthouse Project has captured the interest of skywatchers from around the world who want to learn more about the lighthouses, space weather and the aurora borealis. Here are some examples of the excellent questions we’ve received so far:

Q: The lighthouses are flashing red, what does that mean?

20120308_satenvA: As with other early warning systems, Red indicates the highest level of alert. In this case “Red alert” means geomagnetic storms will be possible overnight and observers should be on high alert for storm conditions and the possibility of active Northern Lights. Red is used by the National Oceanic and Atmospheric Administration to indicate the KP-index has reached kp=5 or more, indicated that a geomagnetic storm is in progress. So, when the lighthouses are glowing red, it means there is a chance the lights will be really good tonight. 

Q: When a Coronal Mass Ejection erupts and is aimed directly at Earth, does this mean we are guaranteed to witness a Geomagnetic Storm a few days later?

A: Many factors will influence whether or not the incoming gust of solar wind actually trigger a geomagnetic storm, and there are no guarantees that an Earth-directed event will result in geomagnetic storming and colourful auroras on Earth. Once it is known when the CME is expected to reach Earth, we must wait and see if/how the solar wind interacts with Earth’s magnetic field. These interactions can be observed by watching the ACE Real Time Solar Wind data as the CME passes Earth. When there is a major spike in activity, this indicates the magnetic field may soon be stormy. So, when a CME is launched at Earth, it means there is a real chance of storm activity in the hours following.

Q: How often do Coronal Mass Ejections sweep past Earth’s magnetic field?

A: Coronal Mass Ejections are relatively common, however the direction of CME eruptions is quite random. This means it is expected that Earth will be in the path of a Coronal Mass Ejection a few times each month, more or less.

Q: Do Northern Lighthouses tell us that an aurora is visible right now?

A: Northern Lighthouses do not communicate about space weather conditions in real time, rather they provide a forecast of the geomagnetic field conditions that are expected overnight. The best way to remember what the colours mean is to think of the following phrases:

  • Flashing red (STORM), possible storms ahead!
  • Glowing green (UNSETTLED), auroras will be seen!
  • Glowing blue (CALM), gentle auroras in view.