Bright fireballs flash across the sky. Did you see them too?
Wednesday, February 3, 2016, 12:32 PM - Visible for hundreds of kilometres around, two bright fireballs flashed through the sky over the past few days, one over Pennsylvania on Saturday night and another over Lake Michigan on Monday. Did you see them too?
In the evening of Saturday, January 30, just as the last light from the setting sun was disappearing beyond the horizon, anyone out and about may have seen something pretty spectacular in the sky.
More than 670 people have reported their sighting so far to the American Meteor Society, as they witnessed a bright fireball streak overhead at 6:16 p.m. ET.
While these events happen very quickly, and are often only accounted for through written reports from those who spotted it, in this case, the event was captured by more than one video dashcam.
From Gurvir Sahota, in Markham, ON (left of centre, 8 seconds in):
From Mike Grossman, flying over the Hudson River (look above the 8 in the aircraft's registration number, at 6 seconds in):
And about the best view found on the web so far, from Alexander Salvador, in Falls Church, Virginia (you can't miss it):
According to the American Meteor Society, after experts cross-referenced reports about the object's speed and direction, they found that meteor flew from northeast to southwest, and it was very likely directly over south-central Pennsylvania.
Heat map and trajectory for AMS Event #340-216. Credit: American Meteor Society
Update: Second Fireball spotted
Thanks to readers Steve Gray and Jason Kroeker, for reporting this. A second fireball was confirmed spotted over the Great Lakes region on Monday night, around 6:25 p.m. ET. With a flight path roughly north to south over Lake Michigan, this fireball was visible from as far away as Wisconsin and southern Ontario.
Trajectory map for AMS Event #385-2016. Credit: American Meteor Society
What's particularly remarkable about this second fireball is that it's an "earth-grazer."
Normally when we see a fireball meteor, the meteoroid involved plunges fully into Earth's atmosphere, slowing down as it compresses atmospheric gases into glowing plasma. It's ultimate fate is either to be vapourized (for smaller ones), or it slows enough that it can't compress the air enough to make the meteor glow, enters its "dark phase" and then falls to the ground as a meteorite.
Some meteoroids, however, just skim past us, taking a brief and bright dip into the upper atmosphere before exiting again to continue their journey through space. While Saturday's was most definitely the former, according to the American Meteor Society, Monday's appeared to be the latter.
Why does it look so close?
While it is easy to get a sense of distance in the Markham video of Saturday night's fireball, as the meteor is closer to the horizon and dimmer, why does it look so closer - maybe just a few city blocks over - in the Falls Church footage, when it was actually well over 100 km away at the time?
When the meteoroid that produced the fireball finally encountered enough air molecules to compress together to produce light, it was probably somewhere around 80-100 km above the ground. So, at that vertical distance, only its brightness and the curvature of the Earth really come into play (assuming uniformly clear skies). Horizontal distance has less of an effect on our perception of it, at least until we are quite far away.
For the Monday fireball, the video above is from the University of Wisconsin - Madison, roughly 200 kilometres to the east of the meteor's path through the upper atmosphere. The meteoroid was likely at least 100 km up, though, so it again is a matter of perception.
One can only imagine just how bright these would have been if they were viewed from close up.
Did you see either of these fireballs? Leave a note in the comments below, and then head over to the American Meteor Society website to file a report.