A similar-sized meteor to the one that exploded in the sky over Russia today would cause ''significant fatalities'' if it hit Earth.

But the 10-ton meteor was ''very small'' comparatively and objects of that size rarely penetrate the ''amazing defence'' of the Earth's atmosphere, according to Hugh Lewis from the University of Southampton.

Despite it not making contact, nearly 1,000 people have been injured after the meteor exploded over Chelyabinsk in the Ural Mountains this morning.

Dramatic amateur video footage showed the meteor streaking across the sky at around 9.20am local time. It caused a bright flash of light and left a white trail of smoke.

The injuries were caused when the meteor, which was travelling at least 54,000 miles per hour, created a sonic boom, according to Tim O'Brien, associate director of the University of Manchester's Jodrell Bank Observatory.

''It made a sonic boom in the atmosphere, and that hit buildings and shattered windows. That is what seems to have caused the injuries,'' he said.

''It's a completely abnormal experience. This thing appeared in the distance, raced over the horizon and was followed up 30 seconds or a minute later by a huge boom as the shockwave hit the ground. I can imagine that would be very frightening.''

Chelyabinsk's health chief, Marina Moskvicheva, said 985 people in her city had asked for medical assistance and 43 had been taken to hospital after the blast which shattered countless windows in the area.

Sergey Hametov, a resident of Chelyabinsk, said: ''There was panic. People had no idea what was happening. Everyone was going around to people's houses to check if they were okay.

''We saw a big burst of light, then went outside to see what it was and we heard a really loud thundering sound.''

Dr Lewis, an astronautics expert at the University of Southampton, said the meteor was ''very small'' at around five metres in diameter.

''Something that size very rarely penetrates through the atmosphere,'' he said.

''The atmosphere provides us with this amazing defence so it results in this amazing fireball and it fragments into smaller objects.''

But if the meteor were more metallic in its make-up, it may have penetrated the atmosphere and hit the Earth, leaving a crater three times its size and causing ''significant fatalities'', he said.

It would cause a ''quite substantial'' blast which would emanate a large amount of heat transferred from the kinetic energy of the meteor.

''You would probably see considerable fatalities if it hit a populated area,'' he said.

Experts said the meteor appeared to be unconnected to an asteroid predicted to narrowly miss the Earth tonight.

The asteroid, named 2012 DA14, is big enough to flatten London and could come as close as 17,200 miles.