Build that underground shelter and batten down the hatches!

When we say “The sky is falling!” this is what we mean:

People heading to work in Chelyabinsk heard what sounded like an explosion, saw a bright light and then felt a shockwave according to a Reuters correspondent in the industrial city 1,500 km (950 miles) east of Moscow.

A fireball blazed across the horizon, leaving a long white trail in its wake which could be seen as far as 200 km (125 miles) away in Yekaterinburg. Car alarms went off, windows shattered and mobile phone networks were interrupted.

“I was driving to work, it was quite dark, but it suddenly became as bright as if it was day,” said Viktor Prokofiev, 36, a resident of Yekaterinburg in the Urals Mountains.

“I felt like I was blinded by headlights,” he said.

No fatalities were reported but President Vladimir Putin, who was due to host Finance Ministry officials from the Group of 20 nations in Moscow, and Prime Minister Dmitry Medvedev were informed.

A local ministry official said such incidents were extremely rare and Friday’s events might have been linked to an asteroid the size of an Olympic swimming pool due to pass Earth at a distance of 27,520 km (17,100 miles) but this was not confirmed.

Phil Plait fills us in:

[UPDATE: When I wrote the headline for this article, I thought there was evidence the meteor had broken up in a single event while still high up in the atmosphere, so I used the word “explode”. I don’t want to mislead people; there may not have been any explosion at all. To be clear, the “explosion” heard in so many videos below is almost certainly from the shock wave of the meteoroid, and not from it exploding or hitting the ground.]

Apparently, at about 09:30 local time, a very big meteor burned up over Chelyabinsk, a city in Russia just east of the Ural mountains, and about 1500 kilometers east of Moscow. The fireball was incredibly bright, rivaling the Sun! There was a pretty big sonic boom from the fireball, which set off car alarms and shattered windows. I’m seeing some reports of many people injured (by shattered glass blown out by the shock wave). I’m also seeing reports that some pieces have fallen to the ground, but again as I write this those are unconfirmed.

Note: This is almost certainly unrelated to the asteroid 2012 DA14 that will pass on Friday. See below for details.

Do I have any readers in or near Chelyabinsk? I’m very glad to hear no one has died. Let’s hope it stays that way.

This is the sort of event that reminds us that we’re not the center of the universe. It’s completely out of our control, theoretically possible to predict but this one took us by surprise, and it could strike anywhere. The next meteor could just as easily land in the middle of the ocean, or it could hit my neighborhood. And if it did, most of the damage would probably be done before we had time to flee to the basements.

NASA expects another meteor to pass very close by Earth some time today, moving south to north. Chelyabinsk might not be alone in the news.