[BloodEagle]

Major Global Changes:
The Earth is strongly disturbed by the impact, but loses little mass.
100.00 percent of the Earth is melted
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.

[Herra Tohtori]

Major Global Changes:
The Earth is completely disrupted by the impact and its debris forms a new asteroid belt orbiting the sun between Venus and Mars.

Of course, I had to make it so that it was actually hit by an object of similar size on reverse orbit.

I don't know if that thing is relativistic, but nevertheless it's pretty interesting to experiment what a 500-metre diameter* space ship with the density of dense rock traveling at 0.1 c does to it's immediate surroundings... try it out and be amazed. There's a reason why the guys at put a speed limit on the game...


*just estimating size equivalents of a few kilometres long, cool looking ship and a sphere... although it would be most cost-effective to build the space ship as a sphere to begin with.

[TrashMan]

1200 km rock at 30m/s...DEVASTATING....9800m crater

12000 km rock...no more Earth.

120 km rock - .....

[Vasudan Commander]

Dammit, its time like this i wish that guy Ronald Regan was still president of USA. He had the right idea : - scare the world about aliens and asteroids and we'll all put aside our differences.

We can theorize about doomsday, but the ultimate time will come down to when George W Bush looks at the little red button and his desk and says 'hey whats this thing do?'

[Mefustae]

Dammit, its time like this i wish that guy Ronald Regan was still president of USA. He had the right idea : - scare the world about aliens and asteroids and we'll all put aside our differences.

Yes, while still managing to bring the Doomsday Clock to the closest it's been to midnight in the past 50 years.

[Jeff Vader]

Hmph. If you asked me (though I know you wouldn't), I'd say bring 'em on. Big asteroids or equivalent hitting Earth and causing a near extinction or at least a big decrease in population size of the dominating species are one of nature's ways of saying that there are too many people on the planet. Kind of like diseases but more effective.

[TrashMan]

Dang..I jsut wanted to link a great Brewster Rockit comic (concering the Doomsday Clock), but now I can't find it...


this will have to do then:
http://www.comicspage.com/brewster/brewster.html

[Agent_Koopa]

Ejecta:
    What does this mean?


    Your position was inside the transient crater and ejected upon impact

Teehee.

    Projectile Diameter: 20000000.00 m = 65600000.00 ft = 12420.00 miles
    Projectile Density: 1500 kg/m3
    Impact Velocity: 20.00 km/s = 12.42 miles/s
    Impact Angle: 38 degrees
    Target Density: 2750 kg/m3
    Target Type: Crystalline Rock

Major Global Changes:
    The Earth is strongly disturbed by the impact, but loses little mass.
    100.00 percent of the Earth is melted 
    The impact makes a significant change in the Earth's rotation period and tilt of its axis.
    The impact does not shift the Earth's orbit noticeably.

[IceFire]

Why the hell you are worried?

Excuse me, as I clearly shown (perhaps) in my panic message, I would be totally ashamed if we get killed by an asteroid. I mean, we have the money to develop Earth protection systems, but we aren't doing it. It also means the human race is being destroyed by something that is tottally avoidable.

Our civilization is young as well as our species. Are you aware of the number of catastrophes that hit our planet? Much bigger asteroid hit Terra and caused mass extinctions. Even the explosion of Supernovae is an enormous threat...at least one mass extiction was caused by a Supernova exploded in a 200 light years range from here. But something survived and started a new era...

Back where it started^TM

Errmm...supernova caused extinctions?  When did that happen?  I've never heard of it.

[BloodEagle]

Wouldn't a supernova destroy everything in a star system? 

[Ace]

Gamma ray bursts from nearby novae can cause mass extinctions. The one during the pre-Cambrian fits the bill. Same with another in the Triassic, IIRC.

[IceFire]

BloodEagle....yes obviously a supernova would generally destroy everything in the start system where the star went nova.  But our sun isn't likely to go nova...ever...its more likely to grow to a gigantic size, swallow the Earth, and then shrink into a tiny little ball.

I've just never heard of there being actual documented instances where a supernova caused an extinction event on Earth.  I'll look those up Ace...interesting!

[jr2]

The Gamma Ray burst from the supernova travels a long time... and there is no warning.  These happen all the time, they just haven't pointed at our planet... and prolly won't, as the chances are so low... and there's nothing we could do, anyways, so why worry?

