Meteor over western Australia (last Dec.)

Meteor over western Australia (last Dec.)

Meteor over western Australia (last Dec.)

Bad Astronomy
The entire universe in blog form
Sept. 11 2006 10:36 PM

Meteor over western Australia (last Dec.)

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Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

This is a bit old, but still worth pointing out.

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In December 2005, a small chunk of the solar system entered the Earth's atmosphere and blazed a tremendous path across the western Australian sky. The rock (or ice) was probably only a meter or two across, maybe less, but it was as bright as the full Moon. It was seen by many thousands of people as it streaked across the night sky.

It was captured on video, as so many things are these days. Here's a link to the news story with a link to the video, and here's another site with video. You can see it flaring several times, probably as pieces of it broke off due to the tremendous pressure of air as it descended at 20 or so times the speed of sound.

When they're that bright, meteors are called "bolides" or, more colloquially, "fireballs". I saw one once when I was a kid, but it wasn't nearly as bright as this one in Oz. In 1992, a similar rock shot across the skies of the northeast United States, broke apart, and a piece of which landed on a car (unoccupied at the time!).

Meteors like this rarely make it all the way down, and when they do it's usually in small chunks. What's neat is that astronomers can backtrack the path of the meteor and figure out the orbit of the object before it hit the Earth! In fact, this was done very recently for an unexpected meteor shower, and astronomers determined it was from a comet that passes very close -- perhaps dangerously so -- to the Earth. We're in no immediate danger from this comet, but it was unknown until it betrayed its presence by shedding chunks of rock and ice which burned up in our atmosphere. It's interesting to think that our first warning of an Earth-impactor might not be from some remote robotic telescope on a mountaintop, but instead from people seeing a cascading shower of shooting stars...