Northern spring – for a few weeks around the March equinox – is a good time to see especially bright meteors, aka fireballs. It’s fireball season — a time of year when bright meteors appear in greater number than usual. In fact, in the weeks around the start of spring, the appearance rate of fireballs can increase by as much as 30 percent, says NASA. The image below is a capture of a bright fireball seen last night (March 6, 2014) over Canada.
Why does this happen? Why should there be more fireballs at one time of year than at another? The American Meteor Society says:
… evening fireballs seem to peak this time of year from the Northern Hemisphere. This could be due to the fact the antapex radiant [the the point the solar system is moving away from, as we orbit the sun] lies highest above the horizon this time of year during the evening hours.
NASA has a different view on the possible cause. A NASA website suggests:
The reason why is still unknown, but one hypothesis is that more space debris litters this section of Earth’s orbit.
Meteors are debris from space. They typically range in size from a few feet (about a meter) to smaller than a grain of sand. As these objects enter Earth’s atmosphere, they vaporize due to friction with the air.
NASA scientists have set up a network of ground cameras that track and record video of meteors flaming overhead. The footage can be used to pinpoint a meteor’s orbit and origin. Watch the video to learn more.
Speaking of meteors, while spring might be the best time to see fireballs, major meteor showers – sometimes featuring a meteor or more every minute – take place throughout most of the year, with a break between the Quadrantids in early January and April’s Lyrid meteor shower. The next meteor shower will be the Lyrids in April.