Massive asteroid impact in 2036?

[welshdean]

Tunguska wasn't an asteroid, it was most likely a comet fragment.

Meh! Every open minded person 'knows' it was an exploding space-ship!

 

[welshdean]

Ok, question time for all the atronomers on the forums.

Why can't we predict whether or not it will hit us? If it swings past every seven years, doesn't that provide more than enough data for us to determine its orbit?

As the link to Phil's site stated, it's all about accuracy of measurement now, extrapolated into the future. If we're out by a small margin now, that error is magnified by the 25 year wait. We'll be a lot more accurate as time draws nearer the event.

Be prepared, order two extra pints of milk and an extra bag of bagels. Just in case!

 

[gumboot]

I'm no expert, but check this site. http://impact.arc.nasa.gov/news_detail.cfm?ID=45


There were several events that were unusually deadly -- a matter of bad luck for 54 million people:
136th Millennium: A 200-yard-wide asteroid hits the South China Sea just 300 miles from Hong Kong. A 40-yard-high tsunami sweeps the coast and kills 18 million people.

This just doesn't sound remotely plausible. Even the Boxing Day Tsunami only generated a 10 yard high Tsunami, and that was a result of a massively greater energy release located at the sea floor.

Some of their other scenarios don't appear to accurately reflect known historic events, for example:

During the 133rd Millennium a 1.3-mile-wide comet hits the American Midwest at a speed of 100,000 mph. The blast, equivalent to 3 million megatons of TNT or 60,000 H-bombs, kills 7 million instantly and makes a crater 20 miles across. Within days the skies around the globe darken from the dust injected into the atmosphere. Sunlight is blocked. Crops fail and, over the next year, half of the Earth's human population dies, mainly from starvation.

There's theories of impact events causing mass extinction events in earth's history, but even in those instances the hypothesised impact object is magnitudes larger than this one, and causes extinction over a much longer time period.

For example, one hypothesised cause of the Cretaceous-Tertiary Extinction Event is the impact of a body 10-15km across, causing a 100 million gigaton explosion and a 180km crater, however even this took 300,000 years before causing the mass extinction.

This notion that a body 1/10 the size, with an energy release 1/33th the size, could kill half the human race in 1 year just doesn't seem remotely plausible, and that's not even taking into account technological advances in the intervening 133,000 years that would render the human race immune to the weather effects from such an impact.

20th Millennium: An asteroid just 70 yards across explodes in the skies 14 miles above London. 10 million are killed in the 80-megaton blast and firestorm.
273rd Millennium: A 50-yard-wide comet travelling at an unusually fast 150,000 mph explodes in the atmosphere 25 miles above Mexico City. 14 million are killed by the 110-megaton blast and firestorm. 721st Millennium: An almost identical event occurs over Manila, killing 12 million.

Even a modest sized object, directly hitting a major city, would of course cause massive localised destruction and loss of life. That's not in dispute. What I am rejecting is the notion that a modest impact event anywhere in the world's oceans would cause devastation.

If we take the Tunguska event, if landed in a sparsely populated area and very few people were killed. If it had hit a few hours later it would have struck Moscow, and would have caused unprecedented loss of life. But if it had, say, landed in the middle of an ocean, we probably wouldn't have even noticed it.

Impact events can cause megatsunamis, but the thing about a megatsunami is that it only involves surface displacement, and as such only causes a localised wave, so devastation would be limited to the close proximity of the impact. It produces a very high wave that dissipates rapidly as the force is absorbed by the mass of water beneath.

The largest ever recorded megatsunami was on July 9, 1958 in Lituya Bay, Alaska. The wave was 524m high (over fifty times higher than the Boxing Day Tsunami and thirteen times higher than the Krakatoa Tsunami) yet it didn't extend much further than the bay itself, and didn't cause any significant damage beyond the bay.

This contrasts with a regular tsunami caused by an earthquake or volcanic eruption which may not reach such enormous size, but has vastly more momentum behind it because the entire body of water from the sea bottom to the surface is displaced. Such tsunamis can cause destruction thousands of kilometers from the initiation point.

 

[gumboot]

how do I know that a 200-yard wide asteroid hitting the ocean at thousands of miles an hour, would cause a very large tsunami that would drown millions?

its called science.

http://en.wikipedia.org/wiki/Tunguska_event

It's a pity you can't read:

The Tunguska event is the largest impact event over land in Earth's recent history. Impacts of similar size over remote ocean areas would most likely have gone unnoticed before the advent of global satellite monitoring in the 1960s and 1970s.

You fail.

 

[gumboot]

I think its fair to say that a 20 foot high tsunami running through the Indian Ocean would drown millions.

Just like how that 30ft high Tsunami from the 2004 Boxing Day Earthquake drowned millions when it ran through the Indian Ocean?

Oh wait...

I've got an idea. Why don't you just admit you don't know what you're talking about?

 

[gumboot]

Because the moon has been around for billions of years and because the early solar system was a particularly dangerous place.

What's that have to do with Apophis?

The moon also doesn't have an atmosphere...

 

[Skwinty]

This just doesn't sound remotely plausible.

Just too make sure I am on the same page here:

Do you mean the asteroid is 200 yards across prior to entering the earths atmosphere, or 200 yards when it actually impacts the ocean.

I suppose the speed the asteroid is travelling is important in determining the energy release. Would the relationship between speed and energy release be linear?

The article I linked to refers to estimated damage calculated by software written by http://www.lpl.arizona.edu/Support/faculty/faculty.php?nom=Lewis

I wouldn't dismiss his scenario as not remotely plausible without a very good reason.

