2 asteroids in Earth near miss

[Damocles]

What size of astroid would it take to absolutely obliterate earth? What impact would it have on our solar system if us or any planet in solar system was fcuked off the map so to speak??

It absolutely depends.

Theoretically, one asteroid the size of a pea could destroy the Earth, and one bigger than the Moon wouldn't.

To destroy the Earth, the size isn't important, but the amount of energy released. For example, if somebody threw a ball bearing at you, it wouldn't particularly damage you, yet if the same ball bearing was shot out of a high speed gun, it would do some damage. Obviously, the gun is giving the ball bearing energy.

As far as absolutely obliterating the Earth, we would need to measure the sum total of the energy taken to gravitationally collapse the matter that makes up the Earth, compared with the energy released when the asteroid hits us.

To save you the physics/maths, we'd be talking about something bigger than Mars to do that, travelling at 1000 km per second (we need something about 60% the mass of the Earth). The fastest asteroid that we've found went on an orbital velocity of around 30km/s.

Interestingly, we've been hit by a planet before not far off of the size of Mars. We call it Theia, and it hit us before we cooled down about 4.5 billion years ago. There used to be an excellent video show casing this called the "Ultimate Rube Goldberg Machine" but Ch4 has blocked it on copyright grounds. This somewhat explains it:

The remains of the Theia then started orbiting around the Earth, pulling millions of rocks that had just been ejected into space right into it, like a vacuum cleaner sucking up dust. This is what the Moon is, and why there are so many impact craters on it. It's the remnant of a several billion year old collision of Theia with the Earth.

I find it quite cool to look at the Moon and realise that it's a rock floating 240,000 miles away that was formed 4,500,000,000 years ago.

 

[lloydie]

As noted before jupiter does a fair job of mopping them up, as does the moon. Our atmosphere is remarkably thin/deep so wont protect against objects above a certain size, as that lecture points out, it's not a matter of "If?" but "When?"
The good news is that given the will and resources we are more than capable of detecting them and diverting them is not that difficult, even a craft in close proximity will have a gravitational pull sufficient to move them out of the critical path given enough warning.

Edit; didn't see damo's post, and he's right the composition is of paramount importance, obviously a meteorite consisting of loosely compacted ice would not survive the atmosphere. Interestingly people have received frostbite picking up meteorites made of more substantial material as although the outer shell may have melted through the heat generated by friction through the air, the innards retain the temperature of space.

 

[The Fat el Hombre]

I find it quite cool to look at the Moon and realise that it's a rock floating 240,000 miles away that was formed 4,500,000,000 years ago.

Funnily enough I was thinking the complete opposite about the moon before, and how shit and pointless it is

 

[pee dubya]

I find it quite cool to look at the Moon and realise that it's a rock floating 240,000 miles away that was formed 4,500,000,000 years ago.

Funnily enough I was thinking the complete opposite about the moon before, and how shit and pointless it is

It's not pointless! It does something to do with tides n stuff. Without tides you wouldn't have razor clams, disaster.

 

[BulgarianPride]

Without the moon we wouldn't exist. It had a significant impact on our evolution. If you take it away now we can survive, but had it not been there, we would not exist.

 

[Damocles]

I find it quite cool to look at the Moon and realise that it's a rock floating 240,000 miles away that was formed 4,500,000,000 years ago.

Funnily enough I was thinking the complete opposite about the moon before, and how shit and pointless it is

Life wouldn't exist without the Moon. The Earth's rotation wouldn't be stabilised and the poles would be wildly flailing about, bringing on near constant climate change. In fact, the Earth may not even of rotated before the collision, which would have meant no magnetic poles, no atmosphere, no life. Oh, and the Earth would actually be spinning far faster if the Moon disappeared, raising the overall temperature on it, again leading to massive climate shifts.

Let's say that that somehow didn't matter, the Moon controls the tides, which were quite probably the first places inhabited as a nice middle ground for those species who later developed lungs to get onto the land.

Then you have the point of it lighting up the night sky to ensure that our genetic ancestors were never really in complete darkness (starlight alone is shit to see by).

The Moon also taught us about gravity, proved the existence of other spacial bodies, gave us a safe landing point on the first journey into space, and inspired millions of generations of people, creating some of our most ingrained legends leading to a bedrock of morality and society.

Apart from that though, yeah. I think that whole 'water' thing's overrated too.

 

[oakiecokie]

Without the moon we wouldn't exist. It had a significant impact on our evolution. If you take it away now we can survive, but had it not been there, we would not exist.

And neither would this Forum !!
No Blue Moon ??
Unthinkable !!

 

[The Fat el Hombre]

Life wouldn't exist without the Moon.

I don't care, it's still shit.

 

[Damocles]

Life wouldn't exist without the Moon.

I don't care, it's still shit.

I've heard it thinks you're a bit of a dick anyway, so alls even.

 

[The Fat el Hombre]

I don't care what it thinks...