[Mars]

It's a function of distance... we're pretty far away from stars that're gonna supernova... none of the stars within 10 lightyears are canidates (IDT) we might get a little higher radiation from time to time, but not mass extinction inducing levels.

[jr2]

Arr, hrm, I watched a Discovery channel episode to the contrary...

[Herra Tohtori]

Be careful with mixing up supernova and nova with each other.

Nova occurs in a dual star systems with a white dwarf component and a main sequence star orbiting each other close enough for the white dwarf to pull hydrogen onto it's surface from the other star and to form an accretion disk. Occasionally enough hydrogen descends to the surface of the white dwarf to start a nuclear explosion... which is seen as nova. Nova doesn't destroy the star system.

A supernova, however, obliterates the star for the most part, including pretty much everything in the system, and leaves either a particularly dense white dwarf, neutron star or black hole formed from the core of the exploding star. Supernovae themselves are various in types and sizes.


What will happen to sun is that it'll expand to a red giant and finally poof it's outer components to space to form a planetary cloud. The core will remain as slowly cooling white dwarf after that. This event will not be very violent in itself, but at that point most of the inner planets' current orbits are already inside the Sun's radius.

[Mefustae]

So, how much damage would an object 4 inches in diameter traveling at 95% the speed of light do if it were to impact Mt. Markham in Antarctica?

[Grizzly]

It seems nature is to late, a species now has the ability to prevent asteroid impact, and prevent their own extinsion..

If you are able to break down a big asteroid into smaller rocks... they will all burn in the athmosphere.. and how we are going to do that? simple, isn't it?

[TrashMan]

No, not that simple....and that's assuming you detect that asteroid on time in the first place... we're only monitoring about 4% of the universe ATM. So yeah, a big friggin chunk could come smacking down on as at this very instant.

[Bobboau]

So, how much damage would an object 4 inches in diameter traveling at 95% the speed of light do if it were to impact Mt. Markham in Antarctica?

Your Inputs:
    Distance from Impact: 10000.00 km = 6210.00 miles
    Projectile Diameter: 1.00 m = 3.28 ft = 0.00 miles
    Projectile Density: 8000 kg/m3
    Impact Velocity: 299000.00 km/s = 185679.00 miles/s (Your chosen velocity is higher than the maximum for an object orbiting the sun)
    Impact Angle: 90 degrees
    Target Density: 2750 kg/m3
    Target Type: Crystalline Rock

Energy:
    Energy before atmospheric entry: -NaN x 10-NaN Joules = 4.47 x 104 MegaTons TNT
    The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 4.2 x 105years

Atmospheric Entry:
    The projectile begins to breakup at an altitude of 171000 meters = 560000 ft
    The projectile bursts into a cloud of fragments at an altitude of 57500 meters = 189000 ft
    The residual velocity of the projectile fragments after the burst is 291000 km/s = 181000 miles/s
    The energy of the airburst is 1.03 x 1019 Joules = 2.45 x 103 MegaTons.
    Large fragments strike the surface and may create a crater strewn field. A more careful treatment of
    atmospheric entry is required to accurately estimate the size-frequency distribution of meteoroid fragments
    and predict the number and size of craters formed. however it is most likely that there will be 15 impact sites,
    each one spontaneously forming an AT energy based being of unimaginable power that can only be
    defeated by a 1000 foot tall cyborg based upon these creature's physiology piloted by a young boy
    overcoming his social awkwardness and crushing psychological barriers and fueled by his mother's
    damned soul.

Major Global Changes:
    The Earth is not strongly disturbed by the impact and loses negligible mass.
    The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
    The impact does not shift the Earth's orbit noticeably.
    There is an 93% chance of the worldwide ocean level raising more than 40 feet due to southern icecap melting.
    there is a 74% chance of it raising an additional three feet due to the entire human race getting desolved into an orange goo.

Air Blast:
    What does this mean?


    The air blast will arrive at approximately 30300 seconds.
    Peak Overpressure: 144 Pa = 0.00144 bars = 0.0205 psi
    Max wind velocity: 0.34 m/s = 0.76 mph
    Sound Intensity: 43 dB (Easily Heard)

seems pretty accurate