 

[Foolmewunz]

I'm no expert, but check this site. http://impact.arc.nasa.gov/news_detail.cfm?ID=45


There were several events that were unusually deadly -- a matter of bad luck for 54 million people:
136th Millennium: A 200-yard-wide asteroid hits the South China Sea just 300 miles from Hong Kong. A 40-yard-high tsunami sweeps the coast and kills 18 million people. <snip>

That does, it. Mart! Pack up the baby, we've got 133,000 years to get out of here!

Seriously - based on the current population of Hong Kong and the cities of the Pearl River Delta, 18 million is probably a very low figure. A 120 foot tsunami would wash over Hong Kong, Shenzhen, Macao, Guangzhou, Dongguan, Zhongshan and Zhuhai - at minimum. The population of those cities today is over 50 million. In 134 more millenia, it'll be a tad larger.

 

[BenBurch]

Amen. That is the real worry. We could have every meteor down to a foot long in near Earth orbit mapped to a far-the-well, and a high eccentricity comet is still a hazard, particularly as they come at us at much higher velociites than the NEAs do.

SOHO finds a new comet every few days. All of them (nearly) comets we were unaware of, and all of them on pretty much direct courses into or very near the sun (they usually don't come back, most of them vaporize.) Any one of those would have hit the Earth without us having much warning at all.

Now, what I am not clear on is the size of the SOHO comets.

 

[Skwinty]

That does, it. Mart! Pack up the baby, we've got 133,000 years to get out of here!

lol

 

[Thunder]

Question: why are asteroids exploding in the atmosphere? why don't they simply make impact?

 

[Skwinty]

I would think because of the intense heat generated and the effect of rapid expansion as the asteroid hurtles at tremendous speed into the atmosphere.

 

[Undesired Walrus]

a 200-yard wide asteroid impact will be like a sizable nuclear detonation.

and if it hits the ocean, it would create a massive tsunami that could drown/kill millions across the globe.

'Could' being the operative word.

 

[Spindrift]

Question: why are asteroids exploding in the atmosphere? why don't they simply make impact?

Zionist plot?

 

[RecoveringYuppy]

Question: why are asteroids exploding in the atmosphere? why don't they simply make impact?

The air pressure differences that build up across them are extreme. Most aren't strong enough to remain solid long enough to impact Earth intact. Typically it takes an iron composition to surive. However, shattering doesn't always mean that an impact is completely avoided since the remnants might hit so close together that being shattered makes little difference.

 

[Bell]

I'm stocking up on cans of Spam as we speak...

Spam and eggs
Spam and sausage and eggs
Spam spam and eggs
Spam spam spam sausage and eggs
Spam spam ham and eggs with spam spam and spam

Reported.

 

[shadron]

Just too make sure I am on the same page here:

Do you mean the asteroid is 200 yards across prior to entering the earths atmosphere, or 200 yards when it actually impacts the ocean.

I suppose the speed the asteroid is travelling is important in determining the energy release. Would the relationship between speed and energy release be linear?

Ah, no, not quite. It is actually proportional to the velocity squared.

KE = m v^2

The article I linked to refers to estimated damage calculated by software written by http://www.lpl.arizona.edu/Support/f....php?nom=Lewis

I wouldn't dismiss his scenario as not remotely plausible without a very good reason.

Even they, too, labor under the handicap of never having witnessed anything harsher than the Tunguska event. That will tend to straighten out extrapolations which are only a little off, but which accumulate error along the way, slowly but without correction.

 

[Corsair 115]

Just like how that 30ft high Tsunami from the 2004 Boxing Day Earthquake drowned millions when it ran through the Indian Ocean?

Was that the height of the wave on the ocean itself or the height of the wave after it reached shallow water? My understanding is that on the ocean the wave was quite small; it was only upon entering shallower areas that the wave height grew due to the wave 'piling up.'

The moon also doesn't have an atmosphere...

Actually, it does, but it's an extremely thin one, composed mostly of helium and argon. For all practical purposes, however, it has no atmosphere.

 

[Toontown]

I'm no expert, but check this site. http://impact.arc.nasa.gov/news_detail.cfm?ID=45


There were several events that were unusually deadly -- a matter of bad luck for 54 million people:
136th Millennium: A 200-yard-wide asteroid hits the South China Sea just 300 miles from Hong Kong. A 40-yard-high tsunami sweeps the coast and kills 18 million people.
20th Millennium: An asteroid just 70 yards across explodes in the skies 14 miles above London. 10 million are killed in the 80-megaton blast and firestorm.
273rd Millennium: A 50-yard-wide comet travelling at an unusually fast 150,000 mph explodes in the atmosphere 25 miles above Mexico City. 14 million are killed by the 110-megaton blast and firestorm. 721st Millennium: An almost identical event occurs over Manila, killing 12 million.

Ha! They all missed me.

 

[MattusMaximus]

Question: why are asteroids exploding in the atmosphere? why don't they simply make impact?

Have you ever heated a glass bottle in a campfire and then tossed it into a stream? It explodes if you do that, due to the rapid change in temperature and related thermal stresses.

With an asteroid impacting Earth's atmosphere, it would undergo something similar because the vacuum of space, in general, is COLD. And slamming into the atmosphere at ~30 km/sec would heat it up pretty damn quick from the friction.

Not to mention, hitting the top of our atmosphere at such high speeds would be kind of like smacking a near-solid object. If the asteroid in question weren't a really solid lump of metallic material (such as iron), that alone could cause good-sized chunks of it to split off from the main body.