First ever evidence of a comet striking Earth

[Waspie_Dwarf]

First ever evidence of a comet striking Earth

The first ever evidence of a comet entering Earth’s atmosphere and exploding, raining down a shock wave of fire which obliterated every life form in its path, has been discovered by a team of South African scientists and international collaborators, and will be presented at a public lecture on Thursday.

The discovery has not only provided the first definitive proof of a comet striking Earth, millions of years ago, but it could also help us to unlock, in the future, the secrets of the formation of our solar system.

“Comets always visit our skies – they’re these dirty snowballs of ice mixed with dust – but never before in history has material from a comet ever been found on Earth,” says Professor David Block of Wits University.

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[Hobbit Feet]

I thought green glass was from volcanos.

[paperdyer]

I thought green glass was from volcanos.

And old Coke bottles.

Seriously, if the meteor/comet hit with enough force and heat, I can see glass being formed. I guess the color would have been from the composition of the meteor.

[ineffectiveArtist]

Meteors and comets are made from all sorts of minerals. I could see the mineral being spread through the glass as it's being made and giving it colour.

[Sundew]

I thought green glass was from volcanos.

Comets are supposedly made of dust, rock and ice, when they hit the atmosphere most of it probably burns up, perhaps this is just some of the dust fused together by the heat of hitting the atmosphere, much like when the heat from lightning fuses sand together to form fulgurites.

[Waspie_Dwarf]

when they hit the atmosphere most of it probably burns up,

Not so. They may be made of ice but remember that ice at the temperatures experienced in the coldness of space acts more like rock.

Travelling at tens of thousands of miles an hour, the passage through the thin atmosphere takes only a few seconds. In the case of a large comet this will only heat up the surface, the vast majority of the comet will remain intact until they hit the Earth.

The atmosphere protects us from small objects but it is no protection against large asteroids and comets.

[Sundew]

Not so. They may be made of ice but remember that ice at the temperatures experienced in the coldness of space acts more like rock.

Travelling at tens of thousands of miles an hour, the passage through the thin atmosphere takes only a few seconds. In the case of a large comet this will only heat up the surface, the vast majority of the comet will remain intact until they hit the Earth.

The atmosphere protects us from small objects but it is no protection against large asteroids and comets.

Hmm, I guess I was thinking more along the lines of cometary fragments, like some of the meteor showers that are their remains. You are quite correct, I think Comet ISON is about 3 miles across at its core, or at least that's what one estimate I read indicated. That's a lot of ice to melt in a split second upon entering our atmosphere, should one that size hit us. There was also that famous incident over Tunguska, although I think it did not actually hit the earth but blew up at altitude. In any case it made quite a mess. If it happened today over a major city it could have the appearance of a nuclear attack and potentially do as much or more damage.

[TracyTracy]

According to Wikipedia, archaeologists tag this same area with the earliest known glass artifacts of human culture which were bead-like. Sounds as though these beads may have been made from bits of the comet as opposed to being manufactured by humankind. Makes sense!