Exploding mini-asteroid over Urals injures hundreds ..

[brian livesey]

Latest news report: http://www.bbc.co.uk/news/world-europe-21470205. Could the object have been a binary companion to today's asteroid?

[David1952]

It was traveling in the wrong direction. DA14 is going S to N, so any associated rocks would be doing the same. See the DA14 article in the BAA page.

David

[brian livesey]

It looks like it was just a remarkable coincidence.

[Dave Mitsky]

There's more on the Russian fireball at the following links:

http://rt.com/news/meteorite-crash-ural ... binsk-283/

http://www.space.com/19801-possible-met ... ussia.html

http://hosted.ap.org/dynamic/stories/E/ ... TE=DEFAULT

http://www.slate.com/blogs/bad_astronom ... ussia.html

http://news.discovery.com/space/asteroi ... 130215.htm

Here are a few videos:

http://www.youtube.com/watch?v=7c-0iwBEswE (0:09)

http://www.youtube.com/watch?v=4ZxXYscmgRg (0:12)

http://www.youtube.com/watch?v=wKCUmeunLDc (1:19)

https://www.youtube.com/watch?feature=p ... 4Os9T4R7Oo (sonic boom)

Dave Mitsky

[The Bat]

Some fantastic footage of this on the BBC - amazing!

Rachel

[David Frydman]

I would think the peak magnitude was brighter than magnitude minus 20.

Regards, David

[G Burt]

It's unnerving that, whilst we were all waiting for 2012 DA14 to sail serenely by, this other object slipped in 'under the radar'.

Just goes to show that it's the ones you don't see coming that get you...


Best Wishes,

Geoff

[Guy Fennimore]

I couldn't believe it... just an hour or so before the news broke I was reassuring BBC Radio Nottingham listeners that the asteroid posed no danger, and that other major impacts were very rare. Random statistics rule OK!!!

[brian livesey]

If there's one thing that skywatching teaches us, it's that nature is full of surprises.
The object seems to have been reclassified as a small asteroid by some experts. Where, then, does a meteorite end and an asteroid begin?
The Hoba West iron "meteorite" weighs over 60 tons.

[stella]

An asteroid is a minor planet,made of rock and metal, that orbits the Sun
and that has been detected from the Earth.

A meteoroid is smaller and therefore has not been detected from Earth.

A meteor is a meteoroid that has entered the Earth's atmosphere,
and has its surface heated by ram jet pressure, though most quote
this as friction. Also called a shooting star when seen briefly in the night sky.

A meteorite is any remnants of the meteor's passage through the atmosphere
that manages to make it to the surface (Many falling into the sea).

[brian livesey]

There seem to be differing opinions about classification here, Stella. Yesterday on BBC TV, a professional astronomer associated with the Open University, described the object as an "asteroid".
You said that, before entry into Earth's atmosphere, the object wasn't seen and was, therefore, a meteorite not an asteroid. But, for all we know, powerful military radars might have detected the object long before it entered Earth's vicinity ( the military are not likely to tell us! ). Would this mean reclassification as an asteroid?
According to Wiki, in terms of explosive power, the Tunguska object delivered megatons of force.

[stella]

"You said that, before entry into Earth's atmosphere, the object wasn't seen and was, therefore, a meteorite not an asteroid".

No, a meteorite is on the ground, waiting to be found, or in a laboratory, or in a museum,
or for sale on Ebay.

[brian livesey]

On today's http://www.spaceweather.com the head of Nasa's Meteoroid Environment Office describes the object as having been a 17 metres diameter asteroid, weighing approximately 10,000 metric tons, and with an explosive force of 500 kilotons of TNT.
Tunguska events are reckoned to occur at about one-hundred year intervals, which would seem to place this recent event on time; assuming that we classify the object as an asteroid .

[David Frydman]

If it was 500 kilotons why didn't it do more damage?
Maybe it wasn't focused energy.

I think the Tunguska event was much bigger?

Regards, David

[brian livesey]

If the airburst had occured much lower, the blast effects might have been much stronger.