Fireball altitude
Fireballs usually begin glowing about 80 to 120 kilometres up and end about 20 to 50 kilometres up.
A meteor's altitude tells us a great deal. Most meteors begin to glow between about 80 and 120 kilometres above the ground, high in the thin upper atmosphere. Faint meteors burn out quickly at around 80 to 100 kilometres.
Bright fireballs penetrate deeper. Those that drop meteorites often keep glowing down to between about 20 and 40 kilometres. Below that, the surviving fragments have slowed so much that they stop shining and fall in dark flight. A fireball that ends higher than about 50 kilometres has usually burned up completely.
Because scientists know these typical heights, they can quickly judge whether a fireball might have produced meteorites. Strong fireballs with low end heights, slow final speeds and observed fragmentation are the most promising. Fireball networks use the end height and final speed, together with wind data, to calculate where meteorites might have landed.
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Level: Explorer Ages 10 and up